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Pregnancy Care Guidelines

14 Medicines

14 Medicines

14.1 Prescription medicines

Prescribing medicines during pregnancy involves balancing the likely benefit to the pregnant woman against the potential harm to the fetus. Only a small number of medicines have proven safety in pregnancy and a number of medicines that were initially thought to be safe in pregnancy were later withdrawn. General principles include prescribing only well-known and tested medicines at the smallest possible doses and only when the benefit to the woman outweighs the risk to the fetus.

The Therapeutic Goods Administration has categorised medicines that are commonly used in Australia, taking into account the known harmful effects on the developing baby, including the potential to cause birth defects, unwanted pharmacological effects around the time of birth and future health problems.

Therapeutic Goods Administration categorisation of medicines

A - Medicines which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.

B1 - Medicines which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage.

B2 - Medicines which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals are inadequate or may be lacking, but available data show no evidence of an increased occurrence of fetal damage.

B3 - Medicines which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.

C - Medicines which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.

D - Medicines which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These medicines may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.

X - Medicines which have such a high risk of causing permanent damage to the fetus that they should not be used in pregnancy or when there is a possibility of pregnancy.

14.2 Over-the-counter medicines

As few medicines have been established as safe to take during pregnancy, a general principle of use is that as few should be used as possible. However, over-the-counter medicines may be useful for relieving symptoms of pregnancy such as nausea and vomiting (see Chapter 54), heartburn (see Chapter 56), constipation (see Chapter 55) and haemorrhoids (see Chapter 57).

Recommendation

  • Consensus-based
  • V

Advise women that use of prescription and over-the-counter medicines should be limited to circumstances where the benefit outweighs the risk as few medicines have been established as safe to use in pregnancy.

Approved by NHMRC in December 2011; expires December 2016

Recommendation

  • Consensus-based
  • VI

Therapeutic Goods Administration Category A medicines have been established to be safe in pregnancy.

Approved by NHMRC in December 2011; expires December 2016

Recommendation

  • Practice point
  • S

Health professionals should seek advice from a tertiary referral centre for women who have been exposed to Category D or X medicines during pregnancy.

Approved by NHMRC in December 2011; expires December 2016

14.3 Herbal medicines

The use of complementary therapies (including herbal medicines) is increasingly common in Australia (AMA 2002). Women may choose to use them to support wellbeing, because they are perceived to be ‘safe’ alternatives to pharmacological treatments or because they are part of traditional practices in pregnancy. However, there is a lack of evidence on the safety of complementary medicines during pregnancy and some are known to be harmful in the first trimester. 

There is little evidence from randomised trials to support the benefits or safety of herbal medicines (preparations derived from plants) and, even if active ingredients have been studied in trials, supplements may contain other ingredients with unknown effects. Studies have identified harms associated with some European (Cuzzolin et al 2010) and Chinese (Chuang et al 2006) herbal medicines.

Recommendation

  • Practice point
  • T

Few herbal preparations have been established as being safe and effective during pregnancy. Herbal medicines should be avoided in the first trimester.

Approved by NHMRC in December 2011; expires December 2016

14.4 Providing advice on medicines

Health professionals can support women in safe use of medicines by being well informed themselves and by providing advice on relevant information services. Current information on specific medicines in pregnancy is available from:

  • Therapeutic Goods Administration medicines in pregnancy database, which can be searched by name or classification level
  • medicines in pregnancy information services in each State/Territory, which provide advice to health professionals and consumers on supplements, over-the-counter and prescription medicines (see Section 14.6)
  • the National Prescribing Service website, which publishes resources for health professionals and consumers, with an emphasis on quality use of medicines.

14.5 Practice summary: medicines in pregnancy

When

At antenatal visits.

Who

  • Midwife
  • GP
  • obstetrician
  • Aboriginal and Torres Strait Islander health worker
  • multicultural health worker
  • pharmacist.

What

  • Discuss use of medicines with women
    Explain that while many medicines are not safe in pregnancy, they may be needed in some situations (eg to treat high blood pressure, epilepsy, depression) or relieve some symptoms of pregnancy. Advise women to tell the pharmacist that they are pregnant if they are purchasing over-the-counter medicines.
  • Discuss risks and benefits
    If prescribing medicines, explain any risks to the fetus and the benefits of the treatment to the mother so that women can make an informed decision about the treatment.

14.6 Resources

Medicines in pregnancy information services for health professionals - Obstetric drug information.

Websites

Information about specific medicines regarding safety during pregnancy is available from:

References

  • AMA (2002) Complementary Medicine. Australian Medical Association Position Statement.
  • Chuang CH, Doyle P, Wang JD et al (2006) Herbal medicines used during the first trimester and major congenital malformations: an analysis of data from a pregnancy cohort study. Drug Saf 29(6): 537–48.
  • Cuzzolin L, Francini-Pesenti F, Verlato G et al (2010) Use of herbal products among 392 Italian pregnant women: focus on pregnancy outcome. Pharmacoepidemiol Drug Saf 19(11): 1151–58.
Last updated: 
4 December 2018