Women who give birth before age 20 are "more likely to fit a high‐risk profile" than are those whose first birth occurs later, but overall, according to a study of data from the National Longitudinal Study of Adolescent Health (Add Health), they are no more likely to have low‐birth‐weight babies or to deliver preterm.1 The analyses identified a few demographic, social and health‐related correlates of these outcomes, but it also found differences in correlates between black teenagers and those of other races.
Using Wave 4 Add Health data, collected in 2007–2008, when respondents were 24–32 years old, researchers assessed the characteristics of nearly 4,000 participants who had had a singleton live birth since the Wave 1 interview, in 1994–1995. They conducted chi‐square tests and analyses of variance to compare the characteristics and birth outcomes of women who had given birth as teenagers with those of women who had given birth at age 20 or older. Differences among teenage mothers were further explored in multivariate models, which separately considered blacks and women of all other races.
The analyses included 1,101 women who had become mothers at ages 13–19 and 2,846 who had first given birth at ages 20–33. Higher proportions of the former than of the latter were black, had been neither married nor living with a partner at the time of their pregnancy, and had reported circumstances suggesting socioeconomic disadvantage at Wave 1 (i.e., having an unemployed parent, having parents with less than a high school education and not living with both biological parents). Teenage mothers were more likely than others to have smoked while pregnant (26% vs. 19%) and to have initiated prenatal care after the first trimester or not to have gotten such care at all (30% vs. 14%), but they also were more likely to have been using contraceptives when they conceived (30% vs. 20%). Some 8–9% of women in each group had had babies who were low‐birth‐weight (less than 2,500g) and delivered preterm (before 37 weeks’ gestation); however, teenage mothers had delivered at a slightly, but significantly, later gestation than others (mean, 39.3 vs. 39.0 weeks).
At the bivariate level, for both teenage and older mothers, the likelihood of having a low‐birth‐weight baby was positively related to being black, never having been pregnant before and not having received prenatal care (although for teenagers, some of these relationships were only marginally significant). For older mothers, the likelihood of this outcome also increased with baseline body mass index.
The likelihood of preterm birth showed little variation for teenage mothers in bivariate analyses; only having been married or cohabiting at the time of pregnancy was linked to an elevated risk. Among women who gave birth at age 20 or later, however, this outcome was positively related to baseline body mass index, Hispanic ethnicity, nonreceipt of prenatal care and late initiation of care.
Black women of both maternal‐age groups reported significantly lower mean infant birth weights than other women. In addition, for teenagers, those who had been pregnant before or had received prenatal care reported a marginally or significantly elevated infant birth weight; for older mothers, not smoking during pregnancy, receiving prenatal care and being married were positively related to birth weight.
Results of the multivariate analysis revealed that among black women who had given birth as teenagers, infant birth weight was negatively associated with age at Wave 1 (coefficient, –0.2) and positively associated with age at pregnancy (0.2); black teenagers whose parents had less than a high school education had heavier babies than those with more schooling (0.2). Low parental education also was positively associated with gestational age among black teenagers (0.3), as was use of contraceptives at conception (0.3). Among teenage mothers of other races, by contrast, infant birth weight was associated only with being normal‐weight or more (0.2), and gestational age only with being unmarried (−0.9).
As the researchers acknowledge, their study is limited by the use of self‐reported data, "relatively small" numbers, and a lack of information on pregnancy complications and causes of preterm birth. Still, they conclude, the findings "suggest that teenagers as a whole are not at [higher] risk of adverse birth outcomes" than adults. Noting that "conventional risk factors, such as smoking and marital status," may play relatively little role, they suggest that future work examine "the social and environmental context of [teenage] pregnancies and their relations with birth outcomes."—D. Hollander