FRESNO, Calif. (KFSN) --With cases of Zika virus rising across California, there's growing concern about the impact on pregnant women.
Two babies have been born with Zika-related birth defects in the state already.
For months, doctors have been recommending pregnant women to avoid areas with Zika infections and now the CDC is calling for all soon-to-be mothers to be assessed by their doctors.
It's a virus scientists and doctors have limited answers to, but they say the severity of Zika to an unborn child is undeniably true.
"They are quite severe," Dr. Rais Vohra, an associate professor of emergency medicine, said. "It's something the child will have neurological problems for the rest of their lives."
Fresno, Merced and Tulare County are among the 22 counties in California with reported cases and recently two babies in the state had been born with complications.
At this point, it is unclear how likely a baby will develop birth defects if the mom is infected.
"It's definitely not a 100 percent," Vohra said. "It's a minority of patients that will go on to have a baby that is be affected, unfortunately, we don't know exactly what the rate is."
Babies who do develop microcephaly have noticeable small heads because of brain damage.
Some suffer developmental delays, other seizures and intellectual disabilities.
"They are going to have problems with vision, they may have hearing problems," said David Luchini, who is the assistant director Fresno County Health Department. "Several things may happen if the brain is not developed enough."
California currently has 134 travel associated Zika virus infections and 1 sexually transmitted case.
There are no locally transmitted cases, but doctors say the Central Valley is at a higher risk because it does have the species of mosquito that carries the virus.
"People should definitely try to minimize the habitats for mosquitos so avoid any puddles of water," Vohra said.
It's not just women who have to be careful.
Doctors say men can carry the virus for longer periods of time and pass it on to their sexual partner.
With the Rio Olympics kicking off, health leaders say they want travelers to be careful but still expect the number of cases to hold steady.
"I'm not sure if we'll see any major increase," Luchini said. Because we always have a certain amount of the population traveling to places with local transmission."