Oxytocin receptor single nucleotide polymorphism predicts atony-related postpartum hemorrhage.

BACKGROUND: Postpartum hemorrhage remains a key contributor to overall maternal morbidity in the United States. Current clinical assessment methods used to predict postpartum hemorrhage are unable to prospectively identify about 40% of hemorrhage cases. Oxytocin is a first-line pharmaceutical for preventing and treating postpartum hemorrhage, which acts through oxytocin receptors on uterine myocytes. Existing research indicates that oxytocin function is subject to variation, influenced in part by differences in the DNA sequence within the oxytocin receptor gene. One variant, rs53576, has been shown to be associated with variable responses to exogenous oxytocin when administered during psychological research studies. How this variant may influence myometrial oxytocin response in the setting of third stage labor has not been studied. We tested for differences in the frequency of the oxytocin receptor genotype at rs53576 in relationship to the severity of blood loss among a sample of individuals who experienced vaginal birth. METHODS: A case-control prospective design was used to enroll 119 postpartum participants who underwent vaginal birth who were at least 37 weeks of gestation. Cases were defined by either a 1000 mL or greater blood loss or instances of heavier bleeding where parturients were given additional uterotonic treatment due to uterine atony. Controls were matched to cases on primiparity and labor induction status. Genotype was measured from a maternal blood sample obtained during the 2nd postpartum month from 95 participants. Statistical analysis included bivariate tests and generalized linear and Poisson regression modeling. RESULTS: The distribution of the genotype across the sample of 95 participants was 40% GG (n = 38), 50.5% AG (n = 48) and 9.5% AA (n = 9). Blood loss of 1000 mL or greater occurred at a rate of 7.9% for GG, 12.5% for AG and 55.6% for AA participants (p = 0.005). Multivariable models demonstrated A-carriers (versus GG) had 275.2 mL higher blood loss (95% CI 96.9-453.4, p < 0.01) controlling for parity, intrapartum oxytocin, self-reported ancestry, active management of third stage or genital tract lacerations. Furthermore, A-carrier individuals had a 79% higher risk for needing at least one second-line treatment (RR = 1.79, 95% CI = 1.08-2.95) controlling for covariates. Interaction models revealed that A-carriers who required no oxytocin for labor stimulation experienced 371.4 mL greater blood loss (95% CI 196.6-546.2 mL). CONCLUSIONS: We provide evidence of a risk allele in the oxytocin receptor gene that may be involved in the development of postpartum hemorrhage among participants undergoing vaginal birth, particularly among those with fewer risk factors. The findings, if reproducible, could be useful in studying pharmacogenomic strategies for predicting, preventing or treating postpartum hemorrhage.

Postpartum Hemorrhage in Heterozygote Factor XIII Deficient Women Compared With Healthy Women. A Cross-Sectional Experience From Iran.

Postpartum hemorrhage (PPH) is a major cause of maternal mortality, which is a common clinical manifestation in women with rare bleeding disorders. In this study, we compare PPH and its complications in heterozygote factor XIII (FXIII) deficient women with healthy women. In this cross sectional case study, 50 women with heterozygote FXIII deficiency and 50 healthy women are evaluated. Data were initially collected by interviewing the women who were receiving FXIII replacement therapy after their childbirths. Data were analysed using SPSS (Version 22) and a P-value of less than .05 was considered statistically significant. The mean age in the patient and control groups were 31.2 and 32.5 years respectively. The occurring rate of PPH in the patient group was significantly higher than the control group (34% vs 2%) (P-value <.0001). None of the confounding variables such as maternal age, gestational age, numbers, and types of delivery in women with PPH showed any significant differences between the control and patient groups. According to the results of this study, the risk of PPH (early and late), miscarriage, and menorrhagia in women who are heterozygous for FXIII deficiency is significantly higher than healthy women. However, the effect of other factors such as maternal age, gestational age, number, and type of delivery require further studies to delineate any confounding factors.

Recurrence of postpartum hemorrhage in relatives: A population-based cohort study.

