You’ve been seriously bloated, moody and tired. You’ve got monster cramps, and your face is as pimply as a 17-year-old boy’s. In other words, you’re suffering from all of the classic signs of your monthly flow – but your period is totally MIA.

First: Don’t freak. It turns out, there are tons of reasons you’ve got those tell-tale period symptoms, but no period.

“Hormonal changes related to ovulation can affect some of the same pathways in your brain that might be affected by other medical conditions, causing mood swings that feel similar to your period but aren’t related to ovulation or menses,” says Dr Chailee Moss, an obstetrician and gynaecologist at Johns Hopkins Medicine. What’s more, some physical abnormalities in your uterus and ovaries can also cause cramping that feels like PMS, she adds.

While skipping a period every now and then is usually nothing to worry about, if you have a fever, significant nausea or vomiting, or pain that you can’t control with simple OTC medications or that doesn’t improve within a week, check in with your doctor right away.

Otherwise, it’s time to see your doctor if you skip more than three cycles in a row, suggests Chicago-based obstetrician and gynaecologist Dr Jessica Shepherd – here’s what might be going on down there.

1. Anovulation

Every once in a while, your body goes through all of the hormonal changes associated with PMS, but if you didn’t actually release an egg that month, you won’t actually get your period. Known as anovulation, it’s more common than one might think. “Ten to 18% of all regular cycles are anovulatory,” Dr Shepherd adds. In case you’re wondering, yes, that stat can make getting pregnant tricky!

Read more: 6 times your period blood looks different — and what it means about your health

2. Pregnancy

If you’ve had unprotected sex in the last month, were a bit lax about taking your pill, or rely on the pullout method for birth control, it’s worth taking a pregnancy test. Many of the symptoms of early pregnancy, including breast tenderness, mood swings, fatigue and cramping, are the same ones that you were already experiencing month to month before and during your period.

Think there’s a chance you could be pregnant? Take an at-home pregnancy test on the day that you expect your period. If it comes back negative, wait three to four days and try again. “One to two days can make a difference in a positive pregnancy test,” says Dr Moss.

3. Thyroid conditions

Your thyroid, a small butterfly-shaped gland in your neck, regulates many of your body’s functions, including your metabolism and menstrual cycles. If your thyroid gets out of whack, your cycles can become irregular, says Dr Shepherd. The result: You may you go a long stretch without having your period while still experiencing period-like symptoms, says Dr Moss.

Because your thyroid regulates your brain function, mood swings that you thought were PMS may be related to your neurologic function, she explains. And spotting or cramping may occur because the lining of your uterus has built up but hasn’t shed because you’re not ovulating.

Be sure to check in with your doctor if you’re experiencing other symptoms of a thyroid condition, including sudden unexplained weight loss or gain, shaking, heart palpitations or significant fatigue.

Read more: 5 alternatives to pads and tampons you should think about trying

4. Hormonal birth control

One very common side effect of hormonal IUDs is skipped periods. That’s because one of the ways the device prevents pregnancy is by thinning out the endometrial lining so there’s nothing to shed come that time of the month.

And, while they don’t typically nix your flow altogether, birth control pills can result in super-light flows or spotting. So you might feel period symptoms like breast tenderness even without a heavy, full-blown period, says Dr Shepherd.

5. Stress

Stress is a surprisingly common reason for missing your period. “Stress increases your cortisol levels, which affects your hormone balance,” says Dr Shepherd – including the hormones that regulate your ovaries and uterine lining.

Exams, the death of a family member and divorce are all big-time stress-inducing events that can cause periods to go awry. But these life-changing biggies aren’t the only reasons you might be feeling the effects of stress.

“Some people don’t realise they’re so stressed, but once they talk about it they realise they are going through something,” says Dr Shepherd. If you think stress is messing with your periods, talk to your doctor; therapy, exercise, yoga and meditation can all help get your stress under control and your periods back on track.

Read more: 5 period symptoms that might signal a serious health problem

6. PCOS

Frequent skipped periods can be caused by polycystic ovarian syndrome (PCOS). “PCOS is a condition in which a patient has an excess of androgens, which are chemicals in the body that affect ovary function, hair growth, weight gain and sensitivity to insulin,” says Dr Moss.

