Delivery outcome after infertility--a registry study.

Among a total of 379,779 women with 383,589 infants born in Sweden (1983 to 1986), 7.8% had a recorded period of infertility of at least 1 year. Women with a history of infertility had a higher mean age, a lower parity, had fewer previous induced abortions but more spontaneous abortions, extrauterine pregnancies, and stillbirths than women without a history of infertility. They also smoked more. There was an excess of multiple births. Singleton infants showed an increased percentage of low-birth weight infants, short gestational duration, and signs of intrauterine growth retardation. The rate of major malformations was not increased in the total infertile group but may have been increased in the subgroup with at least 4 years of infertility.