Reasons why your period is suddenly lasting forever

Honestly, there's a pretty big range of normal when it comes to your period's length (a typical one can last between two to seven days). If your period is a day or two more or less than your usual, and you don't see any other issues (like extreme menstrual pain or very heavy bleeding), you likely don't need to be concerned.

But-and there's always a but, isn't there?-if your period lasts 10 days or more, or suddenly changes significantly in length for three or more cycles in a row, that warrants a call to your ob-gyn, says Tom Toth, M.D., a reproductive endocrinologist at Boston IVF.

Still, there's no need to panic-most causes of prolonged menstrual bleeding (like most of the ones below) aren't a big deal and can be fixed or improved with the help of your doctor, says Toth.

1. You have an IUD.

One of the most common causes of long periods in younger women are intrauterine devices (IUDs), a type of birth control placed directly into your cervix. There are two main types: a non-hormonal, copper-based IUD (like Paragard), and a hormonal, progestin-based IUD (like Mirena and Skyla).

It turns out that both can cause abnormally long bleeding, especially right after insertion, Toth says. Longer, heavier periods are a known side effect of the copper IUD. The progestin IUD, however, is often marketed to women as a way to reduce or even eliminate their periods. And while it typically does have that effect over time, the first few cycles may have more or longer bleeding than usual, he says.

With either IUD, if the prolonged periods don't settle down after three cycles, it's time to go back to your doctor, as it's possible the IUD moved out of position or simply doesn't play nice with your body.

2. You're actually ovulating.

Menstruation is your body's way of getting rid of the extra blood and tissue it saved up in case your egg got fertilized and there's a baby, but sometimes the hormonal signals get crossed and you can bleed when you release the egg too, says Sherry Ross, MD, an ob-gyn and author of She-ology.

That's called "intermenstrual bleeding," and it occurs when the slight dip in estrogen that happens around ovulation causes some spotting. If the bleeding lasts a few days or happens close to the end of your last cycle, it may seem like your period is continuing forever. It's not normally something to worry about, but if it changes suddenly or if you have serious pain, it's time to see your doctor.