The Effect of a General Healthy Lifestyle Intervention Delivered Around Pregnancy on Gestational Weight Gain and Infant Growth.

OBJECTIVES A life-course perspective emphasizes healthy behaviors before, during, and after pregnancy to support a multi-generational risk reduction in obesity for mothers and infants. Optimal timing, content, and dose of such interventions is not well defined. METHODS We conducted a nested cohort within a randomized trial to evaluate whether a healthy lifestyle intervention around pregnancy led to a "spill-over effect," including a healthier rate (kg/week) of maternal gestational weight gain, and infant growth during the first year. Study enrollment began in 2012, follow-up data collection completed in 2018, and the data were analyzed in 2019. The intervention focused on healthy maternal diet and physical activity but not pregnancy weight or infant feeding. Outcome data were abstracted from electronic medical records. RESULTS Of the 165 women who became pregnant, 114 enrolled in the nested cohort. The average pre-pregnancy BMI was 29.6 (SD 5.1) kg/m2. Mixed effects models suggested clinically insignificant differences in both the rate of gestational weight gain (-0.02 kg/week; 95% CI -0.09, 0.06) and the rate of infant growth (difference at 1 year: -0.002 kg/cm; 95% CI -0.009, 0.005). CONCLUSIONS FOR PRACTICE A behavioral intervention that focused on overall maternal health delivered in the time around pregnancy did not result in a "spill-over effect" on healthy gestational weight gain or healthy infant growth during the first year of life. TRIAL REGISTRATION This study is registered at www.clinicaltrials.gov NCT01316653.