To estimate the relation between maternal alcohol consumption and pregnancy outcome and child development up to the age of 18 months. To estimate the dose response curve at high consumption levels for which numbers are usually small in a single centre study.
A multicentre study was carried out in order to estimate:
the relationship between maternal alcohol consumption and pregnancy outcome and child development up to age of 18 months;
the dose response curve at high consumption levels for which numbers are usually small in a single centre study.
Maternal alcohol consumption was divided into 7 groups, from abstention to greater or equal to 150 g per week absolute alcohol based on 30 g per week intervals. Analyses were made of the relation between maternal alcohol consumption before and in early pregnancy and 5 infant outcome variables: birth weight, crown heel length, occipito frontal circumference and the Apgar scores at 1 and 5 min. The data were analysed for all centres combined and separately.
Children seen in the first part of the study in Berlin, Dundee and Odense were followed up at age 18 months and tested using the Bayley Scales of Infant Development. The 5 scores recorded were: the mental development index (MDI), the psychomotor development index (PDI) and scores for responsiveness, attention span and activity. The data were analysed for the centres combined and separately, allowing for confounding variables.
The results were consistent with previous published work in showing an association between infant's body size and maternal alcohol consumption either before or in early pregnancy at levels of about 120 g per week or more, Drinking only 1 standard drink a day in early pregnancy did not appear to have a detrimental effect on foetal growth. There was no evidence that the development of children of mothers who drink at the levels observed in the studies was impaired either mentally or physically at age 18 months.
On the basis of the findings and a consideration of the literature, it is recommended that women do not drink alcoholic beverages during pregnancy, but if this is not possible because of social pressures, consumption should be restricted to no more than 1 standard drink a day.
The preparatory work began in 1984 when a working group, convened by the European Commission, met to consider the setting up of a prospective study of the effects of maternal alcohol consumption on the outcome of pregnancy. The original objectives as given in the final version of the protocol were to answer the following questions:
1 What is the relation between maternal alcohol consumption during pregnancy and pregnancy outcome? More particularly, at what dose or range of dose are the features of alcohol embryopathy first observed?
2 What relation exists between maternal patterns of alcohol consumption before, during and after pregnancy and child development from birth to age 18 months?
3 What effect on alcohol consumption and pregnancy outcome has a health education intervention aimed at reducing alcohol consumption during pregnancy?
The main objective was to estimate the dose response relationship between alcohol consumption and a variety of outcome measures, including embryopathy. This implied that a substantial number of mothers who were heavy social drinkers needed to be recruited so that the upper end of the dose response curve could be estimated with precision. As most national studies at that time had only small numbers of heavy drinkers, there was a need for collaborative research. Furthermore, investigation of the effects of different types of drink was needed, since several studies had shown that of beer, wine and spirits, it was beer that was particularly associated with adverse outcome in moderate to heavy drinkers.
Two other hypotheses were to be tested. One was an extension of the initial hypothesis to include outcome at 18 months of age and the other was concerned with the effectiveness of health education in reducing alcohol consumption during pregnancy.