Women who consume alcohol during pregnancy expose themselves and their developing children to a range of seriously damaging health outcomes. Among these outcomes is a heightened chance of experiencing a miscarriage. In a study published in September 2014 in the journal Substance Use & Misuse, researchers from four U.S. institutions examined the alcohol-related factors that make it more likely that a pregnant woman will experience a miscarriage. These factors include both the amount and type of alcohol consumed during pregnancy.
Pregnancy and Drinking
Alcohol is toxic to all human beings when consumed in large amounts. Critically, this substance is also classified as a teratogen; this designation means that alcohol has a clearly established harmful impact on the normal course of human fetal growth and development. Once consumed by a pregnant woman, alcohol flows through that woman’s bloodstream and passes through the placenta into the bloodstream of her developing child. Since developing fetuses don’t have fully functioning livers, they can’t eliminate the alcohol that builds up in their systems. The subsequent accumulation of alcohol can severely damage a developing child at any stage of pregnancy, but especially during the first trimester when a fetus is most defenseless.
One of the main consequences of recurring alcohol consumption during pregnancy is the onset of one of a group of mildly to severely damaging conditions collectively known as fetal alcohol spectrum disorders. The worst of these disorders, fetal alcohol syndrome, can produce permanent changes in a newborn child’s weight, physical appearance and mental and emotional skill set. Miscarriage is another potential consequence of fetal alcohol exposure. While small amounts of alcohol may not harm a developing child, doctors usually ask pregnant women to minimize their risks by avoiding all alcohol intake.
Alcohol and Miscarriage
Doctors usually apply the term miscarriage to any spontaneously terminated pregnancy that occurs before a woman is pregnant for a full 20 weeks. At least 80 percent of all miscarriages happen for no clear reason; however, as many as one in five miscarriages has a known cause. Alcohol intake is one of these identified causes. Previous research findings indicate that, generally speaking, a woman significantly increases her chances of experiencing a miscarriage when she consumes as little as four or five standard servings of alcohol per week during the first three months of pregnancy. Alcohol-related miscarriage risks apparently drop during the second trimester of pregnancy. Researchers have not firmly established the miscarriage-related risks of light drinking during pregnancy’s early stages.
In the study published in Substance Use & Misuse, researchers from the University of California at Berkeley, the University of California at San Francisco and two private institutions used information gathered from 1,061 pregnant women to explore the influence that alcohol consumption has on any given woman’s chances of experiencing a miscarriage. One hundred seventy-two of these participants went through a miscarriage. For these individuals and the women who didn’t have a miscarriage, the researchers looked at the amount of alcohol consumed in the average week, as well as the type(s) of alcohol consumed in the average week.
The researchers preliminarily concluded that roughly 3 percent of the study participants consumed at least four alcohol servings in the average week. Thirty-eight percent of the participants consumed fewer than four alcohol servings per week, while 59 percent consumed no alcohol at all. Sixteen percent of the study participants consumed two or more types of alcohol, while 15 percent consumed only wine. Five percent of the participants consumed only hard liquor, while 4 percent consumed only beer.
The researchers concluded that women who consume at least four alcohol servings per week experience a roughly 165 percent increase in their odds of having a miscarriage. The alcohol-related risks for a miscarriage apparently center primarily on the first 10 weeks of pregnancy. The researchers also concluded that, compared to women who don’t consume alcohol during pregnancy, the highest risks for a miscarriage in terms of the type of alcohol consumed appear in women who exclusively drink hard liquor; these women have a roughly 124 percent increase in their miscarriage odds. Based on their overall findings, the researchers believe that doctors and public health officials should include the type of alcohol preferred in their evaluations of pregnant women’s level of miscarriage exposure.