<p>Pregnancy Category B. Telbivudine is not&nbsp;teratogenic&nbsp;and has shown no adverse effects in developing embryos and fetuses in preclinical studies. Studies in pregnant rats and rabbits showed that telbivudine crosses the placenta. Developmental toxicity studies revealed no evidence of harm to the fetus in rats and rabbits at doses up to 1000 mg per kg per day, providing exposure levels 6- and 37-times higher, respectively, than those observed with the 600 mg per day dose in humans.<br />
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There are no adequate and well-controlled trials of Tyzeka in pregnant women. Because animal reproductive toxicity studies are not always predictive of human response, Tyzeka should be used during pregnancy only if potential benefits outweigh the risks.</p>