(Date of issue: July 2011. Version: 1.1)
This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by Public Health England on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.
Drinking alcohol during pregnancy
Alcohol drunk by the mother crosses the placenta and enters the bloodstream of the unborn baby. Babies in the womb cannot process alcohol in the same way as an adult, and as a result alcohol remains in the baby’s brain and body for several hours after it has been cleared from the mother’s bloodstream.
There is strong scientific evidence to show that drinking alcohol in pregnancy can cause miscarriage, stillbirth, birth defects, and lifelong problems for the child with learning, behaviour, and health. Although the risk of these problems has been most clearly linked to heavy drinking, it is not yet known whether drinking any amount of alcohol whilst pregnant is truly ‘safe’.
Alcohol should ideally be avoided for the full nine months of pregnancy and also whilst trying to conceive. If you need help to do this, ask your doctor or midwife for information on the support and treatments available to you.
What if I have already drunk alcohol during pregnancy?
It is not uncommon for a woman to drink alcohol before realising that she is pregnant. If this is the case, you may wish to discuss this with your doctor or midwife. The chance of your baby being affected will depend upon how often and how much you drank, as well as how many weeks pregnant you were. Once you know that you are pregnant, the best thing that you can do to support your baby’s well-being is to avoid further alcohol during your pregnancy.
How can drinking in pregnancy harm my baby?
Drinking alcohol during pregnancy can result in a wide range of different problems in the baby, often referred to as Fetal Alcohol Spectrum Disorders (or FASD for short). The risk of FASD tends to be linked to the amount of alcohol that the child was exposed to in the womb (see below). Some children with FASD are affected by all of the problems listed below while others have only one or a few of these problems. The severity of each problem may differ from one child to the next. Some of the problems associated with FASD may not be obvious at birth and may only become apparent when the child starts school, or later on in life. Fetal Alcohol Spectrum Disorders (FASD) include:
• birth defects of the heart, skull, kidneys, limbs, bones, brain and other organs
• a specific facial appearance (small eyes, thin upper lip, poorly defined groove between top lip and nose)
• problems with eyesight, and hearing
• small size at birth and poor growth throughout life
• small head
• abnormal brain formation or development
• learning and behavioural problems which can range from mild to severe
How much alcohol causes FASD?
Studies have shown that heavy drinking during pregnancy, usually measured as repeatedly consuming more than around five units of alcohol (2 large glasses of wine) per day, carries the greatest risk of a baby being affected with FASD. Babies born to women who drank heavily in pregnancy are at increased risk of the structural birth defects associated with FASD, as well as problems with learning and behaviour.
Studies of pregnant women who drank lower levels of alcohol, or who ‘binge drank’ (occasionally drank more than four to five units of alcohol in a day) have produced mixed results, with some studies showing no clear links with FASD-type problems in the baby and others showing an increased risk of problems with thinking, learning, and behaviour. More research into the potential effects of occasional binge/light drinking during pregnancy on the learning and development of the child is required.
There is currently no level of alcohol that has been proven to be ‘safe’ to drink during pregnancy. It is thought that some babies are more susceptible to alcohol damage than others, and that the mother’s health and genetic make-up may explain why babies of women who drink similar amounts of alcohol can be affected differently.
The only way to be certain that alcohol will not affect an unborn baby is to avoid it completely whilst pregnant.
Is there any stage of pregnancy where it is considered safe to drink alcohol?
No. As soon as an embryo implants into the womb (usually a few days before your period is due) it receives the mother’s blood supply and any alcohol that the mother drinks will pass to the embryo. These early weeks of pregnancy are very difficult to study and so the effects of drinking alcohol during this time are unknown.
Most of the baby’s body and organs are formed between weeks 3 and 8 of pregnancy and it is during this time that heavy drinking can cause structural malformations (birth defects) in the baby.
However, a baby’s brain develops throughout the whole of pregnancy. Drinking alcohol at any time during pregnancy can therefore potentially damage the baby’s developing brain, leading to lifelong difficulties with thinking and learning, and behavioural problems such as ADHD. These problems can be present in children who do not have any of the birth defects or facial features linked to FASD.
Can drinking in pregnancy cause miscarriage or stillbirth?
A number of studies have linked drinking alcohol during pregnancy with miscarriage and one study showed that rates of miscarriage were five times higher in women consuming more than five units of alcohol per week than in women who drank one unit per week or less.
Alcohol consumption during pregnancy has also been linked to stillbirth, with studies showing that the more a woman drinks during pregnancy, the greater the risk of stillbirth.
Can drinking in pregnancy cause premature delivery or low birth weight?
Current scientific evidence suggests that heavy drinking during pregnancy is linked to premature birth (before 37 weeks of pregnancy) and low birth weight, (less than 2500g), both of which are associated with health problems later on in life. The studies carried out to date do not suggest a link with drinking lower levels of alcohol and/or occasional “binge” drinking during pregnancy but do not provide enough evidence to say for certain that drinking alcohol occasionally will not affect the baby’s growth in the womb or timing of birth.
Will my baby need extra monitoring during pregnancy?
As part of their routine antenatal care most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects and to check the baby’s growth. It is important to understand that scans are not able to pick up all birth defects, and will not detect more subtle changes to the brain that might be linked to some learning and behavioural problems.
If you have been drinking heavily your doctor may suggest other specific monitoring or more detailed tests for you or your baby during pregnancy.
Are there any risks to my baby if the father drank?
We would not expect any increased risk to your baby if its father drank alcohol before, or at around the time you became pregnant. However, alcohol is known to affect male fertility, so if you are trying to conceive it may be a good idea for both you and your partner to avoid alcohol.
Who can I talk to if I have questions?
If you have any questions regarding the information in this leaflet please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org. If you are concerned that your child has been affected by alcohol exposure in the womb please speak to your GP or midwife and visit www.nofas-uk.org.
Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks. They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.
Medicines use in pregnancy
Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby. There are, however, some medicines that can harm a baby’s normal development. How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.
If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.
When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.
Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.