Rebecca Gau, a self-described “reasonable Republican” in Mesa, Ariz., is conflicted about many things that her party promotes. But she knows exactly what she thinks about Arizona’s new — or rather, very old — Civil War-era abortion ban. And about the idea that Republicans like her might be happy with the outcome.

“Are you nuts?” she said, adding that she was frustrated with the ban and Republican politicians inserting themselves into women’s health choices.

Ms. Gau, 52, said she probably would not have chosen an abortion for herself. But she said she would never judge a woman for making her own decision. “It is not a cut and dry line,” she said.

Across the country, fractures are emerging among conservative and centrist Republican women, as they confront an unrelenting drumbeat of new abortion bans and court rulings. For years, the party’s message was simple and broad: Republicans oppose abortion. Its politicians rarely dove into the specifics of what the position meant for reproductive health issues like miscarriage, medical emergencies and fertility treatments.

Now, those complicated realities are everywhere. In Alabama, the State Supreme Court ruled that frozen embryos could be considered children, raising concerns over future access to in vitro fertilization procedures. In Florida, women are preparing for a new six-week abortion ban to soon go into effect.

Nowhere is the conversation more intense this week than in Arizona, a key battleground state in the 2024 election. On Tuesday, the State Supreme Court ruled 4 to 2 in favor of reinstating an 1864 law banning all abortion from the moment of conception, except to save the life of the mother. It made no exceptions for rape or incest.