AILSA CHANG, HOST:
Record heat is hitting the middle of the country, and Texas is ground zero. The temperature in Dallas today is expected to be upwards of 105 degrees. That's tough for anybody to endure, but it's especially brutal for pregnant women. Courtney Collins of member station KERA knows all about that. She's six months pregnant. And as she reports, that misery can be explained by science.
COURTNEY COLLINS, BYLINE: Walking across a Dallas parking lot at 3 in the afternoon in July isn't a journey for the faint of heart. The heat radiates off the pavement. And with few trees to shelter you, you can feel your scalp start to burn in seconds. Now imagine the trek with an almost 4-year-old named Bobby and a 2 1/2-year-old named Kate.
REBECCA MABERRY: It's like you're walking on the sun. And kids don't move very fast, and so I hate rushing them. But I'm just like - and then the car is even worse when you get in the car.
COLLINS: Rebecca Maberry has a preschooler, a toddler and is also 25 weeks pregnant with baby number three. She and I are both due this fall, and we happen to agree on what it feels like to be expecting a child when the high temp is hovering near 110 degrees.
MABERRY: It's just kind of inescapable unless I have a fan in my face, or I'm in water.
COLLINS: And we aren't the only pregnant women clutching iced tea like it's the elixir of life. Dr. Robyn Horsager-Boehrer with UT Southwestern says a heatwave is more challenging with a baby on the way. It's science.
ROBYN HORSAGER-BOEHRER: Pregnancy tends to be a state of vasodilatation. Your blood vessels are bigger. They're swollen. Your blood volume's increased. That in itself causes women to be a little bit warmer than normal.
COLLINS: And she says many of her patients found that out the hard way.
HORSAGER-BOEHRER: People never, ever think about what the weather's going to be like when they're pregnant. And that's what you hear, though. If I had known, I might have timed this differently.
COLLINS: And the weekend could be even hotter. For NPR News, I'm Courtney Collins in Dallas. Transcript provided by NPR, Copyright NPR.