To assess the impact of dengue infection during pregnancy on birth outcomes, we conducted a systematic review of 30 published studies (19 case reports, 9 case series, and 2 comparison studies). Studies were identified by searching computerized databases using dengue and dengue hemorrhagic fever, cross-referenced with pregnancy, preterm birth or delivery, low birth weight, small-for-gestational age, spontaneous abortion, pre-eclampsia, eclampsia, or fetal death as search terms. The case reports examined showed high rates of cesarean deliveries (44.0%) and pre-eclampsia (12.0%) among women with dengue infection during pregnancy, while the case series showed elevated rates of preterm birth (16.1%) and cesarean delivery (20.4%). One comparative study found an increase in low birth weight among infants born to women with dengue infections during pregnancy, compared with infants born to noninfected women. Vertical transmission was described in 64.0% and 12.6% of women in case reports and case series (respectively), as well as in one comparative study. The authors conclude that there is a risk of vertical transmission, but whether maternal dengue infection is a significant risk factor for adverse pregnancy outcomes is inconclusive. More comparative studies are needed. Copyright © 2010 by Lippincott Williams & Wilkins.