The Stockholm-Gotland perinatal cohort-A population-based cohort including longitudinal data throughout pregnancy and the postpartum period.

BACKGROUND: Register-based reproductive and perinatal databases rarely contain detailed information from medical records or repeated measurements throughout pregnancy and delivery. This lack of enriched pregnancy and birth data led to the initiation of the Swedish Stockholm-Gotland Perinatal Cohort (SGPC). OBJECTIVES: To describe the strengths of the SGPC, as well as the unique research questions that can be addressed using this cohort. POPULATION: The SGPC is a prospectively collected, population-based cohort that includes all births (from 22 completed gestational weeks onwards) between 1 January 2008 and 15 June 2020 in the Stockholm and Gotland regions of Sweden (335,153 singleton and 11,025 multiple pregnancies). DESIGN: Descriptive study. METHODS: The SGPC is based on the electronic medical records of women and their infants. The medical record system is used for all antenatal clinic visits and admissions, delivery and neonatal admissions, as well as postpartum clinical visits. SGPC has been further enriched with data linkages to 10 Swedish National Health Care and Quality Registers. PRELIMINARY RESULTS: In contrast to other reproductive and perinatal databases available in Sweden, including the Medical Birth Register and the Pregnancy Register, SGPC contains highly detailed medical record data, including time-varying serial measurements for physiological parameters throughout pregnancy, delivery, and postpartum, for both mother and infant. These strengths have enabled studies that were previously inconceivable; the effects of serial measurements of pregnancy weight gain, changes in haemoglobin counts and blood pressure during pregnancy, fetal weight estimations by ultrasound, duration of stages and phases of labour, cervical dilatation and oxytocin use during delivery, and constructing reference curves for umbilical cord pH. CONCLUSIONS: The SGPC-with its rich content, repeated measurements and linkages to numerous health care and quality registers-is a unique cohort that enables high-quality perinatal studies that would otherwise not be possible.

Clinical characteristics and predictors of neonatal outcomes in chorioamnionitis at term gestation: A cohort study.

OBJECTIVE: To investigate the association between clinical and laboratory characteristics of chorioamnionitis in deliveries at term gestation with adverse neonatal outcomes. DESIGN: Retrospective cohort study. SETTING: The study is based on data from the Swedish Pregnancy Register, enriched with clinical data extracted from medical charts. SAMPLE: A cohort of 500 term singleton deliveries in Stockholm County with registered diagnosis of chorioamnionitis (based on the assessment of the responsible obstetrician) in the Swedish Pregnancy Register between 2014 and 2020. METHODS: Logistic regression was used to estimate odds ratios (ORs) as a measurement of the association between clinical and laboratory characteristics and neonatal complications. MAIN OUTCOME MEASURES: Neonatal infection and asphyxia-related complications. RESULTS: The prevalence of neonatal infection and asphyxia-related complications was 10% and 22%, respectively. First leukocyte count in the second tertile (OR 2.14, 95% CI 1.02-4.49), maximum C-reactive protein (CRP) level in the third tertile (OR 4.01, 95% Cl 1.66-9.68) and positive cervical culture (OR 2.22, 95% Cl 1.10-4.48) were associated with an increased risk of neonatal infection. Maximum level of CRP in the third tertile (OR 1.93, 95% Cl 1.09-3.41) and fetal tachycardia (OR 1.63, 95% Cl 1.01-2.65) were associated with an increased risk of asphyxia-related complications. CONCLUSIONS: Elevated inflammatory laboratory markers were associated with both neonatal infection and asphyxia-related complications, and fetal tachycardia was associated with asphyxia-related complications. Based on these findings, the incorporation of maternal CRP in the management of chorioamnionitis should be considered, and a continuous communication between obstetric and neonatal care extending past the delivery time point endorsed.

Accuracy and precision of sonographic fetal weight estimation in Sweden.

