SummaryRead the full fact sheet
- Many women take substances of some kind during pregnancy, often without realising these may cause harm to their unborn baby.
- Sometimes people find it hard to stop taking substances when they are pregnant due to negative past experiences and adverse life events.
- It is best to give your doctor or midwife a list of all medications and drugs you take or have recently taken, including prescription and over-the-counter medicines, nutrition supplements, complementary therapies (such as herbal medicine), social drugs (such as tobacco or alcohol) and other substances that that you have taken including drugs that are not legal.
- Women with pre-existing medical conditions (such as asthma, epilepsy or diabetes) must continue treatment with the appropriate medications during pregnancy under supervision of a doctor. Additionally, women who are taking medications for their mental health may be best not to cease these but consult with a medical professional to seek advice about the continuation of these medicines.
- Ask your doctor or midwife for advice or seek counselling if you need help to stop taking alcohol or other drugs. Sometimes it may be dangerous or harmful to stop taking substances suddenly even though this is something you may want to do. It is best to seek medical advice and support.
- If you are concerned about your long-term medication, the doctor may be able to prescribe a similar medication that does not have any known effects on your baby.
Many women take some kind of drug, substance or medication during pregnancy without realising that this could be harmful to their baby. Sometimes people find it hard to stop because of their past life experiences, ongoing injuries and social stress.
Drugs or medication taken in pregnancy can cross the placenta and impact on the developing baby. There are a range of possible effects that may include infant withdrawal from substances, low birth weight, , and stillbirth.
It is helpful to medical practitioners such as doctors and midwives if they have a full list of all the medications and/or substances you take, or have recently taken so they can best support you and your baby. These include:
- prescription medicines
- over-the-counter medicines
- nutrition supplements (such as )
- (such as herbal medicine).
- drugs that are illegal or not prescribed
- medications or drugs that are prescribed for someone else.
It is helpful if you tell your doctor or midwife if you smoke, drink alcohol or take illegal drugs, even if you only take them occasionally or socially. This helps them to know how to best care for you and your baby.
Effects of medication, drugs or substances during pregnancy
Alcohol and other drugs and medications can cause harm to your baby by:
- interfering with normal growth and development
- impacting on the growth of baby’s organs
- impacting on the placenta which is a source of food and nutrients for your baby
- increasing the risk of pre-term birth
- increasing the risk of baby withdrawing from substances and needing medication after they are born.
The potential for harm to the pregnancy and unborn baby depends on a range of factors that include:
- the type of drug or medication taken
- how the drug or medication is taken
- the size of the dose
- how often it is taken
- whether the drug or medication is used alone or in combination with other drugs or medications
- the individual response of the baby to the drug or medication
- the gestational age of the baby
- other factors, such as maternal physical and mental health, social stress such as family violence, homelessness and .
Harmful drugs, substances and medications
Some drugs, substances or medications may be harmful during pregnancy, depending on the amount and frequency of use. These include:
- Medicines – including some prescription drugs, over-the-counter medicines and complementary medicines, such as herbal remedies or nutrition supplements
- Prescription drugs bought on the street and not prescribed for you – such as or opiate-based pain medication such as codeine or panadeine forte. These can be very problematic if not taken as directed by your doctor.
- – for example, tea, coffee and cola drinks in large quantities
- Illegal drugs – such as , , , or or amphetamines
- Substances used as drugs – such as inhalants (glues or aerosols).
Drugs such as heroin or methamphetamine are often mixed with unknown substances. These unknown substances can also be harmful to the pregnancy or baby.
Birth abnormalities and medicines taken during pregnancy
The risk of a birth abnormality for any baby is about 4 per cent, regardless of the circumstances during pregnancy. This means that even a woman who strictly avoids drugs and medications while pregnant may still have a baby with a birth abnormality.
Most medicines are not harmful to a developing baby. However, some may interfere with the normal development of a fetus (these medicines are described as ‘teratogenic’).
