Endometrial histology after first trimester spontaneous abortion.

The endometrial histology after spontaneous abortion was investigated by performing an endometrial biopsy in the two menstrual cycles subsequent to miscarriage in 12 women. In the first cycle, 66% (8/12) of the biopsies had the following abnormalities: (1) proliferative endometrium (n = 4), (2) proliferative glands and decidualized stroma (n = 1), (3) endometritis (n = 1), and (4) luteal insufficiency (n = 2). In the second cycle, 20% (2/10) of the biopsies demonstrated luteal insufficiency. Forty-five percent (10/22) of the first two cycles after spontaneous abortion demonstrated abnormal endometrial histology, with the first appearing more abnormal than the second (P = 0.06). Two conceptions occurred during the study period; both were uneventful term pregnancies. These findings suggest that a large proportion of the first two menstrual cycles after spontaneous abortion and curettage are abnormal, with the first cycle being more frequently abnormal than the second.