For many adopted or adults and children in foster care, records or other reliable sources may not be available for review. Reporting alcohol use during pregnancy can also be stigmatizing to birth mothers, especially if alcohol use is ongoing. In these cases, all diagnostic systems use an unknown prenatal alcohol exposure designation. A diagnosis of FAS is still possible with an unknown exposure level if other key features of FASD are present at clinical levels.

Confirmed absence of exposure would apply to planned pregnancies in which no alcohol was used or pregnancies of women who do not use alcohol or report no use during the pregnancy. This designation is relatively rare, as most people presenting for an FASD evaluation are at least "suspected" to have had a prenatal alcohol exposure due to presence of other key features of FASD.

Medical organizations strongly discourage drinking alcohol during pregnancy. Alcohol passes easily from the mother's bloodstream through the placenta and into the bloodstream of the fetus, which interferes with brain and organ development. Alcohol can affect the fetus at any stage during pregnancy, but the level of risk depends on the amount and frequency of alcohol consumed. Regular heavy drinking and binge drinking (four or more drinks on any one occasion) pose the greatest risk for harm, but lesser amounts can cause problems as well. There is no known safe amount or safe time to drink during pregnancy.

Prenatal alcohol exposure can lead to fetal alcohol spectrum disorders (FASDs). The most severe form of FASD is fetal alcohol syndrome (FAS). Problems associated with FASD include facial anomalies, low birth weight, stunted growth, small head size, delayed or uncoordinated motor skills, hearing or vision problems, learning disabilities, behavior problems, and inappropriate social skills compared to same-age peers. Those affected are more likely to have trouble in school, legal problems, participate in high-risk behaviors, and develop substance use disorders themselves.

The apprehension is not necessarily data driven and is a cautionary response to the lack of clinical studies in pregnant women. The indication is a trade-off between the adverse effects of the drug, the risks associated with intercurrent diseases and pregnancy complications, and the efficiency of the drug to prevent or ameliorate such risks. In some cases, the use of drugs in pregnancy carries benefits that outweigh the risks. For example, high fever is harmful for the fetus in the early months, thus the use of paracetamol (acetaminophen) is generally associated with lower risk than the fever itself. Similarly, diabetes mellitus during pregnancy may need intensive therapy with insulin to prevent complications to mother and baby. Pain management for the mother is another important area where an evaluation of the benefits and risks is needed. NSAIDs such as Ibuprofen and Naproxen are probably safe for use for a short period of time, 48–72 hours, once the mother has reached the second trimester. If taking aspirin for pain management the mother should never take a dose higher than 100 mg.

Different countries recommend different maximum quantities. For most countries, the maximum quantity for men is 140 g–210 g per week. For women, the range is 84 g–140 g per week. Most countries recommend total abstinence during pregnancy and lactation.

A study published in the British Medical Journal on 10 July 2014 investigated the correlation between human variants of the ADH1B gene, which codes for the ADH1B enzyme (Alcohol dehydrogenase 1B), and cardiovascular health. The study concluded that carriers of one specific variant of this gene (A-allele of ADH1B rs1229984), which is associated with lower alcohol consumption, '...had a more favourable cardiovascular profile and a reduced risk of coronary heart disease than those without the genetic variant.' The study's authors extrapolated from this finding to suggest that '...reduction of alcohol consumption, even for light to moderate drinkers, is beneficial to health.'

This study contradicts previous findings on the causal relationship between light alcohol consumption and cardiovascular health, and has been criticized on its methodology by members of the International Scientific Forum on Alcohol Research, which stated in its analysis that '...[there are] questions about making generalized statements about the effects of alcohol on disease based on results from the analysis of a single nucleotide polymorphism of a gene.'

Moreover, the study fails to explain or discount previous findings that show a causal link between alcohol intake and cardiovascular health that can not be accounted for by genetic predisposition alone.

U.S. Code of Federal Regulations requires that certain drugs and biological products must be labelled very specifically with respect to their effects on pregnant populations, including a definition of a "pregnancy category." These rules are enforced by the Food and Drug Administration (FDA). The FDA does not regulate labelling for all hazardous and non-hazardous substances and some potentially hazardous substances are not assigned a pregnancy category.

Australia’s categorisations system takes into account the birth defects, the effects around the birth or when the mother gives birth, and problems that will arise later in the child's life caused from the drug taken. The system places them into a category of their severity that the drug could cause to the infant when it crosses the placenta(Australian Government, 2014).

There are many short and long term health conditions that are attributed to alcohol consumption. These harmful conditions over prolonged use are well documented to be hard to treat and as some of these health conditions result in permanent damage to several vital organs. there remains a very real implication of death due to one or more of these conditions. Approximately 88,000 deaths have been reported between the years 2006 to 2010 due to excessive alcohol consumption in the United States.

Physicians often state alcohol consumption as a direct cause of several chronic conditions becoming harder to manage, thus recommending small quantities over a low frequency to limit further damaging impairments. Some physicians emphatically recommend giving up alcohol in order to prevent heart disease, brain impairment and liver disease.

Centers for Disease Control defines a drink as 0.6 ounces of pure alcohol and excessive drinking as 8 or more drinks per week for women and 15 or more drinks per week for men.

Major Health Risks

- Sexual functions

Prolonged use of alcohol has been known to impair the nervous system, heart, liver and the reproductive organs resulting in reduced sexual abilities in adult males. Furthermore, due to the mental impairment often related to prolonged use can also lead to tendencies of practicing unprotected sexual intercourse and intercourse with multiple partners. This can result in sexually transmitted diseases along with unintended pregnancies.

- Effects on the unborn

Women who continue to consume alcohol during pregnancy are highly likely to have offspring that have birth defects. As alcohol is able to get directly into the nutrition that the mother is passing on to the baby through her placenta, there is a direct effect to the development of the fetus resulting in damaged cells, birth defects, neurological disorders and miscarriage .

- Effects on the vital organs

Studies have shown a damaging relation between higher amounts of alcohol consumption and organ damage. Cardiovascular problems like high blood pressure, cardiomyopathy and heart attacks have been attributed to excessive alcohol consumption. Beyond the circulatory system, kidney and liver disease is also attributed to alcohol consumption. Effects on brain function have been found, for example memory loss reduced intellectual ability, reduced brain size and coordination.

- Social effects

Prolonged excessive use are known to induce many hard to treat conditions like depression, impulsive decision making, violent and abusive behavior, reduced cognitive abilities. All of these can limit the quality of interactions with family, friends and can lead to harmful behavior towards self and others.