There have been no formal evaluations of the use of T-20 (enfuvirtide, Fuzeon) in pregnant women. However, a case report has shown that adding T-20 and nevirapine (Viramune) to a failing regimen during the last three weeks of pregnancy reduced viral load and prevented transmission of HIV to the foetus. Neither the mother nor the child experienced any adverse events for up to six months after delivery^[1]. Similarly, two case reports have shown that using T-20 with an optimised background regimen can reduce the risk of mother-to-child transmission. However, T-20 does not cross the placenta and may not inhibit HIV replication in the genital tract, so Caesarean delivery is advised^[2].

Although further research is needed, these studies demonstrate that T-20 can be of value in preventing vertical transmission, at least in the last weeks of pregnancy.