INTRODUCTION: Studies on the family aggregation of postpartum hemorrhage (PPH) are scarce and with inconsistent results, and to what extent current birthweight influences recurrence between relatives remains to be studied. Further, family aggregation of PPH has been studied from an individual, but not from a public heath perspective. We aimed to investigate family aggregation of PPH in Norway, how birthweight influences these effects, and to estimate the proportion of PPH cases attributable to a family history of PPH and current birthweight. MATERIAL AND METHODS: Using data from the Medical Birth Registry of Norway, Statistics Norway, and Central Population Registry of Norway we identified individuals as newborns, parents, grandparents, and full and half-siblings, and studied 1 002 687 mother-offspring, 841 164 father-offspring, and 761 011 both-parents-offspring pairs. We used multilevel logistic regression to calculate odds ratios (OR) with 95% CI. RESULTS: If the birth of the mother but not of the father involved PPH, then the OR of PPH (>500 mL) in the next generation was 1.44 (95% CI 1.39-1.49). If the birth of the father but not of the mother involved PPH, then OR was 1.12 (95% CI 1.08-1.16). These effects were stronger in severe PPH. Recurrence between siblings was highest between full sisters (OR 1.47, 95% CI 1.41-1.52), followed by maternal half-sisters, paternal half-sisters, and partners of full brothers. A family history of PPH or birthweight of 4000 g or more accounted for ≤5% and 15% of the total number of PPH cases, respectively. CONCLUSIONS: A history of PPH in relatives influenced the recurrence risk of PPH in a dose-response pattern consistent with the anticipated proportion of shared genes. The recurrence was highest through the maternal line.

Factor VIII levels and bleeding according to factor 8 (F8) mutation in pregnant carriers of haemophilia A: a multicentre retrospective cohort study.

This retrospective cohort study investigated the association between factor 8 (F8) genotype severity and factor VIII (FVIII) levels during pregnancy for 52 women (64 pregnancies) who were heterozygous carriers of mild, moderate or severe haemophilia A. There were no significant differences in FVIII levels for carriers of mild, moderate or severe haemophilia A at baseline [mean (SD) level: mild, 0·78 (0·22); moderate, 0·83 (0·33); severe, 0·70 (0·25) iu/ml; P = 0·81] or in the third trimester [mean (SD) level: mild, 1·42 (0·28); moderate, 1·47 (0·41); severe, 1·37 (0·49) iu/ml; P = 0·80). Post-partum haemorrhage rates were higher for carriers of severe haemophilia A (13/24; 54·2%) compared to carriers of mild haemophilia A (four of 14; 28·6%).

Successful pregnancies in an adult with Meier-Gorlin syndrome harboring biallelic CDT1 variants.

Meier-Gorlin syndrome is an autosomal recessively inherited disorder of growth retardation, accompanied by microtia and patellae a/hypoplasia and characteristic facies. Pathogenic variants in genes associated with the initiation of DNA replication underlie the condition, with biallelic variants in CDT1 the most common cause. Using 10× Chromium genome sequencing, we report CDT1 variants in an adult female, with an inframe amino acid deletion inherited in trans with a deep intronic variant which likely serves as the branchpoint site in Intron 8. Splicing defects arising from this variant were confirmed through in vitro analysis. At 49 years, she represents the oldest patient with a molecular diagnosis described in the literature and is the first reported patient with Meier-Gorlin syndrome to have carried a successful pregnancy to term. Both of her pregnancies were complicated by postpartum hemorrhage and upon subsequent necessary hysterectomy, revealed uterine abnormalities. There is scant knowledge on reproductive ability and success in patients with Meier-Gorlin syndrome. Successful pregnancies among other clinically recognizable forms of primordial dwarfism have also not been described previously. This case is therefore of clinical interest for many forms of inherited growth retardation, and will assist in providing more information and clinical guidance for females of reproductive age.

Carriers of haemophilia: pregnancy, childbirth and postpartum.

Management of haemophilia carrier women during labour and postpartum is yet to be standardized. Pregnancy was accompanied by a marked rise in factor VIII levels compared with only a small rise in factor IX levels. After delivery, a carrier's factor level drops down to prepregnancy levels, which increases the chance of postpartum haemorrhage. Availability of management guideline and care provided in a multidisciplinary approach can help to minimize bleeding complications in carriers of haemophilia and their newborns.

