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How to Determine Your Risk of Miscarriage

Nearly one-third of all women who know they are pregnant will experience a miscarriage—and this number doesn't include the women will miscarry before they even know they are carrying a child, notes the Milton S. Hershey Medical Center at Penn State University. While the majority of miscarriages are unpreventable and caused by chromosomal or genetic defects, certain health and lifestyle factors have been linked to an increased risk of pregnancy loss.

RELATED: How to Talk About Your Miscarriage

Undergo Genetic Testing

Among all pregnancies, chromosomal or genetic abnormalities are the most common cause of miscarriage, accounting for more than half of all miscarriages, notes the Center for Human Reproduction. These can be one-time, random events, or they can be contributed to a genetic issue with the mother's or father's health that, when unidentified, can cause repeated miscarriages.

A healthy fetus has 23 pairs of chromosomes – one set from the mother, and one set from the father; an abnormal number of chromosomes or a defect in any one of the 46 chromosomes can lead to miscarriage, typically in the first trimester. Further testing would be necessary to rule out any inherited or genetic causes or uterine abnormalities that could contribute to miscarriage.

If you have repeated miscarriages, your doctor may want to order karyotyping or microarray testing, which looks for chromosomal abnormalities in a sample of of cells taken from blood, bone marrow, or placental tissue. If you have a family history of disease, you can undergo carrier genetic testing, which will determine if your future children will be at an increased risk for a disease such as sickle cell anemia or cystic fibrosis. More than 900 different types of genetic tests currently exist and can cost anywhere from $100 to $2,000, according to the National Human Genome Research Institute. So talk to your health care provider about what types of genetic tests would be the most beneficial for you and your partner.

Are You Over 35? Over 40?

The risk of miscarriage associated with advanced maternal age– or, being pregnant over the age of 35 – has been well documented, notes [Dr. Monica Grover](http://medicalone.nyc/physicians.shtml), a family medicine physician who specializes in women's health in New York.

"Advanced maternal age is a risk factor for a wide variety of conditions such as infertility, pregnancy complications such as hypertension, congenital abnormalities, and miscarriage," she says. "One of the reasons for this is because miscarriages can be related to a chromosomal abnormality of an ovulatory egg and the chances of these types of eggs increases with maternal age."

Additional research has shown that advanced paternal age, which refers to a father who is 40 years old or more at the time of conception, is related to an increased risk of marriage, Grover adds.

Manage Diabetes, Hypertension

Miscarriages that occur after the first trimester are more likely caused by a mother's chronic health condition than a chromosomal abnormality, Grover points out.

"These conditions can include uncontrolled hypertension or diabetes, auto-immune disorders such as lupus, hormonal disorders such as an underactive or overactive thyroid, or even blood disorders such as sickle cell disease," she explains.

Acute or chronic infections of the urinary tract or infections can lead to later-term miscarriages, as can infections such as the measles, bacterial vaginitis or cytomegalovirus, which can cause chickenpox, can all contribute to pregnancy loss, she says. Ongoing management and treatment for these chronic health conditions is critical during pregnancy.

Address Your Weight and Lifestyle Factors

Being underweight, overweight or obese can contribute to an increased risk for pregnancy loss, Grover notes. "When adjusting for independent risk factors, studies have shown that an underweight body mass index has a similar rate of miscarriage of someone who is morbidly obese BMI," she explains.

The following BMI guidelines can help you determine this risk factor: * Underweight: BMI of 18 or below * Overweight: BMI of 25 to 29.9 * Obese: BMI of 30 to 34 * Morbidly Obese: BMI of 35 or higher

In addition, caffeine intake, smoking, and the use of illicit drugs or alcohol all have been linked to an increased risk of miscarriage. Smoking during pregnancy has been shown to cause placental problems, preterm delivery, and even stillbirth, the CDC notes, and a study published in the American Journal of Epidemiology found that moderate consumption of alcohol during pregnancy – on both the part of the mother and father – leads to an increased risk of miscarriage during the first trimester.

RELATED: The Physical End of My Miscarriage

You can reduce your risk of miscarriage from these controllable factors by healthy eating, limiting caffeine, quitting smoking, and avoiding the use of alcohol during pregnancy. Regular prenatal care from a qualified health care provider is critical.

Photograph by: Keith Brofsky/Photodisc/Getty Images

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