Association of parental characteristics with adverse outcomes of adolescent pregnancy

BACKGROUND: It is well-known that pregnancy in adolescence has an increasedrisk of adverse reproductive outcomes. It remains unclear whether thisassociation is due mainly to the unfavourable sociodemographic status ordue solely to biological immaturity of pregnant adolescents. OBJECTIVE: Thepurpose of this study was to determine the association of parentalsociodemographic characteristics with the adverse outcomes of adolescentpregnancy. METHOD: Data from certificates of live births in TaichungCounty, Taiwan in 1994 of 7994 singleton, first-born babies whose motherswere 15-34 years of age were analysed. The relative risk of having adversepregnancy outcomes for adolescent subgroups was obtained as compared withthat among mothers 20-34 years of age with the same characteristics. Theadjusted relative risk of having adverse pregnancy outcomes for eachcovariate was calculated by a multiple logistic regression analysis.RESULTS: Of 7994 babies born to mothers of 15-34 years of age, 8.3% wereborn to adolescent mothers. In all age groups, the younger adolescentmothers (15-17 years of age) had the highest percentage of both infantswith low birth weight (10.6%) and preterm births (7.1 %). Youngeradolescent mothers in almost all sociodemographic categories had higherrisks of having both low-birth-weight and preterm births than those ofolder adolescent mothers. Multiple logistic regression analysis showed thata younger maternal age is the only significant risk factor for havinginfants with low birth weight (adjusted RR = 2.5, 95% Cl 1.8-4.5 andadjusted RR = 1.7, 95% Cl 1.2-2.6 for younger and older adolescent mothers,respectively) or preterm birth (adjusted RR = 1.9, 95% Cl 1.1- 3.4 andadjusted RR = 1.5, 95% Cl 1.0-2.3 for younger and older adolescent mothers,respectively). CONCLUSIONS: Adolescent pregnancy carries an increased riskof having low-birth-weight and preterm births, and a younger maternal ageis causally implicated.