When Alison was pregnant six years ago, she asked her Toronto-based midwife what she thought about her having a drink. Her midwife advised her to avoid alcohol during the first trimester. But after that, one drink at a time, once or twice week, would be okay. She followed the advice. “I really enjoy a glass of wine, or a beer on a hot summer day,” she says. “I find it relaxing.”
It wasn’t relaxing, though, the one time she ordered a beer at a pub. “People were staring,” she says. “I might as well have had a big flashing sign saying, ‘This is what not to do when you’re pregnant.’”
There are many controversial recommendations for pregnant woman, and the one that’s especially been debated is the recommendation to completely abstain from alcohol. Books and media articles and even some health care providers have suggested the recommendation to avoid alcohol completely puts unrealistic expectations on women and isn’t backed by strong evidence. But most medical experts say we just don’t have enough information about the safety of alcohol, even in low amounts, to condone its use.
Evidence behind low levels of alcohol in pregnancy
Studies evaluating the effects of alcohol in pregnancy have shown clear evidence that drinking alcohol puts fetuses at risk of fetal alcohol spectrum disorder (FASD), a term that covers a range of mild to severe effects that can result from prenatal alcohol exposure. The effects can include facial and other physical changes, brain and central nervous system disabilities, as well as cognitive, emotional and behavioural problems that include difficulty with reasoning and learning from experience. There is no cure for FASD. The frequency of drinks per day and number of days alcohol is consumed during a pregnancy increases the likelihood of FASD occurring, and the severity of the damage. It is estimated that nearly 1% of the Canadian population have FASD, but actual numbers are tricky given that many cases go undiagnosed, says Susan Blue, child health and development manager with Toronto Public Health.
But what’s the evidence around having a single drink on occasion in pregnancy?
Unfortunately, there aren’t a lot of studies looking at drinking low levels of alcohol in pregnancy and the studies that exist aren’t conclusive, explains Jocelyn Cook, scientific director of the Society of Obstetricians and Gynaecologists of Canada. That’s because the studies are too small, researchers have to rely on women’s self-reporting of consumption (which may be under-reported or might not be remembered accurately) and the research is flawed in a myriad of other ways. For example, many studies don’t follow children into adolescence, before which mild cases of FASD might not be apparent.
Jennifer Gunter, a OB-GYN and author based in the US, says that in order to have strong evidence, “you’d have to get 100,000 pregnant women and give half of them measured amounts of alcohol.” (You’d also have to somehow ensure none of the study participants were drinking on top of that.) For ethical and logistical reasons, such studies aren’t done.
There is some research, however. The largest systematic review analyzed 46 studies that included women who reported consuming alcohol at low levels (no more than six Canadian standard drinks over a week). The review found this low exposure did not increase the risk of miscarriage, intrauterine growth restriction, stillbirth, prematurity, birthweight small for gestational age or birth defects. However, the authors noted weaknesses in the studies meant that they could not be confident in their results.
Not only was the systemic review inconclusive, it only looked at certain outcomes. Other, smaller reviews and single studies have examined the relationship between low levels of drinking and behavioural problems, heart issues, IQ and much more. Many studies didn’t find an association between negative outcomes and low alcohol consumption but there are some studies that did find a link between light drinking and small behavioural, intellectual or psychological differences.
With media headlines on these studies one day hailing that a drink with dinner is safe for pregnant women, and another day saying it’s dangerous, it’s “very confusing for women,” says Blue. The truth is there no evidence that having an occassional glass of wine in pregnancy is harmful. There is no evidence that it’s entirely safe either.
The reasons for our current guidelines on zero alcohol consumption
Given that there is no proof that light drinking in pregnancy is safe, all official medical guidelines on alcohol in pregnancy in Canada and almost all medical guidelines around the world advise women the only thing they can do to guarantee their fetus is not harmed by alcohol is to not drink at all during pregnancy. “I think people are being conservative and prudent because there’s so much we don’t know,” explains Cook.
Lisa Graves, chair of the Maternity and Newborn Care Committee of the College of Family Physicians of Canada, explains that we know that a mother’s genetics affect whether she processes alcohol slowly or quickly (the former leading to higher peak blood levels). The same goes for a baby’s genetics. And we know that factors like poor nutrition and stress “reduce a baby’s capacity to have resilience” to any toxin (and alcohol is considered a toxin). Meanwhile, research shows that in a particular stage of development, in the second half of the first trimester, a fetus is more vulnerable to the effects of alcohol. There might, in other words, be rare situations in which risk factors come together and the occasional glass of alcohol leads to harm – and it’s unlikely the research could ever be nuanced enough to prove that.
