Objective The purpose of our study was to evaluate the body mass index (BMI)-specific association between early gestational weight gain (GWG) in dichorionic twin pregnancies and the risk of preeclampsia. Study Design We conducted a retrospective cohort study of all dichorionic twin pregnancies from 1998 to 2013. Data were obtained from a perinatal database and chart abstraction. Prepregnancy BMI was categorized as normal (18.5–24.9 kg/m2), overweight (25–29.9 kg/m2), and obese (≥30 kg/m2). Early GWG was defined as the last measured weight from 160/7 to 196/7weeks' gestation minus prepregnancy weight. GWG was standardized for gestational duration using BMI-specific z-score charts for dichorionic pregnancies. Preeclampsia was diagnosed using American College of Obstetricians and Gynecologists criteria and identified with International Classification of Diseases-9 coding. Early GWG z-score was modeled as a three-level categorical variable (≤ − 1 standard deviation [SD], 0, 3 +1 SD), where −1 to +1 was the referent group. We estimated risk differences and 95% confidence intervals (CIs) via marginal standardization. Results We included 1,693 dichorionic twin pregnancies in the cohort. In adjusted analysis, the incidence of preeclampsia increased with increasing early GWG among women with normal BMI. Women with normal BMI and a GWG z-score < − 1 (equivalent to 2.6 kg by 20 weeks) had 2.5 fewer cases of preeclampsia per 100 births (95% CI: −4.7 to − 0.3) compared with the referent; those with GWG z-score > +1 (equivalent to gaining 9.8 kg by 20 weeks) had 2.8 more cases of preeclampsia per 100 (95 % CI: 0.1–5.5) compared with the referent. In adjusted analyses, early GWG had minimal impact on the risk of preeclampsia in women with overweight or obesity. Conclusion GWG of 2.6 kg or less by 20 weeks was associated with a decreased risk of preeclampsia among women pregnant with dichorionic twins and normal prepregnancy BMI. Current GWG guidelines focus on optimizing fetal weight and gestational length. Our findings demonstrate the importance of considering other outcomes when making GWG recommendations for twin pregnancy. Key Points

Fetal growth restriction (FGR) and small size for gestational age at birth (SGA) are associated with an increased risk of fetal/neonatal mortality. A key element of FGR management is the comparison of expected mortality with expectant management vs. iatrogenic delivery. Further complicating this challenge, maternal hypertensive disorders (chronic hypertension, gestational hypertension, preeclampsia) are often associated with FGR, introducing additional concerns for maternal well-being. Notwithstanding maternal risks, the approach to fetal surveillance is comparable for FGR pregnancies with or without HTN. We sought to determine if neonatal mortality differed in FGR/SGA pregnancies with or without HTN. We used multivariate logistic regression to compare rates of neonatal death (NND) at specific gestational ages in FGR/SGA pregnancies with or without maternal HTN. FGR/SGA was defined as a fetal/neonatal weight <10% by Fenton nomogram. In 3 distinct analyses, we compared rates of NND in pregnancies identified at Magee-Womens Hospital from 2000-2015 with FGR by ultrasound (MWH-US; 1,097 FGR, 258 with HTN, 34 NNDs), with SGA birthweight (MWH-BW; n=8,267, 1,537 HTN, 81 NND), and all deliveries from 2005-2009 US Vital Statistics with SGA birthweight (National-BW; n=1,358,191, 84,598 HTN, 11,427 NND). NND rates were consistently lower for FGR/SGA neonates born to mothers with HTN than for FGR/SGA neonates without HTN [MWH-US Odds Ratio 0.26 (95% C.I. 0.10, 0.68); MWH-BW OR 0.20 (0.10, 0.37); National-BW OR 0.36 (0.33, 0.39)]. Predicted probabilities of NND with and without HTN at specific gestational ages are shown graphically. Gestational-age adjusted NND rates were lower for FGR/SGA pregnancies with HTN than for FGR/SGA pregnancies without HTN. This finding may be attributable to the fact that FGR with HTN is more likely to lead to iatrogenic premature delivery without a fetal indication due to concerns for maternal health. Nonetheless, with the observed effect of HTN on neonatal mortality, estimates of risk with expectant management vs. iatrogenic delivery in FGR pregnancies may be more accurate with adjustment to reflect the presence or absence of HTN.

Objective This study aimed to determine whether early diabetes testing is associated with differences in perinatal outcomes among pregnant women with obesity (body mass index >= 30 kg/m (2) ). Study Design We conducted a retrospective cohort study of singleton pregnancies from 2012 to 2014 at a large academic medical center which examined the association of diabetes testing (HBA1c, 50 g glucose challenge test, or 100 g oral glucose tolerance test) before 24 weeks with perinatal outcomes using propensity score modeling and logistic regression. Results Among women with obesity, 790 out of 2,698 (29.3%) underwent early diabetes testing. Propensity score modeling demonstrated that early testing was associated with higher rates of diabetes diagnosis (odds ratio [OR]: 1.62, 95% confidence interval [CI]: 1.10-2.37, p = 0.01) and a trend toward small for gestational age birth weight (OR: 1.38, 95% CI: 1.00-1.90, p = 0.05) and neonatal composite morbidity (OR: 1.25, 95% CI: 1.00-1.57, p = 0.05) compared with routine testing. Women with inadequate weight gain were more likely a small for gestational age (SGA) infant if they underwent early testing compared with those with routine testing alone (19.8 vs. 11.6%, p = 0.01). Conclusion Early testing targets higher risk women and yields a higher diabetes diagnosis rate, but inadequate weight gain in these women may increase risk SGA birth weight and neonatal morbidity. Randomized clinical trials are urgently needed to assess whether early diabetes testing improves outcomes in women with obesity.

Objective Antenatal magnesium sulfate (MgSO (4) ) is known to affect the central nervous system of preterm infants, and there is biologic rationale for influence on other phenotypes. This study investigated the effect of MgSO (4) exposure on the trajectory of ponderal index (PI, kg/m (3) ) from birth to 2 years of age. Study Design A secondary analysis of a U.S. randomized controlled trial investigating MgSO (4) versus placebo administration among women at high risk for preterm delivery was performed. Multivariable logistic regression was used to assess the relationship between PI from birth to 2 years of age and exposure to MgSO (4) versus placebo. Results There was a larger decrement in PI from birth to 2 years of age in infants exposed to MgSO (4) compared with placebo ( p =0.032). There was a statistically significant one-way interaction between newborn sex and treatment group ( p =0.019). Change in PI in males exhibited a greater decrement in those exposed to MgSO (4) versus placebo ( p =0.227), whereas female infants exposed to MgSO (4) had a smaller decrement ( p =0.04). Conclusion MgSO (4) exposure in preterm infants is associated with a larger decrease in PI from birth to 2 years of age. In addition, the direction of effect of MgSO (4) on the change in PI over the first 2 years of life is different by sex.