For years, the advice around alcohol and pregnancy has been straightforward: there is no established safe amount to drink while pregnant. But one question continues to cause confusion: does an occasional drink really matter, particularly during the earliest weeks before someone may even know they’re pregnant?
New research published in September 2026 in the journal Nutrients adds to evidence that it may.
Researchers following more than 3,200 women and their partners in Rotterdam found that alcohol consumption during early pregnancy was associated with a higher risk of miscarriage, including among women reporting relatively low levels of drinking.
Curiously, the same study found that women who drank lightly before becoming pregnant appeared less likely to experience infertility. The researchers cautioned against interpreting that as evidence that alcohol improves fertility. Differences in health, lifestyle and socioeconomic factors between drinkers and non-drinkers may help explain the association.
Taken together, the findings illustrate why alcohol and reproductive health can be difficult to study. But when it comes to drinking after conception, the evidence points in a much clearer direction.
The Numbers Behind the Alcohol and Miscarriage Risk
According to data from Vanderbilt University Medical Center, each week a woman consumes alcohol during the first five to ten weeks of pregnancy is associated with an incremental 8% increase in miscarriage risk. That research found the risk continued climbing through the ninth week of pregnancy and accrued regardless of whether a woman reported fewer than one drink or more than four drinks each week, and independent of the type of alcohol consumed.
The September 2026 study in Nutrients, led by Morena Martinez Mayans and colleagues at Erasmus MC University Medical Center in Rotterdam, built on those findings by analyzing both timing and amount. Preconception intake of fewer than one glass per week and one or more glasses per week among women was associated with lower odds of infertility – women who drank lightly before conception appeared more likely to conceive. This association almost certainly does not reflect a causal benefit of alcohol on fertility. The study’s authors attributed it to confounding, not biology.
Moderate alcohol consumers in this population tended to have higher socioeconomic status and more favorable lifestyle factors than abstainers, including higher education levels and lower body mass index. People who abstain from alcohol entirely often do so because of illness, a history of problem drinking, or other health conditions that may independently reduce fertility. In epidemiology, this pattern is known as “sick quitter” bias: it makes moderate drinkers appear healthier than they are on any given variable, distorting the statistical picture.
Among men, alcohol consumption was not associated with infertility or miscarriage. Male partners in the Generation R Next Study showed no meaningful link between their drinking habits before conception and reproductive outcomes. The association between alcohol and miscarriage risk, in this dataset, was specific to women drinking during early pregnancy.
Why Early Pregnancy Is the Critical Window
Alcohol can disrupt fetal development at any stage during pregnancy, including before a woman knows she is pregnant. Most women don’t confirm a pregnancy until four to six weeks in – often after a missed period – and by that point, the embryo has already been developing for several weeks.
When a pregnant woman drinks alcohol, it travels through her blood and into the baby’s blood, tissues, and organs. Alcohol breaks down much more slowly in the baby’s body than in an adult, meaning the baby’s blood alcohol level remains elevated longer than the mother’s. The fetal liver is not developed enough to metabolize alcohol the way an adult liver does, so even a modest drink can expose the embryo to alcohol concentrations that linger for hours.
Research examining the biological mechanisms behind alcohol-related pregnancy loss has found that alcohol alters maternal and fetal metabolism and can limit fetal nutrient availability. When organs, the nervous system, and the placenta itself are forming, reduced nutrient supply can interfere with the signaling processes that sustain a healthy pregnancy. The 2026 Nutrients study noted this as one of the key reasons the research was conducted: many women and their partners do not have accurate information about when the risk window begins.
Beyond Miscarriage: The Broader Reproductive Risks
Alcohol use during pregnancy is associated with increased risk of miscarriage, preterm birth, stillbirth, and sudden infant death syndrome (SIDS), according to the CDC. Alcohol can cause problems for the baby throughout pregnancy, including before a woman knows she is pregnant.
Alcohol use during pregnancy can cause a range of lifelong behavioral, intellectual, and physical disabilities known as fetal alcohol spectrum disorders (FASDs). FASDs encompass a spectrum of preventable conditions that can occur in a person exposed to alcohol before birth, ranging from subtle learning and attention difficulties to full fetal alcohol syndrome (FAS), the most severe form. People with FAS have central nervous system problems, minor facial features, and growth problems.
Binge drinking during pregnancy carries its own risks. Current drinking and binge drinking in the past 30 days were reported by 11.5% and 3.9% of pregnant women, respectively. Given how many early pregnancies go unrecognized for weeks, a share of that drinking almost certainly occurred during critical developmental periods.
The Confounding Problem and What It Means
The Generation R Next Study, like all observational research, has real limitations that shape how its findings should be used. Data on alcohol consumption were self- or partner-reported, which may have introduced recall and social desirability biases. People tend to underreport alcohol use when they believe they’re being judged, which means the true amounts consumed in this study are likely somewhat higher than what was recorded.
The study also acknowledged that very early miscarriages – those occurring before a clinical pregnancy was recognized – may have been misclassified as non-conceptions rather than pregnancy losses. If early, unrecognized pregnancies were lost and those women were categorized as “trying to conceive” rather than “had a miscarriage,” the miscarriage risk associated with drinking could be underestimated, not overstated.
The apparent fertility benefit seen in women who drank lightly before conception illustrates how observational data can mislead. Because moderate drinkers in this population tended to be healthier, more educated, and leaner than abstainers, the statistical association with better fertility outcomes reflects those lifestyle advantages – not a causal effect of the alcohol itself. The study’s authors were explicit on this point, writing that preconception and early-pregnancy counseling should focus on the risks of miscarriage and fetal health outcomes, not on any apparent fertility signal in the preconception data.
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What to Do Now
What This Means If You’re Pregnant or Trying to Conceive
The new research doesn’t tell us that a single drink will cause a miscarriage. Observational studies can’t establish that kind of cause-and-effect relationship, and individual risk depends on many factors.
What it does add to is a larger body of evidence suggesting that alcohol exposure during early pregnancy may increase the risk of pregnancy loss. Previous research has also found that miscarriage risk rises with continued alcohol exposure during the first several weeks of pregnancy.
That’s particularly relevant because pregnancy may go unrecognized during part of this window. Someone can therefore be exposed to alcohol before realizing they’re pregnant.
Current CDC guidance states that there is no known safe amount of alcohol during pregnancy, no known safe time to drink during pregnancy, and no type of alcohol known to be safer than another. The agency also recommends avoiding alcohol when trying to become pregnant.
For someone who drank before realizing they were pregnant, the message shouldn’t be one of panic. The CDC recommends stopping once pregnancy is recognized and discussing any concerns with a healthcare provider. Stopping alcohol at any point prevents further exposure, and fetal development continues throughout pregnancy.
The new study doesn’t prove that every small exposure is harmful. Instead, it reinforces why health authorities don’t recommend trying to identify a “safe” amount: research hasn’t established one.
Disclaimer: The author is not a licensed medical professional. The information provided is for general informational and educational purposes only and is based on research from publicly available, reputable sources. It is not intended to constitute, and should not be relied upon as, medical advice, diagnosis, or treatment. Always consult a licensed physician or other qualified healthcare provider regarding any medical condition, symptoms, or medications. Do not disregard, avoid, or delay seeking professional medical advice or treatment because of information contained herein.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.
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