Page last updated: Tuesday, November 18, 2008
Alcohol and pregnancy - the Danish experience by Dr. Erik Skovenborg
The first reported association between maternal alcoholism and a characteristic pattern of cranio-facial, limb and cardiovascular defects in the offspring was published in The Lancet Saturday 9 June 1973 (1). Since then the results of a large body of research have been published; a search in PubMed for reports concerning pregnancy and alcohol leads to a list of 15535 articles! What insight might we gain from that mountain of evidence?Recommendations about drinking during pregnancy

1996 the Royal College of Obstetricians and Gynaecologist published a guideline on alcohol consumption in pregnancy. The RCOG Guideline concluded: "There is no conclusive evidence of adverse effects in either growth or IQ at levels of consumption below 120 gms per week. Nonetheless, it is recommended that women should be careful about alcohol consumption in pregnancy and limit this to no more than one standard drink (8 gms of alcohol) per day."

A recent review of obstetrical textbooks published over the last 4 decades identified 81 texts (2). Only 14 (17%) of the texts contained a consistent recommendation that pregnant women should not drink alcohol. Although there was a slight upward trend toward recommendations for abstinence in more recent texts, only 24% af the 29 texts published after 1990 were in this category. More than half (52%) of texts published after 1990 contained a sentence condoning drinking at some level. The remaining texts (30%) contained no recommandations at all.

Clearly the consumption of alcohol during pregnancy cannot be deemed without risk, however, controversy continues as to whether there is any safe level which women should be advised not to exceed. What should we tell future mothers-to-be about the nature of the risk and the magnitude of the risk? The results from recent surveys of large groups of Danish pregnant women may be of assistance in the quest for an answer. Alcohol and spontaneous abortion

New data from a survey of over 24,000 pregnancies demonstrate an association between an average weekly consumption of 7.5 units (12 gms of alcohol) or more and a five-fold rise in the risk of spontaneous abortion during the first trimester (7-11 completed weeks of gestation) as compared with women taking 1.5 units or less per week. There was no link between alcohol intake and abortion during the second trimester (3). Alcohol and preterm delivery

Preterm delivery is to some degree hazardous and is associated with increased risks of the baby dying during or shortly after birth. Based on a group of 18,000 pregnant Danish women’s own estimates of their drinking at 16 weeks, the figures showed that those who consumed 4.5 to 13.5 units (12 gms of alcohol) per week had a slightly lower risk of preterm delivery than those who took less than 1.5 units weekly. But those who consumed 15 or more units per week were nearly three times more likely to have a preterm delivery. The figures were similar when based on the women’s estimates of their alcohol use at 30 weeks (4). Alcohol and stillbirth

The resulting data of a study of over 24,000 pregnancies not only demonstrated a risk of stillbirth 2-3 times greater for women consuming 7.5 units (12 gms of alcohol) or more per week, as compared with those taking less than 1.5 units per week. When focusing on just one of the causes of a stillbirth, fetoplacental dysfunction (harmful changes in the way the developing foetus is nourished through the placenta), the researchers found a rising risk, from 1.37 stillbirths per 1000 births for women taking less than 1.5 units weekly to 8.83 per 1000 births for those drinking 7.5 or more units per week (5). Foetal alcohol syndrome (FAS)

Drinking alcohol during pregnancy can cause serious physical and mental problems in the unborn child - namely Foetal Alcohol Syndrome (FAS) This includes:

  1. Head and face deformities, such as a small skull, distorted and flattened out face, drooping eyelids and a large space between lip and nose.
  2. Central-nervous-system dysfunction causing mental retardation and hyperactivity.
  3. Major organ system malfunctions resulting in heart defects, ear infections, hearing loss, poor eyesight and bad teeth.
  4. Arrested growth both before and after birth.

