Maternal implications
Zika virus infection is asymptomatic or presents with a mild self-limited illness for most people, including pregnant women.
Serious complications from Zika virus infection are rare; however, an increase in Guillain-Barre syndrome and other neurological and autoimmune syndromes has been reported in areas where outbreaks have occurred.
Evidence is still emerging.
Fetal implications
It has been demonstrated that Zika virus crosses the placental barrier and it has been detected in blood and tissues of affected fetus/infants.
There is a probable association of ZIKV infection with congenital microcephaly, however, a causal relationship has not yet been proven. An increase in the number of central nervous system malformations in fetuses and neonates was reported in French Polynesia following an epidemic of ZIKV infection. At least 17 cases were reported in 2014–15, coinciding with the ZIKV outbreaks on the French Polynesian islands.
In October 2015, the Brazilian Ministry of Health reported an unusual increase in the number of babies born with microcephaly. As of 9 January 2016, 3530 (284/100 000 live births) cases of microcephaly including 46 deaths have been reported across 21 states in Brazil, compared to the expected 150–200 cases per year that were reported in 2010–14 (5.7/100 000 live births in 2010). The Ministry of Health of Brazil has suggested this increase is associated with the ongoing ZIKV outbreak. Although this evidence does not prove causality, it seems increasingly likely that the increase in microcephaly in Brazil may be associated with the ongoing ZIKV outbreak.
Effect on breastfeeding
There is no evidence that Zika virus can be transmitted to babies through breast milk.