Adolescent pregnancy: understanding the impact of age and race on outcomes

Abstract

Purpose: To determine the independent effects of maternal age and race/ethnicity on poor pregnancy outcomes, with and without controlling for other factors.

Methods: Logistic regression analysis of 54,447 linked birth, fetal death, and infant death certificates in California from 1980-87.

Results: Women of young maternal age (10-13 years) are approximately 2.5 times more likely to have a low birthweight infant and 3.4 times more likely to have a preterm birth than women of "prime" childbearing age. African-American women are 1.7 times more likely to have a low birthweight infant, and 2 times more likely to have a preterm birth than their white and Hispanic counterparts. The association of infant death with maternal age and race/ethnicity is statistically significant in the unadjusted models, however, those associations disappear completely when birthweight and gestational age are considered. Interactions between maternal age and race/ethnicity explained very little of the variability for any of the outcomes.

Conclusions: Maternal age at delivery and race/ethnicity are independently and significantly associated with poor pregnancy outcomes such as low birthweight and premature births. However, young maternal age and race/ethnicity do not appear to interact in a manner that produces a differential effect on the birth outcomes assessed in this study. The incidence of infant mortality is unrelated to maternal age or race/ethnicity, after controlling for prematurity and low birthweight, underscoring the importance of intervention efforts aimed at their prevention.

PIP: Logistic regression analysis of 54,447 linked birth, fetal death, and infant death certificates in California from 1980-87 revealed that maternal age at delivery and race/ethnicity are independently and significantly associated with poor pregnancy outcomes such as low birth weight (LBW) and premature delivery. Mothers 10-13 years of age were 2.5 times more likely to have a LBW infant and 3.4 times more likely to have a preterm birth than mothers 20-24 years old. Nearly 25% of the youngest mothers received no or late prenatal care compared with only 3-4% of mothers over 25 years of age. The probability of a poor pregnancy outcome declined progressively with age among Blacks, Whites, and Hispanics. However, in each age group, Black mothers faced substantially higher probabilities of poor pregnancy outcomes than White or Hispanic women. Black women were 1.7 times more likely to have a LBW infant and 2 times more likely to have a preterm birth than their White or Hispanic counterparts. Associations of infant mortality with maternal age and race/ethnicity lost significance when birth weight and gestational age were controlled. All age and race/ethnicity main effects were significant at the p 0.001 level. Interactions between maternal age and race/ethnicity explained very little of the variability for any of the outcomes.