Addition of estradiol to progesterone for luteal supplementation in patients stimulated with GnRH antagonist/rFSH for IVF: a randomized controlled trial

BACKGROUND: The role of progesterone for luteal support in stimulated cycles for IVF is well established. However, controversy still surrounds the benefit of additional supplementation with estradiol (E2) in GnRH agonist (GnRHa) cycles, while no such data are available for GnRH antagonists. The aim of this randomized controlled trial (RCT) was to compare ongoing pregnancy rates in patients stimulated with recombinant FSH (rFSH) and GnRH antagonist for IVF, who received micronized progesterone for luteal phase supplementation, with or without the addition of E2. METHODS: Two hundred and one patients underwent ovarian stimulation with a fixed dose of 200 IU rFSH and GnRH antagonist. Patients were randomized to receive, for luteal phase supplementation, either 600 mg of micronized progesterone vaginally (n=100, progesterone group) or 600 mg of micronized progesterone and 4 mg of E2 valerate orally (n=101, progesterone/E2 group). The main outcome measure was ongoing pregnancy at 12 weeks per patient randomized. RESULTS: Demographics, stimulation parameters and embryological data were comparable for the two groups compared. Twenty-six ongoing pregnancies were achieved in the progesterone (26%) and 30 in the progesterone/E2 group (29.7%). (Difference: 3.7 and 95%, CI: -15.8 to 8.6%). CONCLUSION: It appears that the addition of E2 to progesterone in the luteal phase after stimulation with rFSH and GnRH antagonist does not enhance the probability of pregnancy.