The Effects of Drugs on the Fetus and Nursing Infant

J M Friedman, Janine E Polifka Johns Hopkins University Press, £34.00, pp 648 ISBN 0 8018 5345 1

“Breast is best” is good advice that hopefully emanates from our maternity units. But the statement is not necessarily true if the breast milk is laced with any drug that the mother is being treated with.

Because of their generally low molecular weight and lipid solubility, almost all drugs that happen to be circulating in the mother are secreted in breast milk. Consequently, it is a reasonable assumption that suckling infants will receive any maternal medication too. But the crucial questions are: to what extent? and will it be sufficient to produce biological activity in the child?

One of several strengths of The Effects of Drugs on the Fetus and Nursing Infant is that it attempts to answer these questions. The book is a compendium of synthesised and analysed information on 250 of the most commonly used medications in the United States, whence the book derives.

The title suggests that it is equally concerned with teratology, and it is. But there are far fewer data relating to the harmful effects of drugs on the embryo and fetus. Much of the so called information is anecdotal or conjectural, and so not truly reliable. It is disappointing that for so many of the drugs the teratogenic risk is recorded as “undetermined,” but this reflects the care and precision with which the authors have presented the available data. They have critically evaluated and summarised reference books and published studies for each drug, and, as well as providing a resume, they classify the teratogenic risks according to magnitude—minimal, moderate, high—and also according to the quality and quantity of the data on which that risk estimate is based.

With regard to the risks related to breastfeeding, any reported adverse effects for each drug are noted, and the dose expected to be ingested by the nursing infant is calculated and also expressed as a proportion of the lowest therapeutic dose. Key references are appended for further study should more information be needed.

Nowadays much detailed information is stored on computerised databases (these are listed at the end) available on request from various sources in the United States. In anticipation of a more global distribution, a useful addition to the book would be mention of sources in other continents. For instance, the United Kingdom National Teratology Information Service, in Newcastle, accepts both telephone and written inquiries.

Despite being in paperback, The Effects of Drugs on the Fetus and Nursing Infant weighs 800 g and is 3.5 cm thick, which probably relegates it from the pocket to the office, but this should not inhibit use of an excellent source of reference.—MARY J SELLER, reader in developmental biology, University of London