Maternal mortality in the United States: are the high and rising rates due to changes in obstetrical factors, maternal medical conditions, or maternal mortality surveillance?

BACKGROUND: National Vital Statistics System reports show that maternal mortality rates in the United States have nearly doubled, from 17.4 in 2018 to 32.9 per 100,000 live births in 2021. However, these high and rising rates could reflect issues unrelated to obstetrical factors, such as changes in maternal medical conditions or maternal mortality surveillance (eg, due to introduction of the pregnancy checkbox). OBJECTIVE: This study aimed to assess if the high and rising rates of maternal mortality in the United States reflect changes in obstetrical factors, maternal medical conditions, or maternal mortality surveillance. STUDY DESIGN: The study was based on all deaths in the United States from 1999 to 2021. Maternal deaths were identified using the following 2 approaches: (1) per National Vital Statistics System methodology, as deaths in pregnancy or in the postpartum period, including deaths identified solely because of a positive pregnancy checkbox, and (2) under an alternative formulation, as deaths in pregnancy or in the postpartum period, with at least 1 mention of pregnancy among the multiple causes of death on the death certificate. The frequencies of major cause-of-death categories among deaths of female patients aged 15 to 44 years, maternal deaths, deaths due to obstetrical causes (ie, direct obstetrical deaths), and deaths due to maternal medical conditions aggravated by pregnancy or its management (ie, indirect obstetrical deaths) were quantified. RESULTS: Maternal deaths, per National Vital Statistics System methodology, increased by 144% (95% confidence interval, 130-159) from 9.65 in 1999-2002 (n=1550) to 23.6 per 100,000 live births in 2018-2021 (n=3489), with increases occurring among all race and ethnicity groups. Direct obstetrical deaths increased from 8.41 in 1999-2002 to 14.1 per 100,000 live births in 2018-2021, whereas indirect obstetrical deaths increased from 1.24 to 9.41 per 100,000 live births: 38% of direct obstetrical deaths and 87% of indirect obstetrical deaths in 2018-2021 were identified because of a positive pregnancy checkbox. The pregnancy checkbox was associated with increases in less specific and incidental causes of death. For example, maternal deaths with malignant neoplasms listed as a multiple cause of death increased 46-fold from 0.03 in 1999-2002 to 1.42 per 100,000 live births in 2018-2021. Under the alternative formulation, the maternal mortality rate was 10.2 in 1999-2002 and 10.4 per 100,000 live births in 2018-2021; deaths from direct obstetrical causes decreased from 7.05 to 5.82 per 100,000 live births. Deaths due to preeclampsia, eclampsia, postpartum hemorrhage, puerperal sepsis, venous complications, and embolism decreased, whereas deaths due to adherent placenta, renal and unspecified causes, cardiomyopathy, and preexisting hypertension increased. Maternal mortality increased among non-Hispanic White women and decreased among non-Hispanic Black and Hispanic women. However, rates were disproportionately higher among non-Hispanic Black women, with large disparities evident in several causes of death (eg, cardiomyopathy). CONCLUSION: The high and rising rates of maternal mortality in the United States are a consequence of changes in maternal mortality surveillance, with reliance on the pregnancy checkbox leading to an increase in misclassified maternal deaths. Identifying maternal deaths by requiring mention of pregnancy among the multiple causes of death shows lower, stable maternal mortality rates and declines in maternal deaths from direct obstetrical causes.

Temporal changes in pre-existing health conditions five years prior to pregnancy in British Columbia, Canada, 2000-2019.

BACKGROUND: Pre-existing health conditions increase the risk of obstetric complications during pregnancy and birth. However, the prevalence and recent changes in the frequency of pre-existing health conditions in the childbearing population remain unknown. OBJECTIVES: To estimate the temporal changes in the prevalence of pre-existing health conditions among pregnant women in British Columbia, Canada. METHODS: We carried out a population-based cross-sectional study of 825,203 deliveries in BC between 2000 and 2019 and examined 17 categories of physical and psychiatric health conditions recorded within 5 years before childbirth. We also undertook age-period-cohort analyses to evaluate temporal changes in pre-existing health conditions. RESULTS: The prevalence of any pre-existing health condition was 26.2% (n = 216,214) with overall trends remaining stable during the study period. Between 2000 and 2019, the prevalence rates of anxiety (5.6%-9.6%), bipolar (1.6%-3.4%), psychosis (0.7%-0.8%), and eating disorders (0.2%-0.3%) increased. The prevalence of hypertension increased sharply from 0.06% in 2000 to 0.3% in 2019. Diabetes mellitus and stroke rates increased, as did the prevalence of systemic lupus, multiple sclerosis, and chronic kidney disease. Advanced maternal age was strongly associated with both psychiatric and circulatory/metabolic conditions. A strong birth cohort effect was evident, with rates of psychiatric conditions increasing among women born after 1985. CONCLUSIONS: In British Columbia, Canada, 1 in 4 mothers had a pre-existing health condition 5 years prior to pregnancy. These findings underscore the need for multi-disciplinary care for women with pre-existing health conditions to improve maternal, foetal, and infant health.

Mining the Gap: Deriving Pregnancy Reference Intervals for Hematology Parameters Using Clinical Datasets.

BACKGROUND: Physiological changes during pregnancy invalidate use of general population reference intervals (RIs) for pregnant people. The complete blood count (CBC) is commonly ordered during pregnancy, but few studies have established pregnancy RIs suitable for contemporary Canadian mothers. Prospective RI studies are challenging to perform during pregnancy while retrospective techniques fall short as pregnancy and health status are not readily available in the laboratory information system (LIS). This study derived pregnancy RIs retrospectively using LIS data linked to provincial perinatal registry data. METHODS: A 5-year healthy pregnancy cohort was defined from the British Columbia Perinatal Data Registry and linked to laboratory data from two laboratories. CBC and differential RIs were calculated using direct and indirect approaches. Impacts of maternal and pregnancy characteristics, such as age, body mass index, and ethnicity, on laboratory values were also assessed. RESULTS: The cohort contained 143 106 unique term singleton pregnancies, linked to >972 000 CBC results. RIs were calculated by trimester and gestational week. Result trends throughout gestation aligned with previous reports in the literature, although differences in exact RI limits were seen for many tests. Trimester-specific bins may not be appropriate for several CBC parameters that change rapidly within trimesters, including red blood cells (RBCs), some leukocyte parameters, and platelet counts. CONCLUSIONS: Combining information from comprehensive clinical databases with LIS data provides a robust and reliable means for deriving pregnancy RIs. The present analysis also illustrates limitations of using conventional trimester bins during pregnancy, supporting use of gestational age or empirically derived bins for defining CBC normal values during pregnancy.

Association between gestational weight gain and severe adverse birth outcomes in Washington State, US: A population-based retrospective cohort study, 2004-2013.

