<p>Pregnancy Category C. There arc no adequate and well controlled studies of this drug in pregnant women. This drug should be used during pregnancy only if the potential benefits outweigh the risks. The Centers for Disease Control and Prevention recommend that HIV-infected mothers should not breast-feed their infants to avoid risking postnatal transmission of HIV. Because of the potential for HIV transmission and the potential for serious adverse effects in nursing infants, mothers should be instructed not to breast feed if they are receiving efavirenz.</p>