[Antibiotics during pregnancy and breast feeding: consequences for the treatment of respiratory infections].

Respiratory infections are the second most frequent cause for antibiotic prescriptions during pregnancy, after genito-urinary infections. Overall, antibiotics are relatively innocuous. The following should be avoided: the tetracyclines, cotrimoxazole, chloramphenicol, metronidazole and the quinolones. Aminoglycosides should be administered controlling the plasma level. The beta-lactones (principally the penicillins) and the macrolides sold in France, are without any danger. Nevertheless, the rise in distribution volume and the overall physiological changes which accompany the developing pregnancy, particularly in the third trimester lead to a diminution in the serum concentration of these antibiotics and imply an adaptation, often a doubling, of the therapeutic dose administered. From the epidemiological data concerning the organisms involved in the respiratory infections, nearly the totality of extra-hospital infections may be cured by macrolides or penicillins (ampicillin). During more serious infections (nosocomial, or the immuno-depressed) the maternal prognosis should take precedence, adjusting the antibiotic to the organism, before the toxic risk to the child. All the antibiotics are excreted in the mother milk, but in very small quantities; they are generally destroyed in the digestive tract of the child so that the risk of any secondary effect during lactation is minimal.