BACKGROUND: Suboptimal weight gain during pregnancy is a potentially modifiable risk factor. We aimed to investigate the association between suboptimal gestational weight gain and severe adverse birth outcomes by pre-pregnancy body mass index (BMI) categories, including obesity class I to III. METHODS AND FINDINGS: We conducted a population-based study of pregnant women with singleton hospital births in Washington State, US, between 2004 and 2013. Optimal, low, and excess weight gain in each BMI category was calculated based on weight gain by gestational age as recommended by the American College of Obstetricians and Gynecologists and the Institute of Medicine. Primary composite outcomes were (1) maternal death and/or severe maternal morbidity (SMM) and (2) perinatal death and/or severe neonatal morbidity. Logistic regression was used to obtain adjusted odds ratios (AORs) and 95% confidence intervals. Overall, 722,839 women with information on pre-pregnancy BMI were included. Of these, 3.1% of women were underweight, 48.1% had normal pre-pregnancy BMI, 25.8% were overweight, and 23.0% were obese. Only 31.5% of women achieved optimal gestational weight gain. Women who had low weight gain were more likely to be African American and have Medicaid health insurance, while women with excess weight gain were more likely to be non-Hispanic white and younger than women with optimal weight gain in each pre-pregnancy BMI category. Compared with women who had optimal weight gain, those with low gestational weight gain had a higher rate of maternal death, 7.97 versus 2.63 per 100,000 (p = 0.027). In addition, low weight gain was associated with the composite adverse maternal outcome (death/SMM) in women with normal pre-pregnancy BMI and in overweight women (AOR 1.12, 95% CI 1.04-1.21, p = 0.004, and AOR 1.17, 95% CI 1.04-1.32, p = 0.009, respectively) compared to women in the same pre-pregnancy BMI category who had optimal weight gain. Similarly, excess gestational weight gain was associated with increased rates of death/SMM among women with normal pre-pregnancy BMI (AOR 1.20, 95% CI 1.12-1.28, p < 0.001) and obese women (AOR 1.12, 95% CI 1.01-1.23, p = 0.019). Low gestational weight gain was associated with perinatal death and severe neonatal morbidity regardless of pre-pregnancy BMI, including obesity classes I, II, and III, while excess weight gain was associated with severe neonatal morbidity only in women who were underweight or had normal BMI prior to pregnancy. Study limitations include the ascertainment of pre-pregnancy BMI using self-report, and lack of data availability for the most recent years. CONCLUSIONS: In this study, we found that most women do not achieve optimal weight gain during pregnancy. Low weight gain was associated with increased risk of severe adverse birth outcomes, and in particular with maternal death and perinatal death. Excess gestational weight gain was associated with severe adverse birth outcomes, except for women who were overweight prior to pregnancy. Weight gain recommendations for this group may need to be reassessed. It is important to counsel women during pregnancy about specific risks associated with both low and excess weight gain.

Maternal age and severe maternal morbidity: A population-based retrospective cohort study.

BACKGROUND: One of the United Nations' Millennium Development Goals of 2000 was to reduce maternal mortality by 75% in 15 y; however, this challenge was not met by many industrialized countries. As average maternal age continues to rise in these countries, associated potentially life-threatening severe maternal morbidity has been understudied. Our primary objective was to examine the associations between maternal age and severe maternal morbidities. The secondary objective was to compare these associations with those for adverse fetal/infant outcomes. METHODS AND FINDINGS: This was a population-based retrospective cohort study, including all singleton births to women residing in Washington State, US, 1 January 2003-31 December 2013 (n = 828,269). We compared age-specific rates of maternal mortality/severe morbidity (e.g., obstetric shock) and adverse fetal/infant outcomes (e.g., perinatal death). Logistic regression was used to adjust for parity, body mass index, assisted conception, and other potential confounders. We compared crude odds ratios (ORs) and adjusted ORs (AORs) and risk differences and their 95% CIs. Severe maternal morbidity was significantly higher among teenage mothers than among those 25-29 y (crude OR = 1.5, 95% CI 1.5-1.6) and increased exponentially with maternal age over 39 y, from OR = 1.2 (95% CI 1.2-1.3) among women aged 35-39 y to OR = 5.4 (95% CI 2.4-12.5) among women aged ≥50 y. The elevated risk of severe morbidity among teen mothers disappeared after adjustment for confounders, except for maternal sepsis (AOR = 1.2, 95% CI 1.1-1.4). Adjusted rates of severe morbidity remained increased among mothers ≥35 y, namely, the rates of amniotic fluid embolism (AOR = 8.0, 95% CI 2.7-23.7) and obstetric shock (AOR = 2.9, 95% CI 1.3-6.6) among mothers ≥40 y, and renal failure (AOR = 15.9, 95% CI 4.8-52.0), complications of obstetric interventions (AOR = 4.7, 95% CI 2.3-9.5), and intensive care unit (ICU) admission (AOR = 4.8, 95% CI 2.0-11.9) among those 45-49 y. The adjusted risk difference in severe maternal morbidity compared to mothers 25-29 y was 0.9% (95% CI 0.7%-1.2%) for mothers 40-44 y, 1.6% (95% CI 0.7%-2.8%) for mothers 45-49 y, and 6.4% for mothers ≥50 y (95% CI 1.7%-18.2%). Similar associations were observed for fetal and infant outcomes; neonatal mortality was elevated in teen mothers (AOR = 1.5, 95% CI 1.2-1.7), while mothers over 29 y had higher risk of stillbirth. The rate of severe maternal morbidity among women over 49 y was higher than the rate of mortality/serious morbidity of their offspring. Despite the large sample size, statistical power was insufficient to examine the association between maternal age and maternal death or very rare severe morbidities. CONCLUSIONS: Maternal age-specific incidence of severe morbidity varied by outcome. Older women (≥40 y) had significantly elevated rates of some of the most severe, potentially life-threatening morbidities, including renal failure, shock, acute cardiac morbidity, serious complications of obstetric interventions, and ICU admission. These results should improve counselling to women who contemplate delaying childbirth until their forties and provide useful information to their health care providers. This information is also useful for preventive strategies to lower maternal mortality and severe maternal morbidity in developed countries.

Association Between Prepregnancy Body Mass Index and Severe Maternal Morbidity.

Importance: Although high body mass index (BMI) is associated with adverse birth outcomes, the association with severe maternal morbidity is unclear. Objective: To examine the association between prepregnancy BMI and severe maternal morbidity. Design, Setting, and Participants: Retrospective population-based cohort study including all singleton hospital births in Washington State, 2004-2013. Demographic data and morbidity diagnoses were obtained from linked birth certificates and hospitalization files. Exposures: Prepregnancy BMI (weight in kilograms divided by height in meters squared) categories included underweight (<18.5), normal BMI (18.5-24.9), overweight (25.0-29.9), obesity class 1 (30.0-34.9), obesity class 2 (35.0-39.9), and obesity class 3 (≥40). Main Outcomes and Measures: Composite severe maternal morbidity or mortality included life-threatening conditions and conditions leading to serious sequelae (eg, amniotic fluid embolism, hysterectomy), complications requiring intensive care unit admission, and maternal death. Logistic regression was used to obtain adjusted odds ratios (ORs) and adjusted rate differences with 95% confidence intervals, adjusted for confounders (eg, maternal age and parity). Results: Overall, 743 630 women were included in the study (mean age, 28.1 [SD, 6.0] years; 41.4% nulliparous). Prepregnancy BMI was distributed as follows: underweight, 3.2%; normal weight, 47.5%; overweight, 25.8%; obesity class 1, 13.1%; obesity class 2, 6.2%; and obesity class 3, 4.2%. Rates of severe maternal morbidity or mortality were 171.5, 143.2, 160.4, 167.9, 178.3 and 202.9 per 10 000 women, respectively. Adjusted ORs were 1.2 (95% CI, 1.0-1.3) for underweight women; 1.1 (95% CI, 1.1-1.2) for overweight women; 1.1 (95% CI, 1.1-1.2) for women with class 1 obesity; 1.2 (95% CI, 1.1-1.3) for women with class 2 obesity; and 1.4 (95% CI, 1.3-1.5) for women with class 3 obesity compared with women with normal BMI. Absolute risk increases (adjusted rate differences per 10 000 women, compared with women with normal BMI) were 28.8 (95% CI, 12.2-47.2) for underweight women, 17.6 (95% CI, 10.5-25.1) for overweight women, 24.9 (95% CI, 15.7-34.6) for women with class 1 obesity, 35.8 (95% CI, 23.1-49.5) for women with class 2 obesity, and 61.1 (95% CI, 44.8-78.9) for women with class 3 obesity. Conclusions and Relevance: Among pregnant women in Washington State, low and high prepregnancy BMI, compared with normal BMI, were associated with a statistically significant but small absolute increase in severe maternal morbidity or mortality.

