Hormonal Effects on the Uterus and Endometrium

Endometrium is the lining of the uterus. It is where the fertilized egg normally implants during pregnancy. This study was designed to better understand the way(s) that female sex hormones (estrogen and progesterone) cause the uterus to grow and develop. It is known that these hormones are necessary to prepare the uterus for pregnancy, but the way the hormones work is unknown. Researchers would like to identify the genes that are affected by female sex hormones by using a variety of tests (in situ hybridization, immunohistochemistry, and culture of human endometrium). Researchers will select women who have regular monthly menstrual cycles and study them for two cycles; 1. \The first cycle (PRE-BIOPSY CYCLE) will include daily measurements of the patient's body temperature and progesterone measurements during the last 14 days (luteal phase) of the menstrual cycle. 2. \ The second cycle (BIOPSY CYCLE) will include measurements of urinary luteinizing hormone (LH) to determine the day of the LH surge. Luteinizing hormone is the hormone that causes the ovary to release the developed egg. Ovarian ultrasounds will be performed before the biopsy to determine development of the egg. Blood tests will be taken on the day of the biopsy to have an overall idea of the hormones circulating in the patient's blood. An endometrial biopsy will be taken at one of three possible times to identify endometrial products under conditions of estrogen, estrogen/progesterone, or steroid hormone withdrawal.\