Structural and ultrastructural patterns of the human preovulatory endometrium following clomiphene citrate treatment

To investigate ultrastructural modifications in the endometrium of women receiving clomiphene citrate (CC) treatment, we performed endometrial biopsies in the preovulatory phase in 17 patients with anovulatory infertility and 16 normo-ovulating women with tubal or male sterility. Histology, scanning and transmission electron microscopy (SEM and TEM) revealed midproliferative phase aspects in 11.7% of the treated group and 6% of the controls, late proliferative aspects in 76.4% and 82%, and postovulation days 1-3 characteristics in 11.7% and 12% respectively. No significant differences were observed between the patients and controls; our data indicate that CC taken in a dose not exceeding 100 mg/day from day 3 of the cycle can induce endometrial maturation that is almost identical with that of a spontaneous preovulatory phase. This type of endometrium should therefore allow implantation of a fertilized egg and maintain unmodified the complex biohumoral relations with the embryo.