Truths and Myths About Causes of Miscarriage

A Reality Check for Common Miscarriage Claims

Sad couple with doctor getting news of early miscarriage
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People say a lot of things about what does and does not cause miscarriages, and a lot of it can be confusing. Even doctors vary in their opinions about what they consider fact and what they consider myths when it comes to the causes of miscarriage. For example, one physician might tell you that stress can cause miscarriages, while another might claim this to be a myth.

The truth is usually somewhere in the middle. The following are common claims that are out there about miscarriage causes and risk factors. Before you get started, it may help to read up on the difference between a cause and a risk factor when it comes to miscarriage.

Claim: Video Display Terminals Cause Miscarriages

There was one study in the 1980s that found an increased risk of miscarriage in women who used video display terminals for a lengthy period of time on a regular basis. But subsequent research has not found a link between video display terminals and miscarriage.

It's been noted that there are potential biological effects associated with electromagnetic fields that raise some concern over their role in miscarriage, but the lack of data at the current time does not reveal any clear causal link.

Claim: Elective Abortion Increases Risk of Miscarriage

There could be a grain of truth to the claim that elective abortion increases the risk of miscarriage. There are studies that have found an increased risk of miscarriage in women who had terminated a pregnancy. But the evidence is mixed, and any theoretical increased risk might be limited to women who had an abortion via D & C (a surgical elective abortion.)

A large study published in The New England Journal of Medicine found that elective medical abortion (an abortion achieved through the use of medications rather than surgery) was not associated with any increased risk of subsequent miscarriage.

Claim: Stress Causes Miscarriages

There is some evidence that stress during pregnancy may elevate miscarriage risk. There have been several studies in recent years that found evidence of a link between stress and miscarriage or stillbirth, although the evidence doesn't prove that the stress is what caused the miscarriages in those cases.

It is very difficult to evaluate the role of stress in miscarriages, and while many studies have investigated this relationship, the answer is still unknown. Most people, it seems, will tell you that they have stress in their lives. It could be that unusual or chronic stress may be more important. It's also important to note that we all process stress differently. For example, one person may feel "very stressed" by relatively minor stressors, while another may feel only "moderately stressed" when faced with greater obstacles.

That said, there is some biological evidence pointing towards a role of stress in miscarriage. Stress leads to the release of "stress hormones" such as cortisol in the body. Elevated cortisol levels, in turn, have been associated with an increased risk of miscarriage in some studies. Looking at population studies, ordinary stress has not often been associated with an increased risk of miscarriage, but "major stress," such as the economic downturn in Denmark was linked with a greater risk of miscarriage.

One of the most comprehensive studies to date published in 2017 suggested that stress increases the risk of miscarriage by around 42 percent.

Certainly, it doesn't feel good to be stressed, whether or not it plays a role in miscarriage. Take a moment to learn about stress management and what you can do to reduce the stress in your life today.

Claim: Taking Aspirin During Pregnancy Causes Miscarriage

There is evidence that taking aspirin during pregnancy may increase miscarriage risk. On the other hand, some doctors even prescribe ​low dose aspirin as a part of recurrent miscarriage treatment.

For women who have recurrent miscarriages due to antiphospholipid syndrome, a type of clotting disorder, low-dose aspirin may lessen the risk of miscarriage. For women without recurrent miscarriages, however, use of aspirin during early pregnancy has been linked with an increased risk of miscarriage in some studies.

In contrast to aspirin, using non-steroidal anti-inflammatory drugs (NSAIDS) such as Advil (ibuprofen) and Aleve (naproxen) appears to clearly increase the risk of early miscarriage.

Claim: Birth Control Pills Can Cause Miscarriage

Although taking a large dose of birth control pills within a few days of intercourse can work as emergency contraception, there is no evidence that birth control pills will cause a miscarriage in an established pregnancy or that taking birth control pills will increase risk of future miscarriage.

Claim: If You Get Pregnant While You're Still Nursing, You Have to Wean

There's no evidence that breastfeeding during pregnancy causes miscarriage or any harm whatsoever to the developing baby.

Pregnant moms who want to continue breastfeedng can do so without worry.

Claim: Strenuous Exercise Is Not Safe During Pregnancy

No one knows for sure whether strenuous exercise increases miscarriage risk and the majority of obstetricians instead recommend exercise during pregnancy. There was a large study in 2007 that indicated women who engaged in ​strenuous exercise were more likely to have miscarriages, but there have been several other studies that found no link between exercise and miscarriage.

Light and moderate exercise during pregnancy are almost certainly beneficial. Some doctors advise keeping your heart rate under 140 beats per minute to be on the safe side.

Claim: Taking a Hot Bath Can Cause a Miscarriage

Hot tub use during pregnancy may increase the risk of miscarriage according to a 2003 study. In that study the risk of miscarriage was doubled on average with early first trimester hot tub use, and increased further with greater frequency of use.

The problem with hot tubs (or hot baths) is related to an increased body temperature overall rather than submerging your abdomen. Allowing your body temperature to get too high during pregnancy has also been linked with neural tube defects and is not recommended.

