Pituitary response to luteinizing hormone-releasing hormone after induced abortion in the first and second trimesters.

Luteinizing hormone-releasing hormone (LHRH) (100 microng) was administered subcutaneously to healthy female volunteers 2 and 4 weeks after induced abortion in the first trimester (group A) and the midtrimester (group B). Four patients were studied in each group. The response to LHRH was determined in terms of plasma LH and follicle-stimulating hormone levels. Adequate pituitary response occurred in subjects of group A at both 2 and 4 weeks. In group B pituitary unresponsiveness was found at 2 weeks which persisted to some extent at 4 weeks. These data are in accord with the pituitary unresponsiveness observed after termination of pregnancy at term and suggest that the duration of pregnancy has an influence on the development of this unresponsiveness.