Teenage pregnancy: risk factors for adverse perinatal outcome.

OBJECTIVES: To assess the perinatal outcome of teenage pregnancy in a large cohort and to determine risk factors for low birth weight (LBW) in teenage pregnancy. STUDY DESIGN: All singleton first deliveries to mothers of age 16-24 years between 1990 and 1997 were included. The deliveries were subdivided into three maternal age groups (16-17 and 18-19 compared to 20-24 years) and parameters of perinatal outcomes were compared. To adjust for potential confounding effects on the association between young maternal age and birth weight, logistic regression analysis was performed for LBW with maternal ethnicity, pregnancy-induced hypertension, lack of prenatal care and malformations of the newborn. RESULTS: Among a total of 11 496 patients, 600 (5.2%) were 16-17 years old, 2097 (18.2%) were 18-19 years old and the remaining 8799 (76.6%) were 20-24 years old. Bedouin ethnicity and lack of prenatal care were common in the youngest mothers. Rates of preterm delivery were 14.2%, 9.8% and 8.8% in the three age groups, respectively (p < 0.05). Rates of malformations, small for gestational age, LBW and very LBW were also significantly higher in the youngest mothers. Rates of pregnancy-induced hypertension, operative delivery and Cesarean delivery were not significantly different among the three age groups. A multivariate analysis on LBW was performed to assess the unique contribution of young maternal age, adjusted for potential confounders. Adjusted ORs for LBW were 1.25 (95% CI 1.00-1.56) for maternal age < 18 years, 1.80 (95% CI 1.54-2.03) for Bedouin ethnicity, 2.57 (95% CI 2.14-3.07) for pregnancy-induced hypertension, 1.55 (95% CI 1.30-1.84) for lack of prenatal care and 4.09 (95% CI 3.2-5.2) for malformations. CONCLUSIONS: Teenage pregnancy was found to be associated with adverse outcome such as LBW, preterm delivery, small for gestational age and malformations. The risk for LBW was affected mainly by demographic factors (maternal ethnicity, lack of prenatal care) and medical factors (pregnancy-induced hypertension, malformations).