Can Sex Change Your Period?


Can sex alter or delay your monthly period? The short answer is no, not in any clear and evidence-based way. According to Planned Parenthood, the only circumstance when sexual intercourse can ‘change’ your period is if you get pregnant, in which case your period (and menstrual cycle) stops completely.

That said, sex and sexual arousal can cause a release of oxytocin and a surge in certain hormones. As we know, hormones play a key role in your menstrual cycle phases, so it is possible for any hormonal change to have an impact on your cycle. However, there is no easy, consistent answer as to how that impact will manifest.

Having said that, several other factors can change your period, some physical and some not. So let’s dive right in.

How Does Pregnancy Affect Your Period & Menstrual Cycle

During your reproductive years, if you are sexually active and have unprotected sex near or during ovulation this increases your chances of getting pregnant. Your ovary releases a follicle (oocyte) each month, around Days 13-15 of a 28-day menstrual cycle. After the oocyte is released from the ovary (ovulation), it moves into the fallopian tube.

After ovulation, the oocyte moves through the fallopian tube for 12-24 hours, waiting to be fertilized. Your sex drive may also increase during ovulation. It’s worth noting that sperm can live inside a female body for up to 5 days so the window for getting pregnant is longer than just a couple of days. 

If an egg is fertilized and implants in the uterine lining, key hormonal changes occur to support the pregnancy, including an increase in progesterone and human chorionic gonadotropin (HCG). This prevents the uterine lining from breaking down and shedding, which as a result causes periods to stop. 

It is normal and expected for your period to stop during the entirety of your pregnancy. But pregnancy should be confirmed with a pregnancy test. Breastfeeding can also delay the return of your period. 

Why Do I Sometimes Bleed After Sexual Intercourse?

Aside from pregnancy, there isn’t a way sex can dramatically change or affect women's periods or menstrual cycles. The reason why this misconception exists is that many women experience spotting or bleeding after sex

It’s important to keep in mind that not all vaginal bleeding is menstrual bleeding. Non-period bleeding after sex can happen for a variety of reasons, including vaginal tears that can most commonly be caused by vaginal dryness or infection, and less commonly by certain types of cancers.

If you do experience spotting between periods, leakproof underwear can be helpful, but talking to your doctor is best! 

Vaginal Tears Caused by Sex

Sometimes you can endure minor, microvaginal tears during sex. This can lead to some light spotting or bleeding afterward. 

Typically, during arousal, blood flow is increased to the genitals including the vagina and a release of fluid occurs from a variety of places, including from the vaginal venous system, through the vaginal mucosa, and into the vaginal lumen. This provides natural lubrication and the absence of this lubrication can generate a feeling of dryness during sex. 

If you have sex while experiencing vaginal dryness, there is a higher risk of tearing and bleeding. According to The Cleveland Clinic, vaginal dryness can be a side effect of the following: 

  • A drop or change in hormones, particularly estrogen levels (commonly occurs close to menopause or while breastfeeding)
  • Certain medications like antihistamines 
  • Lack of foreplay before sex
  • Low sex drive (which may be impacted by your menstrual cycle phase)

Minor tears are not uncommon and the bleeding typically is light and quickly resolves. However, if you notice excessive bleeding or heavy bleeding right after sex it could be an indication of a major tear and you should visit your doctor ASAP.

To help relieve uncomfortable sex or spotting due to vaginal dryness, you can try regular drug store lubricant before and during sex. In more serious circumstances, you may also visit your doctor. 

Perhaps a Sign of Infection 

If you experience pain or a lot of bleeding after sex it could also be a sign of a vaginal or cervical infection. When a sexually transmitted infection is untreated, it can spread up through the reproductive tract and lead to  Pelvic Inflammatory Disease (PID). PID can be a source of pain and/or bleeding during and after sex. 

There are risk factors that can lead to vaginal, cervical, and reproductive tract infections: 

  • Sexually transmitted infections (STI), like chlamydia and trichomoniasis can travel from the vagina or cervix to one of the organs of the reproductive tract including the uterus and fallopian tubes.
  • Untreated STIs
  • Unprotected sex with multiple partners is a big one, so it’s always recommended to use a contraceptive, like a condom, when having sex with someone whose sexual history you don’t know very well.
  • Douches are another common (but lesser-known) cause of infection. Women typically use douches because it helps them ‘feel clean’ but douching is responsible for killing a lot of the ‘good’ and ‘healthy’ bacteria in your vagina. Douches offset the balance of healthy vulva and vaginal bacteria which can increase the risk of acquiring sexually transmitted infections and non-sexually transmitted infections as well...

Sexually transmitted infections can cause no symptoms at all or they can cause smelly discharge, a change in discharge color, irregular vaginal bleeding after sex, or irregular bleeding in general... 

If you have symptoms plus risk factors, plus lower abdominal pain, then you may have pelvic inflammatory disease and you should visit your doctor who will prescribe antibiotics or other medication to help. These infections will not go away on their own and can lead to things like infertility and pelvic abscesses. It is important to note that even non-sexually transmitted infections can lead to pelvic inflammatory disease.

