On May 28, the Food and Drug Administration (FDA) proposed a new system for labeling drugs effects when used during pregnancy or while breast feeding. Critics of the lettering system have noted that it leads to an overly simplified and possibly inaccurate understanding of the risks drugs may pose to the fetus or breastfeeding infant.

The current system labels drugs as Category A, B, C, D or X. Category A drugs have shown no risk in many studies of pregnant women. Those in Category B have no evidence of risk in humans. Category C drugs should be used with caution; human studies are lacking, and animal studies may show negative effects on the developing fetus. Category D drugs are indicated as unsafe, but approved for use in the case of a life-threatening disease. Lastly, Category X drugs are contraindicated for use during pregnancy or breastfeeding.

The proposed system would provide more information about each drug, replacing the lettering system with a more comprehensive analysis.

Specifically, the new labeling would include:

Fetal Risk Summary. This section would describe any known effects of the drug on the fetus and if these risks were found in animal or human studies. The summary would also include a determination based on available data.

Clinical Considerations. The second block of information would detail the effects of the drugs use before a woman knows that shes pregnant. Also, this section would address any possible risk to the mother and baby, provide dosing information and suggest methods of handling any possible complications.

Data. The third and final section of information would discuss in detail the available data regarding use of the drug in humans and animals, according to the studies that were used to develop the Fetal Risk Summary.

The FDAs goal is to help women, their physicians and their pharmacists have better information about the effects of prescription medicines so that pregnant women, nursing mothers and breastfeeding infants will benefit, says Rear Admiral Sandra Kweder, M.D., of the Center for Drug Evaluation and Research, FDA.

Marc B. Taub, O.D., assistant professor at Southern College of Optometry, agrees. It seems that this new system will both simplify and improve upon the letter classification systemthe greater amount of information and detail provided will assist doctors in choosing the correct medication for all of their patients.

The FDA will accept comments on this proposal until the end of August. Go to www.regulations.gov, and reference docket number FDA-2006-N-0515.