Abstract
Objective:To compare the effects of fresh embryo transfers (ET) and elective frozen/thawed embryo transfers (eFET) on implantation, clinical pregnancy, and live birth rates in poor ovarian responders, as defined by the Bologna criteria.Materials and Methods:All electronic databases of embryo transfers between January 2011 and January 2014 were retrospectively reviewed. Two hundred fifty-nine of all the fresh ET and 96 of all eFET were included into the study. An antagonist protocol with letrozole was used for the controlled ovarian hyperstimulation (COH) in all participants.Results:The mean age was 36.9 years (range, 21-43 years) in the fresh ET arm and 37.2 years (range, 21-43 years) in the eFET arm (p=0.45). The clinical pregnancy rate was 35% (90/259) versus 29% (28/96); the abortion rate was 27% (20/75) versus 36% (9/25); and the live birth rate was 21% (55/259) versus 17% (16/99). There were no significant differences between groups and p values were 0.32, 0.52, and 0.42, respectively. The mean E2 level was 389 (range, 50-2055 pg/mL) in the fresh ET group (on hCG day) and 418 pg/mL (range, 121-3073 pg/mL) in the eFET group (on day 14 of cycle) (p=0.122). No differences were found between the two groups with respect to the total number of retrieved oocytes (p=0.55) and number of metaphase II (MII) oocytes (p=0.81). The number of embryo transfers was statistically different (p=0.005). The effects of age, total number of retrieved oocytes, number of MII oocytes, type of treatment, number of ET, and the day of ET and E2 level to live birth outcomes were investigated using binary logistic regresion analyses, and no stastical effect was determined by any of the parameters. P values were p=0.50, 0.66, 0.45, 0.30, 0.30, 0.08, and 0.90, respectively.Conclusion:E2 levels tend to be lower in poor responders, thus the receptivity of the endometrium may be damaged less than normal, which may explain why pregnancy results are the same between eFET and ET groups.
Highlights
The success rates among infertility treatments are steadily increasing with the new technological developments in the multiple oocyte collecting process through controlled ovarian hyperstimulation (COH) and cryopreservation methods
The mean serum E2 level measured on hCG trigger day in the fresh embryo transfers (ET) arm was 389 pg/mL and on day 14 of the cycle in the elective frozen/thawed embryo transfers (eFET) arm it was 418 pg/mL
In this study we found no significant differences regarding clinical pregnancy, abortion, and live birth rates between the eFET and fresh ET groups
Summary
The success rates among infertility treatments are steadily increasing with the new technological developments in the multiple oocyte collecting process through controlled ovarian hyperstimulation (COH) and cryopreservation methods. Pregnancy rates in patients who are so-called poor responders are still low[1,3]. There has to be a good quality embryo as well as a normal receptive endometrium. Endometrial receptivity arises 6 to 10 days after ovulation and this period is called the “implantation window”(4). In COH cycles, endometrial receptivity is negatively effected because of the supraphysiologic hormonal environment[6,7,8,9]. The aim of this study was to compare the effects of elective frozen/thawed (eFET) and fresh embryo transfers (ET) on implantation rates, clinical pregnancy, and live birth outcomes in poor ovarian responders, as defined by the Bologna criteria
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