[A comparative study of serum progesterone and biopsy of the endometrium in infertile females].

We have titrated the serum progesterone and performed an endometrial biopsy on 69 infertile women, on the 21st day of the cycle. In 19 cases (27.5%), the serum progesterone levels were normal and the endometrium was at an advanced secretory stage. In 28 cases (40.5%), although the serum progesterone levels were normal, the endometrium was at an early secretory stage in 9 cases. In 29 cases (42%), the serum progesterone levels were under 8 ng/ml but for 20 of them, the endometrium was at an advanced secretory stage. In 12 cases (17.5%), there were anovulatory cycles.