Impact of an Antenatal Family-based Behavioral Treatment with a Nutrition and Exercise Lifestyle Intervention Program on Infant Weight-for-length at Birth.

Background: World Health Organization (WHO) growth standards, including weight-for-length, are used to monitor infant size. Excessive infant weight-for-length at or above the 85th percentile is a risk for childhood overweight. Although antenatal interventions like the nutrition and exercise lifestyle intervention program (NELIP) have successfully prevented excessive gestational weight gain, strategies to improve the intervention remain of interest. This study investigated the impact of adding a family-based behavioral treatment (FBBT) to NELIP on infant weight-for-length at birth based on WHO growth standards and gestational weight gain.

Methods: Participants were recruited for the NELIP group (n = 68), followed by the NELIP + FBBT group (n = 48). In addition to full analyses, a subgroup of NELIP (n = 48) was matched to NELIP + FBBT based on pre-pregnancy BMI, parity and age.

Results: The number of infants with excessive weight-for-length at birth was significantly different between the NELIP + FBBT and the full NELIP group when maternal pre-pregnancy BMI was considered (φ = .275; p = .032). Significantly fewer infants had weight-for-length at or above the 85th percentile in the NELIP + FBBT group (29.2%) compared to the matched NELIP group (50.0%) with a medium effect size (φ = .213; p = .037). There were no significant differences between groups in any measures of maternal gestational weight gain.

Conclusions: The inclusion of a FBBT improved the effectiveness of a NELIP by decreasing the prevalence of excessive infant weight-for-length at birth, especially in participants with pre-pregnancy obesity, which could have implications on future childhood overweight and obesity.

Clinicaltrials: gov identifier: NCT01129505.