Estradiol supplementation during the luteal phase of in vitro fertilization cycles: a prospective randomised study

To find the optimal dosage of estradiol (E2) for luteal phase support through the addition of different doses of E2 to progeserone (P) luteal phase support in patients undergoing long GnRH agonist in vitro fertilization (IVF) treatments.

Two hundred and eighty-five women undergoing IVF treatment with a long GnRH agonist protocol were prospectively randomized into three groups. Group 1 (n = 95) received P and 2mg E2, group 2 (n = 95) received P and 4 mg E2 and group 3 (n = 95) received P and 6 mg E2 as luteal phase support. The primary outcome was the clinical pregnancy rate (PR). The secondary variables of interest were the implantation rate (IR), miscarriage rate and multiple PR.

The clinical PR was 31.6%, 40% and 32% respectively in groups 1, 2 and 3 and the differences between groups were not statistically significant. However, the miscarriage rate was significantly lower in group 2 (2.6%) than in group 1 (20%) but was not significantly lower than in group 3 (9.6%).

For luteal phase support, adding 2, 4 or 6 mg of oral E2 to P creates no statistical difference in terms of pregnancy rates. However, a significantly higher miscarriage rate was found when 2mg E2 was used. Therefore, in the luteal phase support, 4 mg of oral estradiol in addition to progesterone can be considered to reduce the miscarriage rate.

For luteal phase support, adding 2, 4 or 6 mg of oral estradiol to progesterone showed no statistical difference in terms of pregnancy and implantation rates, but a significantly higher miscarriage rate was found when 2mg estradiol was used.