For pregnant women infected with Zika in the third trimester, the risk of birthing a child with microcephaly could be quite low, according to preliminary results of an ongoing comprehensive study being conducted by scientists in Colombia. The early data has been published in The New England Journal of Medicine.
The study is monitoring thousands of cases of Zika infection. The populations being monitored include a subgroup of 1,850 pregnant women — 532 with Zika infections contracted in the first trimester, 702 in the second trimester and 616 in the third trimester. More than 90 percent of the women infected in the third trimester have given birth, and no cases of microcephaly or brain abnormalities have been reported in this subgroup to date.
Still, when contextualized, this good news does not alleviate concerns about Zika's potential impact on pregnancy outcomes even when infection occurs late in pregnancy. Another study, published in NEJM, suggests Zika infections late in pregnancy could increase the risk of complications like miscarriage and stillbirth.
Regarding the preliminary report, Margaret Honein, PhD, epidemiologist and chief of the birth defects branch of the CDC, told NPR, "I think it's somewhat reassuring that there were not major birth defects identified...but I want to make sure we understand there is still a lot that we don't know."
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Olympics could see as few as 15 Zika infections, researchers claim