To determine whether women delivering their first child at age 35 years or older are at increased risk of adverse (non‐genetic) pregnancy outcomes.

A cross‐sectional analytic study of singleton deliveries in Northern Sydney Area Health Service (NSAHS) hospitals.

All women aged >20 years delivering their first child between 1 January 1990 and 31 December 1991.

Obstetric complications and procedures, type of delivery and neonatal outcomes.

Compared with women aged 20‐29 years, women delivering their first child at > 35 years were at increased risk of pre‐existing maternal hypertension (adjusted odds ratio [OR], 3.5; 95% confidence interval [CI], 1.7‐7.0), antepartum haemorrhage (adjusted OR, 2.4; 95% CI, 1.6‐3.7), preterm delivery (33‐36 weeks) (adjusted OR, 2.0; 95% CI, 1.5‐2.8) and breech presentation (adjusted OR, 1.8; 95% CI, 1.3‐2.4). Women aged >35 years were also substantially more likely to have an operative delivery, induced labour and/or epidural anaesthesia. Neither these women nor their infants were at increased risk of pregnancy‐induced hypertension, gestational diabetes, threatened premature labour, postpartum haemorrhage, very preterm delivery (<32 weeks), perinatal death, low Apgar scores or the need for neonatal resuscitation.

Women who delay the birth of their first child face some increased risks, but these risks, for the most part, are manageable in the context of modern obstetric care.