A lower rate of possible Zika-related deficits was found in offspring of women in French territories in the Americas than has been reported in Brazil.
During the past year, Latin American countries and the U.S have reported on the outcomes of pregnancies of women infected with Zika virus. Reports, primarily from Brazil, demonstrate teratogenic effects, mainly on the ocular and central nervous systems. Now, researchers report on the outcomes of pregnancies of Zika-infected women in the French territories in the Americas (French Guiana, Guadeloupe, and Martinique). The investigators prospectively examined pregnant women with suspected Zika virus infection and enrolled 546 women in any stage of pregnancy who had laboratory-confirmed Zika virus infection on the basis of a positive result on a reverse-transcriptase polymerase chain reaction assay on blood, urine, or both.
The pregnancies included 555 fetuses and resulted in 11 miscarriages (2.0%), 32 cases of microcephaly of any degree (defined as greater than 2 standard deviations below the mean for sex and gestational age; 5.8%), and 28 other cases of central nervous system defects (5.0%). Overall, 7% of fetuses or infants had either neurologic or ocular defects possibly associated with Zika. The rate of neurologic or ocular defects was highest when Zika virus infection occurred during the first trimester of pregnancy (12.7%) versus the second or third trimester (3.6% and 5.3%, respectively).
The proportion of ocular and nervous system birth defects reported in this population is similar to a report from the U.S. (6%) but much lower than in a report from Brazil (42%). This difference is largely unexplained except if the predominant Zika strain differs among different countries. As the authors note, some defects may not be evident until these offspring are followed for a longer period.