Pregnancy outcomes among women with class III obesity with normal early glucola.

Background: Because obese women are at increased risk for insulin resistance and development gestational diabetes (GDM), the American College of Obstetricians and Gynecologists (ACOG) recommends early GDM screening in this population. For obese women with a normal early 1-hour 50 g oral glucose challenge test (eGCT), the risk of developing GDM later in the pregnancy is unknown. Thus, we aimed to assess the risk of developing gestational diabetes based on the value of a normal eGCT.

Study design: Retrospective cohort of non-anomalous singleton pregnancies with maternal body mass index (BMI) ≥40 at the time of entry to prenatal care at a single institution from 2013 to 2017. Pregnancies with abnormal early 1-hour 50 g glucose challenge test (eGCT), multiple gestation, late entry to care, type 1 or 2 diabetes, and missing diabetes-screening information are excluded. Primary outcome was development of GDM. Secondary outcomes include fetal growth restriction, macrosomia, gestational age at delivery, large for gestational age, delivery BMI, total weight gain in pregnancy, induction of labor, shoulder dystocia, and cesarean delivery. Bivariate statistics compare demographics, pregnancy complications and delivery characteristics of women who had an eGCT≤ 100 mg/dL (low-normal eGCT) and women who had an eGCT of 101-134 mg/dL (high-normal eGCT). Regression models used to estimate odds of primary outcome.

Results: Of 169 women, 66(39%) had a low-normal eGCT, and 103(61%) had a high-normal eGCT. Women in the low-normal eGCT group were more likely to use recreational drugs (p = 0.03), other baseline demographics did not differ. The rate of GDM was low in this population (5.3%), with no difference in the rate of GDM between with a low-normal eGCT (1.5%) and high-normal eGCT (7.7%) (p = 0.09). The median neonatal birthweight was higher in the high-normal GCT group (3405 g) as compared to the low-no GCT (3285 g) (p = 0.03).

Conclusions: Among women with class 3 obesity, the specific value of an early normal GCT was not associated with developing gestational diabetes mellitus later in the pregnancy. Larger studies are needed confirm these findings.