Rochester, Minnesota - Having a miscarriage can be shocking, stressful and sad. It’s understandable that you want to do everything you can to avoid going through it again. Although there are some steps you may be able to take to lower your risk of another miscarriage, in most cases, a miscarriage isn’t related to anything a pregnant woman did or did not do. The majority of miscarriages are due to chromosomal abnormalities that happen for no clear reason. Many women who have a miscarriage go on to have normal pregnancies and deliver healthy babies.

In general, a miscarriage is defined as the loss of a pregnancy before 20 weeks gestation. Because it is not a topic that receives much attention, miscarriage tends to be more common than people might think. Doctors estimate that up to 25 percent of all recognized pregnancies end in miscarriage.

Most miscarriages happen because the fetus isn’t developing normally. Problems with the baby’s genes or chromosomes are usually the result of errors that occur by chance as the embryo divides and grows. They typically aren’t due to an inherited disorder, and usually aren’t caused by a mother’s behavior or health.

That said, there are a few risk factors that can raise the chances of having a miscarriage. Among the most significant is advanced maternal age. This one doesn’t apply to you right now, and it won’t for some time. Women older than 35 have a higher risk of miscarriage than do younger women. At 35, the risk of miscarriage is about 20 percent risk. At 40, it goes up to about 40 percent. At 45, it’s about 80 percent.

Another risk factor that doesn’t sound like it fits your situation is having certain medical conditions. Some disorders that may raise the risk of a miscarriage include uncontrolled diabetes, high blood pressure, thyroid disease, infections, hormonal problems and problems with the uterus or cervix.

When it comes to lifestyle choices you can control, it is important to avoid smoking, drinking alcohol or using illegal drugs when you are pregnant. Not only do these activities raise your risk for a miscarriage, they endanger the health of your baby throughout pregnancy. If you are on prescription medication, ask your doctor if it’s safe to continue taking that medication during pregnancy.

Staying at a healthy weight before you become pregnant and throughout your pregnancy may also help ensure your baby’s health. Being underweight or overweight appears to be linked to an increased risk of miscarriage, as well as other health concerns during pregnancy. For example, women who are significantly overweight are more likely to develop gestational diabetes.

None of the following activities cause miscarriage: lifting, straining, having sex or exercising.

If you have questions or concerns about becoming pregnant again, talk to your health care provider. He or she can review your health and family history, talk with you about risk factors and discuss any preconception care that could be helpful.

As you go forward, please keep in mind that, in almost all cases, miscarriages are beyond a mother’s control. If you become pregnant again, unless an underlying medical condition is identified that needs special care, you shouldn’t need to do anything differently. Get regular prenatal care and focus on taking care of yourself and your baby. - Dr. Yvonne Butler Tobah, Obstetrics and Gynecology, Mayo Clinic, Rochester, Minnesota.