Exposure to Dengue Virus During Pregnancy: Incidence and Impact on Maternal and Child Outcomes.

Dengue virus (DENV) is the most common arbovirus globally, with its incidence growing dramatically in recent decades. Although the effects of DENV infection during pregnancy are unclear, reported associations with adverse health outcomes include miscarriage, prematurity, and low birth weight. In this study, we used an IgG ELISA to identify mothers exposed to DENV during pregnancy by testing samples obtained from a previous study that followed a cohort of pregnant women in Kenya to investigate parasitic infections during pregnancy. We compared adverse pregnancy and infant health outcomes between seronegative mothers and those who seroconverted. Of the 289 participants tested for DENV exposure during pregnancy, we estimated that ∼12 women (4%) would have been exposed to DENV during their gestation period. However, we found that 34 mothers (11.8%) had been exposed to DENV during pregnancy. None of these mothers were hospitalized during pregnancy because of severe DENV infection, suggesting that many may have undergone asymptomatic seroconversion. The demographic risk factors of socioeconomic status, education level, bed net use, and maternal age were not associated with mild or asymptomatic DENV in pregnancy. Although mild or asymptomatic DENV during pregnancy was not associated with late prematurity, reduced postnatal childhood developmental measures, or adverse maternal pregnancy outcomes, we observed an increased risk of low birth weight. The larger-than-expected burden of DENV in pregnancy in this coastal Kenyan cohort and the observed potential risk of low birth weight provide evidence that a more comprehensive study is warranted to fully understand DENV infection during pregnancy.