New Study: Risk of Alcohol Exposure in Early Pregnancy Underestimated

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You probably know that alcohol is not safe during pregnancy. One reason is fetal alcohol syndrome and another reason is an increased chance of spontaneous abortion (miscarriage). You can read up on the dangers of alcohol in pregnancy here.

A new study from Vanderbilt University Medical Center looks at the risk of miscarriage from alcohol exposure in early pregnancy. Although only about 10 percent of women continue to drink during pregnancy, this study found that about 50 percent of women drink during the first 30 days of pregnancy, a time when they are pregnant but don’t yet know it. The study found that compared to women who were not drinking, these women had a 37 percent higher risk of miscarriage.

The study is also important because it finds that anything more than one drink per week is just as risky as binge drinking, and the type of alcohol does not matter. So, if you thought that an occasional glass of wine couldn’t hurt, you need to keep reading.

In fact, according to the study, for each week that more than one drink of alcohol per week is consumed in the first 5 to 10 weeks of pregnancy, the risk of miscarriage goes up by eight percent.

This study also warns that even moderate drinking, such as two glasses of wine per week, increases miscarriage especially between weeks five and ten.

Key Findings From the Study

The research team recruited 5,353 women to answer questions about their alcohol use in early pregnancy, including the time just before they learned they were pregnant. The women came from eight metropolitan areas in the United States. The results are published in the American Journal of Obstetrics and Gynecology:

  • Just under 50 percent of the women reported using alcohol in early pregnancy, of which 12 percent had a miscarriage.
  • The median amount of alcohol used was just 2 drinks per week.
  • Each week of alcohol use during weeks 5 through 10 was associated with an eight percent increase in miscarriage risk.
  • Although about 95 percent of women stopped using alcohol once they knew they were pregnant, the average amount of time from conception to quitting was 29 days, usually when they missed their first period.
  • Women who were exposed to alcohol during those 29 days had a 37 percent higher risk of miscarriage than women who were not drinking.

Surprisingly, women who were most likely to be drinking during early pregnancy were white, college-educated, and have higher income.

Bottom Line

Studies show that about one in six pregnancies end in miscarriage. This study suggests that a significant part of that risk occurs in early pregnancy, even before women learn that they are pregnant. This study also warns that even moderate drinking, such as two glasses of wine per week, increases miscarriage especially between weeks five and ten.

The researchers conclude that the risk of alcohol exposure in early pregnancy is underestimated. They warn that no amount of alcohol is safe during pregnancy. If you may be pregnant, the researchers suggest using a home pregnancy test instead of waiting for a missed period. This test can diagnose pregnancy earlier. The earlier you stop drinking, the better. Better yet, if you are actively trying to get pregnant, or not actively trying to prevent pregnancy, stop drinking right now.

Christopher Iliades
Dr. Chris Iliades is a medical doctor with 20 years of experience in clinical medicine and clinical research. Chris has been a full time medical writer and journalist since 2004. His byline appears in over 1,000 articles online including EverydayHealth, The Clinical Advisor, and Healthgrades. He has also written for print media including Cruising World Magazine, MD News, and The Johns Hopkins Children's Center Magazine. Chris lives with his wife and close to his three children and four grandchildren in the Boston area.

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