Effects of maternal lifestyle intervention during pregnancy on untreated partner weight: Results from fit for delivery study

To test the hypothesis that untreated partners of pregnant women receiving a prenatal lifestyle intervention (vs. standard care) would lose more weight during pregnancy and postpartum.

Fit for Delivery was a study of 401 pregnant women with overweight/obesity (OW/OB) and normal weight (NW) randomized to prenatal lifestyle intervention or standard care. Mother's self-report of partners' weight was obtained at study entry (<16 weeks gestation), 30 weeks gestation, and 6 and 12 months postpartum.

At study entry, 157 of 200 (78%) of intervention mothers and 144 of 201 (72%) of standard care mothers reported having a partner. In intent-to-treat analyses, there was no significant treatment × time effects on partner weight (P = 0.67). In secondary analyses, partners of OW/OB intervention women lost weight from study entry to 6 and 12 months postpartum (-0.5 ± 9.5 kg, -1.0 ± 9.3 kg; P < 0.05), while partners of standard care women gained weight during the same time frame (+2.5 ± 6.7 kg, +2.9 ± 7.4 kg; P < 0.05); adjusting for partner study entry BMI removed these effects.

Lifestyle intervention delivered to pregnant women did not significantly reduce weight of untreated partners. Future research is needed to test prenatal interventions that engage partners and use objective measures of weight.