The last day Byron Stribling spent with his wife, Harmony, was the Fourth of July in 2021. A great day, he always says.

The holiday fell on a Sunday. The congregation at their church in Belzoni, a small town in the Mississippi Delta, blessed the couple and prayed for a safe delivery for Ms. Ball-Stribling. She was eight months pregnant and scheduled to have a C-section five days later.

At a barbecue, the Striblings feasted on ribs, collard greens, potato salad and cornbread. But around midnight, Ms. Ball-Stribling threw up and said her chest hurt. “She wanted to lay down, but I told her, ‘We need to go somewhere,’” Mr. Stribling, 32, recalled.

Ambulances in the Delta are unreliable, and the only hospital in Belzoni closed over a decade ago. So they piled into his car and sped toward Yazoo City, Miss., the closest town with an emergency room, about 30 miles away.

On the way, Ms. Ball-Stribling had a seizure. Panicked, Mr. Stribling called 911. The dispatcher told Mr. Stribling to pull over and start CPR, so he slammed on the brakes and pumped her chest on the side of the road until an ambulance came. But he already knew he had lost her, there on the shoulder of Route 49-W.

What killed Harmony Ball-Stribling? The death certificate says the cause of death was complications of pre-eclampsia, a life-threatening blood pressure disorder that can develop during pregnancy, exacerbated by hypertension and hardening of the arteries. But that’s not the whole story.