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Can a guy kick start your period?

It’s a common question that many women ask – can having sex with a guy actually induce or “kick start” your period? The short answer is yes, it is possible for a guy to help kick start your period in some circumstances. However, there are a lot of factors involved and it doesn’t work for everyone. In this article, we’ll explore the connection between sex and menstruation, look at the science behind it, and discuss some tips for using sex to try to induce your period.

The Link Between Sex and Menstruation

There does appear to be a link between sexual activity and the onset of menstruation. Some key points:

  • Having an orgasm causes uterine contractions which may help shed the uterine lining
  • Semen contains prostaglandins which can help ripen the cervix and induce menstruation
  • Sex triggers hormone changes which influence the menstrual cycle
  • Physical stimulation from sex may disrupt the hormones that delay menstruation

So in theory, the act of having sex – specifically heterosexual vaginal intercourse – can provide the physical and hormonal stimulation needed to start the menstrual flow for some women.

The Science Behind Sex Inducing a Period

Scientifically speaking, here is what happens in the body that allows sex to potentially kick start a period:

Uterine Contractions

When a woman has an orgasm, her uterus contracts. These contractions are one way that having an orgasm from sex might help shed the uterine lining and start bleeding. The muscular contractions can apply pressure to the uterus, dislodging some of the tissue lining built up inside. If enough lining is shed, this can result in a light menstrual flow.

Cervical Ripening

Semen contains high levels of prostaglandins – hormones that help ripen or soften the cervix. When semen comes into contact with the cervix during sex, the prostaglandins are absorbed. This can help induce menstrual bleeding by softening and dilating the cervical opening, allowing the lining to be discharged.

Hormone Changes

Sex triggers the release of several hormones, like oxytocin, prolactin, and cortisol. These hormones influence bodily processes like pregnancy, bonding, and menstruation. Fluctuating hormone levels around the time of ovulation can contribute to an environment that promotes the shedding of the uterine lining when sex occurs.

Disrupted Menstruation Delay

Some research indicates that orgasms (from sex or masturbation) may disrupt hormone signals that delay menstruation. Having an orgasm produces oxytocin and decreases production of hormone like prostaglandin F2alpha which tells the body to delay menstrual bleeding. This interruption can therefore allow an impending period to start.

Tips for Using Sex to Induce a Period

If you’re trying to use sex as a way to induce menstruation, here are some tips that may help:

  • Have sex around the time of expected ovulation or just before your anticipated period. This is when the uterus is primed and cervix is softest.
  • Make sure to orgasm – this causes key bodily changes like uterine contractions.
  • Have sex regularly – the more you have sex, the higher chance of triggering menstrual flow.
  • Try positions with deep penetration to stimulate the cervix.
  • Stay relaxed before and after sex to benefit from hormonal changes.
  • Consider using sperm or prostaglandin supplements as well to enhance effect.

Keep in mind results can vary based on the individual and where you are in your cycle. Be patient and keep trying every few days around your predicted period.

When Does Sex Work Best to Induce a Period?

Timing can be key for effectively using sex to bring about menstruation. Some of the best times to try are:

  • Right Before Your Expected Period: Have sex in the days leading up to when you expect your next period. This is when PMS symptoms show up and the uterine lining is ready to shed.
  • When Ovulating: Have sex during your fertility window, around days 10-15 of your cycle. Increased estrogen during ovulation primes the uterus.
  • After a Delayed Period: If your period is late, having sex can help get it back on track.

The days closest to when you would normally expect your period are ideal, as your body is already gearing up for menstrual flow. However, results can vary so you may want to try having sex regularly in the days leading up to your anticipated period as well as when ovulation hormones are peaking.

How Quickly Can Sex Induce a Period?