Teratogenic drugs and medicines
Numerous drugs or drug groups may cause birth abnormalities in a developing fetus, including:
- ACE (angiotensin converting enzyme) inhibitors used to treat high blood pressure or congestive heart failure
- Angiotensin II antagonists, also used to treat high blood pressure or congestive heart failure
- Isotretinoin (an acne drug)
- high doses of vitamin A
- Male hormones
- some antibiotics
- some anticonvulsant medications
- some cancer-fighting medications
- some drugs that treat certain rheumatic conditions
- some thyroid medications
- the blood-thinning drug warfarin
- the hormone diethylstilbestrol (DES).
This list is not complete. For example, the teratogenic effects of illegal drugs (such as cannabis or methamphetamines) are not clear, because of the lack of medical studies.
Pregnancy risk classification for medicines
Medicines in Australia are given a risk category by the Australian Drug Evaluation Committee for drugs used in pregnancy, according to their safety information. This category applies only to recommended doses.
The classifications include:
- A – medications that have been taken by a large number of pregnant women without any proven increase risk of birth defect.
- B – medications that have been taken by only a limited number of pregnant women. Human data is lacking and they are further categorised based on available data from animal studies.
- B1 – animal studies have not shown any increased risk.
- B2 – animal studies are limited, but there does not seem to be any increased risk.
- B3 – animal studies show an increased risk, but it is not clear if this risk applies to humans.
- C – medications that, due to their effects, may cause harm to the fetus without causing birth defects. These effects may be reversible.
- D – drugs that have caused or may cause birth defects. However, the health benefit may outweigh the risk.
- X – drugs that have a high risk of birth defects and should not be used during pregnancy.
See your doctor or pharmacist for further information and explanation.
Medicines that may be necessary during pregnancy
Good health in the mother is vital to ensure healthy development and growth of her unborn baby. Women with pre-existing medical conditions (such as , , , thyroid conditions, or ) must continue treatment with appropriate medications during pregnancy.
Sometimes, a prescription medication has the potential to cause harm to the baby. However, stopping the prescribed medication could also pose a threat to both the mother and her baby. For example:
- If a pregnant woman who has asthma stops taking her medication, there is a risk of slowing the growth of her unborn baby.
- If a pregnant woman who has epilepsy stops her anti-epileptic medications, she may have an increased risk of having seizures, and complications to her pregnancy and unborn baby.
- Poorly managed maternal diabetes increases the health risk for the unborn baby.
In some cases, your doctor may be able to prescribe a similar medication that is considered safer to use during pregnancy.
Illnesses (such as an acute respiratory infection like ) or complications during pregnancy (such as ) may be treated with prescription drugs. Do not stop taking or alter the dose of a prescribed medicine without the knowledge and consent of your doctor.
Untreated, some illnesses or pregnancy complications may risk the health of the mother or baby, or both. Discuss any concerns you may have about medicines with your doctor or midwife.
Smoking, caffeine and alcohol during pregnancy
Some pregnant women may be unaware that smoking and consuming alcohol and caffeinated drinks during pregnancy could risk the health of their unborn baby. For example:
- Smoking – a woman who smokes during pregnancy increases her risk of miscarriage and stillbirth. Babies have a greater risk of low birth weight, prematurity and sudden unexpected death in infants ().
- Caffeine – there may be an association between heavy use (greater than 7 cups of coffee per day use during pregnancy) and the incidence of miscarriage and risk of low birth weight.
Alcohol consumption during pregnancy
Drinking alcohol during pregnancy has been associated with miscarriage, babies who are small for their gestational age and intellectual impairment in children (known as ). No completely safe level of alcohol consumption has been determined for pregnant women.
The National Health and Medical Research Council recommendations for women who are pregnant, or might soon become pregnant, are that:
- Not drinking alcohol is the safest option.
- The risk of harm to the fetus is highest when there is high, frequent, maternal alcohol intake.
- The risk of harm to the fetus is likely to be low if a woman has consumed only small amounts of alcohol before she knew she was pregnant or during pregnancy.
