She said the sentencing “makes a case for Parliament to start looking at this issue in detail.”

Louise McCudden, the head of external affairs at MSI Reproductive Choices, a Britain-based women’s health organization, said in an interview that even if prosecution was rare, the law must be changed.

“Any case is too many,” she said.

Ms. Creasy, the Labour lawmaker, told BBC Two’s “Newsnight” that “Abortion is a health care issue, not a criminal matter.”

What were the calls for tighter rules?

Groups that campaign against abortion argued that the case illustrated the tragic consequences of the government’s decision to allow abortion pills to be sent by mail. They also said that Parliament should act based on the case, by further restricting the procedure.

“The government should urgently turn back the clock and end this disastrous policy of cheap, convenient, pills-by-post abortions,” Andrea Williams, the chief executive of Christian Concern, an advocacy group, said in a statement.

“At 32 weeks’ gestation, an unborn baby has a 95 percent chance of survival if delivered,” she added. “Our abortion law rightly recognizes that these precious humans deserve protection.”