OBJECTIVETo determine whether fetal overgrowth precedes the diagnosis of gestational diabetes mellitus (GDM) and to quantify the interrelationships among fetal overgrowth, GDM, and maternal obesity.
RESEARCH DESIGN AND METHODSWe conducted a prospective cohort study of unselected nulliparous women and performed ultrasonic measurement of the fetal abdominal circumference (AC) and head circumference (HC) at 20 and 28 weeks of gestational age (wkGA). Exposures were diagnosis of GDM ‡28 wkGA and maternal obesity. The risk of AC >90th and HC-to-AC ratio <10th percentile was modeled using log-binomial regression, adjusted for maternal characteristics.
RESULTSOf 4,069 women, 171 (4.2%) were diagnosed with GDM at ‡28 wkGA. There was no association between fetal biometry at 20 wkGA and subsequent maternal diagnosis of GDM. However, at 28 wkGA, there was an increased risk of AC >90th percentile (adjusted relative risk 2.05 [95% CI 1.37-3.07]) and HC-to-AC ratio <10th percentile (1.
CONCLUSIONSDiagnosis of GDM is preceded by excessive growth of the fetal AC between 20 and 28 wkGA, and its effects on fetal growth are additive with the effects of maternal obesity.Gestational diabetes mellitus (GDM) is one of the most common acquired medical disorders of pregnancy (1), and the major complication of GDM is excessive fetal growth. Low-and middle-income countries have a GDM prevalence similar to that in high-income countries, although the prevalence is particularly high in Vietnam, India, Bangladesh, and Sri Lanka (2). Pregnancies affected by GDM carry an increased risk of adverse outcome for the mother and the offspring in the short term (1,3,4), and the