What Can Cause a Miscarriage

What Can Cause a Miscarriage: You Did Nothing Wrong

Having a miscarriage is a devastating experience. Unfortunately, it happens more often than many people may realize. Studies show that up to 20% of pregnancies end in miscarriage, making it the most common complication that can happen in pregnancy.

If you’re reading this because you’ve recently suffered a pregnancy loss, we are so sorry. Although it may feel like it, you aren’t alone. Chances are that someone you know has also gone through a miscarriage, even if they haven’t opened up about it.

After having a miscarriage, it’s normal to have a lot of questions. What caused it? Could it have been prevented? Did you do something to make this happen? A 2015 U.S. national survey found that 41% of women who had miscarried felt that they did something wrong to cause it.

So let’s set the record straight: You didn’t cause this. There are a lot of myths and misinformation floating around about why miscarriages happen, so let’s go over what can cause a miscarriage, according to medical research – and what can’t.

What can cause a miscarriage?

The vast majority (up to 70%) of miscarriages occur because of a random chromosomal defect as the baby is growing in the womb. The key word here is random. This means it was a freak accident and there’s nothing you or your doctor could have done to prevent it.

Medical conditions of the mother can also cause miscarriage, including:

  • Structural problems in the uterus (such as fibroids)
  • Infections
  • Hormonal issues
  • Thyroid disease
  • Uncontrolled diabetes
  • Autoimmune disorders


If your doctor discovered that a health condition led to your miscarriage, remember that it’s not your fault and this wasn’t in your control. Talk with your doctor about getting treatment before getting pregnant again to reduce the risk of miscarrying.

Miscarriages also become more common as you get older: At age 35, the risk is about 20%; at age 40, the risk is around 40%; at age 45, the risk is around 80%.

It can be significantly harder to come to terms with it if your doctor isn’t able to tell you the reason for your miscarriage. Unfortunately, this can happen sometimes. Doctors don’t know the cause of every single miscarriage.

If you don’t know why you miscarried, don’t blame yourself. Miscarriages are almost never the result of something the parent did or didn’t do. It’s very very unlikely that you did anything to cause your miscarriage. And we’ll tell you why.

Common questions about what can cause a miscarriage

Did I miscarry because I drank caffeine or alcohol?

Probably not. Some women worry that because they had a few drinks in early pregnancy, it made them miscarry later on. But having small amounts of caffeine (up to 200 milligrams per day) or a couple alcoholic drinks won’t make you miscarry. That being said, heavy drinking in pregnancy can increase the risk for miscarriage and other pregnancy complications.

Is my miscarriage because I had sex?

Nope. No amount of sex or orgasm, no matter how wild or what position you did it in, can lead to miscarriage. Penetrative sex during pregnancy doesn’t harm the baby in any way, as the fetus is protected by the uterus.

However, getting certain STIs such as chlamydia and gonorrhea while pregnant are linked to miscarriage, so be sure that you or your partner use a condom if you are having sex with other people during your pregnancy.

Can exercise or heavy lifting cause miscarriage?

No – exercise doesn’t cause miscarriage. In fact, doctors even recommend moderate exercise (at least 2.5 hours per week) for most women to help promote a healthy pregnancy and soothe discomforts like back pain and swelling. Your baby is tightly secured inside the uterus and doesn’t get shaken around during a workout. There are lots of prenatal workouts and yoga classes you can find online. Activities that are generally safe during pregnancy include walking, swimming, riding a stationary bike, yoga, pilates, low-impact aerobics, and strength training.

If you lifted some weights at the gym or helped a friend move some boxes, not to worry, this didn’t make you miscarry. Heavy lifting can become risky during pregnancy if you lift a lot and over a long period of time. The Centers for Disease Control and Prevention states that jobs that are very physically demanding and involve bending over at the waist over 20 times each day or lifting heavy objects every few minutes over a prolonged period can increase the chance of miscarriage or premature birth.

I flew on a plane in the first trimester – did it cause my miscarriage?

There’s no evidence that flying can lead to miscarriage. If you have no pregnancy complications, you can travel safely until close to your due date, according to the American College of Obstetricians and Gynecologists.

I was stressed during pregnancy – is this a reason for miscarriage?

It’s natural to feel a bit stressed during pregnancy and worry that it may impact your baby’s health. But no, stress can’t cause miscarriage, research shows. The same is true for stress over a long period of time or a single stressful event.

Did I miscarry because of a prior abortion or use of birth control?

No. Some women are concerned that their miscarriage happened because they had a past abortion, or that their previous birth control method could somehow be related. But studies show that prior abortion (even if you’ve had more than one) and contraception don’t increase the risk of miscarriage.

The hormones in birth control don’t fundamentally alter your uterus, eggs or ovaries and have no impact on future pregnancies. Even if you continued taking the pill before you realized you were pregnant, studies show that there’s no increased risk for miscarriage or birth defects.

Using an IUD in the past is also not related to miscarriage. However, getting pregnant with an IUD in place (which is extremely rare) has a very high risk of miscarriage.

Can the flu or COVID vaccines cause miscarriage?

Despite what you may have heard or read online, it’s safe to get the flu and COVID vaccine during pregnancy and these vaccines don’t cause miscarriage. It’s actually recommended for pregnant mothers to get vaccinated against the flu and COVID because becoming infected with these viruses carries a higher risk of death and pregnancy complications.

After a miscarriage: Moving forward

Hopefully learning about what does and doesn’t cause a miscarriage can lessen any feelings of guilt you have about what happened. Be kind to yourself and remember that this wasn’t your fault. Take comfort in knowing that for the most part, miscarriages are a one-time thing. Having one miscarriage won’t increase your chance of miscarrying the next time around, and most people who miscarry go on to have a successful pregnancy. If you need emotional support to come to terms with your pregnancy loss and help you work through your grief, don’t hesitate to reach out to a loved one, your doctor, or a mental health provider.



Miscarriage. Mayo Clinic. Aufgerufen am 08. Februar 2022. 

Why did I miscarry and was it my fault? Tommy’s. Aufgerufen am 08. Februar 2022.

Bardos J, MD, MBE et al.: A National Survey on Public Perceptions of Miscarriage. Obstet Gynecol. 2015;125(6):1313-1320. 

Jellesen R et al.: Maternal use of oral contraceptives and risk of fetal death. Paediatr Perinat Epidemiol. 2008;22(4):334-340. 

Magnus MC, PhD et al.: Covid-10 Vaccination during Pregnancy and First-Trimester Miscarriage. N Engl J Med. 2021;385:2008-2010. 

Physical Demands (lifting, standing, bending) – Reproductive Health. CDC. Aufgerufen am 08. Februar 2022. 

Travel during pregnancy. ACOG. Aufgerufen am 08. Februar 2022.

Horiuchi I et al.: Cytogenetic Analysis of Spontaneous Miscarriages Using Long-Term Culturing of Chorionic Villi. Journal of Fetal Medicine. 2019;6:1-6.  

How much coffee can I drink while I’m pregnant? ACOG. Aufgerufen am 08 Februar 2022.

The Flu Vaccine and Pregnancy. ACOG. Aufgerufen am 08 Februar 2022. 


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