For those who desire to spend some time in a hot tub or hot bath, the American Pregnancy Association recommends not allowing your body temperature to exceed 101 degrees F, to program your hot tub to a lower temperature, and to spend no longer than 10 minutes in the tub.

Claim: You Shouldn't Eat Cheese or Deli Meats When You Are Pregnant

This claim that you should avoid cheese or deli meats while pregnant is partially true. Not only are you more likely to develop food poisoning while pregnant, but some of the organisms which cause food poisoning are linked with an increased risk of miscarriage. These include:

  • Listeria
  • Salmonella
  • E. coli
  • Toxoplasmosis

It's important to note that you don't have to avoid all cheese or deli meats during pregnancy. Learn more about the foods to avoid to reduce your risk of miscarriage.

Most cases of food poisoning linked to miscarriage are related to dairy products (such as soft cheeses) which have not been pasteurized, to meats that have not been thoroughly cooked, or to vegetables that haven't been washed.

Claim: Having Sex During Pregnancy Can Cause Miscarriage

There's no evidence that sex during pregnancy poses any risk of miscarriage. Sex doesn't even seem to be able to trigger labor in women with full-term pregnancies, so you should definitely not worry about orgasms or uterine contractions causing miscarriage.

Sex usually doesn't cause miscarriage. But, there are a few exceptions such as women with a condition called placenta previa and those with cervical insufficiency.

Claim: If You Don't Wait to Try Again, You Risk Another Miscarriage

There's always a risk of miscarriage in any pregnancy, but there's no real evidence that you need to wait any set period of time after a first-trimester miscarriage before you try again. In the past it was often recommended that people wait a few months before trying again. One of the reasons behind this recommendation was that it was more difficult to predict an expected birth date. With the advent of early ultrasound this is rarely a concern today.

An older study also suggested a higher rate of miscarriage when women became pregnant right away after having a pregnancy affected by a neural tube defect, but this may be related to low folic acid levels prior to the first pregnancy which persist for the second pregnancy.

Doctors may advise waiting for different reasons for individual women, however, so check with your doctor.

For example, if a woman has a miscarriage related to a medical condition such as uncontrolled diabetes, it's important to stabilize the medical condition before trying again.

Claim: Progesterone Cream Can Prevent Miscarriage

Don't rush out and buy that cream yet. Some doctors do believe that progesterone supplements might help women with recurrent miscarriages but this is controversial and there's no strong evidence that the supplements help with the exception of women who are undergoing in vitro fertilization and a small subset of women with recurrent miscarriages. As for over-the-counter progesterone creams, the dosage varies heavily and some of the creams don't even contain any active progesterone.

It's best to find a doctor who is willing to prescribe supplements if you want to use progesterone during pregnancy.

Claim: A Bicornuate Uterus Causes Miscarriages

A bicornuate uterus can mean increased risk of preterm labor, but there's no evidence that it increases risk of miscarriage. However, a uterine septum can mean increased risk of miscarriage, and the two malformations look similar on imaging tests.

Learn more about the different types of uterine abnormalities and miscarriage risk.

Claim: Being Hit in the Abdomen Can Lead to Miscarriage

Minor trauma such as falling, being hit in the abdomen, or having a fender bender is not likely to cause a first-trimester miscarriage, but it can cause placental abruption in the second or third trimester and potentially lead to late pregnancy loss.

In contrast, high-velocity trauma, such as a motor vehicle accident or major fall can significantly increase the risk of miscarriage. Plus, the risk of a fall or trauma of any kind is much greater later in pregnancy.

Claim: Riding a Roller Coaster Can Cause a Miscarriage

No one has researched the safety of riding roller coasters during pregnancy, or the effect of other amusement park rides. There is a theoretical risk that the jerking motions could lead to placental abruption later in pregnancy, and although riding a roller coaster in very early pregnancy is most likely not going to cause problems, no one really knows where the cut-off point lies for safe versus risky.

Due to the uncertainty over the effect of roller coasters on pregnancy, the American Pregnancy Association recommends avoiding these rides no matter how far along you are in your pregnancy.

Claim: Obesity Increases Risk of Miscarriage

Obesity does appear to increase the risk of miscarriage, but the relationship between body weight and miscarriage is still not well understood.

Though obesity is linked with miscarriage and recurrent miscarriages, it's not known if being overweight is actually a cause of miscarriage.

Claim: Getting Sick During Pregnancy Can Cause a Miscarriage

Certain bacterial and viral infections can increase the risk of a miscarriage. Examples include:

  • Fifth disease
  • Rubella (German measles)
  • Bacterial vaginosis
  • Chlamydia
  • Listeria


Claim: Moms Over 35 Have a Higher Risk of Miscarriage

The risk of miscarriage is higher for moms over 35, and is almost 50 percent for moms in their early 40s.

It's important to note, however, for a pregnant woman who is 35 years old, the chances are still higher that she will have a normal pregnancy than that she will have a miscarriage.

Claim: The Miscarriage Must Have Been My Fault

Miscarriage almost never happens because of something the mother did or did not do. It is important to emphasize this point as many women wonder what they may be done to cause a miscarriage.

Chromosomal abnormalities in the baby are the most common reason for a miscarriage, and these abnormalities are in turn not caused by anything a woman does or does not do, but happen by chance alone.

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