See the CDC factsheet on PIDs here.

Gynecological Cancers

Gynecological cancers include things like cervical cancer, uterine cancer, and vaginal cancer. Post-sex bleeding is can be an early sign of these cancers. Other symptoms that usually accompany gynecological cancer include abnormal vaginal discharge and pelvic pain or pressure. 

If you notice these symptoms, you should visit your doctor to rule out the possibility of cancer and also make sure you are up to date with your pap smear screening as per age-related guidelines.

The American Cancer Society estimates that 113,520 women in the United States will be diagnosed with cancers of the reproductive organs in 2020. Developing cancer of any kind is very serious. So, it’s extremely important to take preventative measures for early detection and treatment. 

The best way to prevent cervical cancer is to get the HPV vaccine (recommended for ages 9-45yo) and to have regular pap smear screenings as per age-related guidelines. A Pap smear test (sometimes referred to as a smear test) is used to detect irregular cervical cells most commonly caused by the human papillomavirus (HPV). HPV is a common cause of cervical cancer so detection and prevention of HPV is a very effective preventative measure for cancer.

HPV can be prevented by either getting the vaccine (which is FDA approved for both men and women up to the age of 45) and using protection, like a condom, during sex.

Factors That *Can* Change Your Period Include Polycystic Ovary Syndrome, Birth Control & More

The menstrual cycle is an intricate physiologic process. It’s normal to experience subtle changes in your menstrual cycle and period month to month. While sex doesn’t affect or change your period, there are lifestyle, emotional, medical, and physical factors that can cause changes to your period.

Some of the things that delay or stop your period can be cause for medical concern but some are natural as well. So, track your menstrual cycles in a period app and if you notice anything unusual try to avoid going into panic mode! 

Natural Causes of Amenorrhea (or Missed Period)

  • Pregnancy (as mentioned above)
  • Breastfeeding: Breastfeeding can delay the return of your period for up to 6 months. and is referred to as lactational amenorrhea.
  • Perimenopause: Perimenopause means “around menopause”. Hormonal changes and estrogen irregularities during this time cause periods to become more infrequent.
  • Menopause: Menopause happens when your menstrual cycle comes to a complete end and is medically defined as having gone 12+ months without a period. 

Emotional & Lifestyle Factors That Cause Amenorrhea

  • Extreme stress: Extreme stress can affect the functioning of the hypothalamus which is a part of your brain responsible for hormone regulation. In non-medical terms, stress can send your menstrual cycle haywire. Once your level of stress decreases, periods should return to normal. 
  • Extreme exercise: Female athletes can often experience interrupted menstrual cycles. This is often due to energy deficiency which results from not taking in enough calories to balance the exercise output.  This causes hormone imbalance and can lead to temporary period loss, low bone mineral density, and increased risk of bone fractures and/or breaks. 
  • Extreme weight loss: Women who have significant weight loss especially within a short period of time or are severely underweight as per guidelines may experience hormonal changes that interrupt or halt ovulation and menstrual blood flow. 

Physical & Medical Factors That Cause Amenorrhea

  • Polycystic ovary syndrome (PCOS): PCOS is characterized by higher, sustained levels of certain hormones than normal.
  • Uterine fibroids or polyps: Growths on the inner lining of the uterus or within the uterus can cause irregular menstruation and heavy menstrual bleeding..
  • Uterine scarring: The presence of scar tissue on the uterine lining can interfere with the normal shedding of the endometrium. Scarring can be caused by procedures like cesarian section, polyp removal, or dilation and curettage (D&C) surgery after a miscarriage. 
  • Birth control: Birth control pills are meant to impact hormones so they naturally will disrupt the normal rise and fall of certain hormones.
  • Other medications: Some medications like chemotherapy treatments, antidepressants, and blood pressure drugs can affect period regularity
  • Hormone production disruption: Any other condition that can cause a hormone imbalance like an under or overactive thyroid gland or a tumor on the pituitary gland can lead to amenorrhea or abnormal menstruation

When to See a Doctor

Your period can fluctuate month-to-month due to any of these factors. It will also change more broadly as you get older. Many of these changes are totally normal and nothing to worry about. Having said that, there are times when these changes are cause for concern. As a general rule of thumb, you should always visit your health care provider if you:

  • Experience abnormally heavy or very irregular periods
  • Feel unusual pelvic pain
  • Miss one or more periods
  • Notice unusual and smelly vaginal discharge

Otherwise, do always discuss your period during your annual medical check-up. Note how many menstrual products you typically use on your heaviest day (as an indicator of heavy flow), whether you experience clotting (and, if yes, how big clots are), how many days your period lasts, the first day of your last period, and whether you have any additional symptoms (pain, nausea, headaches, etc.)

Most of the time, your healthcare provider will tell you that minor fluctuations are normal. But they are also the most qualified to tell you if something sounds concerning or could be improved with treatment. Worst case scenario: You’ll set your mind at ease, so there’s really nothing to lose!

Medically reviewed by Dr. Chimsom T. Oleka, M.D, Written by Jane Flanagan — Updated on September 20, 2021.