Maternal pre-gravid body weight and risk for placental abruption among twin pregnancies

Association of Maternal Eating Disorders With Pregnancy and Neonatal Outcomes

IMPORTANCE

The prevalence of eating disorders is high among women of reproductive age, yet the association of eating disorders with pregnancy complications and neonatal health has not been investigated in detail, to our knowledge.

OBJECTIVE

To investigate the relative risk of adverse pregnancy and neonatal outcomes for women with eating disorders.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study included all singleton births included in the Swedish Medical Birth Register from January 1, 2003, to December 31, 2014. A total of 7542 women with eating disorders were compared with 1 225 321 women without eating disorders. Statistical analysis was performed from January 1, 2018, to April 30, 2019. Via linkage with the national patient register, women with eating disorders were identified and compared with women free of any eating disorder. Eating disorders were further stratified into active or previous disease based on last time of diagnosis.

MAIN OUTCOMES AND MEASURES

The risk of adverse pregnancy outcomes (hyperemesis, anemia, preeclampsia, and antepartum hemorrhage), the mode of delivery (cesarean delivery, vaginal delivery, or instrumental vaginal delivery), and the neonatal outcomes (preterm birth, small and large sizes for gestational age, Apgar score <7 at 5 minutes, and microcephaly) were calculated using Poisson regression analysis to estimate risk ratios (RRs). Models were adjusted for age, parity, smoking status, and birth year.

RESULTS

There were 2769 women with anorexia nervosa (mean [SD] age, 29.4 [5.3] years), 1378 women with bulimia nervosa (mean [SD] age, 30.2 [4.9] years), and 3395 women with an eating disorder not otherwise specified (EDNOS; mean [SD] age, 28.9 [5.3] years), and they were analyzed and compared with 1 225 321 women without eating disorders (mean [SD] age, 30.3 [5.2] years). All subtypes of maternal eating disorders were associated with an approximately 2-fold increased risk of hyperemesis during pregnancy (anorexia nervosa: RR, 2.1 [95% CI, 1.8-2.5]; bulimia nervosa: RR, 2.1 [95% CI, 1.6-2.7]; EDNOS: RR, 2.6 [95% CI, 2.3-3.0]). The risk of anemia during pregnancy was doubled for women with active anorexia nervosa (RR, 2.1 [95% CI, 1.3-3.2]) or EDNOS (RR, 2.1 [95% CI, 1.5-2.8]). Maternal anorexia nervosa was associated with an increased risk of antepartum hemorrhage (RR, 1.6 [95% CI, 1.2-2.1]), which was more pronounced in active vs previous disease. Women with anorexia nervosa (RR, 0.7 [95% CI, 0.6-0.9]) and women with EDNOS (RR, 0.8 [95% CI, 0.7-1.0]) were at decreased risk of instrumental-assisted vaginal births; otherwise, there were no major differences in mode of delivery. Women with eating disorders, all subtypes, were at increased risk of a preterm birth (anorexia nervosa: RR, 1.6 [95% CI, 1.4-1.8]; bulimia nervosa: RR, 1.3 [95% CI, 1.0-1.6]; and EDNOS: RR, 1.4 [95% CI, 1.2-1.6]) and of delivering neonates with microcephaly (anorexia nervosa: RR, 1.9 [95% CI, 1.5-2.4]; bulimia nervosa: RR, 1.6 [95% CI, 1.1-2.4]; EDNOS: RR, 1.4 [95% CI, 1.2-1.9]).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that women with active or previous eating disorders, regardless of subtype, are at increased risk of adverse pregnancy and neonatal outcomes and may need increased surveillance in antenatal and delivery care.

The relationship between maternal body mass index and pregnancy outcomes in twin compared with singleton pregnancies

OBJECIVE

Women with twins have an a priori increased risk for many of the complications associated with maternal obesity. Thus, the impact of maternal obesity in twins may differ from that reported in singletons. In addition, given the increased metabolic demands in twin pregnancies, the impact of maternal underweight may be greater in twin compared with singleton gestations. Our objective was to test the hypothesis that the relationship between maternal pre-pregnancy body mass index (BMI) and adverse pregnancy outcomes differ between twin and singleton gestations.

METHODS

This was a retrospective population-based study of all women who had a singleton or twin hospital birth in Ontario, Canada, between April 2012 and March 2016. Data were obtained from the Better Outcomes Registry & Network (BORN) Ontario. The relationship between maternal BMI category and pregnancy complications was assessed separately in twin and singleton gestations. The primary outcome was a composite variable that included any of the following complications: preeclampsia, gestational diabetes, or preterm birth before 32^0/7 weeks. Relative risk (aRR) and 95% confidence intervals (CI) for adverse outcomes for each BMI category as defined by WHO (using normal weight category as reference) were generated using modified Poisson regression, adjusting for maternal age, nulliparity, smoking, previous preterm birth, and fetal sex.

