Adolescent Pregnancies: Influence of Gestational Weight Gain and Body Mass Index on Large for Gestational Age Neonates [11].

OBJECTIVE: Excessive gestational weight gain and obesity are risk factors for macrosomia, birth trauma, and other perinatal complications. This study aims to investigate the contribution of gestational weight gain and body mass index (BMI, calculated as weight (kg)/[height (m)]) on large for gestational age (LGA) and macrosomia in adolescent compared with adult pregnancies.

METHODS: Population-based cohort study, all live births in Ohio (2006-2012). Analyses limited to 346,635 singleton live births in primiparous women with available data on BMI and gestational weight gain. Multivariate logistic regression estimated the association between young age, gestational weight gain, and BMI on LGA and macrosomia (birth weight more than 4,000 g) while adjusting for important confounders including race, prepregnancy BMI and diabetes, and tobacco use. Adolescent-specific BMI was used for mothers younger than 19 years.

RESULTS: Obesity and excessive gestational weight gain increased the risk of LGA and macrosomia in all mothers regardless of age. Maternal age younger than 20 years decreased LGA and macrosomia risks approximately 20-40% within the same gestational weight gain categories (odds ratio [OR] range 0.6-0.8, P<.05). Excessive gestational weight gain was common in adolescents (58.4%) and demonstrated a similar magnitude of risk increase for LGA and macrosomia (adjusted OR [aOR] 2.0, confidence interval [CI] 1.9-2.1) as in adult mothers 61.6% (aOR 2.2, CI 2.1-2.3) despite adjustment for coexistent risks.

CONCLUSION: Excessive gestational weight gain and obesity are prevalent in mothers of all ages and are associated with higher LGA and macrosomia risks. Young maternal age decreases LGA and macrosomia risk, but excessive gestational weight gain demonstrates the same degree of risk increase for these outcomes in adolescents as it does in adult women. Interventions should be aimed to improve rates of adolescents and women achieving appropriate gestational weight gain across all age groups.