Obstetric outcomes and placental findings in gestational diabetes patients according to maternal prepregnancy weight and weight gain.

OBJECTIVE: We assessed clinical outcomes and placental pathology among pregnancies complicated with gestational diabetes mellitus (GDM) according to their pregestational body mass index (BMI) and weight gain during pregnancy.

STUDY DESIGN: Pregnancy outcome and placental pathological reports of all GDM deliveries, during 2009-2015, were reviewed. We compared women with pregestational BMI > 30 and or gestational weight gain >20 kg (high-BMI group), and women with pregestational BMI < 30 and weight gain less than 20 kg (normal BMI group).

RESULTS: Out of the 429 women with GDM, 221 (51.5%) were in the high-BMI group and 208 (48.3%) were in the normal BMI group. As compared to the normal BMI group, the high-BMI group displayed a higher rate of GDMA2 41.6 versus 30.2%, p = .01, higher birth weight, 3475 ± 508 g versus 3242 ± 503 g, p < .001, more large for gestational age neonates, 33.1 versus 13.9%, p < .001, and a trend for more cesarean deliveries (CD), 49.3 versus 40.8%, p = .07, respectively. By logistic regression analysis, past CD and high BMI were independently associated with CD, while GDM type and birth weight were nonsignificant. Pathological reports were available for 143 of these patients. Placental weight was increased among the high-BMI group, but did not retain significance after adjustment for birth weight, and GDM type. No differences were demonstrated in other placental histological findings.

CONCLUSIONS: GDM pregnancies accompanied by increased weight gain or elevated pregestational BMI are associated with adverse obstetric outcomes, despite similar placental findings. Patient should be advised accordingly, as gestational weight gain may determine delivery mode.