If you’ve attributed changes in your period to sex, you’re not the only person to think there is a connection between the two. Some folks even say that sex can delay your period — but does intercourse actually have any effect on your menstrual cycle? If you’ve been wondering whether sex can really delay your period, then you’re in the right place because we spoke to some experts to find out how your body can be affected.‍

Can sex delay your period? 

Sex can do a lot of awesome things: It can boost your immune system, improve bladder control, lower blood pressure, lower heart attack risks, relieve stress, and even improve sleep. But can sex delay your period? The answer is no.  

Sex itself doesn’t have an effect on delaying or starting a period, according to Dr. Rashid Bani. Irregular and painful periods affects 14 percent of people  who are at the childbearing age (which, medically speaking, is between ages 12 and 51 — however, we are not saying one should be any specific age to become pregnant). 

"Basically, at the start of a person's menstrual life (menarche), periods can be quite irregular but over time and further into adulthood, they usually settle down into a more regular pattern." Dr. Bani tells O.school. There are several factors that can contribute to a delayed period, however, sex is not one of them. ‍

What other factors can delay your period? ‍

There are so many factors that might cause your period to be irregular: hormonal birth control, exercising aggressively, dietary changes, stress, thyroid imbalance, Polycystic Ovary Syndrome, or a variety of other chronic illnesses. While you may have sex while experiencing irregular periods, it is not the actual cause of the period delay. However, some individuals have experienced a correlation.

Niamh, 21, from England, finds that if she has “particularly rough sex,” then her period is delayed. “At one point it has delayed my period a full month, meaning I’ve skipped a period,” she says. This situation has happened to Niamh a few times even though her period is very regular. 

“This is something that I used to really worry about and I was constantly panicking and concerned that I was pregnant,” she says. “However, I’ve come to realize what this is and found that now I know this I tend to wait it out a few weeks now before I begin to get concerned.”

If intercourse delays a period, Missouri-based OGBYN, Dr. Corey Babb, says the most common reason for this is pregnancy. “There are other causes for delayed periods, but no correlation with intercourse exists in the current medical literature,” he explains. “In a reproductive-age woman, a change in the frequency of the menstrual cycle is something that should be discussed with a healthcare professional. Going without a period for more than six months, regardless of sexual activity, it’s something that should be addressed as well.”

If you are not pregnant and have been experiencing bouts of late cycles, visit a healthcare professional to get to the root of your issue. Dr. Bani suggests that if your period is delayed by five days, and pregnancy is a possibility, take a pregnancy test. ‍

Can sex start your period? ‍

According to a 2014 study in the Obstetrics and Gynecology International Journal, 9 percent of folks (who have not experienced menopause yet) experience vaginal bleeding after sex. These numbers are compared to 43 to 63 percent of people who have gone through menopause and experience dryness, itching, spotting, and bleeding during or after sex.

Dr. Bani says it usually doesn’t contribute to beginning a cycle. If bleeding does occur during sex, it’s usually not caused by a period. “Things like stress, hormonal treatments, [and] time differences when traveling can affect when a [person] has [their] period, but sex, unless there is an STI, would not cause a period to arrive early.” 

Dr. Babb says  “There are no research studies that demonstrate a definite relation to having sex and altering the start date of menses. That said, it is well known that orgasms (associated with intercourse, or without) cause contractions within the uterus as part of the autonomic response associated with that event.” Dr. Babb goes on to explain that, “In theory, those contractions may precipitate the start of menses. For women that engage in penile-vaginal intercourse, semen causes the cervix to soften slightly, due to a type of chemical called a prostaglandin that is present within the ejaculate. This, coupled with orgasm, could potentially lead to the start of a period.”

If someone does begin to bleed during sex, Dr. Bani says, “Bleeding during sex, or after sex which is known as postcoital bleeding, should not in any circumstances be solely attributed to the start of a period.”‍

Can certain STIs/STDs cause bleeding after sex?‍

STIs like chlamydia and gonorrhea have mostly no symptoms but they are known to contribute to spotting. Other side effects include pain during sex, pain when peeing, and abdominal pain. The more bleeding that occurs, the more serious the infection. Syphilis and genital herpes are two other types of STIs that can cause bleeding when open lesions are irritated. 

Again, sex causing a “jump-start” in a period is something that some people have experienced.

Tia*, 38, and based in the UK is someone who has experienced a jump-start in her period when having intercourse. . “I’ve never had this happen when my period wasn’t due, so I never talked to a doctor—I actually just assumed it was coming anyway and the sex coincided, or perhaps slightly prompted my period coming on,” she says. Tia was diagnosed with endometriosis seven years ago when she was already in her 30s. “I think the biggest emotional factors for me from having endometriosis are chemical. I have very bad PMS, severe and chronic pain before and during my period and I have also become anemic several times, which made me very tired,” she says. 

Tia doesn’t think her endometriosis and bleeding during sex are correlated, however. “I’ve never had any bleeding outside of when I am expecting my period. I think sex can cause bleeding for a number of other reasons—polyps for example— and that if someone is having bleeding every time they have sex, they should go to the GP.”‍

Can endometriosis cause bleeding after sex?‍

Endometriosis can cause inflammation, polyps, and fibroids which can cause pain and bleeding, especially after sex. Other causes for bleeding or spotting during or after sex can be because of infections like pelvic inflammatory disease, cervicitis, vaginitis, or STIs like chlamydia or gonorrhea. 

Utilizing lube (extra is always better, folks) even if you aren’t normally dry can create a much more satisfying sexual experience. According to an Indiana University study, 70 percent of participants found that lube made sex more pleasurable and enjoyable. 

Overall, a regular menstrual cycle is bound to alternate at the slightest hormonal or lifestyle change. It’s imperative to keep track of your start and end dates and pay attention to your body’s needs and changes. While sex doesn’t contribute to starting or delaying a period, it can affect the body in a plethora of other ways—both positive and negative. Remember to tune in and stay alert of any minor changes in order to assure your body is operating at its fullest potential. An app like Clue can be super helpful, or even keeping a journal!