the prevalence of heterotopic pregnancy is estimated at 0.6‑2.5:10,000 pregnancies. there is a significant increase in the incidence of heterotopic pregnancy in women undergoing ovulation induction. an even greater incidence of heterotopic pregnancy is reported in pregnancies following assisted reproduction techniques such as in vitro fertilization (ivf) and gamete intrafallopian transfer (gift), with an estimated incidence at between 1 and 3 in 100 pregnancies. if there is embryo transfer of more than 4 embryos, the risk has been quoted as 1 in 45. in natural conceptions, the incidence of heterotopic pregnancy has been estimated to be 1 in 30 000 pregnancies.