The luteal phase and early pregnancy after combined GnRH-agonist/HMG treatment for superovulation in IVF or GIFT.

Endometrial biopsies showing inadequate development were observed after ovarian stimulation with the GnRH agonist Buserelin and HMG for IVF or GIFT when luteal supplementation was omitted. Ninety-one patients were randomly allocated to two luteal supplementation regimens: in 41 women HCG and in 50 women progesterone and oestradiol valerate. The pregnancy patients treated with a combination of the GnRH agonist and HMG a delay of implantation of 1.3 days was observed compared to pregnancies after clomiphene citrate-HMG stimulation. This delay was not due to slower preimplantation embryo development after GnRH agonist-HMG treatment. Temporarily defective function of the corpus luteum was evidenced by measuring serum progesterone, 17 beta-oestradiol and 17-hydroxyprogesterone in the patients receiving progesterone and oestradiol valerate. This inadequate corpus luteum function could be related to the prolonged blockage of pituitary gonadotrophic function after arrest of the GnRH agonist.