Influence of the Timing of Malaria Infection during Pregnancy on Birth Weight and on Maternal Anemia in Benin

Abstract

Although consequences of malaria in pregnancy are well known, the period of pregnancy in which infection has the highest impact is still unclear. In Benin, we followed up a cohort of 1,037 women through pregnancy until delivery. The objective was to evaluate the relationship between the timing of infection and birth weight, and maternal anemia at delivery. At the beginning of pregnancy, peripheral infections were associated with a decrease in mean birth weight (−98.5 g; P = 0.03) and an increase in the risk of anemia at delivery (adjusted odds ratio [aOR] = 1.6; P = 0.03). Infections in late pregnancy were related to a higher risk of maternal anemia at delivery (aOR = 1.7; P = 0.001). To fully protect the women during the whole pregnancy, already implemented measures (insecticide-treated nets and intermittent preventive treatment) should be reinforced. In the future, a vaccine against pregnancy-associated malaria parasites could protect the women in early pregnancy, which seems to be a high-risk period.

Maternal Anemia in Pregnancy: Assessing the Effect of Routine Preventive Measures in a Malaria-Endemic Area

“…Similar findings had been made in a cohort study of pregnant women receiving SP-IPTp in a neighboring area in Benin, which established an increased risk for maternal anemia at delivery in women infected by malaria parasites after 6 months of gestation. 27 An alternative explanation to the increase of malaria infection at delivery might be the resistance of malaria parasites to SP (but not MQ), because high SP resistance has been shown in children of the study area (more than 80%). 28 However, this hypothesis was not supported by the results of the investigations made on pregnant women in a nearby area, showing that there was no variation in the prevalence of triple and quadruple mutants of P. falciparum strains implicated in SP resistance from the beginning to the end of pregnancy.…”

Malaria Modifies Neonatal and Early-Life Toll-Like Receptor Cytokine Responses

“…Malaria transmission in this area can be characterized as hyperendemic, with two peaks during the rainy seasons (April to July, September to November), and an entomological inoculation rate estimated at 35 to 60 infective bites per person per year (13). The STOPPAM study design has been described in detail elsewhere (37). In total, 1,037 women less than 24 weeks pregnant were enrolled in 3 clinics (Come, Akodeha, and Ouedeme Pedah) in the Come district.…”

“…Since the timing of occurrence of PAM during pregnancy is associated with fetal and infant malaria outcomes (37,38), parasitological data were collected from all mothers starting with inclusion, during the second trimester, and thereafter throughout pregnancy up to and including delivery. These data were then combined with measures of innate immune activity at birth and during infancy.…”

Placental Cytokine and Chemokine Profiles Reflect Pregnancy Outcomes in Women Exposed to Plasmodium falciparum Infection

“…We made use of a large subgroup drawn from the STOPPAM cohort (2008 to 2012) of Ͼ1,000 pregnant women (24,25). The STOPPAM project was designed both to enable the accurate quantification of the effects of pregnancy-associated malaria (PAM) on maternal and fetal health in order to optimize strategies for preventive intermittent treatment and to facilitate development of a PAM vaccine.…”

“…Here, we assessed the levels of 16 cytokines/chemokines (IFN-␥, IL-10, IL-12p70, IL-13, IL-1␤, IL-2, IL-4, IL [24,25] selected on the basis of pathological pregnancy outcomes) living in an area where malaria is mesoendemic. With the benefit of precise gestational age determination by ultrasound and of newly published African in utero weight charts (26), we compared the cytokine/chemokine profiles of different clinical groups segregated according to defined pregnancy outcomes, such as maternal anemia, preterm delivery, and low birth weight for gestational age.…”