I just found this report on the BUPA website.....
Alcohol is, for many, one of life's pleasures and roughly nine out of ten women enjoy an alcoholic drink.1 But is alcohol safe in pregnancy? After all, any alcohol that enters the mother's blood stream is shared with the developing baby.
Pregnancy is conveniently divided into "trimesters" or three-month periods of time. Each has its own particular issues.
First trimester (0-3 months)
Giving up entirely, or drinking just one or two drinks a week, is thought to be best for the first few weeks of pregnancy when the baby is just beginning to develop and form in the womb. Research has shown that this is indeed a good idea. Miscarriage, which sadly is not uncommon, is slightly more common in women who continue to drink more than three drinks per week.1 However, the actual increase in risk is small: miscarriages are more likely to have occurred for reasons other than drinking alcohol.2 This slight increase in the risk of miscarriage falls after the first few weeks and by the second trimester there is no difference in miscarriage statistics between women who do drink and those who don't.
In contrast, drinking to excess is associated with a rare condition called "fetal alcohol syndrome". This condition is rare but can result from heavy and consistent alcohol consumption through pregnancy (18 units of alcohol per day or more). Children with fetal alcohol syndrome are born with small heads and facial abnormalities. Their intelligence is also permanently affected. Between one and two children in every 1,000 live births are born with fetal alcohol syndrome.1
The social effects from excessive drinking are also unwelcome during pregnancy. Excessive drinking increases the likelihood of domestic and road traffic accidents. It is also linked to social and relationship discord.
Social drinking is also carries some risks. Drinking more than 15 units of alcohol a week can lower the birthweight of your baby, while consuming more than 20 units each week has been associated with intellectual impairment.1
Second trimester (3-6 months) and third trimester (6-9 months)
In the second and third trimester, drinking alcohol does not increase the risk of miscarriage. However it has been shown to affect the rate at which the baby grows within the womb. Birth weight has been shown to be lower in babies born to women who drink 15 units or more each week during their pregnancy.1,3 This link has been shown to be true when careful analysis takes into account other factors that can affect birth weight (for example smoking and duration of pregnancy).1 Consuming more than 20 units each week has been associated with intellectual impairment.1
There are worries that even fairly modest regular drinking can have effects on the baby that may not become apparent for several years after birth. One study from the United States found that children exposed to alcohol in the womb were more likely to display behavioural and conduct disorder at the age of six than children from abstinent mothers. The differences between the groups persisted when other relevant factors were taken into account. They concluded that childhood behaviour could be influenced by any level of alcohol exposure, but that the larger the "dose" the greater the risk.4 Children who were exposed to alcohol while in the womb are also known to be less effective at suckling and more likely to show disturbed sleep patterns.5
Specific questions associated with drinking alcohol during pregnancy
Is there a level below which alcohol consumption is considered safe?
The short answer is no. However the risk seems to be dose related. In other words if you drink only one or two units of alcohol per week the chance of a problem is very small (but not nil). If you drink three or four units every day the risks are higher. Steady alcohol drinking each day increases the risk of miscarriage and can cause lower birth weight. Occasional heavy binge drinking is also hazardous.
If I drink only occasionally is that safe for my baby?
Probably, but drinking any alcohol increases risks for the baby (if only very slightly). The best answer is probably to either avoid alcohol or only drink one or two units of alcohol each week while you are pregnant. The first trimester is the most important time to reduce your alcohol intake or avoid it entirely.
How do I calculate how many units of alcohol I am drinking?
The definition is that one unit is equivalent to:
- one half pint of ordinary strength beer, lager or cider
- one quarter pint of strong beer or lager
- one small glass of wine
- one single (pub) measure of spirits
- one small glass of sherry
So, someone who has a pint of lager four times a week is drinking eight units per week. The safe upper limit for drinking in non-pregnant women is just 14-21 units per week.6 In pregnancy this level of drinking poses definite but small risks to the baby. If you can't stop drinking entirely it is better to cut down as much as you can. After all, the less you drink, the lower any risks become. If you would like to see how many units you are drinking, please use our alcohol calculator.
Is drinking beer or wine safer than drinking spirits?
The type of alcoholic drink doesn't matter, it's the number of units of alcohol drunk that counts. So, if you drink only one measure of gin (one unit), this is safer than drinking one pint of normal strength lager (two units). However, two measures of gin would have the same effect as drinking one pint of lager.
Summary
Drinking alcohol is, for many, one of life's pleasures. In pregnancy, however, it can cause problems and damage the developing baby. The risk of drinking an occasional unit of alcohol is small. Heavy drinking - whether steadily or in binges - is dangerous for the baby and should be avoided. The most vulnerable time is the first trimester. The best level of alcohol during pregnancy is zero.
to top
References
- Royal College of Obstetricians and Gynaecologists. Professor DJ Taylor. Clinical green top guidelines: Alcohol consumption in pregnancy (9).
- Moderate alcohol intake in pregnancy and the risk of spontaneous abortion. Kesmodel U, Wisborg S. Alcohol and Alcoholism. 2002;37(1):87-92.
- Commentary on the recommendation of the Royal College of Obstetricians and Gynaecologists concerning alcohol consumption in pregnancy. Guerri C, Riley E, Ströömland K. Alcohol and Alcoholism.1999. 34 (4):497-501
- Prenatal alcohol exposure and childhood behaviour at age 6 to 7 years: I. Dose-response effects. Sood B, Delaney-Black V Covington C et al. Paediatrics. 2001;108 (2)
- MIDIRS. Informed choice: alcohol and pregnancy. National Electronic Library for Health 2002. Supported by the Royal College of Midwives, the Royal College of General Practitioners and the Royal College of Obstetricians and Gynaecologists.
- Sensible Drinking: The Report of an Inter-Departmental Working Group, Department of Health, December 1995:10.20