Home > Alcohol consumption and pregnancy: a retrospective cohort study.

Long, Jean (2012) Alcohol consumption and pregnancy: a retrospective cohort study. Drugnet Ireland , Issue 40, Winter 2011 , p. 25.

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This study estimated the prevalence of peri-conceptional alcohol consumption and the relationship between it and maternal characteristics and perinatal outcomes.1 This was a retrospective cohort study of 61,241 singleton births at a large Dublin maternity hospital in the period 2000–2007, based on antenatal, delivery, postnatal and neonatal records. Self-reported alcohol consumption at the booking visit (usually between 12 and 20 weeks gestation) was categorised as: never (lifetime abstainers), low (0–5 units per week), moderate (6–20 units per week) and high (more than 20 units per week).

The numbers and proportions reporting each category of alcohol consumption were: abstainers (11,613, 19%), low or occasional drinkers (43,455, 70.9%), moderate drinkers (6,059, 9.9%), and high or heavy drinkers (114, 0.2%). The categories reporting any level of alcohol consumption accounted for 81% of the cohort.
The profile of those who never drank alcohol indicates that 23% were under 25 years old, 73% were married, 32% were housewives, 25% were unemployed, 57% were not Irish, 10% had private health care, 68% had had at least one previous pregnancy, 36% had not planned their current pregnancy, 23% had booked antenatal care after 20 weeks gestation, 18% smoked cigarettes, 1.5% had used illicit drugs at some point in their life and 21% had been referred for antenatal care by a social worker.   
The profile of low alcohol consumers indicates that 18% were under 25 years of age, 66% were married and 86% were Irish. Just over one third (34%) were in non-manual employment, while one quarter were professionals, managers or business owners. Twenty-eight per cent had private health care. Just under three-fifths (59%) had had at least one previous pregnancy and 34% had not planned their current pregnancy. Only a small minority (11%) had booked antenatal care after 20 weeks gestation. Twenty-three per cent smoked during their current pregnancy and less than 1% had used illicit drugs at some point in their life. Twelve per cent had been referred for antenatal care by a social worker.
The profiles of low and moderate alcohol consumers were similar in that these groups were marginally older than those who had never consumed alcohol. The occasional drinkers were less likely to smoke than the moderate drinkers, and more likely to have had a previous pregnancy and to have planned this pregnancy. The moderate drinkers were more likely than the occasional drinkers to be single, to smoke cigarettes and to have private health insurance.
The profile of heavy drinkers was very different to that of the other three groups: they were very young (45% of the group were under 25 years of age), just under 80% were single, one third were unemployed, 90% were Irish, only 3.5% had private health care, 68% were pregnant for the first time, 75% had not planned their current pregnancy, 70% smoked during their pregnancy, 9% had used illicit drugs at some point in their life and 40% had been referred by a social worker.
The profiles of those who consumed alcohol were compared to the profile of the group who never drank alcohol. Factors associated with moderate alcohol consumption included being in employment, being of Irish nationality, having private health care and smoking. Factors associated with high consumption included maternal age less than 25 years and illicit drug use. High alcohol consumption was also associated with very preterm birth (less than 32 weeks gestation) even after controlling for socio-demographic factors.
Only three cases of Fetal Alcohol Syndrome (FAS) were recorded (0.05 per 1,000 total births), one each in the low, moderate and high consumption groups. The fact that cases of FAS occurred in the low and moderate consumption groups may be explained by under-reporting of alcohol consumption by pregnant women, as FAS does not normally occur in the infants of low and moderate users.
There is a need to ensure a consistent and accurate approach to recording alcohol intake at the first antenatal visit. Other countries include measures of binge drinking at this visit and, given that binge drinking is very common in Ireland, this may be an important measure to identify risk of and prevent negative outcomes. It is clear that some pregnant women currently under-report their alcohol consumption.
This and other studies completed from routinely collected patient data at this large Dublin maternity hospital demonstrate the value of analysing such data to identify issues and improve current practice.
 
1. Mullally A, Cleary BJ,Barry J,Fahey T and Murphy DJ (2011) Prevalence, predictors and perinatal outcomes of peri-conceptional alcohol exposure: retrospective cohort study in an urban obstetric population in Ireland. BMC Pregnancy and Childbirth, 11: 27.
Item Type:Article
Issue Title:Issue 40, Winter 2011
Date:2012
Page Range:p. 25
Publisher:Health Research Board
Volume:Issue 40, Winter 2011
EndNote:View
Accession Number:HRB (Electronic Only)
Subjects:A Substance use, abuse, and dependence > Prevalence > Problem substance use
E Concepts in biomedical areas > Pregnancy
VA Geographic area > Europe > Ireland > Dublin
G Health and disease > Substance use disorder > Alcohol use
T Demographic characteristics > Pregnant woman
A Substance use, abuse, and dependence > Prevalence > Substance use behaviour > Alcohol consumption

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