Now she is growing, but the development of her brain is stunted by the birth defect, and slowly, day by day, her adopted parents Kely and Josimar Oliveira are learning what this means: can she see, does she hear them?
Discoveries like these -- heart-shredding moments - are happening every day at the Altino Ventura Foundation Clinic in Recife.
This port city in Brazil's northeast was Ground Zero for the country's Zika outbreak; months on, it is seeing the babies born under a global spotlight age quietly, their symptoms and burdens growing daily.
But for Kely Oliveira, the choice to bring Maria Vitoria into her home was a simple one. She said: "For me it was love really, you know, a mother's love," she explains. "When we saw her, we fell in love with her. I didn't want to know what she had, what she didn't ... to me that doesn't matter. She's my daughter."
For Maria Vitoria and her adoptive mother Kely, this is a particularly special moment: today the eight-month-old will, for the first time, be given glasses to help her vision.
"She needs them," Kely says. "She has a problem with her eyesight." Microcephaly hampers a child's development and the eyes are often one of the areas affected.
"I took her to the eye doctor and he said that at the moment she only needs glasses to stimulate her eyesight," Kely explains, adding "these babies need to wear glasses to avoid harming their eyesight even further."
Maria Vitoria's difficulties don't end there; she has been attending regular physical therapy sessions, and has medical appointments three days a week.
"It is a bit of a rush, her schedule is full," Kely says, admitting that her life has been overtaken by the vast amount of medical assistance her child needs. "It is a lot of different doctors and it's not just in one place, it's several places."
Much of what happens at the clinic also happens fast; as the youngest victims of the world's newest pandemic are put through a barrage of tests.