There may be a higher risk of miscarriage for those with endometriosis, which occurs when certain tissue builds up outside of the uterus and can’t be cleared out during a period.

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Endometriosis occurs when endometrial-like tissue builds up outside of the uterus. That means the tissue can’t be expelled through the vagina during a period. Endometriosis may affect fertility in some people.

Once pregnant, symptoms of endometriosis may be temporarily alleviated. They tend to return once the pregnancy is complete.

It was previously thought that once a person with endometriosis became pregnant, the condition wouldn’t affect their pregnancy. However, some studies have shown a link between endometriosis and miscarriage, though the reason isn’t clear. A miscarriage is classified as a pregnancy loss that occurs before 20 weeks of gestation.

Here’s what science says about the link between endometriosis and miscarriage.

Two large studies looked at the relationship between endometriosis and miscarriage. Both studies found endometriosis to be a risk factor for miscarriage.

One review of studies found a significantly increased risk of previous miscarriage for people with endometriosis. The other cites that the increased risk of miscarriage for people with endometriosis is almost 80 percent. These studies were carried out in 2016 and 2017.

Another 2017 study found that milder cases of endometriosis in particular were related to a greater risk of miscarriage.

However, a 2019 cohort study of people undergoing in-vitro fertilization (IVF) found no statistically significant increased miscarriage risk in those with endometriosis.

More research is needed to definitively determine whether endometriosis is a risk factor for miscarriage.

There are other factors that could increase the risk of miscarriage. Being 35 years of age or older is one risk that affects all genders.

For the pregnant partner, additional risks include:

Many people wonder if they’ve done something wrong following a miscarriage. Most miscarriages occur because the fertilized egg in the uterus isn’t developing normally, not because of anything they did. Miscarriages aren’t caused by exercise, stress, or sex.

If you experience the following symptoms during early pregnancy, it could mean that you’re going to have or are having a miscarriage, and you should seek immediate medical attention:

  • vaginal bleeding
  • pain and cramping in your lower abdomen
  • fluid releasing from your vagina
  • tissue releasing from your vagina
  • a cessation of pregnancy symptoms

Some light bleeding in pregnancy before 12 weeks can be normal — it isn’t necessarily because of a miscarriage. Discuss your symptoms with your doctor, who may give you an ultrasound to determine whether the fetus is still living and developing as expected.

If your doctor does determine that you’re having a miscarriage, there isn’t usually anything they can do to prevent it. Knowing what is happening can help some people to process it psychologically.

Your doctor will also want to monitor you. Occasionally, tissue from the pregnancy may be retained in the uterus following miscarriage. That can lead to complications. Your doctor will want to be sure this isn’t happening to you. If it is, you may need some medication, or in rare cases, a minor operation.

Doctors don’t understand the reason for the potential link between endometriosis and miscarriage, so there’s nothing they can do to reduce your risk. However, they will want to monitor your pregnancy closely.

You may be able to help reduce your risk of miscarriage by avoiding all of the other risk factors for miscarriage.

You may have trouble conceiving if you have endometriosis. You may also be at increased risk for miscarriage once you’ve conceived. Some studies have found evidence that the incidence of miscarriage in those with endometriosis is likely higher than in those who don’t have it.

More research is needed in this area to understand the reasons behind these results.

Generally, a miscarriage occurs when a fetus isn’t developing correctly. In these cases, there is nothing you can do to prevent it from happening. If you experience signs of a miscarriage, speak with your doctor immediately to determine what is happening, and whether you need any treatment.

It’s normal to have feelings of grief following a miscarriage, and your doctor can help you find support.