Menstruation - Menstruation and Sex

Menstruation and Sex

Sexual intercourse during menstruation does not cause damage in of itself, but the woman's body is more vulnerable during this time. Vaginal pH is higher and less acidic than normal, the cervix is lower in its position, the cervical opening is more dilated, and the uterine endometrial lining is absent, thus allowing organisms direct access to the blood stream through the numerous blood vessels that nourish the uterus. All these conditions increase the chance of infection and STD transmission during menstruation.

Sexual intercourse may also shorten the menstrual period. Some sources say that achieving orgasm helps the uterus to contract and expel the lining. However, it is more likely that because semen contains luteinizing hormone (LH) and follicle stimulating hormone (FSH), and the vagina easily absorbs these hormones, the woman's hormone balance is slightly offset and the follicular phase of the menstrual cycle begins earlier. Similarly, levonorgestrel-releasing intrauterine devices and oral birth control pills alter the default hormone-release cycle, although by different mechanisms such as maintaining a high progestin level throughout a woman's cycle.