Expression of ß-catenin in human trophoblast and its role in placenta accreta and placenta previa.

OBJECTIVES: To investigate the expression of ß-catenin in chorionic villi, and to explore its roles in placenta accreta and placenta previa. METHODS: We compared ß-catenin expression in the control group, placenta accreta group (lesion area and normal zones), and placenta previa group (placental central and placental edge zones) by immunohistochemistry, Western blotting, and RT-PCR techniques. RESULTS: Compared with the normal group, the placenta accreta group had a longer length of stay, greater bleeding volume, and lower newborn birth weight. Further, the expression of ß-catenin was lower in both placenta previa and placenta accreta groups than in the control group, as measured by immunohistochemistry. Compared with the control group, expression of ß-catenin was significantly lower in the placenta previa and placenta accreta groups by Western blotting and RT-PCR. Importantly, the level of placental ß-catenin was significantly different when compared between the lesion and normal zones of placenta. CONCLUSION: The expression of ß-catenin in placenta accreta might play an important role in the regulation of placental cell invasion; low expression of ß-catenin in placenta accreta might be responsible for excessive trophoblastic invasion.

ACTA2 mutation and postpartum hemorrhage: a case report.

BACKGROUND: ACTA2 encodes smooth muscle specific α-actin, a critical component or the contractile complex of vascular smooth muscle. Mutations in ACTA2 are the most common genetic cause of thoracic aortic aneurysm, and are also the cause of other disorders, including Moyamoya disease, coronary artery disease and stroke as well as Multisystemic Smooth Muscle Dysfunction Syndrome. We note that ACTA2 is also expressed in uterine smooth muscle, and this raises the possibility that women harboring ACTA2 mutations might exhibit uterine smooth muscle dysfunction. CASE PRESENTATION: We present a young woman whose ACTA2 mutation was ascertained during pregnancy because of her father's history of dissecting aneurysms. She was delivered at full term by cesarean section and subsequently had severe uterine hemorrhage due to uterine atony. Although her atony was successfully treated with uterotonic medications, she required blood transfusion. CONCLUSIONS: This case raises the possibility that women with ACTA2 mutations may be at risk of uterine muscle dysfunction and hemorrhage. Obstetricians should be alerted to and prepared for this possibility.

Mild factor XIII deficiency and concurrent hypofibrinogenemia: effect of pregnancy.

Factor XIII (FXIII) deficiency is a rare bleeding disorder. Patients with mild congenital FXIII deficiency tend to be asymptomatic, but may demonstrate significant bleeding symptoms with surgery, trauma, and pregnancy. Postpartum hemorrhage has been described in mild FXIII deficiency. We present a case of mild FXIII deficiency and concurrent hypofibrinogenemia manifested by recurrent postpartum hemorrhage, menorrhagia, and miscarriage. Mutational analysis identified a previously unreported heterozygous mutation of the FXIIIA subunit (p.Trp315Arg). No mutation was noted in the fibrinogen gene. FXIII levels decreased approximately 50% from nonpregnant levels to their nadir during labor, whereas fibrinogen levels rose approximately 1.5-fold from decreased nonpregnant levels to their peak at the time of labor. This case illustrates the course of mild FXIII and fibrinogen deficiencies during pregnancy, labor, and postpartum, and raises possible management options for prevention of antepartum and postpartum hemorrhage in women with these deficiencies.

Postpartum haemorrhage in a woman with essential thrombocythemia carrying calreticulin mutation: a case report.

Coagulation disorder associated with essential thrombocythemia may exacerbate the prothrombotic state physiologically occurring during pregnancy. We report a case of a severe postpartum haemorrhage in a 35-year-old woman previously diagnosed with essential thrombocythemia and carrying the somatic calreticulin mutation. She was referred to our Thrombosis and Haemostasis Unit for pregnancy management. A treatment with low-dose aspirin was prescribed until the labour started, as the platelets count raised above 1000 × 10/l. At the time of bleeding, no residual placenta was detected at the revision of the uterine cavity.Although the postpartum is a high-risk period for thrombotic events, we have to carefully evaluate in women with essential thrombocythemia the likelihood of developing a hemorrhagic complication.

