Anytime bodily fluids are coming out of someone, it's uncomfortable. Blood coming out from the mysterious nether regions is particularly unsettling, and to many, men and women, a little gross. For most women periods take up three to five days each month for around four decades. That adds up, so women and their partners are almost guaranteed to want to have sex at some point during that time.
There is nothing wrong with having sex while a woman is on her period, but there are some details about this situation you (and she) might want to know first. Dr. Tami Serene Rowen, assistant professor at UCSF's department of obstetrics, in the division of gynecology helped us go over everything you wanted to know — but were too embarrassed to ask — about having sex during that time of the month.
1. The Basic Biology
Sex ed. told you the basics about a woman's menstrual cycle, but here's what's important to know for this situation. A period marks the end of the body's monthly attempt to get pregnant. Awaiting a fertilized egg, the uterus developed a thickened lining to keep this potential occupant happy. If an egg doesn't get fertilized, the body can't sustain this special womb, so hormone levels drop and the lining is shed. "The bleeding is because there is a blood supply that went into those tissues, and it bleeds until the tissue comes out enough and the blood vessels start to close off," says Rowen.
2. What it Feels Like
Women may already be in a considerable amount of pain during their period, so sex may seem like it would add to that. The short answer is: it shouldn't. "There's no reason why a woman would have more pain on her period [during sex] versus not being on her period," says Rowen. In other words, if she does experience pain, it's not likely from the combination of sex and her period, but pain that would have resulted from either of those two situations anyway.
3. Caution About STIs
Because there is blood involved, partners should be cautious about STIs. But they should be cautious about those anyway during sex because exchange of potentially infectious fluid, including blood, is always a possibility. "Use a condom if anyone's in any way concerned about sexually transmitted infections," says Rowen. "But mainly the blood-borne ones. Things like gonorrhea or chlamydia are not going to be more likely to be transmitted during the period." If either of you are at all worried about STIs (blood-borne or not), use protection.
4. Sex and Cramping
There is some debate over whether sex increases or decreases cramping. Rowen says the answer is unclear. "The cramping is because, as the blood is being expelled, the body is releasing its own natural chemicals that cause contractions of the uterus to help expel the blood," says Rowen. "There's no reason why sex or penetration or hitting the uterus is going to make that worse." Again, if a woman is having bad cramps, that was probably going to happen with or without sex.
5. Oral Sex
Penile sex or fingering during a woman's period doesn't carry any special risk versus sex otherwise. Oral sex is a different story. "I would caution against oral sex," says Rowen. "There's going to be an increase in bacteria and inflammation in the blood itself." If you still want to have oral sex while a woman is on her period, consider using a dental dam or other barrier.
6. The Blood
Women can vary widely in how much blood comes out of them during their period, but it's generally not that much. "Women bleed a very small amount over the course of their periods," says Rowen. "It might seem like it's a lot but it's two shot glasses, basically." Believe it or not, you might not see any blood, even with penetrative sex.
7. What the Blood Should (and Shouldn't) Look Like
If you want to be a stellar partner, take note of any blood you do see because there is a difference between period blood and other bleeding that could be problematic. Period blood, because it's been in the uterus a while and includes other tissue cells, is generally dark and thick and may be clotted. "The kind of stuff that you want to be worried about — that [indicates] there could be some kind of injury to the vagina — is really bright red blood," says Rowen. Period blood doesn't generally look like the blood you'd see from a cut.
8. Women Can Get Pregnant on Their Period
Yes. You can absolutely get a woman pregnant if you have sex with her on her period. While the period is the least likely time for a woman to get pregnant (because the egg is gone), sperm could wait for the next egg to be released. Sperm can stay in a woman's body for seven days. So if a woman has a short cycle and you have sex with her near the end of it, she can become pregnant.