Frozen zygote intrafallopian transfer: a successful approach for transfer of cryopreserved embryos**Presented at the 41st Annual Meeting of the Pacific Coast Fertility Society, Indian Wells, California, April 14 to 18, 1993

Advanced scheduling for zygote intrafallopian transfer is possible via the use of a hormone replacement cycle for patients who have experienced repeated implantation failures

PURPOSE

Zygote intrafallopian transfer (ZIFT) is an effective option for patients who have experienced repeated implantation failures (RIF) in assisted reproductive technology (ART) treatment. However, advance planning for the day of the operation can be problematic. Using a hormone replacement cycle (HRC) makes it possible to plan for the day of ZIFT. In the present study, we evaluated whether HRC-ZIFT is useful for RIF patients who have experienced difficulties obtaining morphologically good embryos in vitro.

METHODS

A total of 55 patients with a history of five or more unsuccessful transfers received HRC-ZIFT between June 2008 and June 2013. The oocyte pick-ups were performed and the oocytes showing two pronuclei (2PN) were cryopreserved. After receiving more than five 2PN oocytes, the operation day was scheduled in advance, and as a consequence, a HRC was started and ZIFT was performed. The clinical outcomes were evaluated.

RESULTS

The average age of the patients was 39.3 years, and the previous OPU and ET attempts numbered 7.5 and 6.9, respectively. The number of previously transferred embryos was 11.8, and the number of morphologically good embryos (MGEs) was only 1.2. The number of transferred 2PN oocytes was 6.7, and the subsequent pregnancy rate was 23.6 %. No ectopic or multiple pregnancies were observed, but there were 6 cases of miscarriage.

CONCLUSION

Among RIF patients, in particular those who have difficulty obtaining MGEs in vitro, ZIFT might be a useful option. The HRC allows patients and medical staff to plan for the operation day in advance.

Successful pregnancy outcome after cryopreservation of all fresh embryos with subsequent transfer into an unstimulated cycle

OBJECTIVE

To assess the pregnancy outcome of freezing and storing all fresh embryos produced in a stimulated IVF cycle and replacing them in a subsequent nongonadotropin-stimulated cycle.

DESIGN

Retrospective study.

SETTING

University-associated assisted reproductive technology program.

PATIENTS

We studied 36 patients (age range 23 to 44 years) who underwent cryopreservation of all fresh embryos in a controlled ovarian hyperstimulation (COH) cycle because of either the risk of severe ovarian hyperstimulation (24 patients, group 1) or the presence of an endometrial lining < 8 mm in thickness (12 patients, group 2). Five hundred fifty-five embryos were generated for replacement in 63 cycles. All embryos were cryopreserved in 1.5 M propanediol at the pronuclear or two-cell stage, and 264 embryos subsequently were transferred into a hormone replacement cycle (70%) or natural ovulatory cycle (30%). The average number of embryos transferred per patient was 4.2.

RESULTS

Twenty-one clinical pregnancies were achieved, giving a pregnancy rate (PR) of 58.3% per patient (33.3% per cycle). The live birth rate was 50% per patient (28.6% per cycle). The implantation rate was 9.1%. Groups 1 and 2 had a similar PR per patient (58.3%). With 208 cryopreserved embryos remaining and considering the 33.3% PR per cycle, we expect the overall extrapolated PR to be 63.9%.

CONCLUSIONS

This is the first series showing that freezing and storing all fresh embryos produced in a stimulated IVF cycle and replacing them in a subsequent nongonadotropin-stimulated cycle results in successful PRs. These results underlie the importance of a successful cryopreservation program in IVF and could be a possible approach to overcoming the alleged adverse effects of COH on the endometrium, thereby improving the chances of pregnancy when numerous embryos are obtained simultaneously.

Tubal versus uterine transfer of cryopreserved embryos: a prospective randomized trial

OBJECTIVE

To compare pregnancy rates after fallopian tubal and uterine transfer of cryopreserved embryos.

DESIGN

Prospective randomized trial with assignment to treatment groups by a random number table.

SETTING

University of Iowa Hospitals and Clinics, a tertiary care academic institution.

PATIENTS

Forty patients with patent fallopian tubes and at least three cryopreserved embryos.

INTERVENTIONS

Cryopreserved embryos were thawed and transferred to the fallopian tube by laparoscopy or to the uterus by a transcervical catheter.

MAIN OUTCOME MEASURES

Clinical and ongoing pregnancy rates.

RESULTS

Tubal transfer of cryopreserved embryos resulted in statistically higher clinical (68% versus 24%) and ongoing pregnancy rates (58% versus 19%) when compared with uterine transfer.

CONCLUSIONS

Tubal transfer of cryopreserved embryos is highly effective and offers an improved pregnancy rate when compared with uterine transfer of embryos. This method of transfer should be considered in patients with patent fallopian tubes and at least three cryopreserved embryos.