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Preparing for pregnancy - medicines and other drugs

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When you are planning to become pregnant it is a very good idea to consider whether medicines and drugs that you are taking may affect fertility (how easily you could become pregnant) and whether they are safe during pregnancy.

Many pregnancies are unplanned, so if you find out that you are pregnant you need to talk to your doctor or a pharmacist as soon as you can to see if the medicines or drugs are safe for your baby.

Prescription medicines

If you take any prescribed medicines, you should talk to your doctor when you are planning to become pregnant or as soon as you think you are pregnant.

  • It is very important to continue taking medicines that have been prescribed for health problems, such as asthma, diabetes, depression and epilepsy. Most of these medicines will not harm a baby.
  • Many women are worried about the effects that medicines may have on their unborn baby, and may stop taking them, but this can lead to health problems for the mother, which are also not good for the baby.

Your doctor or pharmacist will be able to tell you if your medicine is suitable to use during pregnancy, or if there is a different medicine that may be safer.

In South Australia you can contact the SA Pharmacy Obstetric and Paediatric Medicines Information Service located at the Women’s and Children’s Hospital.

  • A pharmacist can advise you if a particular prescription or non-prescription medicine is safe while you are pregnant or breastfeeding.
  • You can contact the service Monday to Friday 9am to 5pm on 08 8161 7222.

In Australia you could ring the National Medicines Line 1300 633 424 (1300 MEDICINE)  9am - 5 pm Monday to Friday (Eastern Standard Time).

Non-prescription medicines

When you are planning to become pregnant, check with a pharmacist or your doctor about which non-prescription drugs are safe during pregnancy.

Some products that you can buy from the pharmacy, health food store or supermarket may not be safe for use during pregnancy.

There is more information about these medicines in the topic Medicines during pregnancy.

  • Folic acid - it is recommended that all women who are planning to become pregnant, and women who are in their first 3 months of pregnancy, take folic acid tablets to help lower the risks of some birth defects. You do not need a prescription to get these tablets, and they are safe during pregnancy. For more information have a look at the topic Folic acid (Folate).
  • Iron and calcium – it is often recommended that pregnant women take extra iron and calcium, and these are safe in normal doses.
  • Other vitamins and minerals - a well balanced diet should supply you with the vitamins and minerals you need during pregnancy.


Drinking high amounts of caffeine may make it more difficult to become pregnant and it seems that high levels may make miscarriage more likely. In humans, even large amounts of caffeine do not appear to cause an increased risk of birth defects. You can find out more by going to the sites listed in the topic 'Caffeine in pregnancy'.

Also Mother to baby Caffeine in pregnancy

Illegal drugs

If you are taking any illegal drugs and want to become pregnant, you really need to stop using first. The following information is about some common drugs, but drugs not listed here may also affect fertility or harm an unborn baby.

Marijuana (cannabis)

In women, long-term use of marijuana may affect the menstrual cycle and lead to lower levels of hormones involved in reproduction and fertility. Men may have a low sperm count.

These effects do not totally prevent pregnancy, but may lower the chances of becoming pregnant. The effects on fertility appear to go away when people stop using marijuana.

Marijuana use during pregnancy has not been shown to cause an increased rate of birth defects, but, like tobacco use, the baby’s growth may be reduced. There is some evidence that exposure to marijuana before birth affects a baby's behaviour and may cause long-term behaviour problems.

For more information, including information about effects on a baby have a look at Marijuana and pregnancy https://mothertobaby.org/fact-sheets/marijuana-pregnancy/   

Ice, Speed and Ecstasy

The use of amphetamine-like substances such as methamphetamine (including ice) and ecstasy during pregnancy has also been associated with slower development and small abnormalities in the newborn. It is possible that if a mother uses any of these drugs while breastfeeding, the drug will be present in her milk and may have effects on the baby.

Using dexamphetamine for medical reasons (eg treatment of ADHD) appears to have low risk for birth defects.

For more information:

Resource in Australia

Medicines Line 1300 MEDICINES (1300 633 424) Monday to Friday 9am to 5pm EST

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The information on this site should not be used as an alternative to professional care. If you have a particular problem, see your doctor or midwife.


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