Frozen zygote intrafallopian transfer: a successful approach for transfer of cryopreserved embryos

To assess whether frozen ET to the fallopian tube is a possible alternative for cryopreserved embryos.

Fifty-four patients (mean age 35 years) participated, in which their embryos were cryopreserved in 1.5 M propanediol at the pronuclear or two-cell stage. Each patient then underwent a steroid replacement cycle consisting of oral micronized 17 beta-E2 2 mg on days 2 to 4, 4 mg on days 5 to 7, 6 mg on days 8 to 10, and 8 mg from day 11 on. Serial ultrasounds were performed to evaluate the endometrium until an optimal thickness of > or = 10 mm triple layer was achieved. At this time, 100 mg IM progesterone was initiated and the zygote intrafallopian transfer (ZIFT) procedure was performed on the third day of P administration. The average number of embryos transferred was 4.4.

Twenty-two clinical pregnancies resulted, giving a pregnancy rate of 41%. Eight miscarriages occurred and one ectopic pregnancy resulted, giving a live birth rate of 24%. Implantation rate was 10.8%. The highest chance of pregnancy was seen in patients who never had a previous IVF, GIFT, or ZIFT (61%).

This is the first report of a series of frozen ETs to the fallopian tubes. These results indicate that tubal transfer may offer a protective benefit of the tubal environment and avoidance of endometrial trauma, and should be added to our armamentarium of replacing cryopreserved embryos.