Hookworm infection was associated with a 1.42 to 2.58-fold increased risk of elevated placental levels above detection limits for some cytokines (Fig 3): IL-1 (RR = 2.41; 95% CI: 1.38, 4.23), IL-5 (RR = 2.63; 95% CI: 1.19, 5.79), CXCL8 (RR = 1.42, 95% CI: 1.09, 1.87) and IFN-γ (RR = 2.58; 95% CI: 1.09, 6.07) in multivariable models. This evidence concerns the gene IFNG and ancylostomiasis.