Nine cases of heterotopic pregnancies in 4 years of in vitro fertilization.

The incidence of simultaneous intrauterine and extrauterine pregnancy increased after wider use of ovulation induction and the advent of techniques of assisted reproduction. Nine cases of heterotopic pregnancies are reported after in vitro fertilization (IVF) and embryo transfer (ET) between September 1984 and November 1988. The incidence of heterotopic pregnancies in clinical IVF pregnancies was 9 of 312 (2.9%). Superovulation and IVF-ET appear to predispose to heterotopic pregnancy, particularly after tubal disease.