Variation in Excessive Fetal Growth across Levels of Prenatal Care among Women with Gestational Diabetes.

Objective: Examine the association between prenatal care and excessive fetal growth outcomes among mothers with gestational diabetes mellitus (GDM).

Methods: We conducted a retrospective analysis of 2004-2007 singleton live births to South Carolina women, limited to those for whom both birth certificate and hospital discharge data were available (N = 179 957). Gestational diabetes mellitus was identified from birth certificate and/or hospital discharge claims. Measures of excessive fetal growth were large for gestational age (90th and 95th percentiles) and macrosomia (birth weight > 4500 g). The Adequacy of Prenatal Care Utilization index was used to measure prenatal care.

Results: Gestational diabetes mellitus was recorded for 6.9% of women in the study population. Women with GDM were more likely than other women to have an infant with excessive fetal growth, regardless of the level of prenatal care; however, there was a significant interaction between GDM status and levels of prenatal care. All women with GDM had increased odds for large infant outcomes. However, those receiving inadequate prenatal care were markedly more likely to experience excessive fetal growth outcomes (odds ratio = 1.38, confidence interval = 1.15-1.66) than women also with GDM and intermediate/adequate prenatal care. Similar patterns were noted for large for gestational age (95th) and macrosomia (total birth weight ≥ 4500 g).

Conclusions: Observed associations suggest a link between inadequate prenatal care and a higher risk for excessive fetal growth among women with GDM. Further research is needed to clarify the nature of the association and suggest ways to get high-risk women into care sooner.