How often are infants born alive after attempted abortions?

It hardly ever happens, according to Dr. Daniel Grossman, a professor of obstetrics, gynecology and reproductive sciences at the University of California, San Francisco. He performs abortions and is a spokesman for the American College of Obstetricians and Gynecologists, where he leads a committee on health care for underserved women.

A healthy fetus becomes viable — potentially able to survive outside the womb — at about 24 weeks of pregnancy. Only about 1.3 percent of abortions in the United States in 2015 were performed in or after the 21st week of pregnancy, according to the Centers for Disease Control and Prevention. Less than 1 percent of all abortions are done after 24 weeks, and many are performed because the fetus has a fatal condition or the pregnant woman’s life or health is at severe risk.

If an abortion is performed at 20 weeks or later, a drug may be injected to stop the fetal heartbeat before the fetus comes out of the womb, Dr. Grossman said. In other cases, suction devices and other instruments end the fetus’s life before it is removed, he said.

What happens in rare cases when a baby is born alive after a pregnancy is cut short?

Dr. Grossman said there were painful situations in which the fetus might be at the edge of viability and labor must be induced to save the mother’s life. For instance, a condition called pre-eclampsia, involving high blood pressure and other problems, can kill both mother and fetus, and in most cases the only treatment is to deliver the baby. If it seems unlikely that the baby will survive, the family may choose to provide just comfort care — wrapping and cuddling the baby — and allow the child to die naturally without extreme attempts at resuscitation.

The bill would force doctors to resuscitate such an infant, even if the parents did not want those measures, said Dr. Jennifer Conti, an obstetrician gynecologist who is a fellow of Physicians for Reproductive Health, an advocacy group. Doctors who violated the law would be subject to criminal penalties, as would anyone who saw the violation and failed to report it, she said.