Genetic background and risk of postpartum haemorrhage: results from an Italian cohort of 3219 women.

Postpartum haemorrhage (PPH) is a leading cause of maternal mortality, particularly in the developing countries, and of severe maternal morbidity worldwide. To investigate the impact of genetic influences on postpartum haemorrhage, in association with maternal and intrapartum risk factors, using a candidate gene approach. All women (n = 6694) who underwent a vaginal delivery at the Obstetric Unit of a large University hospital in Milan (Italy) between July 2007 and September 2009 were enrolled. The first consecutive 3219 women entered the genetic study. Postpartum haemorrhage was defined as ≥500 mL blood loss. Eight functional polymorphisms in seven candidate genes were chosen because of their potential role in predisposing to or protecting from haemorrhagic conditions: tissue factor (F3), factor V (F5), tissue factor pathway inhibitor (TFPI), platelet glycoprotein Ia/IIa (ITGA2), prothrombin (F2), platelet glycoproteins Ibα (GP1BA) and angiotensin-converting enzyme (ACE). After correction for the already known PPH risk factors, only the promoter polymorphism of the tissue factor gene (F3 -603A>G) showed a significant association with PPH, the G allele exerting a protective effect (P = 0.00053; OR = 0.79, 95% CI = 0.69-0.90). The protective effect against PPH of the TF -603A>G polymorphism is biologically plausible since the G allele is associated with an increased protein expression and Tissue Factor is strongly represented in the placenta at term, particularly in decidual cells of maternal origin.

Genetic contribution to postpartum haemorrhage in Swedish population: cohort study of 466,686 births.

OBJECTIVE: To investigate the familial clustering of postpartum haemorrhage in the Swedish population, and to quantify the relative contributions of genetic and environmental effects. DESIGN: Register based cohort study. SETTING: Swedish population (multi-generation and medical birth registers). MAIN OUTCOME MEASURE: Postpartum haemorrhage, defined as >1000 mL estimated blood loss. PARTICIPANTS: The first two live births to individuals in Sweden in 1997-2009 contributed to clusters representing intact couples (n = 366,350 births), mothers with separate partners (n = 53,292), fathers with separate partners (n = 47,054), sister pairs (n = 97,228), brother pairs (n = 91,168), and mixed sibling pairs (n = 177,944). METHODS: Familial clustering was quantified through cluster specific tetrachoric correlation coefficients, and the influence of potential sharing of known risk factors was evaluated with alternating logistic regression. Relative contributions of genetic and environmental effects to the variation in liability for postpartum haemorrhage were quantified with generalised linear mixed models. RESULTS: The overall prevalence of postpartum haemorrhage after vaginal deliveries in our sample was 4.6%. Among vaginal deliveries, 18% (95% confidence interval 9% to 26%) of the variation in postpartum haemorrhage liability was attributed to maternal genetic factors, 10% (1% to 19%) to unique maternal environment, and 11% (0% to 26%) to fetal genetic effects. Adjustment for known risk factors only partially explained estimates of familial clustering, suggesting that the observed shared genetic and environmental effects operate in part through pathways independent of known risk factors. There were similar patterns of familial clustering for both of the main subtypes examined (atony and retained placenta), though strongest for haemorrhage after retained placenta. CONCLUSIONS: There is a maternal genetic predisposition to postpartum haemorrhage, but more than half of the total variation in liability is attributable to factors that are not shared in families.

[Von Willebrand disease in the Netherlands: the WiN study]. / De ziekte van von Willebrand in Nederland: de WiN-studie.

Von Willebrand disease is the most common inherited bleeding disorder and is characterised by mucocutaneous bleeding. Von Willebrand disease is caused by reduced levels or reduced function of von Willebrand factor. Depending on the cause, von Willebrand disease is distinguished into various types with their own characteristics and treatment options. The frequency and severity of bleeding in patients with von Willebrand disease is strongly determined by von Willebrand factor levels, factor VIII levels and the type of von Willebrand disease. Eighty-five percent of all adult females with von Willebrand disease reports menorrhagia. A high percentage have postpartum excessive blood loss (37% of all deliveries). The quality of life is reduced in patients with von Willebrand disease. Patients with von Willebrand disease have a reduced risk of arterial thrombosis such as a myocardial or cerebral infarction.

