Infants whose mothers were infected with Zika virus had rates of birth defects that were 20-times higher than those born in the years just prior to the epidemic, according to a new study.
The Centers for Disease Control and Prevention (CDC) found 6% of infants with an infected mother developed birth defects compared to 0.3% of those whose mothers were not infected.
“These data demonstrate the critical contribution of population-based birth defects surveillance to understanding the impact of Zika virus infection during pregnancy,” researchers said in the study published Thursday in the Morbidity and Mortality Weekly Report.
The CDC compared data from 2013-’14 (before Zika’s introduction in the U.S.) from Massachusetts, North Carolina and Georgia to 2016 data from the U.S. Zika Pregnancy Registry. In the pre-Zika period, 747 infants and fetuses had at least one of the birth defects that have been linked to the virus (2.86 per 1,000). Among those with Zika-infected mothers last year, 26 of 442 (58.5 per 1,000) had birth defects. The rate for the pre-Zika period is for live births while the rate for 2016 represents completed pregnancies.
Brain abnormalities and microcephaly were most common in both groups and were 33 times higher in those whose mother was infected. Other birth defects included neural tube defects, eye abnormalities and other consequences of central nervous system dysfunction like joint contractures.
Pregnant women should avoid travel to areas with Zika and protect themselves from mosquito bites and sexual transmission of Zika, according to the CDC.
Pediatricians should report suspected congenital Zika cases to their state, local, tribal or territorial health officials and provide clinical information to the U.S. Zika Pregnancy Registry or Puerto Rico Zika Active Pregnancy Surveillance System so the CDC can monitor outcomes and adjust recommendations accordingly.