At its most basic, sex is about the exchanging of bodily fluids. But there’s one fluid you don’t want to see on the sheets when you’re naked—and that would be blood. The good news: Postcoital bleeding, as it’s officially called, may be embarrassing and surprising. But it’s not always a reason to immediately freak out.
“A small amount of spotting is probably normal and fine if it happens one time or on a rare occasion,” Nichole Mahnert, MD, an ob-gyn at Banner University Medical Center Phoenix, tells Health. But if it happens more than once, it's time to check in with your doctor. “Most causes are not dangerous, but a few are,” Felice Gersh, MD, an ob-gyn and the founder and director of the Integrative Medical Practice of Irvine in Irvine, California, also tells Health.
If you notice red spots on the bed or between your legs after getting it on, make sure to talk to your ob-gyn to figure out whether one of these issues is to blame.
It's a birth control side effect
One of the main perks of hormonal birth control is its ability to regulate your cycle. But “any type of hormonal contraceptive can lead to spotting after intercourse,” says Dr. Mahnert. Typically, you’d notice this when you start a new pill, for example; it can take a few months for your body to adjust to it.
But something else could be going on. Hormonal contraception "can occasionally cause significant atrophy, or drying up, of the vagina, [and as a result] intercourse can cause tearing and some bleeding,” Dr. Gersh says. If you think your BC is behind your post-sex blood drops, your ob-gyn can help you look into better options.
You have an STI
Sexually transmitted infections can cause many un-fun symptoms, and post-sex bleeding is definitely one of them—especially if the infection leads to an inflammation of the cervix, called cervicitis, says Dr. Gersh. “A very irritated cervix can bleed with rubbing,” she explains.
STIs like chlamydia, gonorrhea, and trichomoniasis can result in cervicitis, so any spotting could be caused by one of these common infections, warns Dr. Mahnert. “Most women do not have symptoms of STIs, which is why it’s important to seek treatment when you do have a symptom like abnormal bleeding,” she says.
An endometrial polyp is to blame
This sounds scarier than it is. “Polyps are like tear drops of tissue that form in the reproductive tract on the cervix or inside the uterus,” explains Dr. Gersh. They're benign, and they can range in size from a few millimeters to a few centimeters. Polyps can hang down from the cervix into the vagina, where they might get touched or hit during sex. “They have many blood vessels feeding them and can bleed if bumped around, so you’d see small amounts of blood after intercourse,” she says.
It's worth noting that polyps are more common among older women, generally age 40 and above. If you suspect a polyp is to blame for any blood you see after sex, your ob-gyn can diagnose you, says Dr. Gersh.
Vaginal dryness has caused tearing
If you’re not wet enough during sex, there’s a chance you might bleed—all that friction from penetration can tear sensitive vaginal tissues, says Dr. Gersh. (Of course, this would obviously be a painful experience.) “Your doctor can talk to you about options that include lubricants, moisturizers, and vaginal estrogen,” says Dr. Mahnert, depending on the cause of the dryness.
But make sure to talk to your doctor instead of self-diagnosing and treating it on your own. “In general, women should steer away from the feminine hygiene aisle at the drugstore because those products can make symptoms worse,” adds Dr. Mahnert. Plus, that dryness could be related to an underlying issue, like your hormonal birth control.
You have bacterial vaginosis or a yeast Infection
These two infections are so common; it's estimated that three out of four women will experience at least one in her lifetime. “Any kind of infection can cause inflammation and irritation, which can result in bleeding" during sex, says Dr. Mahnert.
That said, bleeding isn’t the most common symptom with bacterial vaginosis or a yeast infection. They're typically characterized by changes in the color or odor of vaginal discharge as well as vaginal discomfort like prolonged itching, she explains. “But if the cervix is infected and becomes inflamed (aka, cervicitis), there could be some small amounts of blood seen after sex, due to the rubbing,” says Dr. Gersh.
It's a sign of a fibroid
Your uterus is made up of glandular and muscular tissue, and a fibroid is a benign overgrowth of that muscular tissue. A fibroid can be as small as a pea or larger than a grapefruit, and it typically grows out of the uterine wall from a stalk. “More than 75% of women will have fibroids at some point in their reproductive years,” says Dr. Mahnert. Most women will never even know if they have one, though. And if one is diagnosed, most of the time, no treatment is necessary.
Problems can arise if a fibroid grows too large. Should that happen, your doctor may want to discuss treatment options, like removing it during surgery. Where exactly the fibroid is also plays a role in triggering bleeding. “Fibroids can cause bleeding when they are all or partially within the uterine cavity,” says Dr. Gersh. “They have a lot of blood to them and with the bouncing movements of sex, they can begin to bleed.”
You might have cervical cancer
Cervical cancer is rare in women who get regular Pap tests. Still, the American Cancer Society estimates that 13,240 new cases of invasive cervical cancer will be diagnosed in 2018. And “bleeding with sex is the main symptom of cervical cancer,” says Dr. Gersh. “The bleeding is typically light and painless. It’s due to the vascular nature of cervical cancer and that the friction of sex can irritate tissue and cause bleeding.”
If you have continued or persistent abnormal bleeding, tell your MD. She'll want to examine your cervix closeup, and she'll make sure you’re up to date with your Paps and HPV testing, says Dr. Mahnert. Sure it's scary. But play it safe and give your doctor the chance to officially rule it out.