High gestational weight gain does not improve birth weight in a cohort of African American adolescents.

BACKGROUND: Because pregnant African American women and teens are at risk of low birth weight, they are frequently counseled to strive for gestational weight gains at the upper limits of the Institute of Medicine's recommended ranges. OBJECTIVE: The objective was to examine whether such weight gains improve birth outcomes in a cohort of disadvantaged African American adolescents of low (<19.8), average (> or =19.8 to < or =26.0), or high (>26) prepregnancy body mass index (BMI; in kg/m2). DESIGN: Data were extracted from the medical charts of 1120 African American adolescents who received prenatal care at an inner-city maternity clinic between 1990 and 2000 and analyzed by using analysis of covariance and multivariate regression methods. RESULTS: Data were available for 815 adolescents, 711 of whom delivered at term (> or =37 wk). Fifty-eight percent (n = 409) of all term deliveries and 74% of the high-BMI adolescents (n = 126) had gains in the upper half of or above the recommended ranges. For all BMI groups, the most significant differences in birth outcomes were found in comparisons of teens who gained below the recommended ranges with those who gained in the lower half of the recommendation range. Further gains were not clearly beneficial, particularly for infants of high-BMI mothers. CONCLUSIONS: African American adolescents entering pregnancy underweight or at average weight should be counseled to gain within the recommended ranges, whereas overweight adolescents need support to avoid excessive gestational weight gain. Such advice would be prudent in light of the known associations between obesity and the increased likelihood of chronic diseases.

Interventions to improve diet and weight gain among pregnant adolescents and recommendations for future research.

Pregnant adolescents are at particular risk for both inadequate and excessive gestational weight gain and for inadequate intake of micronutrients that support healthy fetal development. This article reviews the available literature on prenatal nutrition interventions intended to address such risks to identify effective strategies and needs for further research. A medical model providing enhanced prenatal care aimed at improved birth weight predominated. No studies rigorously evaluated the independent influence of nutrition education on prenatal dietary behaviors or outcomes; few applied a conceptual framework or targeted dietary attitudes, behaviors, skills, or self-efficacy. Positive effect on birth outcomes was evident, likely due to multidisciplinary teams supporting the special psychosocial needs of pregnant adolescents; individualized education and counseling encouraging optimal dietary choice and appropriate gestational weight gain; home visits providing prenatal education, support, and outreach to highest-risk teens; visual presentation and tracking of gestational weight gain; and support/discussion groups. Nevertheless, greater effects could likely be achieved by applying behavior-change strategies that have been implemented effectively with other, similar populations. Further research is needed to test such approaches with pregnant, high-risk teens.