Dr. Orvan W. Hess, a fellow at the Yale School of Medicine who developed the fetal heart monitor, died on Sept. 6 at Yale-New Haven Hospital. He was 96.

Hess, an obstetrician and gynecologist, was also a pioneer in the clinical use of penicillin to treat bacterial infections.

The fetal heart monitor, which is used to detect early signs of fetal distress during labor, has been credited with reducing the number of stillbirths.

“It was a huge change because it allowed us to get an initial understanding of what was going on for the fetus during labor,” said Dr. Joshua Copel, a professor of obstetrics, gynecology and pediatrics at the medical school.

While developed for “high-risk” pregnancies, fetal monitoring is also applied in the majority of normal pregnancies.

“It’s a ubiquitous tool in obstetrics,” Copel said.

It was while Hess was a research fellow at the medical school in the 1930s that he began his work on a way to electronically measure fetal heart activity. After serving in World War II as a surgeon, Hess returned to Yale in 1949 and continued his work alongside Dr. Edward Hon.

Hess received the American Medical Association’s scientific achievement award in 1979 for being one of the first doctors to report the successful use of penicillin as a treatment for a streptococcus infection.

He served as president of the Connecticut State Medical Society and director of health services for the Connecticut Welfare Department.

Hess’ wife died in 1998. He is survived by two daughters, five grandchildren and five great-grandchildren.

–Andrew Dervan