Duration of Luteal Phase Support in Frozen Embryo Transfer Cycles: A Randomized, Controlled Phase III Trial

Background: Luteal phase support for frozen embryo transfer (FET) cycles is essential for maintaining conceptus. The luteal phase is supported with different dose and duration of estradiol (E2) and progesterone (P) until 8-12 week of pregnancy. E2 has teratogenic effects on fetus such as low birth weight and urogenital abnormalities, moreover an increased risk of throm-boembolism for pregnant woman. We aimed to evaluated the consequences and ongoing pregnancy rate after interrupting E2 at a time to identify gestational sac with heart beat while P continued until twelve gestational weeks in women undergone FET cycle.Materials and Methods: A total of 291 patients were eligible for recruitment (30 pregnant women in each arm) with surplus embryos who undergone FET. Endometrial prepared with stand-ard long GnRH protocol and for luteal phase support patients re-ceived 6mg oral E2 and intramuscularly P 100 mg/d and embryos on day 2-3 were transferred. Control group continued E2 until 12 week of pregnancy, while for cases after identify gestational sac with heart beat (the 6 week of pregnancy) by vaginal ultra-sonography, E2 will discontinued. P will remain use until twelfth gestational week in both groups. The E2 and P of maternal serum were assessment at the 12 weeks of gestational.Results: Thirteen patients not consent to participate and 200 patients who agreed to participate were not randomized because they did not achieve pregnancy or carry out all randomized cri-teria. Sixteen patients were therefore randomized. There were no significant differences in the spontaneous abortion (0/30[0%] vs. 2/30[6.7%]) and blighted (1/30[3.3%] vs. 3/30[10%]), be-tween the study and control (P> 0.05). The mean serum E2 concentration (3994.85 ± 2072.74 and 3184.88 ± 1566.61 pg/ mL, respectively) and P (57.56 ± 7.27and 55.56 ± 10.38 ng/ mL, respectively) at 12 weeks of gestational were not different between case and control group (P> 0.05).Conclusion: There was no significant complication following interrupt of E2 at 6 gestational weeks, because placenta is a major source for product of E2 and P. Our knowledge about side effects of hormonal treatment in first trimester is unclear which makes this important.

Keywords:

Estradiol , Frozen Embryo Transfer , Luteal Phase Support , Ongoing Pregnancy Rate , Progesterone