Individual efficacy of intermittent preventive treatment with sulfadoxine-pyrimethamine in primi- and secundigravidae in rural Burkina Faso: impact on parasitaemia, anaemia and birth weight

Abstract

Objective: To assess the efficacy at individual level of intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) in primi- and secundigravidae in rural Burkina Faso.

Methods: Data of 1441 women enrolled in a health centre randomized trial and delivering a live-singleton between September 2004 and October 2006 were analysed at individual level. Prevalence of peripheral and placental parasitaemia, anaemia (PCV <33%), low-birth weight (<2500 g; LBW), mean packed cell volume (PCV) and birth weight were compared in relation to the number of directly observed SP doses.

Results: Two or more doses of SP significantly reduced the risk of placental parasitaemia [adjusted odds ratio (AOR) = 0.04, 95%CI = 0.003-0.60, P = 0.023] and anaemia at delivery (AOR = 0.31, 95%CI = 0.18-0.52, P < 0.001). IPTp was associated with reduced risk of LBW in primigravidae (AOR = 0.11, 95%CI = 0.07-0.17, P < 0.001) but not secundigravidae (AOR = 0.70, 95%CI = 0.26-1.91, P = 0.452). For each increment in number of SP doses mean PCV increased by 1.0% (95%CI = 0.4-1.7, P = 0.005) at 32 weeks gestation, by 1.2% (95%CI = 0.2-2.2, P = 0.025) at delivery and mean birth weight by 220 g (95%CI = 134-306 P < 0.001) in primigravidae and by 102 g (95%CI = 55-148, P = 0.001) in secundigravidae.

Conclusion: The risk of malaria infection was significantly reduced by IPTp with SP in primi- and secundigravidae in rural Burkina Faso. The impact on clinical outcomes is lower and mainly limited to primigravidae for LBW. Incomplete uptake of IPTp-SP and limited effect in low risk groups together may substantially dilute the measurable impact of effective interventions. This needs to be taken into account when evaluating interventions at community level.