Human endometrial maturation is markedly improved after luteal supplementation of gonadotrophin-releasing hormone analogue/human menopausal gonadotrophin stimulated cycles.

In human cycles stimulated for ovulation with gonadotrophin-releasing hormone (GnRH) agonists and human menopausal gonadotrophin (HMG), a luteal phase defect has been described. To evaluate the influence on the endometrium, endometrial development in GnRH agonist/HMG stimulated cycles was assessed in cycles with and without luteal phase supplementation. Endometrial histological maturation, ultrastructure and oestrogen receptor (ER) and progesterone receptor (PR) status were analysed in the mid-luteal phase. Serum concentrations of oestradiol and progesterone were measured daily from days 1-5 of the luteal phase. Supplementation of the luteal phase was achieved with either human chorionic gonadotrophin or natural progesterone, administered intramuscularly or intravaginally. In non-supplemented cycles all endometrial features were consistent with an impaired progesterone bioavailability. After supplementation of the luteal phase, fewer signs of luteal phase deficiency were visible, especially with the intravaginal route of progesterone administration. We concluded that the endometrial parameters confirm the need for luteal support in GnRH agonist/HMG stimulated cycles.