Why You Have Two Periods in One Month, According to an Ob-Gyn

Your flow can do some pretty wacky things from time to time. We asked an ob-gyn what might really be going on.

Your period doesn't get weird slang names—“on the rag,” “shark week,” and “code red,” to name a few—for nothing. To be frank, those two to seven days every month are annoying at best and agonizing at worst.

So getting two periods in one month seems entirely cruel. What is my body doing?! you shout to no one in particular. The silver lining of it all? Menstruation gives you a clue into what’s going on with your health—and this is one problem that may be about way more than just picking up an extra box of tampons this month.

First things first, we have to ask: Are you pregnant? “If you’re sexually active, this is one of the initial things I think about. Some women do get irregular bleeding when pregnant,” says Mount Kisco, New York-based ob-gyn Alyssa Dweck, MD, author of The Complete A to Z for Your V. And if you were trying for a baby, rest assured that the irregular bleeding can be totally normal and not indicative that there’s something wrong. Take a pregnancy test and, if positive, call your ob-gyn; they’ll let you know when they want you to come in for an appointment.

Now that that’s out of the way, you should also know that, well, nothing may be going on. “Just because you have two periods that happen to land within the same calendar month doesn’t mean there’s a problem,” says Dr. Dweck. That’s because a normal menstrual cycle is between 24 and 38 days, according to the American College of Obstetricians and Gynecologists (ACOG). If your period came at the very beginning of this month and then showed up again at the end, this falls within a typical window.

Consider your age too: Is it possible you’re going through perimenopause, a time when periods are known to do some pretty wacky things? This is the decade or so before you go through the transition to menopause; consider it a possible cause if you’re over 40 years old. “Perimenopause is a time when your hormones can be all over the place, ovulation can be sporadic, and you can get your period twice in a month," says Dr. Dweck.

The issue is if you’re bleeding sooner than that or in between periods. At that point, a too-soon period may indicate a hormonal imbalance with estrogen, progesterone, or testosterone, which are all involved in ovulation. “This can cause irregular ovulation. Essentially, your uterus isn’t sure when or how much to bleed,” says Dr. Dweck. As one example, the hormonal disorder polycystic ovary syndrome (PCOS) can cause irregular bleeding.

Then there’s your thyroid, the gland that regulates your metabolism. One that’s over- (hyper-) or under- (hypo-) active can change up the frequency of your flow, Dr. Dweck says.

As you can see, figuring out why you're suffering through two periods in one month isn’t so cut and dry. Other “structural” problems, like uterine fibroids or polyps may also bring on an additional bleed, and you can have breakthrough bleeding from an IUD or hormonal birth control pills, the ACOG notes.

All that's to say, be in touch with your ob-gyn, but don’t panic. “You can have a weird period episode, especially since stress, diet changes, travel, or exercise can cause irregularities, but if it’s happening over and over, you should be seen by your doctor,” says Dr. Dweck.

Along with a physical exam, he or she may run additional testing—blood work, ultrasound, etc.—depending on what’s suspected. After that, the underlying cause will inform treatment, whether it’s thyroid medication, a new birth control, or a plan for managing PCOS. Your body can do some weird stuff sometimes, but luckily your ob-gyn can help you crack this menstruation mystery.

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