Drugs During Pregnancy An Issue of Risk Classification and Information to Prescribers

Abstract

The Swedish system for the classification of fetal risk of drugs was the first of its kind and was implemented in 1978. Drugs for use in pregnant women are classified in 4 general categories--A to D. The US Food and Drug Administration (FDA) introduced a system in 1979 also using the letters A to D, together with an X category. However, the definitions differ considerably between the FDA system and the Swedish system, resulting in a very different allocation of drugs to the respective categories. In the Swedish system, category A includes drugs that have been extensively used and/or for which there are reliable clinical data indicating no evidence of disturbance of the reproductive process. Category B includes drugs for which data from pregnant women are insufficient for making any solid estimation of human teratogenic risk, and classification is therefore based on animal data, with allocation to 3 subgroups. For products in category C, the pharmacological action of the drug may have undesirable effects on the human fetus or newborn infant. Finally, category D contains drugs for which human data indicate an increased incidence of malformations. The categorisation statement is always followed by a short explanatory text. In contrast to the FDA system, the Swedish system has been well accepted, as judged by an interview study including 934 physicians and pharmacists. We believe that much of the American dissatisfaction may be a consequence of shortcomings in the category definitions of the FDA system. The FDA system requires an unrealistically high quality of data, e.g. the availability of controlled studies in pregnant women that fail to demonstrate a risk to the fetus are needed for a drug to be assigned to category A. Consequently, the majority of drugs on the US market are allocated to category C, interpreted as 'risk cannot be ruled out'. The distribution of drugs into the various categories is thus very different between the Swedish and FDA systems. We think that the issue of this debate reflects a fundamental problem related to public health information: how should a large, compounded, changing and difficult to evaluate databank be organised before it is made available to professionals and secondarily to lay people?

Documentation of Contraception and Pregnancy When Prescribing Potentially Teratogenic Medications for Reproductive-Age Women

“…While we recognize the shortcomings of the current FDA risk classification (17,18) and opinions differ about what level of teratogenic risk requires the provision of contraceptive counseling, we believe that clinicians should engage women in shared decision making when potentially teratogenic medications are prescribed. Given the large number of women in our study, we had to rely on available electronic databases for information about contraceptive counseling, contraception use, and pregnancy test results.…”

The significance of E. coli treatment in perinatal period

“…Screening for asymptomatic bacteriuria and treatment is recommended for selected groups such as pregnant women, where benefi t has been shown [2,3].…”

“…Extensive clinical experience shows that penicillin, cephalosporin and erythromycin (except erythromycin estolate) can be considered safe both for developing fetus and pregnant woman [2,27]. Th erefore, all pregnant women should be screened for bacteriuria and subsequently treated with antibiotics [1,28,29].…”

“…Resistance rate in E. coli is generally about 40%. During pregnancy, quinolones and tetracyclines are contraindicated in the fi rst trimester, while sulphonamides should not be used in the last trimester [2,3].…”

Use of hypnotics in high risk patient groups

“… br. 1-2 ba lečenja i zvaničnog stava regulatornih tela koja ne preporučuju upotrebu hipnotika u trudnoći [14,15]. Razlog za ovakvu diskrepanciju između kategorizacije leka, naročito kod FDA, i podataka iz studija i kliničke prakse leži utome što FDA zahteva neuobičajno visoki stepen potvrde koji je moguće dobiti jedino kroz kontrolisana istraživanja na velikom broju trudnica, što je retko moguće ostvariti.…”