US regulators have put forward plans to change the labels on prescription drugs that would provide better information about the effects of medicines used during pregnancy and breast-feeding.

The US Food and Drug Administration is proposing changes which it says “would give healthcare professionals more comprehensive information for making prescribing decisions. In the 1990s, the agency says it recognised the shortcomings of pregnancy and breastfeeding information in prescription drug labeling and began reviewing ways to improve the information. Current labelling uses a letter category system to describe the risks of drug use during pregnancy but the FDA notes that stakeholders say that process “leads to an inaccurate and overly simplified view of these risks, and does not facilitate updating of labelling as new information becomes available”.

Sandra Kweder of the FDA's Center for Drug Evaluation and Research, said this proposal “would help make drug labelling a better communication tool and would potentially have a huge impact on public health and well being for women." There are about six million pregnancies in the USA every year, and the women involved take an average of three to five prescription drugs during pregnancy. Additionally, women with pre-existing medical conditions, such as asthma or high blood pressure, may need to continue to use drugs to treat those conditions during pregnancy.

Under the new system, new drug labels would include three sections devoted to pregnancy and breast-feeding – foetal risk summary, clinical considerations and data. New drugs will have to conform immediately to the revised labelling standard, Dr Kweder said, while for older treatments, the label requirements would be phased in over time.