Antepartum dalteparin versus no antepartum dalteparin for the prevention of pregnancy complications in pregnant women with thrombophilia (TIPPS): a multinational open-label randomised trial.

BACKGROUND: Thrombophilias are common disorders that increase the risk of pregnancy-associated venous thromboembolism and pregnancy loss and can also increase the risk of placenta-mediated pregnancy complications (severe pre-eclampsia, small-for-gestational-age infants, and placental abruption). We postulated that antepartum dalteparin would reduce these complications in pregnant women with thrombophilia. METHODS: In this open-label randomised trial undertaken in 36 tertiary care centres in five countries, we enrolled consenting pregnant women with thrombophilia at increased risk of venous thromboembolism or with previous placenta-mediated pregnancy complications. Eligible participants were randomly allocated in a 1:1 ratio to either antepartum prophylactic dose dalteparin (5000 international units once daily up to 20 weeks' gestation, and twice daily thereafter until at least 37 weeks' gestation) or to no antepartum dalteparin (control group). Randomisation was done by a web-based randomisation system, and was stratified by country and gestational age at randomisation day with a permuted block design (block sizes 4 and 8). At randomisation, site pharmacists (or delegates) received a randomisation number and treatment allocation (by fax and/or e-mail) from the central web randomisation system and then dispensed study drug to the local coordinator. Patients and study personnel were not masked to treatment assignment, but the outcome adjudicators were masked. The primary composite outcome was independently adjudicated severe or early-onset pre-eclampsia, small-for-gestational-age infant (birthweight <10th percentile), pregnancy loss, or venous thromboembolism. We did intention-to-treat and on-treatment analyses. This trial is registered with ClinicalTrials.gov, number NCT00967382, and with Current Controlled Trials, number ISRCTN87441504. FINDINGS: Between Feb 28, 2000, and Sept 14, 2012, 292 women consented to participate and were randomly assigned to the two groups. Three women were excluded after randomisation because of ineligibility (two in the antepartum dalteparin group and one in the control group), leaving 146 women assigned to antepartum dalteparin and 143 assigned to no antepartum dalteparin. Some patients crossed over to the other group during treatment, and therefore for on-treatment and safety analysis there were 143 patients in the dalteparin group and 141 in the no dalteparin group. Dalteparin did not reduce the incidence of the primary composite outcome in both intention-to-treat analysis (dalteparin 25/146 [17·1%; 95% CI 11·4-24·2%] vs no dalteparin 27/143 [18·9%; 95% CI 12·8-26·3%]; risk difference -1·8% [95% CI -10·6% to 7·1%)) and on-treatment analysis (dalteparin 28/143 [19·6%] vs no dalteparin 24/141 [17·0%]; risk difference +2·6% [95% CI -6·4 to 11·6%]). In safety analysis, the occurrence of major bleeding did not differ between the two groups. However, minor bleeding was more common in the dalteparin group (28/143 [19·6%]) than in the no dalteparin group (13/141 [9·2%]; risk difference 10·4%, 95% CI 2·3-18·4; p=0·01). INTERPRETATION: Antepartum prophylactic dalteparin does not reduce the occurrence of venous thromboembolism, pregnancy loss, or placenta-mediated pregnancy complications in pregnant women with thrombophilia at high risk of these complications and is associated with an increased risk of minor bleeding. FUNDING: Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, and Pharmacia and UpJohn.

When should we use diagnostic imaging to investigate for pulmonary embolism in pregnant and postpartum women?

Pulmonary embolism (PE) is a leading cause of death in pregnancy and postpartum. Clinicians face a difficult choice when deciding whether to use diagnostic imaging to investigate for suspected PE in these patients, between risking potentially catastrophic consequences of missed diagnosis if imaging is withheld and risking unnecessary iatrogenic harm to both mother and fetus if imaging is overused. This paper explores the options for imaging and evidence for the use of clinical features, clinical predictions scores or biomarkers to select pregnant and postpartum women for imaging. It also considers where future research could be most appropriately directed.

Venous thromboembolism and antithrombotic therapy in pregnancy.

OBJECTIVE: To present an approach, based on current evidence, for the diagnosis, treatment, and thromboprophylaxis of venous thromboembolism in pregnancy and postpartum. EVIDENCE: Published literature was retrieved through searches of PubMed, Medline, CINAHL, and The Cochrane Library from November 2011 to July 2013 using appropriate controlled vocabulary (e.g. pregnancy, venous thromboembolism, deep vein thrombosis, pulmonary embolism, pulmonary thrombosis) and key words (e.g., maternal morbidity, pregnancy complications, thromboprophylaxis, antithrombotic therapy). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English or French. There were no date restrictions. Grey (unpublished) literature was identified through searching the websites of clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. VALUES: The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventative Health Care (Table 1).

