Maternal BMI, glucose tolerance, and adverse pregnancy outcomes

Abstract

Objective: The purpose of this study was to estimate the association of pregravid body mass index (BMI), independent of 3-hour oral glucose tolerance test (OGTT) results, with pregnancy outcome.

Study design: In this secondary analysis of a cohort of women with untreated mild gestational glucose intolerance, which was defined as a 50-g glucose loading test between 135 and 199 mg/dL and fasting glucose level of <95 mg/dL, we modeled the association between pregravid BMI, OGTT results, and both pregnancy complications and neonatal adiposity.

Results: Among 1250 participants, both pregravid BMI and glucose at hour 3 of the OGTT were associated with increased risk of gestational hypertension. Maternal pregravid BMI also was associated positively with large-for-gestational-age infants; both maternal BMI and fasting glucose were associated with birthweight z-score and neonatal fat mass.

Conclusion: Among women with untreated mild gestational glucose intolerance, pregravid BMI is associated with increased gestational hypertension, birthweight, and neonatal fat mass, independent of OGTT values.

Figure 1

Predicted probability* of primary outcome, gestational hypertension, preeclampsia, SGA and LGA, by prepregnancy maternal BMI. Predicted probabilities of pregnancy outcome presented for a hypothetical multiparous white women with mean values for age (27.9) and OGTT values (fasting: 85.3, 1h: 166.5, 2h: 144.3, 3h: 117.1). Models include parity, maternal age, race/ethnicity, maternal pregravid BMI and all four OGTT values.

Figure 2

Predicted birth weight z-score and fat mass by prepregnancy maternal BMI. Predicted birth weight z-score and neonatal fat mass presented for a hypothetical multiparous white women with mean values for age (27.9) and OGTT values (fasting: 85.3, 1h: 166.5, 2h: 144.3, 3h: 117.1). Models include parity, maternal age, race/ethnicity, maternal pregravid BMI and all four OGTT values.