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Bust a Myth about Miscarriage

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Fertility Myths

I caused my second miscarriage because I was so stressed out about this pregnancy. I can’t go see a fertility doctor until I have three miscarriages, and everyone says to wait three months before I try again. There’s nothing I can do because most miscarriages are unexplained, but I know if I have another one, I am not very likely to ever have a successful pregnancy.

Fertility Facts

Miscarriage refers to the loss of pregnancy that occurs during the first 20 weeks of pregnancy. Miscarriage is more common than many women may think. Studies reveal that anywhere from 10 to 25 percent of all clinically recognized pregnancies end in miscarriage.

A second miscarriage, however, is not as common. According to Joseph A. Hill, M.D., a reproductive endocrinologist with Fertility Centers of New England, recurrent pregnancy loss is defined as two or more pregnancy losses prior to 20 weeks, and it occurs in approximately 1 percent of pregnancies. “Evaluation after recurrent pregnancy loss should commence after two losses,” he says. “Once a normal period has occurred following a miscarriage, the couple can resume trying to conceive, but they should seek help after two losses to determine potential causality.”

It’s a myth that most miscarriages are unexplained, says Dr. Hill. “This is not true, as the majority of losses are chromosomally abnormal. This may be hard to prove using conventional karyotype analysis, but newer techniques using CGH (comparative genomic hybridization) or FISH (fluorescent in situ hybridization) have found the incidence of chromosomal abnormalities may be as high as 70 percent.”

Most chromosomal abnormalities in early pregnancy losses arise spontaneously because of non-disjunction (the failure of chromosome pairs to separate properly during cell division) or because of other genetic errors in the egg, the sperm or in the early embryo.

To follow are other factors that have been linked to miscarriage.

    Age. Older women who conceive are more likely than younger women to experience a miscarriage, since they are more likely to conceive embryos with chromosomal abnormalities. Women under the age of 35 have about a 15 percent chance of a miscarriage, and women between 35 and 45 have a 20 to 35 percent chance of miscarriage. Women over the age of 45 have around a 50 percent chance of miscarriage.

    Lifestyle Factors. There are certain lifestyle factors that may make you more likely to suffer a miscarriage, including:

    • Alcohol: Drinking three or more alcoholic drinks per week is associated with a higher rate of miscarriage.
    • Smoking: Smoking cigarettes is associated with both infertility and miscarriage. According to the American Society for Reproductive Medicine (ASRM), female smokers who are using IVF have higher rates of miscarriage. The effects of smoking are also more pronounced in older patients.
    • Caffeine: Consuming caffeine during pregnancy is also related to miscarriage, especially in early trimester pregnancies. A 2008 study by the Kaiser Permanente Division of Research found that women who consumed 200 mg or more caffeine each day (two or more cups of regular coffee) were twice as likely to have a miscarriage as women who consumed no caffeine. Women who consumed less than 200 mg of caffeine a day had a 40 percent increased risk.

    Previous Miscarriage . Having two or more miscarriages places women at a slightly greater risk of having another miscarriage. Studies from large samples of pregnant women show that if a woman has had two miscarriages, her chance of having a third is 20 percent. For women who have had four previous miscarriages, her chance of having a fifth is 40 percent.

    Thrombophilia. Thrombophilia is a disorder that involves a genetic predisposition to form harmful blood clots, which can lead to stroke or heart attack. Thrombophilia can cause clotting of blood vessels in the placenta, which makes it difficult or impossible for the fetus to receive an adequate blood supply and can result in a miscarriage. Thrombophilia most commonly causes miscarriage in the second and third trimesters of pregnancy, and rarely causes miscarriage in the first 10 weeks of gestation.

    Uterine Abnormalities. Abnormalities of the uterus cause about 10 to 15 percent of recurrent miscarriages. These uterine abnormalities include an abnormally shaped uterus or divided uterus, uterine fibroids, or uterine scars. Uterine abnormalities can cause miscarriage by limiting the growth of the fetus or restricting its blood flow. Women with fibroids that may be affecting their fertility can receive a treatment called a myomectomy, which removes the fibroids but preserves the uterus.

    Other Risk Factors. Other risk factors that may be related to miscarriage include exposure to toxins (radiation, lead, mercury, cleaning solvents, and pesticides), poorly controlled diabetes, obesity, hormonal problems, certain infections, and certain invasive tests.

A miscarriage is a shock and a traumatic experience. But having one or more miscarriages does not mean that you will never be able to have a healthy term pregnancy. “One of the biggest myths about miscarriages is that once you have had several losses, you are unlikely to have an eventual success,” Dr. Hill says. “This is not true as based on epidemiological studies. Even after four miscarriages, the chance of a healthy baby is approximately 60 percent.”