Objectif : Présenter une approche, fondée sur les données actuelles, envers le diagnostic, la prise en charge et la thromboprophylaxie de la thromboembolie veineuse pendant la grossesse et la période postpartum. Résultats : La littérature publiée a été récupérée par l'intermédiaire de recherches menées dans PubMed, Medline, CINAHL et The Cochrane Library entre novembre 2011 et juillet 2013 au moyen d'un vocabulaire contrôlé (p. ex. « pregnancy ¼, « venous thromboembolism ¼, « deep vein thrombosis ¼, « pulmonary embolism ¼, « pulmonary thrombosis ¼) et de mots clés (p. ex. « maternal morbidity ¼, « pregnancy complications ¼, « thromboprophylaxis ¼, « antithrombotic therapy ¼) appropriés. Les résultats ont été restreints aux analyses systématiques, aux essais comparatifs randomisés / essais cliniques comparatifs et aux études observationnelles publiés en anglais ou en français. Aucune restriction n'a été imposée en matière de dates. La littérature grise (non publiée) a été identifiée par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales. Valeurs : La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau). Recommandations 1. La tenue d'un examen objectif s'avère requise lorsque la présence d'une thrombose veineuse profonde ou d'une embolie pulmonaire est soupçonnée sur le plan clinique. (II-2A) 2. Pour diagnostiquer la présence d'une thrombose veineuse profonde, il est recommandé d'avoir recours à une échographie; lorsque l'examen initial donne des résultats négatifs, il est recommandé de mener une nouvelle échographie à au moins une reprise au cours des sept jours suivants. Dans le cadre de chacun des examens, l'intégralité du système veineux (de la veine iliaque externe à la veine poplitée) doit être visualisée et des manœuvres de compression doivent être appliquées de la veine fémorale à la veine poplitée. (II-2B) 3. Pour diagnostiquer la présence d'une embolie pulmonaire, tant la scintigraphie de ventilation-perfusion que l'angiographie par tomodensitométrie peuvent être utilisées. (II-2A) Chez les femmes enceintes, la scintigraphie de ventilation-perfusion constitue le test à privilégier. (III-B) 4. Ni la seule détermination du taux de D-dimères ni l'application de règles de prédiction cliniques ne devraient être utilisées pour écarter la présence possible d'une thromboembolie veineuse chez les femmes enceintes sans avoir recours à un examen objectif. (III-D) 5. Les femmes enceintes ayant obtenu un diagnostic de thromboembolie veineuse aiguë devraient être hospitalisées ou encore faire l'objet d'un suivi étroit en clinique externe au cours des deux premières semaines suivant l'établissement du diagnostic initial. (III-C) 6. L'héparine de bas poids moléculaire est l'agent pharmacologique à privilégier, par rapport à l'héparine non fractionnée, pour la prise en charge de la thromboembolie veineuse pendant la grossesse. (II-2A) 7. Il est extrêmement rare de constater une thrombocytopénie induite par l'héparine chez les femmes enceintes. La consultation d'un hématologue ou d'un spécialiste de la thrombose est recommandée au moment d'envisager l'utilisation d'héparanoïdes pour la prise en charge d'une thromboembolie veineuse, le cas échéant. (II-3B) 8. L'utilisation d'antagonistes de la vitamine K pour la prise en charge de la thromboembolie veineuse pendant la grossesse ne devrait être envisagée que dans des circonstances exceptionnelles. (II-2A) 9. Nous nous prononçons contre l'utilisation des inhibiteurs du facteur Xa et des inhibiteurs directs de la thrombine administrés par voie orale pour la prise en charge de la thromboembolie veineuse pendant la grossesse. (III-D) 10. Pour la prise en charge de la thromboembolie veineuse aiguë pendant la grossesse, nous recommandons le respect de la posologie recommandée par le fabricant pour chacune des héparines de bas poids moléculaire, en fonction du poids actuel de la patiente. (II-1A) L'héparine de bas poids moléculaire peut être administrée une ou deux fois par jour, selon l'agent sélectionné. (III-C) 11. Chez les femmes enceintes dont le traitement initial fait appel à de l'héparine de bas poids moléculaire à dose thérapeutique, la numération plaquettaire devrait être déterminée au départ, puis l'être à nouveau une semaine plus tard, aux fins du dépistage de la thrombocytopénie induite par l'héparine. (III-C) 12. Chez les femmes enceintes qui présentent une thromboembolie veineuse aiguë, nous recommandons la mise en œuvre d'une anticoagulation thérapeutique pendant au moins trois mois. (I-A) 13. À la suite du traitement initial, l'intensité de l'anticoagulation peut être atténuée en passant à une dose intermédiaire ou prophylactique pour le reste de la grossesse et pour une période d'au moins six semaines à la suite de l'accouchement. (III-C) 14. Chez les femmes enceintes qui présentent une thrombose veineuse profonde aiguë proximale de la jambe, l'utilisation de bas de contention gradués peut être envisagée pour le soulagement des symptômes. (III-C) 15. Le recours à la thrombolyse pendant la grossesse ne devrait être envisagé qu'en présence d'une embolie pulmonaire massive ou d'une thrombose veineuse profonde menaçant l'intégrité d'un membre. (III-C) 16. Les filtres de veine cave ne devraient être utilisés que chez les femmes enceintes qui présentent une thrombose veineuse profonde ou une embolie pulmonaire aiguë et des contre-indications à l'anticoagulation. (III-C) 17. Une veinographie par tomodensitométrie et/ou une imagerie par résonance magnétique devraient être menées pour écarter la présence possible (lorsque celle-ci est soupçonnée) d'une thrombose veineuse cérébrale. (I-C) 18. Une anticoagulation faisant appel à une dose thérapeutique devrait être mise en œuvre lorsque la présence d'une thrombose veineuse cérébrale est confirmée. (II-2A) 19. À la suite d'une thrombose veineuse cérébrale, la mise en œuvre d'une thromboprophylaxie devrait être envisagée dans le cadre des grossesses subséquentes. (II-1C) 20. Dans les cas de thrombophlébite superficielle, une échographie de compression devrait être menée pour écarter la présence possible d'une thrombose veineuse profonde; (II-2A) de plus, une échographie de compression devrait être menée à nouveau lorsqu'une aggravation de la phlébite mène les fournisseurs de soins à soupçonner la présence d'une propagation proximale. (III-C) 21. L'administration d'héparine de bas poids moléculaire (selon des doses prophylactiques ou intermédiaires) pendant de 1 à 6 semaines est recommandée chez les femmes qui présentent une thrombophlébite superficielle bilatérale, chez les femmes très symptomatiques et chez les femmes qui présentent une thrombophlébite superficielle située à ≤ 5 cm du système veineux profond (jonctions saphénofémorale et saphénopoplitée) ou affectant ≥ 5 cm d'une veine. (I-A) 22. La seule mise en œuvre d'une observation est recommandée chez les femmes présentant une thrombophlébite superficielle qui sont exposées à de faibles risques de thrombose veineuse profonde et chez les femmes qui ne nécessitent pas la mise en œuvre d'une maîtrise des symptômes. Ces femmes devraient faire l'objet d'un suivi clinique mené dans les sept à dix jours; de plus, une nouvelle échographie de compression devrait être menée chez ces femmes dans un délai d'une semaine. (I-A) 23. La tomodensitométrie et/ou l'imagerie par résonance magnétique (avec ou sans angiographie) sont les modalités d'imagerie de référence pour ce qui est d'écarter la présence possible d'une thrombose de la veine ovarienne. (II-2A) 24. Lorsque la présence d'une thrombose de la veine ovarienne est confirmée, nous recommandons l'administration d'antibiotiques à large spectre par voie parentérale; nous recommandons également que ce traitement se poursuive pendant au moins 48 