Background: Treatment of gestational diabetes (GDM) reduces the risk of large for gestational age (LGA) birthweight and associated complications in infants. Pregnant people with gestational glucose intolerance (GGI, abnormal glucose loading test (GLT) without GDM) usually remain untreated. We examined the risk of LGA among women with GGI in a large cohort.
Methods: In a retrospective cohort study of 44,628 singleton pregnancies delivered at an academic center at >28 weeks' gestation, pregnancies with a GLT >140 mg/dl and either a normal 3-hour 100-gram oral glucose tolerance test (OGTT) or one abnormal OGTT value were classified as GGI, and those with 2 abnormal OGTT values as GDM. We used generalized estimating equations for logistic regression to examine the risk of LGA (birthweight >90th percentile for gestational age) in GGI versus normal glucose tolerance (NGT, GLT <140 mg/dl) pregnancies after adjustment for age, gender, 1st trimester BMI, parity, insurance, race/ethnicity, and marital status. A second model adjusted for gestational weight gain (GWG) .
Results: LGA was present in 7.7% of 36,964 pregnancies with NGT, 9.6% of 4357 with GGI and normal OGTT, 14.3% of 15with GGI and one abnormal OGTT value, and 14.5% of 1800 with GDM. The odds of LGA were higher in GGI than NGT pregnancies (adjusted OR 1.4 [1.3-1.5], p<0.001) . When compared separately with NGT, both types of GGI had elevated odds of LGA: normal OGTT adjusted OR 1.2 [1.1-1.4], p<0.001, one abnormal OGTT value adjusted OR 1.8 [1.5-2.1], p<0.001. The latter was similar to that in GDM compared to NGT: adjusted OR 1.8 [1.5-2.0], p<0.001. Increased odds of LGA were also present for GGI/GDM groups after GWG adjustment: normal OGTT OR 1.3 [1.2-1.5] p<0.001, 1 abnormal OGTT value OR 1.8 [1.5-2.1] p<0.0GDM OR 2.2 [1.9-2.5] p<0.001.
Conclusion: Infants of untreated people with GGI have increased risk of LGA birthweight. The risk of LGA in GGI pregnancies with one abnormal OGTT value was similar to that in GDM in a clinical setting where only GDM was treated.
J.Maya: None. D.J.Selen: None. T.Thaweethai: None. S.Hsu: None. C.Yu: None. K.James: None. A.Kaimal: None. M.Hivert: Advisory Panel; American Heart Association, Research Support; American Diabetes Association. C.E.Powe: None.
MGH (Physician Scientist Development Award and Claflin Distinguished Scholar's Award)