pregnancy medications

Drugs and Medications in Pregnancy

Prescription and over the counter medications

Drugs and medications are substances that may have the capacity to harm your baby. Some pills and medicines are safe for use in pregnancy, including medications to treat conditions such as asthma, thyroid problems and diabetes. This safety has been determined by looking at statistics and outcomes in women and their babies that have reported using them while they were pregnant.

In some cases, we know that medication can potentially affect the baby. Still, the risk to the two of you without the prescription is higher, such as some epilepsy drugs. If you are on medication to control a condition, please ask your maternity care provider about any known risks and benefits before taking them.

To be sure a medicine is safe in pregnancy:

  • always check with your doctor, midwife or pharmacist before taking any medicine
  • make sure your doctor, dentist or other healthcare professional knows you’re pregnant before they prescribe or give you treatment
  • talk to your doctor immediately if you take regular medication, ideally before you start trying for a baby or as soon as you find out you are pregnant
  • use as few over-the-counter medicines as possible.

Medicines and treatments that are usually safe during pregnancy include:

  • paracetamol
  • most antibiotics
  • dental procedures, including local anaesthetics
  • some types of vaccinations, including tetanus and flu
  • nicotine replacement therapy

Always check with your midwife, doctor or pharmacist before taking any medication.

Other drugs

Substances such as cannabis, ecstasy, cocaine and heroin can affect your baby. For some drugs, the evidence around safety in pregnancy is evident, for others less so.

Like smoking and alcohol, we know enough to be sure that recreational drugs in pregnancy must always be considered unsafe, even in small amounts. Nearly all drugs pass through the placenta and affect your baby in some way. Some drugs reduce the oxygen your baby gets. Others can affect your baby’s development. Later in pregnancy, they can change how well your placenta works.

Some drugs are addictive for babies too. They will then withdraw from them after birth. If you use any of these drugs, you need to talk to your maternity care team. They can give you advice about how these drugs can affect your baby and provide appropriate support.

How can midwives help?

Your maternity care providers are not there to judge you or your choices. The information is necessary so they can provide the best possible care for you and your baby. Prior knowledge of your drug use assists your care team to support your baby and keep them safe and well if they are born with effects from the drugs.

They can also talk to you about further support options while you are pregnant and after the birth of your baby. For example, some dependent drug users need medication to stabilise or come off these drugs to keep the baby safe. If you are using drugs, you are not alone. Nor does it make you a bad parent. These drugs are more commonly used than you might realise. If you feel uncomfortable with your carer and how they deal with your health needs, it is essential to look at your options and find someone with whom you do feel comfortable.

If you took a drug on a one-off occasion before realising you were pregnant, it’s unlikely to have affected your baby. However, it is still important to discuss this with your maternity care provider.

Effects of drugs include (28):

Cannabis (marijuana)

  • Unsettled baby
  • More easily startled
  • May cause long term behaviour and learning problems
  • Smoking-related risks including premature labour, low birth weight, increased risk of cot death

Speed (amphetamines)

  • Placental insufficiency (placenta can’t carry enough oxygen)
  • Placental abruption (placenta separating from your uterus)
  • Premature labour
  • Low birth weight
  • Withdrawal symptoms (not many studies on this problem)
  • Potential learning delay

Crystal meth (methamphetamine)

  • Placental insufficiency
  • Placental abruption
  • Premature labour
  • Low birth weight
  • Withdrawal symptoms
  • Potential learning delay


  • May affect baby’s motor development (co-ordination and movement)
  • May cause congenital abnormalities (limited evidence)

Opioids (heroin, morphine etc.)

  • Growth retardation
  • Brain developmental delay
  • Difficulty breathing when born
  • Withdrawal symptoms
  • Drug weaning in nursery
  • Behavioural problems

Cocaine and crack cocaine

  • Increased risk of miscarriage
  • Increased risk of placental abruption
  • Growth retardation
  • Behaviour and learning difficulties

If you use heroin or other opioids, it is vital to get treatment as soon as you can. Trying to quit on your own could be dangerous for you and your baby. It could cause a miscarriage, premature birth, or your baby could be stillborn. The safest way to quit is with medical help, as part of a drug treatment programme.


Herbal and homoeopathic remedies and aromatherapy

Not all ‘natural’ remedies are safe in pregnancy. Some can affect your uterus, and therefore the baby. If you decide to use herbal or homoeopathic remedies or aromatherapy, contact a Traditional Medicine Society to make sure that your practitioner is qualified.

Tell the practitioner that you are pregnant and tell your pharmacist and midwife or doctor which herbal, homoeopathic or aromatherapy remedies you are using.


Dr Janelle McAlpine (PhD), Clinical Midwife
Photo by Andrey_Popov used under license from