RESULTS

A total of 487,870 women with singleton (n = 480,010) and twin (n = 7860) pregnancies met the inclusion criteria. The risk of the composite primary outcome, preeclampsia, gestational diabetes, and cesarean delivery increased with high maternal BMI in both singleton and twin gestations, but these associations were weaker in twin compared with singleton gestations (association of BMI ≥ 40.0 kg/m² with primary outcome: aRR = 3.10, 95%-CI 2.96-3.24 in singletons compared with aRR = 1.74, 95%-CI 1.37-2.20 in twins). In singleton pregnancies the risk of preterm birth at < 32^0/7 weeks increased with maternal BMI, mainly due to an increased risk of provider-initiated preterm birth. In twin gestations, however, underweight (but not overweight or obesity) was associated with the greatest risk of preterm birth at < 32 weeks (aRR 1.67, 95%-CI 1.17-2.37), mainly due to an increased risk of spontaneous preterm birth (aRR 2.10, 95%-CI 1.44-3.08).

CONCLUSION

In healthy women with twin pregnancies, underweight is associated with the greatest risk for preterm birth, while the association of maternal obesity with adverse pregnancy outcomes is weaker than that observed in singletons.

Anomalies of the placenta and umbilical cord in twin gestations

The frequency of twin gestations has increased over the last few decades, mainly due to maternal age at childbearing, and the use of assisted reproductive technologies. Twins are at higher risk of aneuploidy, structural anomalies, and placental abnormalities. Some of the placental and umbilical cord abnormalities found in twin gestations are nonspecific and can be found in singleton gestations (ie, placenta previa, placental abruption, single umbilical artery, velamentous cord insertion, vasa previa, etc). However, other anomalies are unique to twin gestations, and are mainly associated with monochorionic twins-these include intraplacental anastomosis and cord entanglement. Most of these conditions can be diagnosed with ultrasound. An accurate and early diagnosis is important in the management of twin gestations. Determination of chorionicity, amnionicity, and the identification of placental anomalies are key issues for the adequate management of twin pregnancies. Pathologic placental examination after delivery can help in assessing the presence of placental and umbilical cord abnormalities, as well as providing information about chorionicity and gaining insight into the potential mechanisms of disease affecting twin gestations.

Maternal pre-gravid body mass index and obstetric outcomes in twin gestations

OBJECTIVE

The aim of this study is to evaluate the impact of maternal pre-gravid and/or first trimester overweight and obesity, and the adverse obstetrics outcome in twin pregnancies.

STUDY DESIGN

This is a retrospective study of women who delivered viable twins after 23 weeks of gestation with available prepregnancy body mass index (BMI) and/or were at their earliest visit during the first trimester of pregnancy in the period 2007-2011. The patients were divided into four subgroups according to their BMI (underweight, normal weight, overweight and obese) according to the WHO classification and their outcomes were compared. Obstetrical outcomes of interest including gestational diabetes, gestational hypertension, preterm birth, antepartum hemorrhage, intrahepatic cholestasis of pregnancy, method of delivery and neonatal intensive care unit (NICU) admission were all studied and compared.

RESULT

Electronic records of 1228 pregnant subjects who delivered twins were abstracted. Five hundred and four patients with twin gestations with available BMI were identified (underweight BMI<18.5% (n=22), normal weight BMI 18.5-24.9% (n=260), overweight 25-29.9% (n=114) and obese ⩾30% (n=108)). Obstetric complications occurred more often in the overweight and obese groups as compared with the normal weight group. There was an increased risk of gestational diabetes in overweight and obese women (odds ratio (OR), 3.3; 95% confidence interval (CI) 1.52-7.3; P=0.001) and (OR, 3.2; 95% CI, 1.41-7.1; P=0.002), respectively. There was an increased risk of gestational hypertension in the obese group compared with the normal weight group (OR, 2.29; 95% CI, 1.1-4.7; P=0.02) but not in the overweight group (OR, 1.71; 95% CI, 0.8-3.6; P=0.1). In addition, an increased risk of very preterm delivery (<32 weeks) in the overweight group and obese groups was seen when compared with the normal weight group (OR, 2.2; 95% CI, 1.18-4.20; P=0.014 and OR, 2; 95% CI, 1.024-3.91; P=0.04, respectively). Increased rate of cesarean section in the obese group was seen when compared with the normal weight group (OR, 2; 95% CI, 1.2-3.4; P=0.006). Risks of antepartum hemorrhage, intrahepatic cholestasis and NICU admission were similar between the groups.

CONCLUSION

In addition to the known obstetrics complications associated with twin gestations, the pregnancy outcomes in twins are further adversely influenced by increased maternal prepregnancy BMI.