However, it has been shown that transmission reduction is considerably more effective when combining sdNVP with two nucleoside reverse transcriptase inhibitors , such as zidovudine and lamivudine . At the same time, sdNVP is prone to resistance formation and might impede subsequent treatment involving NVP or other NNRTIs , while combining NVP with NRTIs has shown to reduce the emergence of NNRTI-resistant mutations . Since 2006, the World Health Organization therefore recommends a triple combination ALK inhibitor prophylaxis regimen consisting of two NRTIs and one NNRTI as the standard PMTCT regimen wherever this is feasible . The United Republic of Tanzania is one of the poorest and least developed countries in the world , and has an overall HIV prevalence of about 6% . HIV prevalence in pregnant women is estimated at 10�C16% . In 2008, the Tanzanian Ministry of Health followed the 2006 WHO guidelines for PMTCT and changed its national standard recommendation from sdNVP to combination prophylaxis. The recommended regimen includes AZT 300 mg twice a day starting in week 28 of pregnancy or as soon as possible thereafter. With the onset of labor, women should take sdNVP, AZT 300 mg every 3 hours, and 3TC 150 mg every 12 hours until delivery. After delivery, a postpartum tail of AZT 300 mg and 3TC 150 mg twice a day should be continued for seven days. All newborns of HIV-positive mothers should FTY720 receive 2 mg/kg sdNVP within 72 hours and a postpartum tail of 4 mg/ kg AZT twice a day for seven days if the mother took AZT during pregnancy for four weeks or longer. Otherwise, the infant postpartum tail should last for four weeks. In both the Tanzanian and WHO recommendations, sdNVP only remains the minimum prophylactic standard for PMTCT if more complex interventions are not feasible . Notably, while Tanzanian guidelines at time of study conduction were based on 2006 WHO recommendations, those were again revised in 2010. WHO now recommends start of AZT intake from gestational week 14 onwards, suggesting that an omission of sdNVP can be considered if AZT was taken for more than four weeks before delivery . Optimal drug adherence is crucial for drug effectiveness: on the one hand, to sufficiently suppress the maternal viral load , which in turn is one of the most important risk factors for MTCT . On the other hand, maladherence to antiretroviral drugs potentially promotes the emergence of resistant viral strains which may lead to failure of subsequent treatment .