Pregnancy in women using intra-uterine contraceptive devices.

Among 1,041 women fitted with intra-uterine contraceptive devices during a period of 21,445 months there were 51 pregnancies: a rate of 2.9 per hundred women years. Pregnancy occurred most commonly in the young and nulliparous. The importance of the patient checking her device is stressed. Pregnancy occurs most commonly soon after fitting, but may occur at any time. In more than half the cases pregnancy occurred with the device in the uterus. Though most pregnancies were uterine there was a high incidence of ectopic pregnancies. Many pregnancies ended in vaginal delivery, but since the Abortion Act 1967 fewer probably now go to term.