Spontaneous foetal losses in women using different contraceptives around the time of conception.

Spontaneous losses between the 5th and 27th weeks of pregnancy were measured in a prospective study of 32 123 women whose contraceptive history around the time of conception was known. Diaphragm use prior to conception was associated with a significant reduction in second-trimester losses, after taking into account the effects of age, parity, race, marital status, alcohol use, and previous spontaneous or induced abortions. Women who used oral contraceptives and stopped them more than one month prior to their LMP experienced a deficit of first-trimester losses but conceptions occurring immediately after stopping the pill were followed by a small but nonsignificant increase in spontaneous abortions. After oral contraceptive failures there was an increase in first-trimester losses, but no change in the incidence of second-trimester ones. IUD failures were followed by a significant two-fold increase in the risk of both first and second-trimester losses: no differences were detected between the different brands.