Characteristics of inner-city pregnant African-American adolescents: Impact of nutrition on maternal health, fetal bone development and adverse birth outcomes.

摘要

Background. Pregnant African-American adolescents may be particularly susceptible to unfavorable birth outcomes due to biological immaturity and disadvantaged social environments. However, the characteristics of this population and the impact of nutrition on maternal health, fetal growth and adverse birth outcomes in this population have not been extensively studied.; Objectives. To describe the characteristics of a large cohort of pregnant minority adolescents and the distribution of pregnancy-associated risk factors in relation to adverse birth outcomes. In addition, we will also characterize maternal hemoglobin and hematocrit concentrations across pregnancy, and their impact on adverse birth outcomes. In addition, the impact of maternal dietary intake, evaluated at entry into prenatal care, on fetal femur length will also be examined in these African-American adolescents.; Methods. A 10-year retrospective chart review will be undertaken from medical records of pregnant African-American adolescents who carried singleton pregnancies and received prenatal care at an inner-city maternity clinic (MCE). The main outcome variables include; adverse birth outcomes, low birth weight (defined as birth weight 2,500 g) and preterm delivery (defined as 37 completed weeks of gestation). Fetal femur length will be collected from ultrasound data available in the medical charts.; Results. This population was more likely to have poor nutrition during pregnancy as evidenced by low prepregnancy BMI and abnormal patterns of weight gain during pregnancy. Moreover, inadequate utilization of prenatal care and a high incidence of sexually transmitted diseases and vaginal infections were evident in this population. Low pre-pregnancy body mass index (BMI), inadequate weight gain and poor prenatal care utilization were strong independent predictors of preterm birth (p 0.05). Low pre-pregnancy BMI, inadequate weight gain, female infant, and self-reported cigarette smoking history were significantly associated with decreased infant birth weight (p 0.05). Compared with the reference group (10.6–12 g/dL), low hemoglobin concentrations (≤10.5 g/dL) were not associated with adverse birth outcomes. High hemoglobin concentrations (>12 g/dL) significantly increased the risk of low birth weight (odds ratio (OR) = 3.31, 95% confidence interval [CI] 1.36, 8.07) during the second and third trimester, and preterm delivery (OR = 2.48, [CI] 1.03, 5.97) during the second trimester. Fetal femur length was significantly shorter in the lowest dairy intake grouping (less than 2 servings/day) in comparison to the highest dairy intake grouping (more than 3 servings/day) and a dose-response relationship was also suggested in the intermediate dietary dairy intake grouping (P = 0.089).; Conclusion. This population should be studied further to develop age appropriate and population specific interventions to improve birth outcomes. More research is needed to optimize iron status in this “at-risk” population and to characterize the mechanisms responsible for these findings. In addition, these results have important implications in relation to the role of dairy intake in fetal skeletal growth.