a woman with malaise

There’s a saying to the effect that sex is like pizza: Even when it’s bad, it’s good. One notable exception, however, may be when you start feeling nauseous after sex. Instead of basking in the afterglow, you’re staring at the ceiling, wishing the room would stop spinning and worrying you might actually throw up on your partner. Or possibly on yourself. In either case, it’s not a good feeling. Nor is feeling nauseous after sex "normal" per se, according to Dr. Adeeti Gupta, an OB/Gyn in Manhattan (via Refinery29). But, yes, it can happen — and not just to women, but to all genders, according to Dr. Shirin Lakhani, a UK-based intimate health specialist (via Marie Claire).

There are a variety of reasons why you might feel nauseous after sex, but one thing on which you may rest assured is that post coital nausea is a sign of neither pregnancy nor miscarriage. Although nausea may be associated with early pregnancy, it takes at least a number of days following conception for the pregnancy hormone, human chorionic gonadotropin, to reach a high enough level so as to cause nausea (per the Mayo Clinic). And in order for a miscarriage to take place, there has to first be implantation of the embryo into the uterine wall (via USC Fertility). And that process takes a number of days as well, according to UCSF Health. So, let’s take a look at what it actually might be.

Nausea after sex could be a sign of dehydration

man in bed reaching for glass of water

"The human body is about 70 percent water," explains Paula Burke, clinical dietitian at MetroSouth Medical Center in Blue Island (via Chicago Tribune). Since all of the bodily systems use and/or lose water as they function, your water volume must constantly be replenished (via the Mayo Clinic). And the Mayo Clinic defines dehydration as being in any state of deficit with regard to water replenishment, all the way from the mildest to the most severe. Although severe dehydration is more likely to put one in imminent danger, even mild dehydration can make you feel off, or even "rotten," as Financial Review puts it. Accordingly, if you find yourself feeling nauseous after sex, perhaps the first thing you should ask yourself is whether dehydration might be your "Occam’s razor" (i.e., the best explanation because it’s the simplest), according to Marie Claire.

So, how much should you be drinking to avoid dehydration-related nausea after sex? The CDC doesn’t offer a specific recommendation with regard to what level of fluid intake constitutes optimal hydration because it varies too much among individuals. However, CDC epidemiologist, Dr. Alyson Goodman suggests that for most adults, it’s most likely somewhere in the vicinity of four 8-ounce glasses of water per day (via Chicago Tribune). Nevertheless, 43% of all adults surveyed by the CDC in 2013 reported drinking less than that, with 36% drinking just one to three glasses per day.

Endometriosis can cause nausea during and after sex

a woman in bed folds her arms over her eyes

Sometimes the presence of endometriosis can cause post coital nausea, according to Janet Brito, PhD, a clinical psychologist and sexologist in Honolulu, via Women’s Health. In endometriosis, tissue similar to that of the uterine lining grows outside the uterus (via Johns Hopkins Medicine). Endometriosis affects up to 10% of women, in whom it can cause "excessive menstrual cramps, abnormal or heavy menstrual flow, and pain during intercourse," according to Johns Hopkins. It can also hinder conception. Perhaps surprisingly, men too are at risk for endometriosis, although only in rare instances. One such time was described in a 2014 case study, in which a man who presented with abdominal discomfort was ultimately diagnosed with endometriosis.

As for where the nausea comes in, apparently, the pain caused by endometriosis has been characterized as "intolerable" by some, according to Atrium Health — and when the pain presents in connection with sexual intercourse, it may last up to two full days and may be "accompanied by vomiting and nausea," a well as "confusion and depression." Atrium Health recommends speaking with a healthcare professional if you’re experiencing post coital nausea concurrent with pain, because endometriosis could be the culprit, and treatments are available that can provide relief, according to Atrium Health.

Additionally, since endometriosis may correlate with increased stroke risk (via Medical News Today), it might be a good idea to consider what’s in your power to do to decrease your stroke risk.

