Adverse prenatal and early postnatal infant outcomes
In summary, pregnancy losses and/or birth defects potentially related to ZIKV in newborns occurred in 43/511(8.4%) symptomatic mothers while microcephaly or other CNS malformations were diagnosed in 25.0%(1/4) of the stillbirths and 3.9%(19/489)[CI95%:2.5-5.9] of the live-born infants. If only the typical CZS phenotype in infants without co-morbidities was considered, then 12/489(2.9%;CI95%:1.7-4.7) infants would be affected by the intrauterine ZIKV-infection or 13/513(2.5%;CI95%:1.5-4.3) fetuses.
Tables S1 and S2 show the overall characteristics and pregnancy outcomes in 511 women. There were 24(4.7%) pregnancy losses. Postmortem examination of one of the four stillbirths (34 weeks) showed severe CNS malformations. There was one stillbirth of unknown cause. The remaining three fetal losses had no malformations and were likely secondary to premature membrane rupture or placental abruption. Of the remaining 487 women, there were 489 live births.
As shown in Figure 1, of the live-born infants, 33(6.7%;CI95%:4.8-9.3) had one or more major abnormalities, and 19(3.9%;CI95%:2.5-5.9) had findings potentially related to ZIKV infection (Table 1). Except for three infants (including two that died shortly after birth due to severe CZS anomalies), those with potential ZIKV infection underwent additional postnatal neuroimaging. Malformations of cortical development, brain volume loss, ventriculomegaly, and calcifications were found. All five infants with severe and 16.7%(1/6) of those with moderate microcephaly had eye abnormalities. Two infants without microcephaly had neurological dysfunctions and were diagnosed with brain abnormalities. Of the 17 infants screened for hearing loss, one failed, but we could not confirm this result. Of the 19 infants with findings potentially related to ZIKV infection, 4(21%) were categorized as mild/moderate and 15(79%) as severe1.