AP Photo/Felipe Dana
Isabela Cristina, 18, who is six months pregnant, shows a photo of her ultrasound at the IMIP hospital in Recife, Pernambuco state, Brazil, Wednesday, Feb. 3, 2016. Isabela Cristina was struck with Zika and was worried about the health of her bay, but her baby's ultrasound scan and other exams turned up normal.
The Centers for Disease Control and Prevention as of Thursday has begun monitoring any bad outcomes that come from women who were infected with Zika during the time they were pregnant.
Zika, which is transmitted mainly by mosquitoes, has been spreading around the Americas over the last year. Once infected with Zika, only about 20% of people ever show symptoms, which most commonly include fever, rash, joint pain, and red eyes. There is no vaccine or treatment available for the virus.
One reason Zika is troubling is because it is a cause of birth defects, including microcephaly - a condition where the baby's head is abnormally small - in babies whose mothers have had Zika. The virus has also been linked to a neurological condition called Guillain-Barré syndrome.
The numbers just account for the 50 states and D.C. The CDC said similar data on the US territories will be out in the next few weeks.