Intergenerational transmission of postpartum hemorrhage risk: analysis of 2 Scottish birth cohorts.

OBJECTIVE: The purpose of this study was to determine risk factors for postpartum hemorrhage (PPH) that includes intergenerational transmission of risk of postpartum hemorrhage. STUDY DESIGN: We linked birth records of women and their daughters and granddaughters in 2 Scottish birth cohorts: the Walker cohort (collected from 1952-1966) and the Scottish Morbidity Records cohort (collected from 1975-present). We determined clinical risk factors for PPH. We then quantified the risk of PPH in women whose mothers/grandmothers had postpartum hemorrhage before and after adjustment for these risk factors. RESULTS: The risk of PPH in women whose mothers/grandmothers had PPH was no greater than in those whose mothers/grandmothers did not have PPH. Our study had sufficient power (80%) to detect an odds ratio of 1.3, should such an increase in odds that is associated with familial history exist. In contrast, the adjusted odds ratios that were conferred by nulliparity, having a large baby, cesarean delivery, and genital tract trauma were 1.47, 1.84, 8.20, and 9.61, respectively. CONCLUSION: Women whose mothers/grandmothers had PPH do not appear to be at increased risk themselves. We confirmed an increased risk of PPH that was associated with nulliparity, delivering a large baby, cesarean delivery, and genital tract trauma. We were unable to demonstrate an effect of intergenerational transmission of PPH, although our study was underpowered to detect an odds ratio <1.3. Thus, we confirm that any risk conferred by familial history, should it exist, is less than that conferred by factors in the index pregnancy itself.

The association of maternal race and ethnicity and the risk of postpartum hemorrhage.

BACKGROUND: There are profound racial and ethnic disparities in obstetric outcomes in the United States, but little is known about disparities in risk of postpartum hemorrhage (PPH). We explored the association of race and ethnicity on the risk of PPH due to uterine atony with sequential adjustment for possible mediating factors. METHODS: This analysis was based on the Nationwide Inpatient Sample, from between 2005 and 2008. The frequencies of atonic PPH and atonic PPH resulting in transfusion or hysterectomy were estimated. We developed multivariable logistic regression models to estimate the odds of these outcomes in maternal racial/ethnic groups by sequentially adding potential mediators. RESULTS: Hispanic ethnicity and Asian/Pacific Islander race were associated with a statistically significant increased odds of atonic PPH in comparison with Caucasians, despite adjustment for potential mediators (adjusted odds ratio [OR] for Hispanics: 1.21, 99% confidence interval [1.18, 1.25]; for Asians/Pacific Islanders: 1.31 [1.25, 1.38], with Caucasians as reference). Similar results were observed for these racial/ethnic groups for atonic PPH resulting in transfusion or hysterectomy. CONCLUSION: Hispanic ethnicity and Asian/Pacific Islander race are significant risk factors for atonic PPH independent of measured potential mediators; biological differences may play a role.

Impact of inherited bleeding disorders on pregnancy and postpartum hemorrhage.

Inherited bleeding disorders are caused by various genetic defects in the proteins involved in haemostasis. Female patients or carriers are faced with the risk of haemorrhage throughout life. During pregnancy and postpartum, this complication affects the health of either the mother or the baby, or both. This retrospective cohort study was designed to assess the occurrence of obstetric bleeding in the three trimesters of pregnancy, along with primary and secondary postpartum haemorrhage among 100 women with inherited bleeding disorders. A questionnaire was designed in order to collect historical data. The patients were evaluated in three groups: haemophilia carriers, von Willebrand disease (VWD) and rare bleeding disorders. In comparison with normal women, significantly severe bleeding was observed among patients in all of the five stages. VWD patients showed a higher frequency of bleeding in first trimester but the rate of miscarriage was lower. Haemophilia carriers were threatened with bleeding complications during the prenatal period, but they also had the highest frequency of postpartum haemorrhage. Based on our results, vaginal bleeding is a serious threat in all three patient groups, especially during the first trimester of pregnancy and in the postpartum period.