Sonographic and Other Nonglycemic Factors Can Predict Large-for-gestational-age Infants in Diet-Managed Gestational Diabetes Mellitus: A Retrospective Cohort Study.

Background Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy. Left untreated or poorly controlled, GDM results in adverse infant outcomes such as large for gestational age (LGA). This study aims to identify nonglycemic maternal and fetal factors predictive of LGA outcomes in pregnancies complicated by diet-managed GDM. Methods This was a retrospective cohort study of singleton pregnancies complicated by diet-managed GDM from 2004 to 2015. Multiple logistic regression analysis was performed on maternal and perinatal factors to identify risk factors for LGA. In addition, a subset univariate analysis was conducted for pregnancies in which fetal ultrasound abdominal circumference measurements were available at gestational weeks 18 to 22, 24 to 28, and 29 to 33. Results A total of 1064 women were included, delivering 123 LGA infants. Women with higher parity (odds ratio [OR] 1.44; CI, 1.23-1.68; P < .001) and higher prepregnancy body mass index (BMI) (OR 1.09; CI, 1.06-1.12; P < .001) were more likely to have LGA infants. Maternal smoking (OR 0.30; CI, 0.14-0.62; P = .001) and higher gestational age at birth (OR 0.91; CI, 0.84-0.99; P = .018) were associated with reduced risk. Subset univariate analysis showed that fetal abdominal circumference measurements at weeks 24 to 28 and 29 to 33 beyond the 75th percentile (OR 5.92 and 13.74, respectively) and 90th percentile (OR 4.57 and 15.89, respectively) were highly predictive of LGA. Conclusions Parity, smoking status, maternal BMI, gestational age, and ultrasound fetal abdominal circumference measurements were identified as useful predictors of LGA. Presence of these predictors may prompt closer monitoring of pregnancy and early therapeutic intervention to improve management and reduce the risk of adverse fetal and maternal outcomes. Highlights In diet-managed gestational diabetes mellitus pregnancies, the novel large-for-gestational-age (LGA) risk factor of fetal abdominal circumference determined at 24- to 28-week fetal ultrasound can identify women at risk as well as the known risk factors of maternal parity, prepregnancy body mass index, and gestational age. Smoking reduces LGA risk but has other harms. Early identification of risk factors for LGA allows early intervention to mitigate LGA risk, such as restriction of excessive further maternal gestational weight gain and other therapies, which may include insulin, though unproven.