2012년 미국불임학회 (ASRM) P-51 Importance of endometrial thickness in frozen-thawed embryo transfer: difference between hormone replacement protocol and natural cycle protocol. (동결란 이식에서 자궁내막의 두께의 중요성 : 호르몬 보충법과 자연주기 동결란 이식법 사이에서 차이점)

I.H. Park1, K.H. Lee1, H.G. Sun1, S.K. Kim1, J.H. Lee1 and Gyun-Ho Jeon2.
1 Mamapapa&baby OB&GY, 1367-5 Hwashin building 4th floor Dal-dong, Nam-gu Ulsan, X, Republic of Korea, 680-805
2 OBGY, Inje University, Haeundae Paik Hospital, Haeundaero 875, Haeundae-Gu Busan, X, Republic of Korea, 612-030.

OBJECTIVE

Endometrial (EM) thickness is an importantprognostic factor of fresh embryo transfer and its significance has been proven by many studies. However, only few studies have evaluated the relationship between endometrial thickness and cycle outcome in frozen-thawed embryo transfer (FET). The purpose of this study is to assess the values of EM thickness in hormone replacement(HRT) cycle FET and in natural cycle FET.

DESIGN

A retrospective study

MATERIALS AND METHODS

We retrospectively reviewed 487 FET cycles using HRT protocol and natural cycle protocol from November 2010 to November 2011. We divided into two groups by EM thickness. Thin EM group was defined by EM < 9 mm and thick EM group was defined by EM ≥ 9mm. We compared cycle outcomes of the two groups in HRT protocol and in natural cycle protocol.

RESULTS

In each group, number of transferred embryos and embryo quality score reflected no difference. In natural cycle protocol, pregnancy rates of thin EM group and thick EM group were similar [31.1%(33/106) vs. 33.3%(52/156), P=0.40]. Ongoing pregnancy rates of thin EM group and thick EM group also were similar [29.2%(31/106) vs. 32.1%(50/156), P=0.12]. In HRT protocol, pregnancy rates of thick EM group were significantly higher than thin EM group [46.3%(50/108) vs. 34.2%(40/117), P=0.04]. Ongoing pregnancy rates of thick EM group were also significantly higher than thin EM group [40.7%(44/108) vs. 29.9%(35/117), P=0.02].

CONCLUSION

In HRT cycle FET, EM thickness above 9 mm on the day of P supplementation is associated with higher pregnancy rates compared with EM thickness below 9 mm. EM thickness can be used as a predictor of IVF prognosis in HRT cycle FET. However, in natural cycle FET, pregnancy rates did not show significant difference by EM thickness. Therefore, we should pay more attentionto endometrial thickness in HRT cycle FET rather than in natural cycle FET.