Delayed childbearing and pregnancy outcome.

This study is to analyze the effect of delayed childbearing on pregnancy outcome among nulliparous women. A hospital-based study was conducted with prospectively collected data from the computerized perinatal data base that includes information about all patients delivered in our Hospital. We studied 17,230 nulliparous women who were > or = 20 years of age with a singleton gestation delivered between 1987 and 1992. We assessed the rates of low birth weight (< 2500 g), preterm delivery (< 37 weeks), small for gestational age, perinatal death (> 500 g and 28 days of life), and selected complications of pregnancy and delivery (ante partum complications, meconium, labor abnormal fetal heart rate, cesarean section, breech presentation, Apgar score, umbilical cord-pH, and rates of neonatal admission). Compared with women aged 20-29 years, women aged > or = 35 years had no significantly higher odds ratio (OR) of low birth weight < 2500 g (OR = 1.3); preterm delivery < 37 weeks (OR = 1.2); small for gestational age (OR = 1.0); and perinatal death (OR = 1.7). In contrast, we found a significantly higher rates of specific antepartal complications (OR = 1.9); cesarean section (OR = 2.5); breech presentation (OR = 1.4); and higher rates of admission to the newborn intensive care unit (OR = 1.4); but excluding infants delivered before 37 weeks of gestation, we found no significantly higher odds ratio of neonatal admission (OR = 1.4). Delayed childbearing is associated with an increased risk of complications of pregnancy and delivery although neonatal outcomes were not appreciably different from those among infants of younger women.