Association between fetal abdominal circumference and birthweight in maternal hyperglycemia

Objectives To compare fetal abdominal circumference and its relationship with birthweight at increasing gestational ages in the context of maternal hyperglycemia of varying severity. Design Retrospective cohort study. Setting Two centers participated in building one database. Population A total of 1538 Korean pregnant women were subjected to a two‐step approach to diagnose gestational diabetes mellitus. Methods Pregnant women were classified into gestational diabetes mellitus, borderline gestational diabetes mellitus, and normal groups. Fetal abdominal circumferences, which were measured with ultrasound at 4‐week intervals starting at 16 weeks of gestation and ending prior to delivery, were evaluated in the groups. Main outcome measure The significance of fetal abdominal circumferences as predictors or risk factors of macrosomia/large‐for‐gestational age. Results Fetal abdominal circumferences measured from 16 weeks of gestation until prior to delivery predicted birthweight in all groups with some exceptions. Fetal abdominal circumferences measured from 32 weeks of gestation until prior to delivery were predictive of macrosomia in all groups. Fetal abdominal circumferences measured from 28 weeks of gestation until prior to delivery were predictive of neonates being large‐for‐gestational age in all groups. Fetal abdominal circumferences measured at 16 and 24 weeks of gestation were also predictive of large‐for‐gestational age in the borderline gestational diabetes mellitus group. Fetal abdominal circumference measured at 24 weeks of gestation was also a predictor of macrosomia/large‐for‐gestational age in normal women. Conclusions Fetal abdominal circumferences measured during the second and especially third trimesters were significantly associated with excessive birthweight, irrespective of the severity of maternal glucose intolerance.