Abstract: Ectopic pregnancy after assisted reproductive technology（ART）is a well known risk. The
rate of ectopic pregnancy is 2 times higher in ART pregnancies than that in spontaneous pregnancies，
especially heterotopic pregnancy，special type of ectopic pregnancy. Tubal factor infertility is main treatment
indication of ART，while it is also identified as the main risk factor for ectopic pregnancy after IVF-ET. It is
necessary to do the casecontrol multi-center study in a big population to understand the risk factors of ectopic
pregnancy after ART，which will be helpful for the ectopic pregnancy prevention after ART.

Key words: Reproductive techniques, assisted, Fertilization in vitro, Embryo transfer, Pregnancy, ectopic, Infertility, female