BOONSBORO, Md. — Maddi Runkles has never been a disciplinary problem.

She has a 4.0 average at Heritage Academy, the small private Christian school she attends; played on the soccer team; and served as president of the student council. But when her fellow seniors don blue caps and gowns at graduation early next month, Ms. Runkles, 18, will not be among them.

The reason? She is pregnant.

The decision by school officials to bar Ms. Runkles from “walking” at graduation — and to remove her from her student council position — would have remained private, but for her family’s decision to seek help from Students for Life. The anti-abortion group, which took her to a recent rally in Washington, argues that she should be lauded, not punished, for her decision to keep her baby.

“She made the courageous decision to choose life, and she definitely should not be shamed,” said Kristan Hawkins, the Students for Life president, who tried unsuccessfully to persuade the administrator of Heritage Academy to reverse the decision. “There has got to be a way to treat a young woman who becomes pregnant in a graceful and loving way.”

David Hobbs, the administrator at Heritage Academy, a nondenominational independent school in Hagerstown, Md., where students take daily Bible classes, declined to discuss Ms. Runkles. In a written statement issued on behalf of the school’s board of directors, he said she would earn a diploma, and called her pregnancy “an internal issue about which much prayer and discussion has taken place.”