Effects of oestradiol for luteal phase support in fresh embryo transfer cycles: A retrospective cohort study

OBJECTIVE: Any benefit of oestradiol supplementation with progesterone for luteal support after fresh embryo transfer in in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI) cycles remains controversial. In this study, we further addressed this question in cycles using gonadotropin-releasing hormone (GnRH) agonist for ovarian stimulation. DESIGN: A retrospective cohort study in a tertiary teaching and research hospital. PATIENT(S): A total of 1602 patients were given oestradiol valerate (E) in addition to progesterone (P) as luteal support. One thousand six hundred and two patients receiving progesterone alone were selected as the control group. MAIN OUTCOME MEASURE(S): Live birth rate. Secondary measures included clinical pregnancy rate, miscarriage rate and premature birth rate. RESULT(S): Clinical pregnancy and live birth rates were similar for the P alone vs the P+E group. In cycles with oestradiol (E2) levels less than 5000 pmol/L on the day of hCG trigger, E supplementation resulted in a significantly higher live birth rate (23.44% vs 32.92%, OR = 1.60 [95% CI 1.05 to 2.46]). In cycles with oestradiol levels 5000 to 10 000 pmol/L on the day of hCG trigger, E supplementation did not increase the live birth rate (34.43% vs 35.42%, OR = 0.90 [95% CI 0.80 to 1.01]). In cycles with oestradiol levels over 10 000 pmol/L on the day of hCG trigger, the live birth rate was significantly lower (36.83% vs 31.37%, OR = 0.78 [95% CI 0.62 to 0.99]) and the premature birth rate was significantly higher (19.66% vs 28.73%,OR = 1.65 [95% CI 1.05 to 2.59]) in the E supplementation group. CONCLUSION(S): Any benefit of oestradiol supplementation for luteal phase support appears to correlate with the serum oestradiol level on the day of hCG trigger. Oestradiol supplementation is beneficial for improving live birth rate in cycles with oestradiol levels less than 5000 pmol/L, but is not recommended in cycles with oestradiol levels over 10 000 pmol/L.