Can Drinking Alcohol Affect a Pregnancy? A Doctor Weighs In

It's a question many women ask themselves once they find out they are pregnant: Does drinking alcohol harm their developing fetus, especially if they were drinking before they knew they had conceived?

In this article, an obstetrician-gynecologist shares what you need to know about the dangers of alcohol during pregnancy.

Can drinking alcohol affect a pregnancy?

According to the U.S. National Institute on Alcohol Abuse and Alcoholism, prenatal alcohol exposure is a leading preventable cause of birth defects and developmental delays in the United States.

Dr. Sudheer Jayaprabhu, an ob-gyn who practices in Texas, explained further: "Drinking alcohol in pregnancy can lead to fetal alcohol syndrome, miscarriages, stillbirths and preterm labor," he said.

When a pregnant woman drinks, alcohol crosses easily from the mother’s bloodstream to the fetus’s blood, tissue and organs, according to the U.S. National Library of Medicine. Because the fetus is unable to break down alcohol as quickly as the mother, its blood alcohol level stays high longer, and this can damage developing organs and systems.

The U.S. Centers for Disease Control and Prevention lists the characteristics and behaviors that children with Fetal Alcohol Syndrome Disorders (FASDs) might have:

• Abnormal facial features, such as a smooth ridge between the nose and upper lip
• Small head size
• Shorter-than-average height
• Low body weight
• Poor coordination
• Hyperactive behavior
• Difficulty with attention
• Poor memory
• Difficulty in school (especially with math)
• Learning disabilities
• Speech and language delays
• Intellectual disability or low IQ
• Poor reasoning and judgment skills
• Sleep and sucking problems as a baby
• Vision or hearing problems
• Problems with the heart, kidney or bones

But how much alcohol is too much?

Will one glass of wine hurt your baby? The fact is, experts say there is no known safe amount of alcohol for a woman to drink when she is pregnant.

“Most medical professionals recommend against even one glass of wine, because there are a lot of other variables involved than just the volume of alcohol consumed,” said Jayaprabhu.

They include:

• Renal function (one person’s kidney function could be different from another)
• The fetus's sensitivity to alcohol
• Genetic susceptibility of patients (some people are more sensitive to alcohol than others)
• Drinking patterns (one glass of wine for five days versus five glasses of wine in one sitting)
• Possibility of use of other substances (tobacco, marijuana, etc.)

The CDC reported in an analysis of previous studies that any binge drinking during pregnancy was associated with the child having problems with thinking skills. (Binge drinking was identified for this study as four drinks on one occasion.) In another study, the authors found that moderate drinking (up to six drinks per week) during pregnancy was associated with the child having behavior problems.

But what if I’ve been drinking in early pregnancy without knowing I was pregnant?

Drinking in very early pregnancy can cause miscarriage. Once you know you are pregnant, you should stop drinking. "It is best to stop drinking if you are trying to get pregnant," Jayaprabhu said. “It is also important to let your doctor know so that they can monitor the baby."

What's the worst time to drink during pregnancy?

While there is no safe amount or safe time to drink during pregnancy, "the first trimester of pregnancy [from six to 13 weeks] is the worst time. This is when most of the crucial development takes place, so damage during this time period will generally lead to the most severe outcomes," Jayaprabhu explained. “Later on, as most structures are developed and growing, we tend to see more behavior defects.”

Bottom line:

The only way to prevent fetal alcohol syndrome is to not drink alcohol during pregnancy. The safest plan is to stop drinking when trying to get pregnant, and if you find yourself unexpectedly pregnant, stop immediately. This will give your baby the best chance for a healthy life, free of the effects of alcohol on their developing body.

Resources:

Sudheer Jayaprabhu, MD, ob-gyn, Christus Health, Irving, Texas

U.S. National Institute on Alcohol Abuse and Alcoholism: Fetal Alcohol Exposure

Medline Plus: Alcohol and Pregnancy

U.S. Centers for Disease Control and Prevention: Alcohol Use During Pregnancy

U.S. Centers for Disease Control and Prevention: Key Findings: The effects of alcohol use during pregnancy and later developmental outcomes: An analysis of previous studies.