Zika virus infection has been occurring in pregnant women at a slow but steady clip over the last couple of months, but cases of liveborn infants with Zika-related birth defects have jumped in recent weeks, according to the Centers for Disease Control and Prevention.
Eight liveborn infants with Zika-related birth defects were reported to the U.S. Zika Pregnancy Registry during the 2 weeks ending May 23, more than any other 2-week period this year, and that was after six such infants were reported for the 2 weeks ending May 9. The total for the 50 states and the District of Columbia is now 72 for 2016-2017. No new pregnancy losses with birth defects were reported over the same 4-week span, so the 50 state/D.C. total remained at eight for 2016-2017, CDC data show.
Since the beginning of 2016, there have been 5,799 pregnant women with laboratory evidence of Zika virus infection in the United Sates: 3,916 in the territories and 1,883 in the states/D.C. In total, 1,579 pregnancies have been completed, with or without birth defects.
The CDC notes that these are not real-time data and reflect only pregnancy outcomes for women with any laboratory evidence of possible Zika virus infection, although it is not known if Zika virus was the cause of the poor outcomes. Zika-related birth defects recorded by the CDC could include microcephaly, calcium deposits in the brain indicating possible brain damage, excess fluid in the brain cavities and surrounding the brain, absent or poorly formed brain structures, abnormal eye development, or other problems resulting from brain damage that affect nerves, muscles, and bones. The pregnancy losses encompass any miscarriage, stillbirth, or termination with evidence of birth defects.