The investigators' research group is working to develop a highly effective, low cost non-surgical method of permanent contraception for women. To support this goal, we need to know more about the normal fallopian tube (tube that passes the egg from the ovary into the womb). The purpose of this study is to learn about how menstrual cycles and hormonal contraceptives affect tubal patency. Normally there is an opening between the tube and uterus to permit the flow of fluid and cells. If this opening is blocked, this can result in infertility. Tubal patency is when a woman's fallopian tubes are not blocked. Tubal patency is determined by an x-ray test called a hystero-(uterus)salpingo-(fallopian tube)graphy (HSG). HSG is a standard radiological imaging study that is used to determine if the fallopian tubes are open and free of disease. It is commonly done in women with an infertility diagnosis. The investigators usually do this test in the first 10 days of the menstrual cycle. Sometimes the tubes will appear to be blocked on the HSG when they are actually open. The timing of the HSG study during the menstrual cycle, or the use of hormonal contraception may make a difference in whether the tubes appear blocked on the HSG when they are actually patent.