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Content note: This article contains mentions of pregnancy loss.

Miscarriage is most likely to occur early in pregnancy (typically within the first 3 months), and for many women, it can happen before they even realize they’re pregnant.

Spotting during pregnancy is also fairly common — as many as half of all pregnant women may experience it.

So how exactly can you tell the difference between a regular period, pregnancy spotting, and bleeding that could be a sign of pregnancy loss or another complication? Here’s what to know, plus when spotting or bleeding warrants a call to your doctor.

(Deep breath — whatever the cause, you can handle it.)

Miscarriages are pregnancy losses that occur within the first 20 weeks of pregnancy. And while they’re relatively common, affecting 10 to 15 percent of known pregnancies, they can look different for different people.

Bleeding is, of course, one of the common symptoms.

Some women have light spotting for a few hours and that’s it. (And if it happens super early in the pregnancy, you might not even realize it’s a miscarriage.) Others have heavier bleeding for several days that looks and feels a lot like a period.

You might also pass other fluids or even tissue that appears as larger, clotted clumps.

So how can you tell miscarriage bleeding from a period or pregnancy spotting? Bleeding caused by a miscarriage also often causes cramps or abdominal pain. And if you had been experiencing early pregnancy symptoms — like breast tenderness or nausea — a miscarriage will cause those symptoms to stop.

Even with all those potential signs, it’s not always possible to tell at home whether you’re having a miscarriage. If you suspect you might be experiencing one, call your OB/GYN. They’ll likely do an exam and run some tests to find out what’s going on and confirm the diagnosis.

PMS and early pregnancy share a lot of symptoms, and some of those symptoms can also apply to a miscarriage.

If your bleeding is a period, it will look and feel like your ordinary monthly visitor. Signs and symptoms include:

  • losing roughly 2 to 3 tablespoons of blood over 5 to 7 days (Your flow may be lighter or heavier, but you should have an idea of how much you typically pass.)
  • breast tenderness
  • mood swings
  • stomach cramping
  • acne or breakouts
  • fatigue

Gentle reminder: If you notice any of these additional symptoms, you may be experiencing a miscarriage:

  • abdominal, back, or pelvic pain or cramps
  • a sudden end to pregnancy symptoms like nausea and frequent urination
  • vaginal discharge (pinkish mucus, blood, tissue, or clots)
  • weight loss

It’s 1,000 percent worth repeating that spotting does not automatically mean you’re having a miscarriage or dealing with another complication. Lots of different things can cause very light bleeding during pregnancy.

In the first trimester, it’s common to experience spotting due to implantation, hormonal fluctuations, or changes to your cervix. Light bleeding from these kinds of things is pretty normal and not usually cause for concern.

Even later on, in your second and third trimesters, spotting can happen as a result of harmless things like sex or a run-of-the-mill OB/GYN exam. As you close in on your due date, a little bit of blood or blood-tinged mucus could also mean your baby is getting ready to come on out into the world.

Usually, you can tell that this kind of bleeding is probably NBD if it’s light and isn’t accompanied by any other symptoms. But how light is “light”? Think a few drops of pink, red, or brown blood in your underwear for a short period of time.

If you know you’re pregnant and you’re experiencing spotting or bleeding, it’s never a bad idea to keep your doctor in the loop. Definitely give your doc a call if you have bleeding that’s heavy enough to warrant a panty liner or pad or if the bleeding comes with other symptoms, since you could be dealing with a complication.

In addition to pregnancy loss, bleeding could be a sign of an infection, problems related to the placenta, or preterm labor, which all require medical attention.

If you were expecting Aunt Flo and are noticing new symptoms such as vaginal discharge; passing tissue or larger clots; cramping in your abdomen, lower back, or pelvis; or the sudden disappearance of common pregnancy symptoms like nausea, give your doctor a call.

In short, err on the side of caution. When calling your doc, be prepared to tell them what the spotting or bleeding looks like, when it started, how long it’s been happening, and whether you’re having any other symptoms (keeping a journal of symptoms can help). From there, your doctor can help you determine what’s going on and what to do next.

Whether you’ve been actively trying to conceive or you weren’t expecting to be expecting, facing a miscarriage can be scary and come with a range of emotions.

Start with the facts, and remember that your doctor is available to help on all fronts.

Early losses occur in about 1 in 10 known pregnancies, so the odds are relatively low (and if it does happen, you’re far from alone in your experience). What’s more, having a miscarriage doesn’t mean you won’t be able to get pregnant or have a healthy baby in the future.

If you’re worried about miscarrying or are having trouble processing a miscarriage, let those thoughts out. Open up to your partner or a trusted friend. Ask your doctor about mental health resources and support groups that can help you cope. Most importantly, remember that there are tons of resources available to help you get through this.