9 causes of miscarriage

If you’ve had a miscarriage or know someone who has, you know how devastating it can be for both partners. Studies show miscarriage is common— between 10 and 25 percent of pregnancies before 20 weeks are affected.

In fact, a recent study in the journal Obstetrics & Gynecology found that 55 percent of both men and women believed that miscarriage happened in only 5 percent or less of all pregnancies, while 15 percent reported that they or their partner had at least one miscarriage.

Sadly, most people don’t talk about it and many women feel shame or even guilt about something that’s out of their control.

Here, find out the most common causes of miscarriage and what you can do to increase your chances of having a healthy baby.

1. Genetic or chromosomal abnormalities
For about half of miscarriages that happen sporadically, it’s usually due to a chromosomal abnormality such as Down syndrome, cystic fibrosis or Turner syndrome.

“There is an internal system that if the chromosomes go awry, the system knows to shut itself down,” said Dr. Susan Gross, a professor of women's heath, pediatrics and genetics at The Albert Einstein College of Medicine in New York City and chief medical officer of Natera, a genetic testing company, said.

For approximately 5 percent of women who have recurrent loss— defined as two or more miscarriages— the reason in up to 50 percent of those cases isn’t clear, according to the American Society for Reproductive Medicine (ASRM).

You can ask your doctor about undergoing a test to identify the source of a miscarriage. If the miscarriage was due to a genetic problem, a genetic counselor or maternal-fetal medicine specialist can help you figure out the likelihood it will happen again.

2. Sperm DNA fragmentation
Another cause for miscarriage that is often overlooked, but is believed to be very common, is a factor known as sperm DNA fragmentation. This occurs when strands of sperm DNA are broken and unable to deliver DNA to the egg. Although there are different levels of severity, the likelihood of miscarriage is 2 to 5 times higher for men that have the condition, compared to men that have healthy sperm, said Dr. Philip Werthman, a urologist and director of the Center for Male Reproductive Medicine and Vasectomy Reversal in Los Angeles, Calif.

There are a host of reasons why sperm DNA fragmentation occurs, including smoking, antidepressant use, exposure to heat, chemotherapy or radiation, a varicocele, an enlargement of veins in the scrotum, or even a fever. Male infertility specialists and some IVF clinics will offer screening, which is very specialized test.

“Only a few places in the country are able to do it well,” Werthman said.

Treatment depends on the issue and can include stopping a medication, taking antioxidant supplements, or having a procedure known as sperm aspiration and intracytoplasmic sperm injection (ICSI). Also, “eggs potentially have the ability to repair DNA damage in a broken sperm,” Werthman said, adding that success largely depends on how much and where the damage is located.

3. Hormones
Luteal phase defect, or low progesterone levels in the second half of the cycle, can cause problems with implantation. Women with the condition will have spotting in the second half of their cycle before their period. Hypothyroidism and diabetes are two other hormonal problems that can lead to miscarriage.

4. Obesity
According to the a report by the CDC National Center for Health Statistics, nearly 1 in 4 women are obese before becoming pregnant, which is an independent risk factor for miscarriage, Hirshfeld-Cytron said.

5. Balanced translocation carrier
Approximately 2 to 5 percent of miscarriages are a result of what’s known as a balanced translocation carrier, which happens when one or both partners has genes that are misplaced.  The problem doesn’t manifest itself until the cells divide and try to make sperm or egg cells, which can then cause the pregnancy to end in miscarriage, Gross said. A simple blood test can determine if you or your partner are carriers. A procedure known as preimplantation genetic diagnosis can help to ensure the embryo is healthy.

6. Abnormalities of the uterus
Another common reason for miscarriage are genetic abnormalities of the uterus. One type, a septum, is the most widely experienced and also the easiest to treat. A septum is an extra piece of tissue on the uterus that doesn’t have the same type of blood supply as the rest of the uterus.

“If the embryo grows on that extra septum, that leads to loss,” said Dr. Jennifer Hirshfeld-Cytron, a reproductive endocrinologist with Fertility Centers of Illinois.

The good news is that with surgery, the chances of having a healthy pregnancy are high.

Other non-genetic abnormalities, such as fibroids, can develop over time. Fibroids are benign tumors that develop in the uterine cavity and can not only cause miscarriage but also impact the success of IVF. Fibroids can be detected on a pelvic exam, a saline sonohysterogram, a type of ultrasound, or an MRI and corrected with surgery.

7. Antiphospholipid syndrome
Thrombophilias are a group of disorders that increase the likelihood of clotting.  Those that are inherited have not been shown to cause miscarriage but those that are acquired can. Antiphospholipid Syndrome, the most common type, causes an elevation in the antiphospholipid antibodies that can cause the blood to clot and interfere with the implantation and growth of the developing embryo, Hirshfeld-Cytron said.

Many women don’t even know they have the syndrome until they’re screened, likely after a loss. If you have the syndrome, blood thinners can help improve your chances of having a healthy pregnancy.

8. Drugs and toxins
Smoking, alcohol and drug use can all increase your risk for miscarriage. Additionally, women exposed to high levels of toxic chemicals like bisphenol A (BPA) found in plastics are 83 percent more likely to have a miscarriage than women with lower levels, according to a study in the journal Fertility and Sterility.

The good news is that when it comes to coffee, experts agree an 8-ounce cup of coffee a day is safe.

9. Infections
Mycoplasma infections that happen in the lining of the uterus have no symptoms but can lead to miscarriage. Causes can include variations of the body’s normal flora and increases or decreases in acidity that cause bacterial overgrowth. Women who have had multiple gynecologic procedures are more at risk.

If your provider believes you have a mycoplasma infection, she may do a biopsy of the lining of the uterus (endometrium) or treat the condition as though it exists, Hirshfeld-Cytron said.

Other infections that can lead to miscarriage include listeria, mumps, rubella, measles, cytomegalovirus, parvovirus, gonorrhea, and chlamydia.

As devastating as a miscarriage is, remember that there are tests and treatments available that can help you have a healthy pregnancy and a healthy baby in the future.