Some pregnant women here are nervous; others are not, despite the city’s efforts to sound the alarm with posters, movie theater ads and other public messages.

Jessenia Rocha, 31, a behavioral health representative at Legacy Community Health, is pregnant with her fifth child. Recently she drove 13 hours to San Luis Potosí, Mexico, for her great-grandmother’s funeral.

“My doctor said, ‘Don’t go,’ but I had to be there,” she said. “So my doctor said, ‘O.K., then wear long sleeves and use repellent.’”

Ms. Rocha stayed only two hours, then drove straight back.

Krystle McConico, 31, a gospel singer expecting her first baby, worries not at all. “Two of my close friends are also pregnant, and we haven’t had one conversation about Zika,” she said. “My physician didn’t mention it at my first appointment.”

Her job has taken her to Africa and Asia without problems. Some of her fearlessness may stem from her belief that God will protect her, she said.

“Also,” she added, “mosquitoes just don’t like me. I can sit on the porch with my mother and father, and they get bitten all over and I get nothing.”