Pain from fibroids

a doctor reads x ray films

Uterine fibroids (aka fibroids) are benign neoplasms that grow in or on the uterus. They’re so common among women that, by age 50, as many as 80% have had a fibroids diagnosis (via USA Fibroid Centers). Like endometriosis, fibroids are not, in an of themselves, life-threatening. Also, like endometriosis, however, fibroids can do a number on your quality of life, and that includes your sex life. Just as endometrial growth outside the uterus (i.e. endometriosis) can induce nausea both during and after sexual activity, so too can growth in the uterus of benign fibroid tumors.

Penetration — any penetration, whether or not deep, could potentially hit a fibroid. That, in turn could cause discomfort, including pain and nausea, according to women’s health expert, Dr. Erin Carey (via Women’s Health). In addition, fibroids are often associated with excessively heavy periods. A heavy period, alone, can lead to feelings of malaise, but depending on how heavy it actually is, it could even cause iron deficiency anemia, according to Healthline. Although iron deficiency is not associated with nausea, iron supplementation is, according to another piece published by Healthline.

Accordingly, if you’re already taking iron supplements, whether or not in connection with fibroids or heavy periods, then that could also explain your nausea, which is a known side effect of iron supplementation.

Vasovagal syncope could be the cause of your post-coital nausea

a woman uncomfortable in bed

Vasovagal syncope describes an episode in which your blood pressure and heart rate decrease suddenly — usually in response to a particular trigger, according to the Mayo Clinic. It can also leave you feeling nauseous, so if you’re feeling nauseous after sex, that could indicate that your sexual activity is a trigger (via Marie Claire). While vasovagal syncope is not a "normal" state of being, per se, it’s also not necessarily something to worry about. According to Cedars-Sinai, it is rarely associated with serious disorders. On the other hand, experiencing post coital nausea probably isn’t on your bucket list, and if it’s being triggered by vasovagal syncope, then nipping it in the bud would seem the obvious solution.

One way that intercourse may trigger vasovagal syncope is deep vaginal penetration. "The cervix is full of nerve endings," explains Dr. Lakhani, and vasovagal syncope involves stimulation of the vagus nerve in particular. Ejaculation has also been associated, albeit rarely, with vasovagal syncope, according to a 2009 study published in the British Medical Journal, Heart. In any case, if you’ve felt nauseous after sex, accompanied by dizziness or even fainting, you might wish to see a healthcare professional to confirm whether vasovagal syncope is the cause and what can be done to prevent it going forward.

Technique might be to blame

photo from From Here To Eternity

As unfair as it may seem, it’s possible that the cause of your post coital nausea is something you’re doing while you’re "doing it." As discussed above, deep vaginal penetration can trigger a vasovagal response, which can lead to feelings of nausea. There is also the possibility that you’re moving around so much that it’s actually causing you to experience motion sickness (via Women’s Health).

If you think that motion sickness might be the culprit for you, then it might be worth consulting with your healthcare provider about the possibility you’re dealing with vertigo. Medical News Today explains that vertigo is an inner ear disorder that presents with dizziness "that causes a person to feel as though they are spinning." That spinning feeling is often accompanied by nausea, and even vomiting. It’s also associated with loss of balance (although that may not be apparent if you’ve been lying around after sex). On the other hand, something else to keep in mind is that while some people with vertigo do suffer bouts of it after sex, they usually also experience it at other times as well.

Nausea after sex can also be caused by the uterine contractions that naturally occur at the time of orgasm, according to Dr. Erin Carey, assistant professor and director of the University of North Carolina’s Minimally Invasive Gynecologic Surgery division. Carey suggests taking a non-steroidal anti-inflammatory drug like ibuprofen or naproxen before having sex, which could help to reduce those contractions.

You might have a kidney infection

a man with back pain getting out of bed

A kidney infection is a urinary tract infection that either originated in the kidneys or originated in either the bladder or urethra and then spread to the kidneys (usually because the initial infection has not been treated), according to the Mayo Clinic. One of the symptoms of a kidney infection, which is also known as pyelonephritis, is nausea that may or may not be accompanied by vomiting. There will usually also be pain in the back and belly, fever, and chills, as well as frequent and painful urination. If you’re feeling well enough to have sex, you probably don’t have a kidney infection.

