She was one of those Religious People.

In 1958 the Hamlins answered an advertisement placed by the Ethiopian government in The Lancet medical journal for an obstetrician and gynaecologist to establish a midwifery school at the Princess Tsehay Hospital in Addis Ababa. They arrived in 1959 with their six-year-old son, Richard. The Hamlins had never seen an obstetric fistula before — they were an "academic rarity" having been virtually eradicated in the United States in 1895. (The first fistula hospital closed its doors in New York City in 1925.) Seeing many cases arrive at the school, they decided to create a dedicated hospital. Fifteen years later, in 1974, they founded Addis Ababa Fistula Hospital and over the years, the hospital has treated more than 60,000 patients.

https://www.economist.com/obituary/2020/04/08/catherine-hamlin-died-on-march-18th