heures à la suite de la défervescence et de l'amélioration clinique. (II-2A) Une antibiothérapie de plus longue durée s'avère nécessaire en présence d'une septicémie ou d'infections compliquées. (III-C) 25. Lorsque la présence d'une thrombose de la veine ovarienne est confirmée, la mise en œuvre d'une anticoagulation (selon des doses thérapeutiques) pourrait être envisagée pendant de 1 à 3 mois. (III-C) 26. Le dépistage systématique de toutes les thrombophilies héréditaires chez toutes les femmes connaissant un premier épisode de thromboembolie veineuse diagnostiqué pendant la grossesse ne s'avère pas indiqué. (III-C) 27. Le dépistage des déficits en protéine S, en protéine C et en antithrombine s'avère indiqué à la suite d'un épisode de thromboembolie veineuse pendant la grossesse, en présence d'antécédents familiaux où figurent ces thrombophilies particulières ou lorsqu'une thrombose se manifeste à un endroit inhabituel. (III-C) 28. Le dépistage des anticorps antiphospholipides s'avère indiqué lorsque les résultats d'un tel dépistage affecteraient la durée de l'anticoagulation. (III-C) 29. Une évaluation du risque personnel de connaître une thromboembolie veineuse devrait être menée avant toutes les grossesses et une fois la présence d'une grossesse confirmée; une telle évaluation devrait également être menée à nouveau tout au long de la grossesse, au fur et à mesure que se manifestent de nouvelles situations cliniques. Les préférences et les valeurs de la patiente devraient être prises en considération lorsque l'on envisage d'avoir recours à la thromboprophylaxie antepartum. (III-B) 30. Les femmes qui sont exposées à un risque accru devraient être avisées des symptômes de la thromboembolie veineuse. (III-B) 31. L'héparine de bas poids moléculaire est l'agentpharmacologique à privilégier, par rapport à l'héparine non fractionnée, aux fins de la thromboprophylaxie antepartum. (III-A) Les doses d'héparine de bas poids moléculaire devraient être utilisées conformément aux recommandations des fabricants. (III-C) 32. L'administration systématique d'un agent anti-Xa et la surveillance du taux de plaquettes ne sont pas recommandées lorsque la patiente fait l'objet d'une thromboprophylaxie selon une dose prophylactique. (II-2E) 33. Nous recommandons la mise en œuvre d'une thromboprophylaxie thérapeutique au cours de la grossesse dans les situations suivantes : a. une anticoagulation thérapeutique à long terme a été utilisée avant la grossesse en raison d'une indication persistante; (III-B) b. des antécédents personnels de multiples thromboembolies veineuses. (III-B) 34. Nous recommandons la mise en œuvre d'une thromboprophylaxie intermédiaire ou thérapeutique au cours de la grossesse dans la situation suivante : a. des antécédents personnels de thromboembolie veineuse et de thrombophilie à risque élevé (déficit en antithrombine, syndrome des antiphospholipides) n'ayant pas auparavant fait l'objet d'un traitement d'anticoagulation. (III-B) 35. Nous recommandons la mise en œuvre d'une thromboprophylaxie selon une dose prophylactique au cours de la grossesse dans les situations suivantes (risque absolu > 1 %) : a. des antécédents personnels de thromboembolie veineuse non provoquée; (II-2A) b. des antécédents personnels de thromboembolie veineuse associée aux contraceptifs oraux ou à la grossesse; (II-2A) c. des antécédents personnels de thromboembolie veineuse provoquée et de quelque thrombophilie à faible risque que ce soit; (I-A) d. la présence d'un facteur V de Leiden homozygote asymptomatique; (II-2A) e. la présence d'une mutation du gène 20210A de la prothrombine homozygote asymptomatique; (III-B) f. la présence d'une thrombophilie combinée asymptomatique; (III-B) g. la présence d'un déficit en antithrombine asymptomatique; (III-B) h. la tenue d'une chirurgie non obstétricale pendant la grossesse, s'accompagnant d'une thromboprophylaxie dont la durée dépend de l'intervention et de la patiente; (III-B) i. un alitement strict antepartum pendant ≥ 7 jours chez une femme dont l'indice de masse corporelle était > 25 kg/m2 au moment de sa première consultation prénatale. (II-2B) 36. La mise en œuvre d'une thromboprophylaxie antepartum en raison de la présence isolée d'un des facteurs de risque associés à la grossesse n'est pas recommandée. (III-E) 37. La mise en œuvre d'une thromboprophylaxie antepartum devrait être envisagée en présence de multiples facteurs de risque cliniques ou associés à la grossesse lorsque l'on estime que le risque absolu global de TEV est supérieur à 1 %, particulièrement chez les patientes qui sont hospitalisées en vue d'un alitement. (II-2B) 38. La mise en œuvre systématique d'une thromboprophylaxie ne s'avère pas nécessaire chez toutes les femmes qui subissent un déclenchement de l'ovulation. (III-C) 39. Lorsque le recours aux techniques de procréation assistée donne lieu à un syndrome d'hyperstimulation ovarienne grave, nous recommandons la mise en œuvre d'une thromboprophylaxie à l'héparine de bas poids moléculaire pour une durée d'au moins 8 à 12 semaines à la suite de la résolution de ce syndrome. (III-B) 40. La mise en œuvre d'une thromboprophylaxie à l'héparine de bas poids moléculaire devrait être envisagée, au moment de la stimulation ovarienne, chez toutes les femmes exposées à un risque accru de thromboembolie veineuse qui ont recours à des techniques de procréation assistée. (III-B) 41. Les femmes qui en viennent à présenter une thromboembolie veineuse en association avec le recours aux techniques de procréation assistée, mais qui n'obtiennent pas une grossesse dans le cadre du cycle en question, devraient être traitées au moyen d'une anticoagulation thérapeutique pendant au moins trois mois. (II-3A) Les femmes qui obtiennent une grossesse dans le cadre du cycle de procréation assistée en question devraient être traitées conformément aux recommandations 12 et 13 traitant de la présence d'une thromboembolie veineuse aiguë pendant la grossesse. (I-A, III-C) 42. Les femmes faisant l'objet d'une anticoagulation thérapeutique ou administrée selon une dose prophylactique ou intermédiaire devraient être avisées de leurs options en matière d'analgésie / anesthésie avant l'accouchement. (III-B) 43. À terme (37 semaines), le passage de l'héparine de bas poids moléculaire thromboprophylactique à l'héparine non fractionnée administrée selon une dose prophylactique pourrait être envisagé de façon à permettre l'offre d'un plus grand nombre d'options en matière d'analgésie pendant le travail. (III-L) 44. Le traitement à l'héparine non fractionnée ou à l'héparine de bas poids moléculaire administrée selon une dose prophylactique ou intermédiaire doit être suspendu à l'apparition spontanée du travail ou au cours de la journée précédant la tenue planifiée d'un déclenchement du travail ou d'une césarienne. (II-3B) 45. Une numération plaquettaire récente devrait être disponible au moment de l'admission en salle de travail ou avant la tenue d'une césarienne pour les femmes qui ont reçu ou qui reçoivent des anticoagulants. (III-B) 46. Chez les femmes qui reçoivent de l'héparine de bas poids moléculaire, une anesthésie centrale peut être administrée comme suit : a. dose prophylactique : de 10 à 12 heures après la dernière dose, au minimum; (III-B) b. dose thérapeutique : 24 heures à la suite de la dernière dose. (III-B) 47. Chez les femmes qui reçoivent de l'héparine non fractionnée, une anesthésie centrale peut être administrée comme suit : a. dose prophylactique (maximum 10 000 U/jour) : sans délai; (III-B) b. perfusion thérapeutique : au moins 4 heures après l'arrêt de la perfusion et lorsque le temps de céphaline activée est normal; (III-B) c. héparine non fractionnée sous-cutanée à dose thérapeutique : lorsque le temps de céphaline