Luteal support with micronized progesterone following in-vitro fertilization using a down-regulation protocol with gonadotrophin-releasing hormone agonist: a comparative study between vaginal and oral administration.

This study aimed to compare the efficacy of micronized progesterone administered as luteal support following ovulation induction for in-vitro fertilization (IVF)- embryo transfer in cycles using gonadotrophin-releasing hormone agonist, either orally (200 mgx4/day) or vaginally (100 mgx2/day) and to characterize the luteal phase hormonal profile during such treatments. A total of 64 high responder patients requiring intracytoplasmic sperm injection due to male factor infertility were prospectively randomized into two treatment groups. Patients treated orally or vaginally were comparable in age (31.9 +/- 6.1 versus 30.6 +/- 5.2; mean +/- SD), number of oocytes retrieved (17 +/- 8.2 versus 18 +/- 7.0), and number of embryos transferred (3.1 +/- 1.2 versus 2.7 +/- 0.9) per cycle. Following low dose vaginal treatment, a significantly higher implantation rate (30.7 versus 10.7%, P < 0.01), but similar clinical pregnancy rate (47.0 versus 33.3%) and ongoing pregnancy rate (41.1 versus 20.0%) was observed, compared with oral treatment. In conception cycles, luteal serum progesterone and oestrogen concentrations did not differ between the treatment groups. In non-conception cycles, late luteal progesterone concentrations were significantly lower following vaginal treatment. As low dose micronized progesterone administered vaginally is simple, easy and well tolerated, it could be recommended as the method of choice for luteal support, especially for high responder patients at risk for ovarian hyperstimulation syndrome.