INTRODUCTION: Fetal growth assessment by ultrasound is an essential part of modern obstetric care. The formula by Persson and Weldner for estimated fetal weight (EFW), used in Sweden since decades, has not yet been evaluated. The objective of this study was to evaluate accuracy and precision of the formula by Persson and Weldner, and to compare it to two other formulae using biparietal diameter instead of head circumference. MATERIAL AND METHODS: The study population consisted of 31 521 singleton pregnancies delivered at 22+0 gestational weeks or later, with an ultrasound EFW performed within 2 days before delivery, registered in the Swedish Pregnancy Register between 2014 and 2021. Fetal biometric ultrasound measurements were used to calculate EFW according to the formulae by Persson and Weldner, Hadlock 2 and Shepard. Bland-Altman analysis, systematic error (mean percentage error), random error (standard deviation [SD] of mean percentage error), proportion of weight estimates within ±10% of birthweight, and proportion with underestimated and overestimated weight was calculated. Moreover, calculations were made after stratification into small, appropriate, and large for gestational age (SGA, AGA and LGA), respectively, and gestational age at examination. RESULTS: For the formula by Persson and Weldner, MPE was -2.7 (SD 8.9) and the proportion of EFW within ±10% from actual birthweight was 76.0%. MPE was largest for fetuses estimated as severe SGA (<3rd percentile, -5.4) and for the most preterm fetuses (<24 weeks, -5.4). For Hadlock 2 and Shepard's formulae, MPE were 3.9 (SD 8.9) and 3.4 (SD 9.7), respectively, and the proportions of EFW within ±10% from actual birthweight were 69.4% and 67.1%, respectively. MPE was largest for fetuses estimated as severe LGA (>97th percentile), 7.6 and 9.4, respectively. CONCLUSIONS: The recommended Swedish formula by Persson and Weldner is generally accurate for fetal weight estimation. The systematic underestimation of EFW and random error is largest in extreme preterm and estimated SGA-fetuses, which is of importance in clinical decision making. The accuracy of EFW with the formula by Persson and Weldner is as good as or better than Hadlock 2 and Shepard's formulae.

Placental location and risk of retained placenta in women with a previous cesarean section: A population-based cohort study.

INTRODUCTION: Some studies have shown that women with a previous cesarean section, compared with women with a previous vaginal delivery, have an increased risk of retained placenta during a subsequent vaginal delivery. It is unknown whether this is mediated by anterior placental location, when the placenta might cover the uterine scar. The aim of this study was to evaluate whether the increased risk of retained placenta in women with a previous cesarean section is mediated by anterior placental location. MATERIAL AND METHODS: This is a population-based cohort study, with data from the regional population-based Stockholm-Gotland Obstetric Cohort, Sweden, from 2008 to 2014. The overall study population included 49 598 women with a vaginal second delivery, where adequate information about placental location from the second-trimester ultrasound scan was available. For the main analysis, including the 3921 women with a previous cesarean section, we calculated the relative risk of retained placenta in women with an anterior placental location, using women with non-anterior placental locations as reference. Relative risks were calculated as odds ratios (OR) with 95% CI. In a second model, adjustments were made for maternal age, height, country of birth, smoking in early pregnancy, infant sex, and in vitro fertilization. RESULTS: In the overall study population, the rate of retained placenta at the second delivery was 2.0%. The proportion of women with a retained placenta was higher among women with a previous cesarean compared with those with a previous vaginal delivery (3.4% vs 1.9%; P < .0001). In the main analysis, including women with a previous cesarean section, the risk for retained placenta was not increased with anterior compared with non-anterior placental location (OR 0.84, 95% CI 0.60-1.20). Adjustments did not affect the estimates in a significant way. CONCLUSIONS: The increased risk of retained placenta in women with a previous cesarean section is not mediated by anterior placental location.

Placental location and pregnancy outcomes in nulliparous women: A population-based cohort study.

INTRODUCTION: The impact of placenta previa on pregnancy, delivery and infant outcomes has been extensively studied. However, less is known about the possible association of placental location other than previa with pregnancy outcomes. The aim of this study was to investigate if placental location other than previa is associated with adverse pregnancy, delivery and infant outcomes. MATERIAL AND METHODS: This is a population-based cohort study, with data from the regional population-based Stockholm-Gotland Obstetric Cohort, Sweden, from 2008 to 2014. The study population included 74 087 nulliparous women with singleton pregnancies resulting in live-born infants, with information about placental location from the second-trimester ultrasound screening. The association between placental location (fundal, lateral, anterior or posterior) and pregnancy outcomes was estimated using logistic regression analysis. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated, and adjustments were made for maternal age, height, country of birth, smoking in early pregnancy, sex of the infant and in vitro fertilization. Main outcome measures were pregnancy, delivery and infant outcomes. RESULTS: Compared with posterior placental location, fundal and lateral placental locations were associated with a number of adverse pregnancy outcomes, the most important being: very preterm birth (<32 weeks of gestation) (adjusted OR [aOR] 1.78, 95% CI 1.18-2.63 and aOR 2.12, 95% CI 1.39-2.25, respectively), moderate preterm birth (32-36 weeks of gestation) (aOR 1.23, 95% CI 1.001-1.51 and aOR 1.62, 95% CI 1.32-2.00, respectively), small-for-gestational-age birth (aOR 1.67, 95% CI 1.34-2.07 and aOR 1.77, 95% CI 1.39-2.25, respectively) and manual removal of the placenta in vaginal births (aOR 3.27, 95% CI 2.68-3.99 and aOR 3.27, 95% CI 2.60-4.10, respectively). Additionally, lateral placental location was associated with preeclampsia (aOR 1.30, 95% CI 1.03-1.65) and severe postpartum hemorrhage (aOR 1.42, 95% CI 1.27-1.82). CONCLUSIONS: Compared with posterior placental location, fundal and lateral placental locations are associated with a number of adverse pregnancy, delivery and infant outcomes.