activée est normal (cela pourrait prendre 12 heures ou plus à la suite de la dernière injection). (III-B) 48. La mise en œuvre d'une anesthésie centrale doit être évitée chez les femmes ayant fait l'objet d'une anticoagulation exhaustive ou en présence de symptômes indiquant une altération de la coagulation. (II-3A) 49. Le retrait d'un cathéter péridural / rachidien laissé in situ postpartum ne devrait être effectué que 4 heures, de 10 à 12 heures ou 24 heures à la suite de l'administration d'héparine non fractionnée à dose prophylactique (maximum 10 000 U/jour), d'héparine de bas poids moléculaire à dose prophylactique (une seule dose quotidienne) ou d'héparine de bas poids moléculaire à dose thérapeutique, respectivement, ou, dans le cas de l'administration d'héparine non fractionnée à dose thérapeutique, que lorsque le temps de céphaline activée est normal. (II-3B) 50. L'administration d'héparine de bas poids moléculaire à dose prophylactique (une seule dose quotidienne) peut être démarrée ou redémarrée quatre heures après le retrait d'un cathéter péridural / rachidien, pour autant que l'on constate une récupération neurologique totale et l'absence de symptômes indiquant des saignements évolutifs ou une coagulopathie. (III-B) 51. L'administration d'héparine de bas poids moléculaire à dose thérapeutique peut être démarrée ou redémarrée au moins 24 heures après un bloc central en injection unique et au moins 4 heures après le retrait d'un cathéter péridural / rachidien, pour autant que l'on constate une récupération neurologique totale et l'absence de symptômes indiquant des saignements évolutifs ou une coagulopathie. (III-B) 52. L'administration d'héparine non fractionnée par voie sous-cutanée peut être démarrée ou redémarrée au moins 1 heure après un bloc central en injection unique, pour autant que l'on constate une récupération neurologique totale et l'absence de symptômes indiquant des saignements évolutifs ou une coagulopathie. (III-B) 53. N'administrez pas des inhibiteurs de l'agrégation plaquettaire (acide acétylsalicylique ou anti-inflammatoires non stéroïdiens) et de l'héparine de façon concomitante lorsqu'un cathéter péridural / rachidien est laissé in situ postpartum. (III-D) 54. Les femmes qui reçoivent une anticoagulation thérapeutique et qui ont subi une anesthésie centrale devraient faire l'objet d'une surveillance étroite visant l'apparition possible d'un hématome spinal. (III-B) 55. La mise en œuvre universelle d'une thromboprophylaxie postpartum n'est pas recommandée. (III-D) 56. Cherchez à déterminer la présence d'un risque accru de thromboembolie veineuse postpartum après chaque accouchement, en fonction des facteurs de risque antepartum, intrapartum et postpartum, et répétez le processus au fur et à mesure que se manifestent de nouvelles situations cliniques. (II-2B) 57. L'héparine de bas poids moléculaire est l'agent pharmacologique à privilégier, par rapport à l'héparine non fractionnée, aux fins de la thromboprophylaxie postpartum. (III-A) Les doses d'héparine de bas poids moléculaire devraient être utilisées conformément aux recommandations des fabricants. (III-C) 58. La mise en œuvre d'une thromboprophylaxie postpartum pharmacologique est recommandée dans les situations suivantes : Présence d'un des facteurs de risque suivants (chacun de ces facteurs de risque donnant lieu à un risque absolu de thromboembolie veineuse > 1 %) : a. quelque antécédent de thromboembolie veineuse que ce soit; (II-2A) b. quelque thrombophilie à risque élevé que ce soit : syndrome des antiphospholipides, déficit en antithrombine, présence d'une mutation du gène 20210A de la prothrombine ou d'un facteur V de Leiden homozygote, thrombophilie combinée; (II-2B) c. alitement strict avant l'accouchement pendant 7 jours ou plus; (II-2B) d. perte sanguine peripartum ou postpartum > 1 litre ou remplacement des produits sanguins et tenue concomitante d'une chirurgie postpartum; (II-2B) e. infection peripartum / postpartum. (II-2B) 59. La mise en œuvre d'une thromboprophylaxie postpartum devrait être envisagée en présence de multiples facteurs de risque cliniques ou associés à la grossesse, lorsque l'on estime que le risque absolu global est supérieur à 1 % : a. présence de deux des facteurs de risque suivants (chacun de ces facteurs de risque donnant lieu à un risque absolu de thromboembolie veineuse < 1 %) : i. indice de masse corporelle ≥ 30 kg/m2 au moment de la première consultation antepartum; (II-2B) ii. fait de fumer > 10 cigarettes/jour pendant la période antepartum; (II-2B) iii. prééclampsie; (II-2B) iv. retard de croissance intra-utérin; (II-2B) v. placenta prævia; (II-2B) vi. césarienne d'urgence; (II­2B) vii. perte sanguine peripartum ou postpartum > 1 litre ou remplacement des produits sanguins; (II-2B) viii. quelque thrombophilie à faible risque que ce soit : déficit en PC ou en PS, présence d'une mutation du gène 20210A de la prothrombine ou d'un facteur V de Leiden hétérozygote; (III-B) ix. cardiopathie maternelle, lupus érythémateux disséminé, drépanocytose, maladie inflammatoire chronique de l'intestin, varices, diabète gestationnel; (III-B) x. accouchement préterme; (III-B) xi. mortinaissance. (III-B) b. présence d'au moins trois des facteurs de risque suivants (chacun de ces facteurs de risque donnant lieu à un risque absolu de thromboembolie veineuse < 1 %) : i. âge > 35 ans; (II-2B) ii. parité ≥ 2; (II-2B) iii. utilisation de quelque technique de procréation assistée que ce soit; (II-2B) iv. grossesse multiple; (II-2B) v. décollement placentaire; (II-2B) vi. rupture prématurée des membranes; (II-2B) vii. césarienne planifiée; (II-2B) viii. cancer maternel. (III-B) 60. L'utilisation d'appareils de compression pneumatique intermittente ou séquentielle constitue une solution de rechange lorsque l'héparine est contre-indiquée pendant la période postpartum. Lorsque le risque de thromboembolie veineuse postpartum est élevé, ces appareils peuvent être utilisés conjointement avec de l'héparine de bas poids moléculaire ou de l'héparine non fractionnée. (III-B) 61. Les femmes qui présentent des facteurs de risque évolutifs et persistants devraient faire l'objet d'une thromboprophylaxie postpartum pendant au moins six semaines à la suite de l'accouchement. (II-3B) 62. Les femmes qui présentent des facteurs de risque antepartum ou intrapartum transitoires devraient faire l'objet d'une thromboprophylaxie postpartum jusqu'à l'obtention de leur congé de l'hôpital ou pendant jusqu'à deux semaines à la suite de l'accouchement. (III-C) 63. Le dépistage universel des thrombophilies n'est pas indiqué chez les femmes qui connaissent des issues de grossesse indésirables (prééclampsie grave, retard de croissance intra-utérin, mortinaissance). (II-2D) 64. Les femmes qui connaissent des pertes fœtales tardives ou des fausses couches récurrentes devraient faire l'objet d'un dépistage visant le syndrome des antiphospholipides. (I-B) 65. L'utilisation d'acide acétylsalicylique à faible dose (avec ou sans héparine de bas poids moléculaire) est recommandée pendant la grossesse pour les femmes chez qui la présence du syndrome des antiphospholipides est confirmée. (I-C) 66. Lorsque la présence du syndrome des antiphospholipides n'a pas été confirmée, l'utilisation concomitante d'acide acétylsalicylique à faible dose et d'héparine de bas poids moléculaire n'est pas recommandée chez les femmes qui présentent des antécédents de fausses couches récurrentes. (I-E) 67. L'héparine de bas poids moléculaire ne devrait pas être utilisée de façon systématique aux fins de l'atténuation du risque de complications à médiation placentaire récurrentes chez les femmes qui présentent ou non une thrombophilie (en l'absence du syndrome des antiphospholipides). (I-C).