There are also practical reasons that experts have settled on the message of avoiding alcohol, rather than saying that women can have an occasional drink in pregnancy. To start with, one drink isn’t well defined. “Now, there are these big wine glasses that are like bowls,” says Brenda Stade, head of the FASD clinic at St. Michael’s Hospital in Toronto. One large glass of wine or one cocktail might actually have the alcoholic equivalent of two standard drinks.
For another, if women are told one alcoholic drink is safe, some women might argue, “alcohol doesn’t affect me as much so I can have two or three,” says Stade. Recommending that women avoid alcohol together avoids misinterpretations. “It’s an easy rule to follow,” explains Maya Nader, who treats pregnant women with alcohol use disorders at the St. Michael’s Family Health Clinic.
Should women get a more nuanced message when it comes to alcohol consumption?
Given there’s currently no proof that one drink on occasion in pregnancy is harmful, some argue the medical community shouldn’t simply tell pregnant women not to drink, but have a more nuanced conversation.
Emily Oster is an economist and author of a book examining the evidence behind recommendations given during pregnancy. She thinks that women should be advised not to binge drink or drink heavily, but should be informed about the lack of clear evidence about the safety of low levels of alcohol during pregnancy and encouraged to decide for themselves. Some women will choose to abstain because they’re not comfortable with the possible risk, others will feel comfortable having a drink, she argues.
Blue takes issue with this. “How would a person even know what their risk is? What their genetic predisposition to the effects of alcohol is?” she asks.
But some medical experts also think the abstinence recommendations might not be respecting women’s autonomy. When England’s Department of Health changed its recommendation from saying that women could have one to two units per week to recommending they abstain, Pat O’Brien, an obstetrician in the UK, decried the move. In a journal article, he wrote that “the strong advice not to drink implies a certainty and confidence in the evidence that simply does not exist” and the position could be seen as “paternalistic,” which could “lead to a loss of confidence in medical advice in general.”
Interestingly, the recommendations of the UK’s Royal College of Obstetricians and Gynaecologists is slightly different from the Department of Health’s recommendations. Their guideline states: “There is no proven safe amount of alcohol that you can drink during pregnancy” and recommends against drinking alcohol during the first three months of pregnancy. “Drinking small amounts of alcohol after this time does not appear to be harmful for the unborn baby, but you should not drink more than one or two units (defined as up to a 175mL glass of wine), and then not more than once or twice per week,” the guideline states.
It’s also apparent from some polls and anecdotes that not all doctors and midwives tell women to teetotal. Natalie, who lives in Ontario, said her first obstetrician told her it was okay to have a single alcoholic drink on occasion, while her second obstetrician told her not to. Natalie did feel comfortable having a glass of wine a week in her most recent pregnancy, after researching the evidence with her partner.
Blue says it’s “unfortunate” that front line providers are still promoting the idea that occasional drinking in pregnancy is fine. “There is no known safe amount,” she says. “We are working to get providers on board with that message.”
Dr. Peter Hutten-Czapski, a family doctor and obstetrician in Temiskaming Shores, Ontario, says that while he thinks the public health message around drinking is “right where it should be,” there is often need for a “more nuanced conversation” in a family doctor’s office. He meets women who are worried about the occasional drink they had in the first trimester, before they knew they were pregnant. “I tell them there is no evidence that a little bit of alcohol causes FASD because my job at that point is to reduce their anxiety,” he says. But he also recommends they stop drinking going forward, explaining that “with everything in pregnancy, we want to be absolutely safe and sure and the best way to do that is to abstain. You know you’re going to be fine if you don’t drink.”
Gunter also recognizes that with alcohol and pregnancy, there is sometimes a need for a longer conversation. Although she doesn’t currently see pregnant patients, when she used to, she advised them to abstain from alcohol completely. But, she also worked to create a judgement-free environment where women could feel comfortable talking about their alcohol use. For those who continued to drink a little in pregnancy, she was okay with that, so long as she understood what’s motivating their decision. “I would want to make sure that decision isn’t based simply on a desire to drink alcohol,” she says, “but that they understand the evidence and they’re comfortable with the level of risk.”
The names of the two women who talked about their alcohol use in pregnancy have been changed.