Adherence to Swedish national pregnancy dating guidelines and management of discrepancies between pregnancy dating methods: a survey study.

BACKGROUND: Swedish national guidelines for pregnancy dating were published in 2010. Follow-up is needed to assess adherence and to identify whether any clinical topics are not covered in the guidelines. METHODS: All units in Sweden that performed ultrasound-based pregnancy dating were asked to complete a web-based questionnaire comprising multiple-response questions and commentary fields. Information was collected regarding baseline information, current and previous clinical practice, and management of discrepancies between last-menstrual-period- and ultrasound-based methods for pregnancy dating. RESULTS: The response rate was 79%. Half of the units offered first-trimester ultrasound to all pregnant women. However, contrary to the guidelines, the crown-rump length was not used for ultrasound-based pregnancy dating in most units. Instead, ultrasound-based pregnancy dating was performed only if the biparietal diameter was between 21 and 55 mm. Management of discrepancies between methods for pregnancy dating varied widely. CONCLUSIONS: The units reported high adherence to national guidelines, except for early pregnancy dating, for which many units followed unwritten or informal guidelines. The management of discrepancies between last-menstrual-period-based and ultrasound-based estimated day of delivery varied widely. These findings emphasize the need for regular updating of national written guidelines and efforts to improve their implementation in all units.

Iodine deficiency in a study population of pregnant women in Sweden.

INTRODUCTION: Iodine deficiency in utero may impair neurological development of the fetus. In Sweden, iodine nutrition is considered to be adequate in the general population. The aim of this study was to evaluate iodine nutrition during pregnancy in Sweden. MATERIAL AND METHODS: In this cross-sectional study, the total study population (n = 459) consisted of two cohorts (Värmland County, n = 273, and Uppsala County, n = 186) of pregnant non-smoking women without pre-gestational diabetes mellitus or known thyroid disease before or during pregnancy. Spot urine samples were collected in the third trimester of pregnancy for median urinary iodine concentration (UIC) analysis. RESULTS: The median UIC in the total study population was 98 µg/L (interquartile range 57-148 µg/L). CONCLUSIONS: According to WHO/UNICEF/IGN criteria, population-based median UIC during pregnancy should be 150-249 µg/L. Thus, our results indicate insufficient iodine status in the pregnant population of Sweden. There is an urgent need for further assessments in order to optimize iodine nutrition during pregnancy.

Maternal, pregnancy and neonatal outcomes in triplet pregnancies in Sweden - a nationwide cohort study.

Background: Triplet pregnancies carry a high risk of pregnancy-related complications. The primary aim of this study was to describe maternal, pregnancy, and neonatal outcomes in expectantly managed triplet pregnancies in Sweden. The secondary aim was to compare outcomes in expectantly managed triplet pregnancies with triplet pregnancies where fetal reduction had been performed with the only indication to reduce the number of fetuses. Methods: Nationwide cohort study based on linkage of data from three national Swedish registers. Triplet pregnancies with delivery at gestational age ≥ 22+0 weeks between 2014 and 2019 were included. Results: In the main cohort of expectantly managed triplet pregnancies (n = 106), 98% (312/318) of infants were liveborn with a mean gestational age at birth of 32+3 weeks and a mean birthweight of 1,726 g. Nine percent (n = 29) suffered from severe neonatal morbidity, and 4% (n = 12) died during the neonatal period. In the reduced cohort (n = 13 pregnancies), all infants were liveborn (n = 22). Mean gestational age at birth (36+0 weeks) and mean birthweight (2,444 g) were higher than in the expectantly managed cohort (P < 0.01 for both comparisons). There were no cases of severe neonatal morbidity (P = 0.24) or mortality (P = 1.00). Conclusion: Overall neonatal survival from 22+0 weeks of gestation in expectantly managed triplet pregnancies in Sweden was high. Nine out of 10 infants did not suffer from severe neonatal morbidity. Fetal reduction was performed in only a very small number of cases and was associated with higher gestational age at birth and higher birth weight.

