Insight - Brazilian studies aim to unravel Zika's link to birth defects

Luana Vieira, 4 months, who was born with microcephaly, is held by her mother Rosana Vieira Alves as they ride the subway after a doctor's appointment in Recife, Brazil, February 3, 2016. REUTERS/Ueslei Marcelino

CHICAGO (Reuters) - At Roberto Santos General Hospital in Salvador, Brazil, Dr. Antonio Almeida and a team of specialists are closely following two groups of women: Those who deliver babies with abnormally small heads and those who deliver apparently normal babies.

The hospital is one of three in this city on Brazil’s eastern coast where investigators are studying the most urgent question of the Zika outbreak: Is the virus causing a spike in birth defects, and, if so, how great is the risk?