Intermittent preventive treatment with sulphadoxine-pyrimethamine but not dihydroartemisinin-piperaquine modulates the relationship between inflammatory markers and adverse pregnancy outcomes in Malawi.

Women in malaria-endemic areas receive sulphadoxine-pyrimethamine (SP) as Intermittent Preventive Treatment in Pregnancy (IPTp) to reduce malaria. While dihydroartemisinin-piperaquine (DP) has superior antimalarial properties as IPTp, SP is associated with superior fetal growth. As maternal inflammation influences fetal growth, we investigated whether SP alters the relationship between inflammation and birth outcomes. We measured C-reactive protein (CRP) and alpha-1-acid glycoprotein (AGP) at enrollment (16-28 gestation weeks (gw)), visit 3 (24-36 gw) and delivery in 1319 Malawian women randomized to receive monthly SP, DP, or DP and single-dose azithromycin (AZ) in the IMPROVE trial (NCT03208179). Logistic regression was used to assess the relationship between adverse outcomes, inflammation, and treatment arm. Elevated AGP at enrollment was associated with adverse birth outcome (aRR 1.40, 95% CI: 1.15, 1.70), with similar associations observed across treatment arms, exceptions being that elevated AGP was associated with low maternal weight gain in SP recipients (aRR 1.94, 95% CI: 1.36, 2.76) and with small for gestational age in DP+AZ recepients (aRR 1.49, 95% CI 1.02, 2.17). At visit 3 there were few associations between inflammation andoutcomes. At delivery, women with elevated AGP receiving either DP or DP+AZ had an increased risk of adverse birth outcomes (aRR 1.60, 95% CI: 1.28, 2.00), including low birth weight, pre-term birth and foetal loss, this was not seen in women receiving SP (aRR 0.82, 95% CI: 0.54, 1.26). The risk of an association between elevated AGP and adverse birth outcome was higher in those receiving DP or DP+AZ compared to those receiving SP (aRR 1.95, 95% CI: 1.21, 3.13). No clear associations between CRP and adverse outcomes were observed. AGP identified women at risk of adverse pregnancy outcomes. SP modifies the relationship between inflammatory biomarkers and adverse outcomes. Our findings provide insights into potential mechanisms by which SP may improve pregnancy outcomes.