Ectopic pregnancies after in vitro fertilization and embryo transfer.

OBJECTIVE

Our objective was to analyze the risk factors, stimulation characteristics, and future fecundity of patients with ectopic pregnancies after in vitro fertilization (IVF).

METHODS

We retrospectively evaluated all cases of ectopic pregnancy occurring between January 1989 and March 1993 (Cornell series 1 to 17). A case-control group of intrauterine pregnancies was used for comparison of the stimulation and transfer characteristics.

RESULTS

Twenty-seven of 1123 pregnancies (2.4%) were ectopic, following 2812 fresh IVF embryo transfers, while 8 of 105 pregnancies (7.6%) were ectopic, following 405 frozen-thawed embryo transfers. Tubal factor was the cause of infertility in the majority (85.7%) of ectopic pregnancies. No difference was found between the ectopics and the matched controls in stimulation and transfer characteristics. Thirty ectopic pregnancies were ampullary, two were interstitial, two were cervical, and one was heterotopic. Twenty of the patients subsequently underwent 29 IVF attempts, with a pregnancy rate of 41.4% per transfer.

CONCLUSIONS

Ectopic pregnancy after IVF appears to be related to preexisting tubal pathology; embryo transfer of cryopreserved thawed embryos in a natural cycle may result in a higher ectopic rate in these patients; in subsequent IVF cycles the intrauterine pregnancy rate of these patients is not decreased.