On the other hand, some low-level kidney infections are asymptomatic, or at least they start that way (via Stanford Health Care). And it’s in that scenario where nausea following sex could be just the beginning of symptoms of kidney infection. And if you have more than one of these symptoms in addition to nausea, best practices dictate getting in touch with your healthcare provider to discuss the possibilities, which might include kidney infection. It’s important because kidney infections can do damage to the kidneys and can also spread beyond the kidneys. Most kidney infections respond well to antibiotics (and by well, we actually mean, get vanquished by) damage to the kidneys. Or the bacteria can spread to the bloodstream and cause a dangerous infection (per the Mayo Clinic).

Gastrointestinal issues

a woman with gastritis

Irritable Bowel Syndrome, aka IBS, can cause nausea at the worst times, according to a self-professed sufferer writing for Self. "I have irritable bowel syndrome, or IBS. I also happen to really like anal sex. As you can imagine, the two don’t always go together," they note. The same is also true for other forms of sexual activity, according to Patient, which explains that in people with IBS, sex can bring on symptoms. Nausea is just one of the various gastrointestinal symptoms that IBS can cause both before, during, and after sex. Others include stomach cramping and the sudden onset of diarrhea (via Self). And IBS is just one of the various gastrointestinal issues that may cause one to experience nausea after sex.

Chronic constipation may also cause you to feel nauseous after sex (via Arthritis Health), which states, "In severe cases, constipation can be painful or even life-threatening. Because normal bowel frequency can vary greatly from person to person, many people may not be entirely sure whether or not they are constipated." And, according to Self, if peptic ulcer is present, nausea is almost inevitably accompanied by heartburn and stomach pain, according to the Cleveland Clinic. In addition, a bowel obstruction could be to blame for nausea, whether after sex or otherwise, especially if it occurs with cramping, bloating, and/or constipation (per Johns Hopkins Medicine). Nausea is also one of the systemic symptoms of colon cancer, according to the Cancer Center.

An allergic reaction

man having an allergic reaction in bed

In rare instances, nausea after sex may be attributable to an allergic reaction — either to something one’s partner ate to which one is allergic (via Women’s Health) or to semen itself, according to Planned Parenthood. Semen allergy is rare (per Healthline). In fact, a 2011 review published in the Mount Sinai Journal of Medicine estimates that only around 40,000 women are affected. In addition, some number of men may also be allergic to semen, according to a 2011 research study investigating the causes of post orgasmic illness syndrome, or POIS, which is discussed in more detail below (via MedicalXpress). If it is a semen allergy that is causing you to feel nauseous after sex, then the answer could be as simple as incorporating a condom into your sexual activity, according to the 2011 review.

It would also be rare to become ill from your partner (in sexual activity) having eaten something to which you’re allergic, according to Women’s Health. Nevertheless, it is possible, as was described in a 2007 case study involving a woman who experienced an allergic reaction after intercourse with her boyfriend, who had eaten Brazil nuts (a common cause of nut allergy), to which the woman was allergic. Doctors confirmed that it was the Brazil nuts (not the semen) by conducting skin-prick testing of the boyfriend’s semen before eating Brazil nuts and after. "We believe this to be the first case of a sexually transmitted allergic reaction," the case study authors wrote.

Post Orgasmic Illness Syndrome (POIS)

a couple having tension in the bedroom

Post-orgasmic illness syndrome, or POIS, "is a rare condition in which a person develops flu-like and allergy symptoms after orgasm," according to the National Institutes of Health’s Genetic and Rare Diseases Information Center. POIS was only first clinically documented in 2002, according to MedicalXpress, and as of 2018, only 50 cases have been reported in medical literature, according to ScienceDirect. POIS is experienced primarily by men following ejaculation, whether immediately or after a delay of several hours, per Rare Diseases. However, "POIS may also occur — although rarely — in females," according to a 2016 academic paper published in the journal of Translational Andrology and Urology.

Symptoms of POIS vary among individuals, but since nausea is only one flu-like symptom, it is unlikely that POIS would be the culprit of your post coital nausea unless you’re experiencing other flu-like symptoms, including "fatigue, weakness, headache, fever, mood changes, memory or concentration problems, stuffy nose, sore throat, and itching eyes" (per Genetic and Rare Diseases Information Center). POIS symptoms may last for as long as a week and may cause emotional distress. Its cause is not yet understood, but some experts believe that it may be autoimmune in nature while others think it might have something to do with a chemical imbalance. A preliminary study from 2020 published in Urology Case Reports suggests that administration of human chorionic gonadotropin may provide some relief.

