Effects of Drinking in the First Few Weeks of Pregnancy

If you did not abstain from alcohol in the weeks before you learned you were pregnant, you might worry about the consequences. Those early weeks are critical for the development of the embryo, yet there is conflicting research regarding the effect of drinking alcohol during the early weeks of pregnancy.

Some studies that show alcohol consumption during the first few weeks of pregnancy—that time when you may not even know that you a pregnant yet—can harm the development of the baby.

There are other studies that claim that drinking during those early day does not harm the fetus at that stage of development. In either case, there is convincing evidence that the pattern of drinking (one drink per day as compared with binge drinking or heavy drinking) has a large impact on the effects.

Many body parts and organs are developing in the embryonic stage of pregnancy which begins at fertilization through week 8. During the first four weeks of pregnancy—when most women are not aware that they are pregnant—the heart, central nervous system, eyes, arms, and legs of the fetus are developing. In addition, developing organ systems may be more vulnerable to damage at the very early stages of development.

Over the years, studies of fetal alcohol syndrome have found that it is the mother's pattern of drinking that has the most effect on the unborn child. The pattern and timing of prenatal alcohol use can greatly influence the impact of adverse effects on the fetus, according to the Centers for Disease Control and Prevention. The most dangerous patterns of drinking to the baby are chronic drinking, heavy drinking and binge drinking.

A study of 5,628 pregnant women in England, Ireland, New Zealand, and Australia found that women who drink during the early weeks of pregnancy did not put their babies at risk for premature birth or low birth weight. Nor did women put themselves at risk for high blood pressure complications during pregnancy.

Even among the women who reported having more than seven drinks a week—about 15 percent of the study group—the rates of premature birth and low-birth-weight babies were the same as those women who did not drink.

It should be noted that this study met with a great deal of controversy when it was published in October 2013.

A year later, another study conducted by the University of Leeds in England found that even women who drank low-level amounts of alcohol during the first weeks of pregnancy ran the risk of premature or unexpectedly small babies.

In the study of 1,264 pregnant women, even mothers who drank as few as two drinks a week, ran a greater risk of premature births and low-weight births, compared to those who did not drink.

Because no one knows definitively how much or little alcohol can affect the development of your developing baby, even in the first early first weeks, the best advice continues to be quitting all alcohol consumption as soon as you intend to become pregnant or as soon as you find out that you are pregnant.