Objective: To analyze endometrial response (endometrial dating and implantation) to exogenous administration of E2-valerate and P in women with low response to gonadotropins undergoing oocyte donation.
Design: Prospective study. A cycle in which endometrial specimens were obtained and subsequent cycles with ET were evaluated. The control group was made up of patients with premature ovarian failure (POF) undergoing the same procedure.
Setting, patients: In Vitro Fertilization program at the Instituto Valenciano de Infertilidad. A total of 37 women with low response to gonadotropins in previous cycles and 33 women with POF.
Interventions: First artificial cycle with E2-valerate and P in the absence of previous pituitary suppression to determine endometrial adequacy. Successive artificial cycles in which ET was performed on cycle day 17. Oocytes donated from infertile patients undergoing IVF.
Main outcome measures: Serum steroid levels were measured during the artificial cycle. Histologic dating of the endometrium on cycle days 15 and 26. Ultrasonographically documented IVF-ET pregnancies.
Results: Postovulatory changes on cycle day 15 were observed in 36.4% of low responders treated with E2-valerate and P in the absence of simultaneous pituitary suppression. Pregnancy rates were higher in women with previous sufficiently (77.8%) or insufficiently (80%) estrogen-primed endometrium than in the cases showing postovulatory changes (37.5%). Pregnancy rates (PRs) per transfer were significantly higher in low responders (63.8%) than in patients with POF (37.2%). Patients with endometriosis had a 71.4% PR per transfer. Embryos derived from oocytes from polycystic ovaries had a 48.3% PR.
Conclusions: Oocyte donation is a reliable alternative for women with low response to gonadotropins, including those with severe endometriosis. The efficacy of the steroid replacement regimen in controlling ovarian function may influence outcome. Thus, women with functional ovaries despite exogenous steroid replacement might be differently treated. Women with polycystic ovaries are an adequate source of oocyte donation.