Zika Virus Infection in Pregnant Women, Yucatan, Mexico

Abstract

We report demographic, epidemiologic, and clinical findings for a prospective cohort of pregnant women during the initial phase of Zika virus introduction into Yucatan, Mexico. We monitored 115 pregnant women for signs of active or recent Zika virus infection. The estimated cumulative incidence of Zika virus infection was 0.31 and the ratio of symptomatic to asymptomatic cases was 1.7 (range 1.3-4.0 depending on age group). Exanthema was the most sensitive clinical sign but also the least specific. Conjunctival hyperemia, joint edema, and exanthema were the combination of signs that had the highest specificity but low sensitivity. We did not find evidence of vertical transmission or fetal anomalies, likely because of the low number of pregnant women tested. We also did not find evidence of congenital disease. Our findings emphasize the limited predictive value of clinical features in areas where Zika virus cocirculates with other flaviviruses.

Keywords: Mexico; Yucatan; Zika virus; congenital abnormalities; infection; pregnancy; pregnant women; vector-borne infections; viruses.

Figure

Distribution of cases of Zika virus infection, by epidemiologic week, Mexico, 2016–2017. A) Suspected and confirmed cases of Zika virus infection in Yucatan State and cases in Mexico. B) Cases of Zika virus infection among 115 pregnant women enrolled in study in 3 areas of Yucatan State.