Births after a period of infertility in Victorian women 1982-1990.

Pregnancies following a period of infertility are often thought to be at increased risk of adverse outcomes. Between 1982-1990, 1465 births were reported to the Victorian Perinatal Data Collection Unit with a history of infertility. We present some characteristics of these births and compare them with all Victorian births in 1986 (n = 61,253) and Australian and New Zealand IVF and GIFT births 1979-1989 (n = 6,675). Women with a history of infertility were older than other Victorian women but younger than the IVF and GIFT group. Multiple births comprised 9% of the infertility group compared with 1.3% in the general Victorian population and 23.7% of IVF and GIFT births. The incidence of low birth-weight (18.6%) and very low birth-weight (4.2%) was higher than in other Victorian births (5.8% and 1.1% respectively) but lower than in IVF and GIFT births (34.6% and 8.9%). Perinatal mortality in the infertility group (33.4 per 1,000) was higher than in the general population (11.1 per 1,000) and similar to the IVF and GIFT group (34.9 per 1,000). The Caesarean section rate after infertility (41%) was more than double the rate in the rest of the Victorian population (16%), and showed a different pattern of indications. The relative risks of low and very low birth-weight, perinatal mortality and Caesarean delivery remained significantly increased for singletons after adjustment for maternal age and parity.