Animal reproduction studies have demonstrated that azithromycin crosses the placenta, but have revealed no evidence of harm to the foetus. There are no adequate and well controlled studies in pregnant women. Since animal studies are not always predictive of human response, Zithrolide should be used during pregnancy only if adequate alternatives are not available.
No data on secretion of azithromycin in breast milk are available, so that Zithrolide should only be used in lactating women where adequate alternatives are not available.