PCOS can result in anovulatory cycles and irregular spotting. It commonly causes cysts to grow on the ovaries, which, if they rupture or cause the ovary to twist, can cause pelvic pain that feels a lot like period cramps.

Up to 20% of women worldwide are affected by PCOS, and it’s more common among women who are overweight or have a mom or sister with by the condition, Dr Moss says. If you think you might be suffering from PCOS, check in with your doctor. While there is no cure, birth control and other medications can help keep symptoms under wraps and get your periods back on track.

7. Uterine polyps

You might associate polyps with your colon, but the same small benign tumors can grow in your uterus. “It’s an overgrowth of lining of the uterus,” says Dr Moss. Polyps in your uterus can cause cramping and period-like discomfort, even when you’re not on your period.

Because polyps can make it harder to get pregnant, and because there is a small risk they may develop into uterine cancer down the line, your doctor will likely want to remove them, most often with a relatively simple procedure known as a hysteroscopy. During a hysteroscopy, a doctor inserts a long tube up through the vagina and into the uterus. The doctor is able to use the scope to both see and cut out the polyps.

Read more: 11 signs your PMS is actually premenstrual dysphoric disorder

8. Ovarian cysts

Every month, your ovaries make several cysts in preparation for ovulation, but only one cyst releases an egg. Although the others usually dissipate on their own by the time you get your period, sometimes one cyst (or more) sticks around.

Cysts can also occur if you have an anovulatory cycle (such as with PCOS). Ovarian cysts often cause no symptoms at all, although they can sometimes trigger period-like pain when you’re not on your period. So if you’re experiencing irregular cramping, talk with your doctor.

“Cysts in and of themselves aren’t usually a problem,” says Dr Moss. “But if they get particularly large, they can cause the ovary to twist, which is painful and requires an emergency procedure to save your ovary.”

9. Gynaecological infections

Some sexually transmitted infections like gonorrhoea and chlamydia can result in a condition known as pelvic inflammatory disease, which can cause significant discomfort that feels like period cramping when you’re not expecting your period. UTIs can also cause period-similar pelvic pain, says Dr Moss.

Whatever your down-there infection, a round of antibiotics should help clear it up. So keep an eye out for red-flag symptoms including fever, significant nausea or vomiting, or pain that doesn’t go away with OTC pain relievers.

Read more: The surprising reason you’re getting side pains once a month

10. Mittelschmerz

If you’ve got PMS-like cramping, bloating, and breast tenderness but no period, one reason may be that it’s not quite time for your period yet – but it’s coming.

German for “middle pain”, mittelschmerz happens about half-way through your menstrual cycle – around day 14 or the time they ovulate, says Dr Nicole Scott, an obstetrician and gynaecologist at IU Health. It’s a totally normal experience – affecting about 20% of women – and it doesn’t mean anything is wrong, she says. Since it’s just your ovaries doing their thing, there’s not much you can do to prevent it and the symptoms should go away within a day or two but if it’s extremely painful or comes with any sign of infection, call your doctor, she adds.

11. Exercising too much

Hitting the gym on the regular is one of the best things you can do to help deal with PMS, but working out too hard or too often can actually mess up your cycle and in some cases make you miss your period all together, Dr Scott says.

All the physical stress, especially if you lose a lot of body fat, can make your period go AWOL and cause abnormal fluctuations in your hormone levels. These fluctuations can cause moodiness, irregular spotting, acne and other PMS-like symptoms. If you miss your period for three cycles or more in a row, talk to your doctor.

12. Ovarian cancer

Ovarian cancer is relatively rare, affecting only about 22 000 women a year in the US, but it’s one of the deadliest cancers for women, killing about 14 000 women a year. A big part of this is because it often shows no, or very subtle, symptoms, Dr Scott says.

Missing your period isn’t the most common symptom of ovarian cancer – those are abdominal bloating, urinary problems, weight loss and pain – but it is a possible symptom, according to the American Cancer Society. So if you’ve missed your period for three months or more or you have other concerning symptoms, call your doctor immediately.

^{This article was originally published on www.womenshealthmag.com}

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