Dysorgasmia could also be to blame

a woman looks miserable in bed

If you’re a woman experiencing nausea after orgasm that is also accompanied by pelvic and/or abdominal pain and/or cramping, it’s possible that the condition known as dysorgasmia is to blame, according to Dr. Grace Huang of the DTAP Clinic Robertson (via AsiaOne). One thing that distinguishes dysorgasmia from other conditions that may cause pain and related nausea after sex is that dysorgasmia is specifically brought on by orgasm (per Femina Physical Therapy). The website defines dysorgasmia "as a painful orgasm, but without any prior pain during sexual intercourse." Symptoms of dysorgasmia may last from seconds to several hours.

The most common cause of dysorgasmia is "pelvic floor muscle dysfunction," which is characterized by rapid contraction of the pelvic floor muscles during orgasm, according to University Hospitals. However, dysorgasmia may occur as a result of some of the other conditions we’ve been discussing, including endometriosis and uterine fibroids, as well as in connection with a kidney or other urinary tract infection. It may also occur in connection with pelvic inflammatory disease (PID) and underlying disease of the reproductive tract. Here are the symptoms women should never ignore.

In addition, mood disorders such as anxiety or depression may contribute to or exacerbate dysorgasmia (per University Hospitals). So too can occasional bouts of personal stress, lingering distress related to previous trauma, and/or issues with self-esteem or body image, per AsiaOne. Dysorgasmia could also present in connection with Sexual Aversion Disorder, discussed below.

Sexual Aversion Disorder

a woman sits pensive at the foot of her bed

Sexual Aversion Disorder, aka SAD, is a "persistent or recurrent extreme aversion to, and avoidance of, all or almost all, genital sexual contact with a sexual partner" which causes distress or interpersonal difficulty, according to a 2010 paper published in the Archives of Sexual Behavior. SAD is one of only two sexual desire disorders that appear in the Diagnostic and Statistical Manual of Mental Disorders (which is regarded as the diagnostic bible/dictionary, depending on whom you ask, in mental health care); the other is Hypoactive Sexual Desire Disorder, which refers to a low sex drive.

Individuals suffering from SAD may be "highly avoidant of all forms of sexual contact." In fact, the mere thought of sexual contact may induce nausea, according to the Center for Treatment of Anxiety and Mood Disorders. But that should probably be the tip-off for you right there. If you’re feeling nauseous after sex, that means that you’ve had sex, and hopefully consensually. Assuming that’s the case, then it seems unlikely that what you’re experiencing rises to the level of SAD.

There are some who believe that SAD is more of an anxiety disorder than a sexual disorder, according to the University of Texas at Austin. In any case, if you do recognize the symptoms of SAD in yourself, you can rest assured that it is treatable using "systemic desensitization," which involves a very gradual re-introduction to the trigger while engaging in relaxation techniques.

Mental health issues may contribute to nausea after sex

an anxious man in bed

"If you’ve ruled out all of the potential physical medical triggers that could be causing your nausea, it might be time to look inwards and address the psychological ones," according to Dr. Shirin Lakhani, a UK-based intimate health specialist (via Marie Claire). These may include both dysorgasmia and Sexual Aversion Disorder, as discussed above. But they also may be somewhat more mundane, according to Dr. Adeeti Gupta, OB/Gyn (via Refinery 29).

For example, your basic garden variety anxiety about sex can cause "butterflies in your stomach or nausea," Dr. Gupta points out. However, if that’s all that’s at work, then the nausea will usually pass "once the pleasurable experience of sex sets in," adds Dr. Gupta. On the other hand, this would tend to suggest that the nausea might return once the pleasurable experience of sex has passed. If that’s the case, and, particularly, if you’re feeling nauseated most of the time after sex, then it’s possible you’re responding to "something about the experience or person that’s making you uncomfortable." If so, it might be worth sharing your experience with a trusted mental health professional.

It’s also worth noting that if you’re already taking an SSRI to treat anxiety or depression, that too could factor into your post coital nausea, according to SingleCare — which also reports nausea and sexual dysfunction are among the common side effects of SSRI medications.