- The level of risk to the individual babies is hard to predict.
Note: A standard drink contains 10 g of alcohol.
Illegal drugs and pregnancy
Knowledge on the effects of illegal drugs during pregnancy is limited. Substances with some known effects include:
- Methamphetamines and amphetamines – increased risk of low birth weight, birth defects, premature birth.
- Cannabis – increased risk of growth restriction sleep problems, behavioural problems later in life.
- Cocaine – increased risk of miscarriage, pre-term birth, growth restriction stillbirth and birth defects (of the brain, heart, genitals and urinary system).
- Heroin – increased risk of low birth weight, prematurity, fetal distress, stillbirth, blood-borne viral disease such as hepatitis, infant withdrawal after birth.
- Inhalants – increased risk of miscarriage, low birth weight, birth defects, SUDI.
Drugs used to treat heroin and other opioid dependence
Methadone, buprenorphine and suboxone are prescription drugs, sometimes called pharmacotherapies. These help treat heroin and opiate dependency.
The risks to the fetus and pregnancy associated with heroin or other opiate use are greatly reduced with both of these treatments. The benefits of pharmacotherapy are reduced if you continue to use heroin or other drugs.
Recommendations for use of medication, drugs and substances during pregnancy
Be guided by your doctor, but general recommendations include:
- Limit yourself to less than 200 mg of caffeine per day (which roughly equates to one espresso-style coffee or 2 cups of instant coffee per day, or 4 cups of medium strength tea or hot chocolate per day, or 6 cups of cola per day).
- Avoid energy drinks.
- Avoid or cut down smoking.
- Avoid or reduce illegal drugs.
- See your doctor, speak to your midwife or seek drug counselling if you need help to quit smoking, alcohol or other drugs.
- Do not assume that non-prescription medications are safe because you can buy them over the counter without a prescription. Be advised by your doctor or pharmacist.
Using alternatives to medications during pregnancy
Whenever possible, use non-drug alternatives to manage minor health concerns during pregnancy. For example:
- Avoid heartburn by eating small, frequent snacks rather than 3 large meals.
- Use salt-water nasal sprays to treat nasal congestion.
- Avoid foods or smells that trigger nausea.
Where to get help
- Drug and alcohol counsellor
- Tel. – for 24-hour confidential drug and alcohol telephone counselling, information and referral
- (WADS) Tel.
- – The Royal Women’s Hospital Medicines Information Service Tel.
- Tel. – for information and support for people concerned about a relative or friend using drugs
- National clinical guidelines for the management of drug use during pregnancy, birth and the early development years of the newborn, 2006, NSW Department of Health, for Australian Government.
- , The Royal Women’s Hospital, Melbourne.
- Pregnancy, alcohol and other drugs, DrugInfo, Australian Drug Foundation.
- , The Royal Women’s Hospital, Melbourne.
- Bánhidy F, Lowry RB, Czeizel AE, 2005, ‘’, International Journal of Medical Sciences, vol. 2, no. 3, pp. 100–106.
- , Department of Health, NSW Government.
- Browne ML, Bell EM, Druschel CM, et al, 2007, ‘’, Birth Defects Research. Part A: Clinical and Molecular Teratology, vol. 79, no. 7, pp. 533–43.
- Browne ML, Hoyt AT, Feldkamp ML, et al, 2011, ‘’, Birth Defects Research. Part A: Clinical and Molecular Teratology, vol. 91, no. 2, pp. 93–101.
- Signorello LB, McLaughlin JK, 2004, ‘’, Epidemiology. Vol. 15, no. 2, pp. 229–39.
- , 2020, National Health and Medical Research Council, Australian Government.
- Gouin K, Murphy K, Shah PS, Knowledge Synthesis group on Determinants of Low Birth Weight and Preterm Births, 2011, ‘Effects of cocaine use during pregnancy on low birthweight and preterm birth: systematic review and metaanalyses’. American Journal of Obstetrics and Gynecology, vol. 204, no. 4, pp. 340.e1-340.e12.