Delayed childbearing and risk of adverse perinatal outcome. A population-based study

Abstract

<h3>Objective.</h3> —To investigate the effect of advancing maternal age on pregnancy outcome among healthy nulliparous women, after adjustment for demographic characteristics, smoking, history of infertility, and other medical conditions. <h3>Design.</h3> —A population-based cohort study was conducted with prospectively collected data from the Swedish Medical Birth Register. <h3>Patients.</h3> —Nulliparous Nordic women (N=173715), aged 20 years and above, who delivered single births at Swedish hospitals from 1983 through 1987. <h3>Outcome Measures.</h3> —Late fetal and early neonatal death rates; rates of very low birth weight (VLBW, &lt;1500 g), moderately low birth weight (MLBW, 1500 through 2499 g), very preterm delivery (≤32 weeks), moderately preterm delivery (33 through 36 weeks), and small-for-gestational-age (SGA) infants (&lt;-2 SDs). <h3>Results.</h3> —Compared with women aged 20 to 24 years, women aged 30 to 34 years had significantly higher adjusted odds ratios (ORs) of late fetal deaths (OR=1.4); VLBW (OR=1.2); MLBW (OR=1.4); very preterm birth (OR=1.2); and SGA infants (OR=1.4). Among women aged 35 to 39 years, the adjusted OR was significantly higher for VLBW (OR=1.9); MLBW (OR=1.7); very preterm birth (OR=1.7); moderately preterm birth (OR=1.2); and SGA infants (OR=1.7). Among women 40 years old and older, the adjusted OR was significantly higher for VLBW (OR=1.8); MLBW (OR=2.0); very preterm birth (OR=1.9); moderately preterm birth (OR=1.5); and SGA infants (OR=1.4). <h3>Conclusions.</h3> —Delayed childbearing is associated with an increased risk of poor pregnancy outcomes after adjustment for maternal complications and other risk factors. (<i>JAMA</i>. 1992;268:886-890)