Phosphodiesterase 8B gene polymorphism in women with recurrent miscarriage: a retrospective case control study.

BACKGROUND: Recurrent miscarriage affects approximately 1% of all couples. There is a known relation between hypothyroidism and recurrent miscarriage. Phosphodiesterase 8B (PDE8B) is a regulator of cyclic adenosine monophosphate (cAMP) with important influence on human thyroid metabolism. Single nucleotide polymorphism (SNP) rs 4704397 in the PDE8B gene has been shown to be associated with variations in serum Thyroid Stimulating Hormone (TSH) and thyroxine (T4) levels. The aim of this study was to investigate whether there is an association between the SNP rs 4704397 in the PDE8B gene and recurrent miscarriage. METHODS: The study was designed as a retrospective case control study. 188 cases with recurrent miscarriage were included and compared with 391 controls who had delivered at least once and with no history of miscarriage or assisted reproduction. RESULTS: No difference between cases and controls concerning age was found. Bivariate associations between homozygous A/A (OR 1.57, 95% CI 0.98-2.52) as well as G/G carriers (OR 1.52, 95% CI 1.02-2.25) of SNP rs 4704397 in PDE8B and recurrent miscarriage were verified (test for trend across all 3 genotypes, p=0.059). After adjustment for known confounders such as age, BMI and smoking the association between homozygous A/A (AOR 1.63, 95% CI 1.01-2.64, p=0.045) and G/G (AOR 1.52, 95% CI 1.02-2.27, p=0.039) carriers of SNP rs 4704397 in PDE8B and recurrent miscarriage remained. CONCLUSIONS: Our findings suggest that there is an association between homozygous A/A as well as homozygous G/G carriers of SNP rs 4704397 in PDE8B and recurrent miscarriage.

Confined placental mosaicism of Duchenne muscular dystrophy: a case report.

BACKGROUND: Small copy number variations confined to the placenta are extremely rare findings in chorionic villus sampling, nonetheless of great clinical importance. To the best of our knowledge, this is the first reported case of confined placental mosaicism for an intragenic Duchenne muscular dystrophy (DMD) gene deletion. CASE PRESENTATION: We describe a pregnant woman where confined placental mosaicism for an intragenic DMD deletion was detected. She was referred for a chorionic villus sampling due to an increased risk of trisomy 21 derived from combined first trimester screening. Rapid aneuploidy detection showed a male fetus with normal results for chromosomes 13, 18 and 21. A chromosomal microarray demonstrated a deletion of exons 61-62 in the DMD gene in approximately 50% of the cells. A follow-up analysis on amniotic cells showed a normal result for the DMD gene. Hence, confined placental mosaicism was confirmed. CONCLUSIONS: We propose tissue specific fragile sites as a possible theoretical mechanism for the formation of submicroscopic copy number variations and highlight that the finding of DMD deletion mosaicism in a chorionic villus sample might be isolated to the placenta. Therefore, confirmation by amniocentesis is of crucial clinical importance to avoid misdiagnosis of the fetus.

Discrepancy between pregnancy dating methods affects obstetric and neonatal outcomes: a population-based register cohort study.

To assess associations between discrepancy of pregnancy dating methods and adverse pregnancy, delivery, and neonatal outcomes, odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for discrepancy categories among all singleton births from the Medical Birth Register (1995-2010) with estimated date of delivery (EDD) by last menstrual period (LMP) minus EDD by ultrasound (US) -20 to +20 days. Negative/positive discrepancy was a fetus smaller/larger than expected when dated by US (EDD postponed/changed to an earlier date). Large discrepancy was <10th or >90th percentile. Reference was median discrepancy ±2 days. Odds for diabetes and preeclampsia were higher in pregnancies with negative discrepancy, and for most delivery outcomes in case of large positive discrepancy (+9 to +20 days): shoulder dystocia [OR 1.16 (95% CI 1.01-1.33)] and sphincter injuries [OR 1.13 (95% CI 1.09-1.17)]. Odds for adverse neonatal outcomes were higher in large negative discrepancy (-4 to -20 days): low Apgar score [OR 1.18 (95% CI 1.09-1.27)], asphyxia [OR 1.18 (95% CI 1.11-1.25)], fetal death [OR 1.47 (95% CI 1.32-1.64)], and neonatal death [OR 2.19 (95% CI 1.91-2.50)]. In conclusion, especially, large negative discrepancy was associated with increased risks of adverse perinatal outcomes.

