Hypertensive disorders of pregnancy in twin gestations complicated by gestational diabetes.

Objective

Gestational diabetes (GDM) in singleton pregnancies is known to be associated with an increased risk for hypertensive disorders of pregnancy. The data are mixed regarding the effect of GDM on the risk for hypertensive disorders of pregnancy in twin gestations. The objective of our study was to assess the rate of hypertensive disorders of pregnancy in twin gestations complicated by GDM.

Methods

This is a secondary analysis of a multicenter randomized trial in which twin gestations were assigned to weekly intramuscular injections of progesterone in order to reduce the rate of preterm birth. We included all twin pregnancies with and without GDM. Women with pregestational diabetes, chronic hypertension, twin pregnancies complicated by twin to twin transfusion syndrome and congenital fetal anomalies were excluded. Our primary outcome was the rate of hypertensive disorders in twin pregnancies complicated by GDM. Our secondary outcomes included the rate of cesarean section, number of neonates who were small for gestational age, Apgar scores, and a composite adverse neonatal outcome. Logistic regression analysis was used to control for confounding variables.

Results

Six hundred fourteen twin pregnancies were included, 570 (93%) without GDM and 44 (7%) with GDM. The group with GDM had a significantly higher prepregnancy body mass index (BMI) and maternal age, and were more likely to have undergone in vitro fertilization (IVF). The rate of hypertensive disorders of pregnancy in the GDM group was significantly higher when compared to the non-GDM group (31.8 versus 17.9%, p = .033, RR 1.78 [95% CI = 1.11-2.84]); however, after adjusting for maternal age, IVF treatment and prepregnancy BMI, this association lost its statistical significance (aRR = 1.36 [95% CI = 0.83-2.21]). The cesarean section rate was higher in the GDM group as compared to the non-GDM group and after adjusting for confounders, the rate of cesarean section was still higher in the GDM group (77.3 versus 61.1%, p = .003, aRR = 1.27 [95% CI = 1.06-1.50]). Neonates born to women in the GDM group were more likely to experience the adverse composite outcome (26.4 versus 8.2%, p = 0.02, RR = 1.81 [95% CI = 1.09-2.99]).

Conclusion

In this prospective cohort of twin pregnancies, the rate of hypertensive disorders of pregnancy did not differ between women with and without gestational diabetes after adjusting for maternal age, IVF treatment, race, and prepregnancy BMI. To better target complications associated with GDM in twin gestations, large prospective studies evaluating the effect of GDM on outcomes specifically in twin pregnancies are warranted.