Medication and Pregnancy

At your first pregnancy visit, we will discuss the medications you are taking and whether or not they are safe in pregnancy. It is also important to mention any over the counter or herbal remedies that you are taking. Ideally, if you take regular medications this should be discussed with a doctor before conception, however this isn’t always possible. The categories used to classify the safety of medications in pregnancy can be confusing and are dependent on the available evidence, without necessarily reflecting clinical practice, so don’t rely on Google or information on the side of the box the medication comes in.

The manner in which medications can affect a baby include:

• Interfering with development
• Affecting baby’s internal organs
• Increasing miscarriage or premature labour risk
• Affecting placental function
• Withdrawal from medication after birth

We weigh up whether or not the risk to the pregnancy outweighs the benefit of the medication and may modify certain medications for example blood pressure medication, diabetes medication and anti-epileptics. It is important not to stop any medications suddenly because sometimes not treating a condition can be more harmful to a pregnancy. This particularly applies to antidepressant medication, something women commonly cease abruptly during their pregnancy with negative impacts on their mental health.

Common medications that you need to typically avoid in pregnancy include non-steroidal anti-inflammatories such as ibuprofen (nurofen), particularly in the third trimester. It may be indicated at other times during the pregnancy but only on a doctor’s advice. ACE inhibitors and angiotensin II receptor antagonists (blood pressure medications) should be avoided, as well as isotretinoin (roaccutane) due to risk of harm to the developing baby. Lithium, some anti-epileptic drugs, some antibiotics and warfarin (blood thinner) also fall into this category and alternatives need to be found.

If you develop any medical conditions during pregnancy, it is always important to discuss any medications you plan to take with your doctor, pharmacist or midwife.

Medication and breastfeeding

A question we are commonly asked is “is that medication safe to take whilst breastfeeding?”. What surprises most families is that there are very few drugs that are of concern whilst breastfeeding and that usually the amount of the drug transferred to the breastmilk is very small.

The medications that should not be taken in breastfeeding are:

• Amiodarone (cardiac medication)
• Chemotherapy agents
• Iodine at high dose
• Oral retinoids (roacccutane)
• Radiopharmaceuticals (for example radioactive iodine in the treatment of Graves’ Disease)

Medications that we recommend women avoid or at the very least have an in depth discussion with a medical professional about include:

• Lithium – may require special monitoring
• Cold and flu tablets – can affect supply
• Oestrogen containing medications e.g. the combined oral contraceptive pill – can affect supply
• Codeine – if Mum is a fast metaboliser of codeine a large dose may be transferred to the baby resulting in sedation or even respiratory arrest

There are a number of variables to consider when evaluating how much drug ends up in breastmilk:

• The amount of drug that enters the mother’s bloodstream
• Whether the drug binds to the protein in Mum’s blood (and therefore is not transferred to the breast milk in large amounts)
• Whether the drug is lipid or fat soluble, as it may dissolve in the fat droplets in breastmilk
• How Mum metabolises medications

It is also important to consider what influences the risk of the drug impacting baby:

• Timing of dose – usually it is recommended to take medication immediately after a feed so the baby receives the lowest possible dose, however this is dependent on the drug’s half life (it’s a cruel but true fact that caffeine has a particularly long half life!)
• How toxic the drug would be to an infant
• How much of the drug is actually absorbed by the baby from the breast milk
• The volume of breast milk a baby receives
• The amount of drug in the breastmilk relative to the mother’s dose

Approach to Medication in Breastfeeding

• Take lowest possible dose
• Select alternative routes of administration e.g. nasal sprays for congestion rather than cold and flu tablets

Further Information and Advice

Resources we love include:

• Women’s and Children’s Hospital Pharmacy Information Line – 8161 7350 – able to discuss medications in pregnancy and breastfeeding with a specialist pharmacist – very useful for patients and health professionals
• Lactmed App – can search a huge database of drugs for evidence based information
• E-lactancia – online database in both Spanish and English
• Mothersafe – several fact sheets about options of treating medical conditions drugs breastfeeding and pregnancy https://www.seslhd.health.nsw.gov.au/royal-hospital-for-women/services-clinics/directory/mothersafe
• Mother to Baby – US based site with excellent information regarding medication in pregnancy and breastfeeding https://mothertobaby.org
• BUMPS – UK based site with database regarding medication safety in pregnancy http://www.medicinesinpregnancy.org/Medicine–pregnancy/

References – NPS : Drugs in Breastfeeding