Gestational diabetes in singleton pregnancies increases the risk of large for gestational age infants, hypertensive disorders of pregnancy, and neonatal morbidity.[1,2,3,4] Compared to singleton gestations, twin gestations are at increased risk for fetal growth abnormalities, hypertensive disorders and neonatal morbidity.[5] Whether gestational diabetes further increases the risk of these outcomes is unclear.
We sought to determine the relation between gestational diabetes and the risk of preeclampsia, fetal growth abnormalities, and NICU admission in a large cohort of twin pregnancies.
We used a retrospective cohort of all twin deliveries at our institution from 1998 to 2013. We excluded pregnancies delivered before 24 weeks, monochorionic-monoamniotic twins, and patients with pre-existing diabetes for a final cohort of 2,573 twin deliveries. Gestational diabetes was defined as two abnormal values on a 100 gram, three-hour glucose challenge test as defined by Carpenter Coustan Criteria or a one-hour value 200mg/dL after a 50 gram glucose test.[1] Multivariable Poisson regression models were used to estimate associations between gestational diabetes and preeclampsia, small for gestational age, large for gestational age and admission to the NICU, after adjustment for pre-pregnancy body mass index, maternal race, maternal age, parity, use of in vitro fertilization, pre-pregnancy smoking, and chronic hypertension as confounders.
The unadjusted incidence of gestational diabetes was 6.5% (n=167). Women with gestational diabetes were more likely than women without gestational diabetes to be 35 years or older, living with obesity, and have conceived with in vitro fertilization. Preeclampsia was more common among twin pregnancies complicated by gestational diabetes: 31% compared to 18% in twin pregnancies without gestational diabetes (aRR= 1.5; 95% CI, 1.1, 2.1). A diagnosis of small for gestational age infant was less common among women with gestational diabetes (17%) compared to women without gestational diabetes (24%), although results were imprecise aRR= 0.8 (0.5, 1.1). There was no association between gestational diabetes and large for gestational age or NICU admission. Among women with gestational diabetes who reached 35 weeks, 62% (n=60) required medical management.
Gestational diabetes is a risk factor for preeclampsia among twin pregnancies. Close blood pressure monitoring and patient education are critical for this high risk group. The association between gestational diabetes and neonatal outcomes in twin pregnancies is less precise, although it may be protective against a small for gestational age infant. Prospective studies to determine if glycemic control decreases risk of preeclampsia in twin pregnancies with gestational diabetes are needed.

Copyright © 2021. Published by Elsevier Inc.

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