Dengue infection in pregnancy: prevalence, vertical transmission, and pregnancy outcome

To estimate prevalence rate of recent dengue infection in parturients, as well as the vertical transmission rate, and to compare pregnancy outcomes among infected women.

A prospective cohort study was performed. Maternal and paired umbilical cord bloods were taken at delivery. A brief questionnaire on febrile illness and dengue in pregnancy was completed by participants. The samples were sent to a World Health Organization Collaborating Center for Arbovirus Reference and Research. Maternal sera were tested with a dengue-specific immunoglobulin M (IgM) capture test. The paired umbilical cord serum was tested to determine when the maternal sample was positive. Dengue reverse transcriptase polymerase chain reaction (PCR) was performed on all dengue IgM-positive sera. Pregnancy outcome was extracted from delivery records.

A total of 2,958 parturients were enrolled, and 2,531 paired maternal-umbilical cord blood samples were available for testing. Dengue-specific IgM was positive in 63 of 2,531 (2.5%, 95% confidence interval [CI] 1.9-3.2%) maternal samples. Only 1 of 64 (1.6%, 95% CI 0.0-9.5%) of the paired umbilical cord sera was IgM-positive. All reverse transcriptase PCR tests were negative. Fifty-six of 63 (88.9%) of dengue IgM-positive women did not report a febrile illness in pregnancy. Apart from a higher mean age in dengue IgM-positive women of 30.6+/-5.2 compared with 29.2+/-4.9 years (P=.025) compared with dengue IgM-negative women, all other characteristics were similar. Rates of preterm birth, mode of delivery, postpartum hemorrhage, low birth weight, and neonatal outcomes were not different.

Recent dengue infection was demonstrated in 2.5% of parturients, with a vertical transmission rate of 1.6%. Pregnancy outcome of recently infected women was not different.

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