While a potentially alarming development, there is no indication that the miscarriages were caused by the Zika Virus:

Two U.S. women who contracted the Zika virus while traveling out of the country miscarried after returning home, and the virus was found in their placentas, a spokesman for the Centers for Disease Control and Prevention said Thursday.

Federal health officials have not previously reported miscarriages in American travelers infected with the mosquito-borne virus while abroad. But there have been miscarriages reported in Brazil, the epicenter of a Zika epidemic that now spans nearly three dozen countries.

The STAT website first reported the U.S. miscarriages, based on information from the CDC’s chief pathologist. The pathologist told STAT the women miscarried early in their pregnancies but provided no additional details.

Last month, officials said a baby born in a Hawaii hospital was the first in the country with a birth defect linked to Zika. Hawaii officials said the baby’s mother likely contracted the virus while living in Brazil last year and passed it on while her child was in the womb. Babies born with this rare condition, known as microcephaly, have abnormally small heads and brain abnormalities.

In cases when women have one or two miscarriages, the cause is usually severe chromosomal problems, experts say. “It’s absolutely possible for an infection, whether it be viral or bacterial, to result in a miscarriage,” said Zev Williams, an obstetrician-gynecologist who specializes in pregnancy loss at the Albert Einstein College of Medicine in New York. “Whether it was caused by Zika remains to be determined,” he said, but urged individuals to take precautions to avoid contracting or transmitting the virus.