Risk Factors
for the dreaded, yet all too common miscarriage

The natural loss of a fetus before a pregnancy has reached its midway point (of twenty weeks) – termed a miscarriage – is a regrettably common occurrence. Often, the first time mother is not aware that as many as twenty-five percent of pregnancies, are miscarried by week six. Couples who miscarry are often left with heartbreak, confusion, unmet expectation and a ton of questions. Here’s the scoop on why the most common miscarriages occur:

Chromosomal abnormalities

Chromosomal or genetic problems are found in more than half of embryos miscarried in the first thirteen weeks. In fact, pregnancies with a genetic problem have a ninety-five percent chance of ending in miscarriage. Most times, these chromosomal complications occur by chance, have nothing to do with the parents and are unlikely to recur.

Age

As a woman grows older, the chances of her having a chromosomal abnormality in pregnancy increase. Women older than age thirty-five have a higher risk – up to twenty percent – of miscarriage than younger women. At age forty, the risk increases to forty percent.

Health Problems

Miscarriages that occur in the third trimester are more likely to be due to maternal factors, such as an illness in the mother. Women with poorly controlled diabetes, for instance, are at risk. Women may develop diabetes after conception, but once treated, are no more likely to lose a pregnancy than other women. Other diseases and conditions linked to increased risk of miscarriage include lupus, high blood pressure, kidney disease, rubella, and herpes simplex.

Hormone Imbalance

Some women do not make enough progesterone, the hormone that prepares the lining of the uterus to nourish a fertilized egg. If the uterine lining cannot sustain an egg, miscarriage will occur. Progesterone supplements can correct this problem. Hormone imbalance also can be caused by diabetes mellitus or thyroid disease. Abnormalities of the Uterus and Cervix Anything physically wrong with the uterus or cervix, such as a misshaped uterus, fibroids, or scar tissue can lead to a miscarriage. A weak cervix may widen too early in pregnancy, without any warning sign of labor, expelling the fetus from the uterus. These physical problems account for up to fifteen percent of repeated miscarriages.

Exercise

A recent study has found correlation between exercise and miscarriage. Of the ninety-two thousand women studied, most types of exercise (with the exception of swimming) correlated with a higher risk of miscarriage prior to eighteen weeks of pregnancy. The more time spent on exercise, the greater the risk of miscarriage: risk increased by ten percent with up to one and a half hours per week of exercise, and to two hundred percent with over seven hours per week of exercise. No relationship was found between exercise and miscarriage rates after the eighteenth week of pregnancy

Caffeine Consumption

Caffeine consumption, at high levels of intake, has also been correlated to miscarriage rates. A 2007 study of over one thousand pregnant women found that women who reported consuming 200 mg or more of caffeine per day experienced a twenty-five percent miscarriage rate, compared to thirteen percent among women who reported no caffeine consumption.

Male and Miscarriage

Age

One study found that pregnancies from men younger than twenty-five are forty percent less likely to end in miscarriage than pregnancies from men between twenty- five and twenty-nine. The same study found that pregnancies from men over forty are sixty percent more likely to end in miscarriage than the twenty-five to twentynine year age group. A virtual tidal wave of research has made it irrefutable that male fertility actually decreases after age thirtyfive.

Smoking

There is an increased risk of miscarriage when the father is a cigarette smoker. A study indicated a four percent risk for husbands who smoke less than twenty cigarettes a day, and an eighty-one percent risk for husbands who smoke twenty or more per day.

- Danielle Watson