Many women wonder how quickly having sex might trigger their period to start. Here’s a look at the timeline:

  • Within Hours: Some women do start their period within hours of having sex. This may occur if your period was already imminent.
  • 24-48 Hours: For most, period occurs 1-2 days after sex. This allows time for hormonal changes like cervical ripening.
  • Longer Delay: It can take 3-5 days or more. Give it time, repeat sexual activity, and consider combining with other period-inducing methods.
  • May Not Induce: Having sex does not induce menstruation for every woman. Cycle timing, hormones, and other factors play a role.

So while you may see bleeding shortly after sex, it more commonly takes up to a couple of days for the full period flow to begin. Allow some time for the hormonal effects to take place.

Effectiveness of Sex for Inducing a Period

Studies show mixed results when it comes to how effective having sex is for jump starting a delayed period. Some key points on effectiveness:

  • Up to 50% Success Rate: Roughly half of women do get their period within a few days after having sex, based on estimates.
  • Depends on Circumstances: Having sex is more likely to induce menstruation when you’re due for your period anyway.
  • Not as Effective Alone: Sex works best when combined with other period-inducing methods like massage.
  • Varies Individually: Some women readily get their periods from sex while others do not.

So having sex can be a toss up – it may cause menstrual bleeding for many women but there’s no guarantee. Consider pairing it with other remedies or speak to your doctor if your period is very delayed.

Risks and Considerations

Before trying to use sex to induce your period, keep the following risks and considerations in mind:

  • Won’t Work if Pregnant: Sex can’t induce a period if you are pregnant. See your doctor to find out why your period is late.
  • Risk of Infection: Having sex with a new partner when not using protection increases your risks of STDs.
  • Partner Cooperation: You’ll need a cooperative sexual partner to try this method regularly.
  • Spotting Only: Sex might only cause minor spotting for some women rather than a full heavy flow.
  • Consult Your Doctor: Speak to your OB-GYN before trying this if you have any medical concerns.

While generally safe, talk to your doctor if you experience severe cramps, heavy bleeding, or other worrying symptoms after trying to induce your period by having sex.

Other Ways to Induce Your Period

While sex can sometimes help kick start your period, there are also many other ways to induce menstruation including:

  • Taking Progesterone Supplements: Progesterone helps build up the uterine lining which triggers shedding and bleeding.
  • Vitamin C: Loading up on vitamin C may help promote menstruation through hormone pathways.
  • Heat Therapy: Applying a heating pad or taking a warm bath helps increase blood flow to the pelvis.
  • Acupuncture: Acupuncture sessions may help regulate the hormones and prompts the period to start.
  • Fennel andParsley: These herbs have emmenagogue properties to stimulate blood flow.
  • Turmeric: Anti-inflammatory and hormone-balancing properties of turmeric may stimulate menses.
  • Massage: Abdominal massage helps discharge built up uterine tissue and encourages menstruation.

You can try these remedies alone or pair them with sexual activity to maximize your chances of getting your period. However, see your doctor if your menstrual cycle remains irregular.

When to See a Doctor

While using sex to induce your period can be safe for many, in some cases you should see a doctor for a missed or delayed period, such as:

  • No period for over 3 months if previously regular
  • Missing 3+ consecutive periods
  • Extremely heavy, painful, or prolonged periods
  • Negative at-home pregnancy test with no period
  • Underlying medical conditions like PCOS or endometriosis
  • Trying to conceive with irregular cycles
  • Recent birth control or medication changes

Your doctor can check for any underlying problems and provide appropriate treatment to regulate your menstrual cycle. Don’t hesitate to seek medical advice for major changes.


Having sex is something that may work to help induce your period for some women – but not every woman. The hormonal changes, uterine contractions, and physical stimulation provided by sex may create an environment that allows menstruation to occur. However, there are no guarantees and results vary individually based on your cycle. For best results, have sex in the days right before your expected next period or when ovulation is occuring and combine the technique with other remedies. While generally safe, be aware of risks like infection and when you need to see your doctor. If used carefully and correctly, sex can be part of bringing about a delayed or irregular period. However, speak to your OB-GYN if your menstrual issues persist despite your best efforts.