<p>Pregnancy category B. The placental transfer of Nalbuphine is high and rapid. There are no well-controlled studies in pregnant women. This drug should be used during pregnancy only if clearly needed. Limited data suggest that Nalbuphine is excreted in maternal milk but only in a small amount (less than 1% of the administered dose) and with a clinically insignificant effect. Caution should be exercised when Nalbuphine is administered to a nursing woman.</p>