Implementation of a home blood pressure monitoring program for the management of hypertensive disorders of pregnancy, an observational study in British Columbia, Canada.

Background: COVID-19 pandemic has influenced health care delivery. We conducted an observational study to understand how obstetric medicine (ObM) physicians utilized home blood pressure monitoring (HBPM) to manage hypertension in pregnancy. Methods: Pregnant participants with risk factors or diagnosis of hypertensive disorders of pregnancy (HDP) were enrolled, May 2020-December 2021, and provided with validated home blood pressure (BP) monitor. ObM physicians completed questionnaires to elicit how home BP readings were interpreted to manage HDP. Results: We enrolled 103 people: 44 antepartum patients (33.5 ± 5 years, gestational age of 24 ± 5 weeks); 59 postpartum patients (35 ± 6 years, enrolled 6 ± 4 days post-partum). ObM physicians used range of home BP readings (70%) for management of HDP. Conclusions: HBPM to manage HDP is acceptable and can be used to manage hypertension during pregnancy. Further studies are needed to assess the generalizability of our findings and the safety of HBPM reliance alone in management of HDP.

Post-partum maternal bradycardia: A case series and literature review.

Background: Unlike tachyarrhythmias, which are common in pregnancy, there is a paucity of data regarding maternal bradycardias. Our objective was to describe the characteristics, associated conditions, and prognosis of women who develop bradycardia post-partum. Method: We conducted a retrospective chart review of patients referred to the Obstetrical Medicine service at British Columbia Women's Hospital from January 2012 to May 2020 for post-partum maternal bradycardia. Results: Twenty-four patients with post-partum bradycardia were included (age 34.2 ± 4.8 years; heart rate 40.4 ± 8.1 beats per minute; blood pressure 131/72 mm Hg). Sinus bradycardia (79.2%) was the most common rhythm. Dyspnea (29.4%) and chest pain (23.5%) were common symptoms. Mean time to resolution of bradycardia was 3.6 ± 3.8 days. Associated conditions potentially explaining the bradycardia were preeclampsia (54.1%), underlying (16.7%), medications (8.3%), and neuraxial anesthesia (8.3%). Conclusions: Maternal bradycardia is an uncommon condition complicating the post-partum period, that is generally self-limiting, with the majority only require clinical observation.

Safety of withholding anticoagulation in pregnant women with suspected deep vein thrombosis following negative serial compression ultrasound and iliac vein imaging.

BACKGROUND: Compression ultrasonography performed serially over a 7-day period is recommended for the diagnosis of deep vein thrombosis in symptomatic pregnant women, but whether this approach is safe is unknown. We evaluated the safety of withholding anticoagulation from pregnant women with suspected deep vein thrombosis following negative serial compression ultrasonography and iliac vein imaging. METHODS: Consecutive pregnant women who presented with suspected deep vein thrombosis underwent compression ultrasonography and Doppler imaging of the iliac vein of the symptomatic leg(s). Women whose initial test results were negative underwent serial testing on 2 occasions over the next 7 days. Women not diagnosed with deep vein thrombosis were followed for a minimum of 3 months for the development of symptomatic deep vein thrombosis or pulmonary embolism. RESULTS: In total, 221 pregnant women presented with suspected deep vein thrombosis. Deep vein thrombosis was diagnosed in 16 (7.2%) women by initial compression ultrasonography and Doppler studies; none were identified as having deep vein thrombosis on serial testing. One patient with normal serial testing had a pulmonary embolism diagnosed 7 weeks later. The overall prevalence of deep vein thrombosis was 7.7% (17/221); of these, 65% (11/17) of cases were isolated to the iliofemoral veins and 12% (2/17) were isolated iliac deep vein thromboses. The incidence of venous thromboembolism during follow-up was 0.49% (95% confidence interval [CI] 0.09%-2.71%). The sensitivity of serial compression ultrasonography with Doppler imaging was 94.1% (95% CI 69.2%-99.7%), the negative predictive value was 99.5% (95% CI 96.9%-100%), and the negative likelihood ratio was 0.068 (95% CI 0.01-0.39). INTERPRETATION: Serial compression ultrasonography with Doppler imaging of the iliac vein performed over a 7-day period excludes deep-vein thrombosis in symptomatic pregnant women.

A systematic review of posterior reversible encephalopathy syndrome in pregnant women with severe preeclampsia and eclampsia.

Background: The association of posterior reversible encephalopathy syndrome (PRES) and severe preeclampsia/eclampsia has been established but the frequency is uncertain. Objectives: To determine the frequency of PRES in severe preeclampsia or eclampsia. Methods: We searched published articles in PubMed, Cochrane library, Embase, and CINAHL from 1990 to 2020. We included articles that reported on six or more cases of PRES with eclampsia or severe preeclampsia who underwent neuroimaging during pregnancy or up to 6 weeks postpartum. Results: We identified 29 studies presenting data on 1519 women with eclampsia or severe preeclampsia. Among 342 women with eclampsia who had neuroimaging, 176 (51.4%) were diagnosed with PRES. Of 121 women with severe preeclampsia, 24 (19.8%) had PRES. The pooled maternal death rate was 5.3% (21/395). Conclusion: PRES is commonly reported on neuroimaging of women with eclampsia/ severe preeclampsia. The role of neuroimaging in eclampsia and especially in women with severe preeclampsia requires re-evaluation as further management is often dictated by this finding.

Illustrated State-of-the-Art Capsules of the ISTH 2022 Congress.

The ISTH London 2022 Congress is the first held (mostly) face-to-face again since the COVID-19 pandemic took the world by surprise in 2020. For 2 years we met virtually, but this year's in-person format will allow the ever-so-important and quintessential creativity and networking to flow again. What a pleasure and joy to be able to see everyone! Importantly, all conference proceedings are also streamed (and available recorded) online for those unable to travel on this occasion. This ensures no one misses out. The 2022 scientific program highlights new developments in hemophilia and its treatment, acquired and other inherited bleeding disorders, thromboinflammation, platelets and coagulation, clot structure and composition, fibrinolysis, vascular biology, venous thromboembolism, women's health, arterial thrombosis, pediatrics, COVID-related thrombosis, vaccine-induced thrombocytopenia with thrombosis, and omics and diagnostics. These areas are elegantly reviewed in this Illustrated Review article. The Illustrated Review is a highlight of the ISTH Congress. The format lends itself very well to explaining the science, and the collection of beautiful graphical summaries of recent developments in the field are stunning and self-explanatory. This clever and effective way to communicate research is revolutionary and different from traditional formats. We hope you enjoy this article and will be inspired by its content to generate new research ideas.

Home blood pressure monitoring in the diagnosis and treatment of hypertension in pregnancy: a systematic review and meta-analysis.

