Hypersecretion of luteinising hormone, infertility, and miscarriage.

The relation between prepregnancy follicular-phase serum luteinising hormone (LH) concentrations and outcome of pregnancy was investigated prospectively in 193 women with regular spontaneous menstrual cycles. The group included 26 nulliparous and 167 multiparous women with various obstetric histories. Of the 147 women with LH concentrations of less than 10 IU/l (normal LH group) 130 (88%) conceived, whereas only 31 (67%) of the 46 women with LH values of 10 IU/l or more (high LH group) did so. In the high LH group, 20 (65%) of the pregnancies ended in miscarriage, whereas only 15 (12%) of pregnancies in the normal LH group did so. The adverse effect of a high prepregnancy LH concentration on fertility and outcome of pregnancy was seen in primigravidae, women with previously successful pregnancies, and women with a history of recurrent miscarriage. These data indicate an important role for hypersecretion of LH before conception in miscarriage. This finding offers the possibility of a simple predictive test for women before pregnancy, and could also be used to identify patients with an endocrine abnormality that can be remedied.