How to Determine Your Chance of Having a Miscarriage

If you are newly pregnant, had a miscarriage before, or know someone who has a miscarriage, you may be concerned about your odds of having a miscarriage. Unfortunately, miscarriages are incredibly common, especially early in pregnancy. Approximately one in every three to five pregnancies ends in miscarriage. Your exact risk of having a miscarriage varies based on your genetics, environment, and other factors.

When reading about miscarriage statistics, it is important to remember that these figures are just numbers. Even if you have a higher than average risk of miscarriage, it does not mean that you will miscarry. In most cases, your odds of having a normal pregnancy are higher than your odds of having a miscarriage.

Determining Your Risk

If you are not yet pregnant and are concerned about miscarrying, you may be able to lower your risk by addressing some preventable ​risk factors. Some risk factors are changeable. For example, if you smoke or drink alcohol, quitting either of these practices will reduce your risk of miscarriage. Preventable risk factors include: 

• Smoking: Both smoking and being exposed to secondhand smoke can increase your chances of having a miscarriage. 
• Drinking: Drinking alcohol while pregnant increases the likelihood your child will be born with fetal alcohol syndrome. Regular alcohol consumption can also increase your likelihood of miscarriage. 
• Your weight: Being underweight or overweight can also increase your odds of miscarrying. Obese women have the greatest risk of miscarriage as compared to overweight and underweight women. 
• Treatable infections: Infections that go untreated are one of the most preventable causes of miscarriage, and are thought to cause approximately 15 percent of miscarriages. Infections associated with miscarriage include malaria, brucellosis, cytomegalovirus, HIV, dengue fever, influenza virus, and bacterial vaginosis.

Other risk factors are harder to avoid, such as: 

• Your age: The older you are, the greater your likelihood of miscarrying. For women in their early 40s, the risk of miscarriage is approximately 50 percent. 
• Your partner's age: The age of your child's father may also affect your odds of miscarrying. 
• Reproductive health conditions: Certain reproductive health conditions, like endometriosis and adenomyosis, can increase your odds of miscarrying. Mullerian anomalies, conditions that affect the size and shape of your uterus, can also make it difficult to successfully carry a pregnancy. 
• Genetics: Certain genetic conditions that affect egg and sperm quality can also increase your odds of experiencing a miscarriage. If you have had multiple miscarriages, see a reproductive endocrinologist and ask about genetic testing, which can diagnose any issues your eggs or your partner's sperm may have. 
• History of miscarriages: Approximately 2 percent of women will have two miscarriages in a row, and 1 percent of women, three or more. 

If you do not have any risk factors, your risk will be in the average range. In most cases, your risk of miscarriage decreases as your pregnancy progresses. After seeing a heartbeat on an ultrasound, your risk of miscarriage will drop, although the miscarriage rates will remain higher for women with specific risk factors.