[Routine pregnancy ultrasound scans can detect malformations. Multidisciplinary care of both the foetus and parent is required following diagnosed malformations]. / Rutinundersökning med ultraljud kan ge besked om avvikelser - Vid diagnostiserad missbildning krävs multidisciplinärt omhändertagande av både foster och föräldrar.

Routine pregnancy ultrasound scans can detect malformations. Multidisciplinary care of both the foetus and parent is required following diagnosed malformations In Sweden, all women are invited to at least one ultrasound examination during pregnancy. The ¼Routine ultrasound screening« is usually performed by a midwife around 18 weeks of gestation. There are several aims of the examination: to check viability, to detect multiple fetuses, to determine the location of the placenta, to check the amount of amniotic fluid, to estimate the date of delivery (if this had not been done earlier) and to detect structural fetal malformations. It is important to offer an adequate education for all providers and assure the quality of the examinations. Nationwide courses are offered once or twice a year, and as a goal, all providers should have a ¼certificate of competence« for this kind of examination. When a fetal malformation is suspected, confirmed after further investigations and the prospective parents decide to continue the pregnancy, multidisciplinary care is offered in cooperation with or at a university hospital.

Targeted thyroid testing during pregnancy in clinical practice.

OBJECTIVE: To evaluate the efficacy of a targeted thyroid testing approach during pregnancy in clinical practice. METHODS: This is a retrospective cohort study performed within Uppsala County, Sweden. Data were derived from the population-based Uppsala Biobank of Pregnant Women, in which blood samples are collected in conjunction with the routine ultrasound screening in gestational week 17-19. For this study, 5,254 pregnant women with an estimated date of delivery between January 1, 2009, and December 31, 2011, were included. On review of their medical records, women who were tested for thyroid dysfunction during pregnancy in clinical practice were identified (n=891). From the remaining untested women, 1,006 women were randomly selected for analyses of thyrotropin (TSH), free thyroxine levels, and thyroid peroxidase antibodies. Thyroid-stimulating hormone levels in both groups were analyzed with regard to trimester-specific upper reference levels as recommended by the International Endocrine Society Guidelines. RESULTS: The proportion of trimester-specific TSH elevation was 12.6% in the targeted thyroid testing group and 12.1% in the untested group (P=.8; odds ratio [OR] 1.04, 95% confidence interval [CI] 0.79-1.37). The proportion of overt hypothyroidism was 1.1% and 0.7% in the groups, respectively (P=.4; OR 1.57, 95% CI 0.55-4.45). CONCLUSIONS: The prevalence of trimester-specific elevated TSH and overt hypothyroidism was equal in targeted thyroid tested and untested women. When implemented in clinical practice, targeted thyroid testing is unsatisfactory. If ongoing studies provide support for treatment of pregnant women with elevated TSH, universal thyroid testing appears the most reasonable approach. LEVEL OF EVIDENCE: : II.

Thyroid testing and management of hypothyroidism during pregnancy: a population-based study.

CONTEXT: There are international guidelines on thyroid function testing and management of hypothyroidism during pregnancy. Few studies have evaluated how they are implemented into clinical practice. OBJECTIVE: In this descriptive study, we assessed the implementation of international guidelines in this field into local guidelines and also into clinical practice. DESIGN AND PARTICIPANTS: In a nationwide survey, all guidelines in Sweden were collected (n = 29), and the adherence of the local guidelines to The Endocrine Society Guidelines 2007 was evaluated. In a follow-up in 1 district, 5254 pregnant women with an estimated date of delivery between January 1, 2009, and December 31, 2011, were included for subsequent review of their medical reports. RESULTS: All but 1 district had guidelines on the subject. All local guidelines included fewer than the 10 listed reasons for thyroid testing recommended by The Endocrine Society Guidelines. Furthermore, most guidelines recommended additional types of thyroid function tests to TSH sampling and lower trimester-specific TSH upper reference limits for women on levothyroxine treatment (P < .001). In the follow-up, the thyroid testing rate was 20%, with an overall frequency of women with trimester-specific elevated TSH of 18.5%. More than half of the women (50.9%) who were on levothyroxine treatment at conception had an elevated TSH level at thyroid testing according to The Endocrine Society Guidelines. CONCLUSIONS: The local guidelines are variable and poorly compliant with international guidelines. Performance of thyroid testing is not optimal, and rates of elevated TSH at testing are extremely high in subgroups.