BACKGROUND: Home blood pressure monitoring is increasingly used for pregnant individuals; however, there are no guidelines on such monitoring in this population. We assessed current practices in the prescription and use of home blood pressure monitoring in pregnancy. METHODS: We conducted a systematic review and meta-analysis of observational studies and randomized controlled trials (RCTs). We conducted a structured search through the MEDLINE (from 1946), Embase (from 1974) and CENTRAL (from 2018) databases up to Oct. 19, 2020. We included trials comparing office and home blood pressure monitoring in pregnant people. Outcomes included patient education, home blood pressure device, monitoring schedule, adherence, diagnostic thresholds for home blood pressure, and comparison between home and office measurements of blood pressure. RESULTS: We included in our review 21 articles on 19 individual studies (1 RCT, 18 observational) that assessed home and office blood pressure in pregnant individuals (n = 2843). We observed variation in practice patterns in terms of how home monitoring was prescribed. Eight (42%) of the studies used validated home blood pressure devices. Across all studies, measurements were taken 3 to 36 times per week. Third-trimester home blood pressure corresponding to office blood pressure of 140/90 mm Hg after application of a conversion factor ranged from 118 to 143 mm Hg (systolic) and from 76 to 92 mm Hg (diastolic), depending on the patient population and methodology. Systolic and diastolic blood pressure values measured at home were lower than office values by 4 (95% confidence interval [CI] -6 to -3) mm Hg and 3 (95% CI -4 to -2) mm Hg, respectively. INTERPRETATION: Many issues related to home blood pressure monitoring in pregnancy are currently unresolved, including technique, monitoring schedule and target values. Future studies should prioritize the use of validated home measuring devices and standardized measurement schedules and should establish treatment targets. PROSPERO REGISTRATION: CRD42020147352.

Anatomic distribution of deep vein thrombosis in pregnancy.

BACKGROUND: Prospective studies of nonpregnant patients have demonstrated that most deep vein thromboses of the lower extremity originate in the calf veins and progress proximally, but the anatomic distribution of thromboses in pregnant patients is unclear. An understanding of the anatomic distribution of deep vein thrombosis in pregnancy has important implications for optimizing diagnostic imaging protocols. We undertook this study to determine the anatomic distribution of deep vein thrombosis of the lower extremity in symptomatic pregnant patients. METHODS: We systematically searched MEDLINE (1966 to January 2009), Embase (1980 to January 2009) and the Cochrane Library using prespecified criteria to identify articles providing objective diagnostic and anatomic information for unselected or consecutive symptomatic pregnant patients with deep vein thrombosis. RESULTS: Six articles from an initial list of 1098 titles met the inclusion criteria. These articles provided information for 124 pregnant women with a diagnosis of deep vein thrombosis. Overall, involvement of the left leg was reported in 84 (88%) of the 96 patients for which the side affected was known, and 87 (71%) of 122 thromboses were restricted to the proximal veins without involvement of the calf veins. Among these cases of proximal deep vein thrombosis, 64% (56/87) were restricted to the iliac and/or femoral vein. CONCLUSION: Despite a paucity of studies in this area, the results of our review suggest that the anatomic distribution of deep vein thrombosis in pregnant women differs from that for nonpregnant patients. In addition to what was previously known--that left-sided deep vein thrombosis is more common in pregnancy--we also found that proximal deep vein thrombosis restricted to the femoral or iliac veins is also more common (> 60% of cases). If confirmed by larger studies, these findings could affect our understanding of the pathophysiology and derivation of diagnostic algorithms for examination of pregnant women with suspected deep vein thrombosis.

Predicting deep venous thrombosis in pregnancy: out in "LEFt" field?

BACKGROUND: Clinicians' assessment of pretest probability, based on subjective criteria or prediction rules, is central to the diagnosis of deep venous thrombosis (DVT). Pretest probability assessment for DVT diagnosis has never been evaluated in pregnant women. OBJECTIVE: To evaluate the accuracy of clinicians' subjective assessment of pretest probability for DVT diagnosis and identify prediction variables that could be used for pretest probability assessment in pregnant women with suspected DVT. DESIGN: A cross-sectional study conducted over 7 years (March 2000 to April 2007). SETTING: 5 university-affiliated, tertiary care centers in Canada. PATIENTS: 194 unselected pregnant women with suspected first DVT. INTERVENTION: Diagnosis of DVT was established with abnormal compression ultrasonography at presentation or on serial imaging. Pretest probability by subjective assessment was recorded by thrombosis experts for each patient before knowledge of results. MEASUREMENTS: The sensitivity, specificity, negative predictive value, and likelihood ratios of subjective pretest probability assessment and their corresponding 95% CIs were calculated on the basis of the diagnosis of DVT. Patients were DVT positive if they had diagnostic compression ultrasonography at initial or serial testing or symptomatic venous thromboembolism on follow-up. Patients were DVT negative if they had negative compression ultrasonography at presentation and no venous thromboembolism on follow-up. A prediction rule for assessing DVT was derived, and an internal validation study was done to explore its performance. RESULTS: The prevalence of DVT was 8.8%. Clinicians' subjective assessment of pretest probability categorized patients into 2 groups: low pretest probability (two thirds of patients) with a low prevalence of DVT (1.5% [95% CI, 0.4% to 5.4%]) and a negative predictive value of 98.5% (CI, 94.6% to 99.6%), and nonlow pretest probability with a higher prevalence of DVT (24.6% [CI, 15.5% to 36.7%]). Three variables (symptoms in the left leg [L], calf circumference difference > or = 2 cm [E], and first trimester presentation [Ft]) were highly predictive of DVT in pregnant patients. LIMITATIONS: Few outcomes occurred. Altogether, 17 events were diagnosed during the study. The prediction rule derived should be validated on an independent sample before applying it to clinical practice. CONCLUSION: Subjective assessment of pretest probability seems to exclude DVT when the pretest probability is low. Moreover, 3 objective variables ("LEFt") may improve the accuracy of the diagnosis of DVT in pregnancy. Prospective validation studies are needed. PRIMARY FUNDING SOURCE: Heart and Stroke Foundation of Ontario.

Can pregnancy-adapted algorithms avoid diagnostic imaging for pulmonary embolism?

The low prevalence of pulmonary embolism (PE) among pregnant patients presenting with suspected PE implies that most of these patients will be found not have the disease. Given this low prevalence, excluding PE in this population has necessitated the use of sensitive and specific diagnostic imaging, such as computed tomography pulmonary angiography or ventilation-perfusion scanning. Recent studies suggest that a clinical prediction rule with D-dimer testing can also be used to exclude a subset of pregnant patients with suspected PE without the need for diagnostic imaging. The YEARS criteria, which consist of clinical signs and symptoms of deep venous thrombosis, hemoptysis, and PE as the most likely diagnosis (a subjective variable), combined with selective D-dimer levels, seem to safely exclude up to one-third of these patients without imaging. The revised Geneva rule using objective variables, combined with nonpregnancy cutoffs for D-dimer levels, offers some promise, although fewer patients avoided imaging (14%). These recent studies provide evidence in support of radiation avoidance for some patients; however, for most, imaging remains the only option. Future studies should focus on improving the safety and techniques of imaging modalities, in addition to improving the specificity of D-dimer testing and objective prediction rules. Studies assessing patients' and physicians' values, preferences, and risk perceptions are also required to assist clinicians in shared decision making when counseling pregnant patients with suspected PE.