Luteal function after delayed ovulation.

Thirty-three infertile patients presenting spontaneous ovulatory cycles with long follicular phases (greater than or equal to 20 days) underwent a luteal function evaluation by basal body temperature, plasma progesterone (P), estradiol, and prolactin determination, and endometrial biopsy study. An endometrial luteal phase deficiency (LPD) was detected in 13 patients (39.4%), although in 10 of them (77%) P levels were normal. This study shows a high incidence of endometrial LPD among cycles with delayed ovulation and that in cases of LPD related to abnormal folliculogenesis, the endometrium is a better indicator than plasma P.