Drinking Alcohol in Early Pregnancy

Pregnant woman with glass of red wine
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It has become a given: You do not drink during pregnancy. So vehemently has this message been drilled into the public consciousness that it leaves the impression that even a little alcohol, even in the early stages of pregnancy, places a fetus at significant risk of birth defects.​​​

But is this actually so? And what if you were a drinker—even a heavy drinker—at the time you became pregnant? Has the damage already been done? When does an occasional drink become a genuine health concern?

Zero Tolerance in the Public Health Message

The first step is to take a deep breath. The vehemence of the public health message, while well-intentioned, can sometimes leave a woman feeling that even discussing the subject of alcohol and pregnancy is forbidden. This shouldn't be the case.

The simple fact is that there is no way to know where the line is between safe and unsafe is. It is all highly individual in the same way that a person's response to alcohol is highly individual.

Drinking During Early Pregnancy

It is well known that drinking during pregnancy can lead to the development of fetal alcohol syndrome (FAS) as well as increase the risk of miscarriage, birth defects, and other health complications. But an occasional drink appears to have less effect during the first trimester than some might assume.

A 2013 study from the University of Adelaide compared birth outcomes in 5,628 women in England, Ireland, Australia, and New Zealand who were pregnant for the first time. In terms of alcohol consumption, the authors found that during the first trimester:

  • More than half of the women reported drinking alcohol.
  • 34% reported at least one binge episode.
  • 25% said that they drank three to seven drinks per week (a drink was defined as a glass of wine or less than a 12-ounce bottle of beer).
  • 19% said that they had one to two drinks per week. 
  • 15% reported having eight to 14 drinks per week.
  • 5% consumed more than 14 drinks per week.

In comparing the participants, both drinkers and non-drinkers, the researchers reported that there was no association between alcohol consumption before 15 weeks and the number of adverse factors at birth. These included low birth weight, small birth size, preterm birth, and preeclampsia (a potentially life-threatening condition in which a pregnant woman develops high blood pressure).

What the study did not show, of course, was whether drinking caused other damage to the baby, specifically the impairment of mental function.

Patterns of Drinking During the First Trimester

Drinking patterns may be more of a factor in fetal brain developmental problems than the practice of drinking itself, according to an analysis from the Texas A&M University Health Science Center which looked at data from both human and animal studies.

Binge drinking (defined as having more than four drinks within two hours) increases the blood alcohol concentration (BAC) far beyond what would be seen in a casual drinker. This exposes the developing fetus to the same levels of alcohol that cause hangover in adults—at a stage where the brain is developing and has less capacity for self-repair.

Long-term studies in humans have confirmed that children of binge-drinking mothers have especially severe cognitive and behavioral problems compared to children of non-binge-drinking mothers.

While this may suggest that mothers who are non-binge drinkers are "safe," the research does not support that belief. Instead, early alcohol exposure may have as much ill effect on fetal brain development as alcohol exposure throughout pregnancy. Moreover, the persistence of drinking is associated with a worsening of defects in the second trimester, resulting in a loss of plasticity (ability to change and develop) of fetal brain tissue.

What All of This Tell Us

The bottom line is this: We don't know for sure where the line is between acceptable and non-acceptable drinking during pregnancy. Some women have more of the enzymes needed to break down alcohol than others. But we don't know how, or if, this changes the amount of alcohol their babies are exposed to.

The choice of drink also makes a difference. A shot of liquor can have 20 times more alcohol per serving than a glass of wine or beer.

If you consumed alcohol before you knew you were pregnant, try not to panic. A baby's major organs, including the brain, don't begin to develop until around the fourth week of pregnancy, around the time you would first miss a period.

If you know that you drank alcohol around the time you conceived, have a history of drinking, or just enjoy the occasional drink, be honest with your doctor or midwife during your prenatal visits.

Don't minimize your alcohol intake or say you're drinking less than you are. This is especially true if you find it hard to stop or cut back. Bending the facts to please your doctor will help no one, including your baby. Honesty allows you to get help if you need it, and to make informed decisions based not on fear, but on facts. 

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