Common Causes of a Miscarriage

Miscarriage, also known as spontaneous abortion, is a common outcome of pregnancy. But no matter how many other women experience miscarriage, when it happens to you, you may feel devastated, sad, and even ashamed or guilty. 

It may help to know that miscarriage isn’t just common, it’s actually normal. Miscarriages occur in about 10-20% of known pregnancies, but also in many unknown pregnancies. That means that you could have been pregnant before, miscarried the fertilized egg, and never realized it.

Our expert and caring OB/GYNS at Columbia Fertility Associates — with offices in Washington, DC, Bethesda, Maryland, and Arlington, Virginia — know how upsetting a miscarriage can be. They also know that most women go on to have healthy, full-term pregnancies after their miscarriages.

You may have already had a miscarriage and are dealing with the range of emotions that accompany loss. Or, you just found out you’re pregnant, and you hope to avoid a miscarriage. Here’s what you need to know about what causes miscarriages, and whether you can prevent them. 

Chromosomal abnormalities

Assisted reproductive technology (ART) not only helps women who have fertility problems achieve a successful pregnancy, but the technology has also greatly enhanced our understanding of pregnancy and miscarriage. A study of donor-generated embryos found that half of them were abnormal and wouldn’t be carried to term.

When the embryo has a condition called aneuploidy, it contains chromosomal abnormalities that prevent it from developing into a healthy baby. Your body spontaneously aborts these embryos.

Miscarriages that occur because of aneuploidy occur in the first 4 weeks of pregnancy. For most of these early, chromosomal-related miscarriages, you’re not even aware that you’re pregnant. However, you might have symptoms of miscarriage, such as cramping or heavy bleeding.

You can’t prevent a miscarriage due to aneuploidy. It’s simply nature’s way of ensuring that an abnormal embryo doesn’t continue to develop.

Maternal age

One of the risk factors for miscarriage is the age of the mother. When you’re under 35, you only have a 15% risk of miscarrying, but if you're over 45, your risk goes up to 50%. 

If you’re an older woman who wants to become pregnant, or if you’re over 35 and are currently pregnant, our doctors consider you a high-risk pregnancy. They recommend more frequent check-ups to be sure that your fetus is developing normally, and that you’re healthy, too.

If you’re undergoing ART, such as in vitro fertilization (IVF), our doctors may recommend lifestyle changes to give you and your baby the best chances for a healthy, full-term delivery. We’ve helped many older women successfully become mothers. 

Medical conditions

Another common reason for miscarriages is the overall health of the mother. If you have a medical condition, it may complicate conception and increase your risk for a miscarriage. 

During your consultation, our doctors conduct a thorough examination and take a medical history to determine if you have an underlying medical condition that could complicate your pregnancy. 

Conditions that may raise your risk for miscarriage include:

If your disease isn’t currently controlled, our doctors work with you and your other health care practitioners to improve your health.

Environmental or external factors

Certain medications and medical treatments can raise your risk for miscarriage. For instance, if you received radiation treatment for cancer, you may have more difficulty becoming and staying pregnant. The anti-acne drug isotretinoin can also cause miscarriages.

Toxic chemicals in your workplace or home could also increase your risk. Our doctors recommend reducing your exposure to chemicals and radiation if you’re planning to become pregnant.


Although most miscarriages are caused by conditions or events beyond your control, you can give your pregnancy its best chance by adopting or maintaining a healthy lifestyle. 

Our doctors may recommend:

If you need help breaking an addiction to drugs, tobacco, or food, our doctors can refer you to a specialist.

Most women go on to have healthy pregnancies after a miscarriage. To learn more about how to move on after a miscarriage, contact our team at Columbia Fertility Associates to schedule a consultation. Phone the office nearest you or fill out our convenient online booking form.

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