The tragedy of FAS is that it is entirely preventable. If a woman, even an alcoholic, stops drinking before she tries to become pregnant, her foetus will not develop FAS or any alcohol-related birth defects. The damage caused by alcohol is probably minimal in the first two weeks of gestation, but during the rest of the first trimester, when the foetus’ organs are forming, the effects may be especially severe. If the drinking continues, additional damage can occur, since the brain develops during all nine months and rapid body growth does not occur until the third trimester.

Nearly all known cases of FAS involve children whose mothers have chronic alcohol problems, however, scientists still do not know why FAS strikes the children of some alcoholic mothers and not others. The available evidence suggests there may be a genetic predisposition to FAS. At present scientists are not able to identify the genes involved and consequently it is not possible for the obstetrician to tell a mother-to-be whether she is particularly sensitive to the harmful effects of alcohol or not.

For years Health Authorities have advised the expectant mothers against any use of alcohol at all. "Even if adverse consequenses to very light drinking have not been detected that doesn’t mean they don’t exist", sounds the argument; the research we have access to at present do not indicate any documented threshold effect. The problem with that argument is that a majority of pregnant women believe that drinking some alcohol during pregnancy is acceptable (6). Even many general practitioners, obstetricians and widwifes do not beleive that an occasional drink is harmful to the foetus. And since they do not beleive that their pregnant patients have to be teetotallers, they will not pass on the zero-limit to the mothers-to-be. Consequently it might be better for the ideal purpose of the Health Authorities to modify the advice on drinking during pregnancy.

Alcohol in pregnancy – The revised Danish National Board of Health-recommendation

Some years ago the Danish National Board of Health (NBH) commissioned Dr. Ulrik Kesmodel, Research Unit of Infant Epidemiology,Skejby Sygehus, Denmark, to perform a review of more than 300 recent studies on alcohol-related birth defects. In his 1999-report on alcohol and pregnancy (7) Dr. Kesmodel concluded: 1)The consumption of 1-2 drinks per week is withour any danger to the foetus. 2)There is some uncertaincy about the effects of 3-6 drinks per week. 3)The intake of "7 drinks per week causes a risk of abortion and reduced birth weight and birth length.

Having considered the 1999-report the Danish NBH decided to change the official recommendation and pregnant women in Demark are now given the following advice and information about drinking alcohol during pregnancy:

  1. Avoid alcohol in pregnancy if possible.
  2. If you drink, drink no more than one drink (12 gms of alcohol) per day.
  3. Do not drink every day.

"What is the evidence", Kesmodel asked, "that the consumption of a few drinks per month or even per week as opposed to daily intake, may be harmful in pregnancy? If there is no consistent data to suggest that an occasional drink is harmful, it is possible that a large proportion of pregnant women and health personnel will not be convinced by repeated statements that total abstinence is necessary during pregnancy. If the only official recommendation is not to drink, then these women are not told that there is a limit, nor approximately what that limit is. So we need to ask the question: Where is the limit? Reaching a consensus on this would allow us to standardize information for these women (6)."

References(1) Jones KL et al. Pattern of malformation in offspring of chronic alcoholic mothers. Lancet 1973;1:1267-77.(2) Loop KQ, Nettleman MD. Obstetrical textbooks; Recommendations about drinking during pregnancy. Am. Journal of Preventive Medicine 2002;23:136-38. (3) Kesmodel U et al. Moderate alcohol intake in pregnancy and the risk of spontaneous abortion. Alcohol & Alcoholism 2002;37:87-92. (4) Kesmodel U et al. Does Alcohol Increase the Risk of Preterm Delivery? Epidemiology 2000;11:512-18. (5) Kesmodel U et al. Moderate alcohol intake during pregnancy and the risk of stillbirth and death in the first year of life. Am. Journal of Epidemiology 2002;155:305-12. (6) Kesmodel U et al. Drinking during pregnancy: attitudes and knowledge among pregnant Danish women. Alcoholism: Clinical and Exp. Research 2002;26:1553-60. (7) Kesmodel U. Alcohol in pregnancy. Ugeskr Læger 1999;161:4989-94.

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