Labelling of drugs in pregnancy ripe for overhaul

GPs and pharmacists who rely on the A, B1, B2, B3, C, D and X letter system can become unnecessarily conservative in the way they prescribe to pregnant women, said Dr Debra Kennedy, a clinical geneticist at the Royal Hospital for Women, Sydney.

“In general, recommendations given to women about medications in pregnancy are cautious at best and scaremongering and inappropriate at worst,” said Dr Kennedy.

“Some women stop taking essential medication because of fears about fetal safety, thus putting themselves and their baby at risk of an untreated illness (which is often a higher risk than the potential risk posed by the medication).”

Dr Kennedy believes it’s the apparent simplicity and ready availability of the categories that encourages clinicians to use the system as a bible rather than a guide.

Instead of totally avoiding some medications, a better understanding of the real risk they pose would allow GPs to weigh up the benefits of using a drug at a particular stage in pregnancy.

Dr Kennedy said the need for accurate drug labelling is growing. Over 80% of women use at least one prescribed or over-the-counter medication at some time during pregnancy, she said. As the average age of women having babies rises, so too will their likelihood of having chronic conditions or medical disorders that complicate pregnancy.

Her call for change comes as the United States undertakes major revisions to its labelling of prescription drugs. Its labels will include a general statement about the background risk of birth defects for all pregnancies and will not include a letter-based system.

Dr Kennedy said Australian regulatory authorities should also begin to evaluate the direction for “an improved, more rational approach” to the labelling of drugs in pregnancy and breastfeeding.

She noted these other problems with the current letter-based system:

• There is an assumption that drugs in the same category carry a similar risk, which is often not true.
• The alphabetical nature incorrectly implies that there is a gradation of risk (with the B category being worse than the A category, and so on).
• The categories don’t take the stage of pregnancy into account.
• They rarely take dose or route of exposure (eg, topical or inhaled versus oral or intravenous) into account.
• They don’t differentiate between different situations such as planned versus unplanned pregnancies and essential versus non-essential medications.
• The categories are rarely changed despite new evidence because of a general reluctance to advocate the safety of drugs in pregnancy.
• Most complementary medicines don’t carry a pregnancy risk category, even though some may have significant effects on pregnancy or fetal development.
• The categories don’t cover environmental agents, chemicals, infectious agents or illicit drugs.
• Contrary to the understanding of many medical practitioners, the categories are not applicable to breastfeeding.

The Medical Journal of Australia is a publication of the Australian Medical Association.

The statements or opinions that are expressed in the MJA  reflect the views of the authors and do not represent the official policy of the AMA unless that is so stated.

CONTACTS:             Ms Poppy Diamantis                              0411 730 842
                             Media Officer, South Eastern Sydney Local Health District (on behalf of Dr Debra Kennedy)