2012년 유럽불임학회 (ESHRE) P-317 Whether recovery period after failed COH-IVF cycle is required in the subsequent FET cycle? (과배란 시험관 시술에서 임신실패 시 동결란 이식 준비까지 회복기간이 필요한가?)

S.G. Kim1, K.H. Lee1, I.H. Park1, H.G. Sun1, J.H. Lee1, Y.Y. Kim1, E.M. Choi1.
1 Mamapapa&baby Obstetrics Gynecology Clinic, Infertility Lab., Ulsan city, Korea South.

INTRODUCTION

While COH (controlled ovarian hyperstimulation) is commonly used to recruit multiple follicles for cycles of IVF, it alters the endometrial development and can impair the endometrial receptivity. COH cycle may also influence adverse effect inpregnancy of the subsequent FET (frozen-thawed embryo transfer) cycle. The purpose of this study is to verify whether recovery period after failed COH-IVF cycle can affect pregnancy rate of the subsequent FET cycle.

MATERIALS AND METHODS

518 cycles from patients who underwent frozen thawed embryo transfer from September 2009 to December 2011, were analyzed. The patients were divided into two groups as follows. In group 1, 174 patients immediately started endometrial preparation on the 3rd day of the first menstrual cycle after failed IVF-ET cycle. Patients of group 2 (344) waited at least one resting cycle before starting endometrial preparation. Cryopreserved embryos were transferred to patients either in natural cycleor in a hormonally manipulated artificial cycle following preparation of the endometrium with estradiol and progesterone. Embryos were frozen on day 3 using a vitrification protocol. Pregnancy identified through detection of G-sac in transvaginal ultrasound examination. Outcomes were statistically analyzed by t test. P value <0.05 was considered statistically significant.

RESULTS

During the study period the 518 FET performed and resulted in 177 pregnancies (34.2%). There was no difference between both groups in patient age (34.0±4.4 in group 1 and 34.6±4.0 years in group 2) and endometrial thickness (9.2 ±2.0 and 9.8 ±2.0 mm). Embryo survival to freezing-thawing (78.9±20.5% and 80.7±20.0%), the number of embryos transferred per patient (2.2±0.4 and 2.2±0.4) and embryo quality were also comparable in both groups. However, the pregnancy rate was significantly higher in group 2 (37.8%) than group 1 (27.0%, p=0.018).

CONCLUSION

The study reveals that starting endometrial preparation for FET at the first menses, immediately after the stimulated cycle, does impair the pregnancy rate. Probably, it may be due to impaired endometrial receptivity by alterations of the endometrial development after previous COH-IVF cycle. Therefore, in order to achieve an increase of pregnancy rate in FET, recovery period is needed for one or more months after a failed COH-IVF cycle.