Drinking Alcohol During Pregnancy Common

Fran Lowry

July 08, 2015

Alcohol use during pregnancy in the United Kingdom, Ireland, and Australia is common, with prevalence ranging from 20% to 80%, according to a review of three international multicenter cohort studies.

"The guidelines for consuming alcohol during pregnancy really are conflicting, particularly the Irish and the UK guidelines, and it's very clear that women are drinking during pregnancy," Linda M. O’Keeffe, PhD, from the University of Cambridge, in the UK, told Medscape Medical News.

"Clinicians and public health professionals need to look at how we communicate the dangers of alcohol consumption during pregnancy and help to bring in public health campaigns," said Dr O'Keeffe, who conducted this review while at University College Cork, in Ireland.

The article was published online July 6 in BMJ Open.

Muddy Waters

"The guidelines in Ireland, Australia, and New Zealand advise women to abstain from drinking alcohol during pregnancy. But the Royal College of Obstetricians and Gynaecologists and the NICE [National Institute for Health and Care Excellence] guidelines in the UK say it's OK to drink up to two drinks twice per week in the second and third trimester of pregnancy, so that's where the confusion is," she said.

"The UK is quite an influential country, and it's very likely that a pregnant woman in Ireland would be following their guidelines, even though Ireland advises abstinence. While it may be the case that lower levels of alcohol are not harmful, governments tend to err on the side of caution because of the potential harm to the baby. However, in the UK, they err on the side of lower levels not appearing to be harmful, and that may be why there is this kind of muddy water," Dr O'Keeffe said.

The investigators analyzed data on prevalence and also predictors of alcohol use during pregnancy from two Irish retrospective studies ― The Growing up in Ireland (GUI) study and the Pregnancy Risk Assessment Monitoring System Ireland (PRAMS Ireland), and from one multicenter prospective international cohort, Screening for Pregnancy Endpoints (SCOPE).

The three studies included a total of 17,244 women, mostly of white ethnicity, and addressed the amount and type of alcohol drunk before and during pregnancy in the UK, Ireland, Australia, and New Zealand.

The studies used a variety of ways to determine prevalence, including postal surveys, trained government interviews, antenatal midwife-collected data, self-administered questionnaires, and anonymous surveys.

Their analysis showed a high prevalence of drinking, including binge drinking, among the pregnant women. Alcohol consumption during pregnancy in Ireland ranged from 20% in GUI to 80% in SCOPE, and from 40% to 80% in Australia, New Zealand, and the UK.

Ireland had the highest rates of drinking, with 90% of women drinking before and 82% drinking during pregnancy. Also in Ireland, 59% of women reported binge drinking before pregnancy, and 45% reported doing so while they were pregnant, determined on the basis of estimates from the SCOPE study.

"The exact prevalence in Ireland could be much lower than that, because estimates of drinking during pregnancy from the PRAMS and GUI studies were quite a bit lower, at 20% to 46%, and only about 3% of women reported binge drinking in PRAMS," Dr O'Keeffe said.

Differences by Race

The amount of alcohol that was drunk also varied widely across the three studies.

Between 15% and 70% of the women said they had consumed 1 to 2 units per week during the first trimester. However, this number dropped substantially in all countries between the first and second trimester, as did the amount of binge drinking.

Although drinking while pregnant was evident across all social strata, several factors were associated with a heightened or lowered risk for alcohol consumption.

Compared with white women, nonwhite women in all studies were less likely to drink alcohol during pregnancy.

In GUI, younger age was associated with lower risk for alcohol use; women younger than 39 years were more likely to drink alcohol during pregnancy compared with women aged 30 to 39 years, with evidence of a linear association overall between age and alcohol use (P for trend < .05).

Also in GUI, a second-level education, being multiparous, and having a body mass index (BMI) > 30 were linked to a lower risk for alcohol use during pregnancy.

In SCOPE, single women were more likely to drink alcohol during pregnancy.

Across all three studies, the strongest and most consistent predictor of drinking alcohol during pregnancy was smoking.

Smokers were 17% more likely to drink during pregnancy in SCOPE (relative risk [RR] = 1.17; 95% confidence interval [CI], 1.12 - 1.22); 50% more likely to drink during pregnancy in GUI (RR = 1.50; 95% CI, 1.36 - 1.65), and 42% more likely to drink in PRAMS (RR = 1.42; 95% CI, 1.18 - 1.70).

"The prevalence is high, and there is a conflict in guidelines that we need to resolve," Dr O'Keeffe said.

"But there is another thing to emerge from our research, and this is that often, the drinking was going on in early pregnancy before women recognized that they were pregnant. This points to the fact that we need to look at women's drinking patterns in general," she said.

"Up to 50% of pregnancies are not planned. In Ireland, the drinking culture is a lot stronger. More women are drinking and starting at a younger age, and this has increased in the last number of decades in Ireland and the UK, so women who become pregnant are exposed to alcohol in the first trimester. This is important, and we need to begin to address this issue," she added.

No Easy Answer

"We have a similar problem in Alberta," said Karen M. Benzies, PhD, professor and acting associate dean of research, Faculty of Nursing, University of Calgary, Alberta, Canada, who was invited by Medscape Medical News to comment on the study.

"The problem is that people come out with population-based studies that say two drinks do not adversely affect infant outcomes. The problem here is that they do not control for the individual maternal capacity to clear alcohol from her system. So it is likely true that generally, one or two drinks may not generate an adverse outcome. But the question remains, if a practitioner does not know the individual maternal capacity to metabolize alcohol and that capacity is compromised, then should the recommendation be to drink in moderation?," Dr Benzies said.

"Also, there was a systematic review published that concluded that alcohol use in pregnancy does not affect rates of preterm birth. The problem here is that preterm birth is not the outcome that is relevant to use of alcohol in pregnancy. It is infant brain development," she said.

"The other problem is that many women do not know that they are pregnant until after the greatest damage to the infant brain has already been done. Many young women binge drink, which has serious implications for fetal development. How can a public service campaign reduce alcohol consumption in these instances? Thus, there is no easy answer," Dr Benzies said.

Dr O'Keeffe and Dr Benzies report no relevant financial relationships.

BMJ Open. Published online July 6, 2015. Full text


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