Some physicians, at a mid-point in their lives, might find an altruistic impulse, or if they’ve had the impulse all along, the need to express it more fully. So it is with Oak Bluffs obstetrician and gynecologist Dr. Jason Lew, with his wife, Injy, and their three daughters, Olivia, 23, a Middlebury College graduate (who just completed Michigan field work in the Obama campaign), Isabelle, 21, a student at Wesleyan University, and Sophie, 17, a senior at the Martha’s Vineyard Regional High School.

Starting in 1982 and running for nearly two decades, Dr. Lew delivered virtually all of the Island-born babies (including mine). He left the Martha’s Vineyard Hospital a few years ago and opened a private gynecology practice in an office off State Road in Vineyard Haven.

And recently he became involved with the Maternal and Infant Health Initiative, a division of the Office of Global Health and Human Rights at Massachusetts General Hospital in Boston.

Last October marked Dr. Lew’s eighth or ninth (he has lost the exact count) trip to Zambia to deliver babies at newly established clinics there. “Two three-week trips, and this last four-week trip,” he recalled in a recent interview at his Oak Bluffs home.

The program began a couple of years ago, when the then-first lady of Zambia, Maureen Mwanawasa, visited Boston to appeal to Dr. Tom Burke at Mass General for help in stemming the country’s maternal and infant mortality rate. When a Zambian woman gives birth, well-wishers tell her, “Mwapusukani,” which means, “You have survived.” Native-born doctors have long been leaving Zambia and expectant mothers in remote areas have little or no access to modern medical care. So Dr. Burke mobilized a team of committed physicians, including Dr. Lew; money was raised (and is still needed), and now clinics and surgical units have been established.

The base of operations is in a central town called Kapiri Mposhi, about a three-hour drive from the capital of Lusaka. “The hospital in Kapiri Mposhi was dirty and dilapidated,” said Dr. Lew. “In the pediatric ward there were often four sick children to a bed.” He said Zambian mothers due to give birth arrive in their brightly colored lengths of cloth called chitangas, which they customarily drape around their waists or fold over their backs to form slings for their babies. As soon as a mother delivers her infant, she uses her chitanga to clean up and then waits until her baby is placed in her arms for the long walk home.

This past fall, the American medical group brought in four huge crates of new equipment, including operating tables and ultrasound machines, to two newly established rural health centers in the towns of Nkole and Mkonshi. Dr. Lew said the new birthing center in Nkole has been outfitted with toilets, showers, solar panels and stethoscopes for monitoring fetal heartbeats. “You know what they’ve traditionally used to listen — or try to listen — to the fetal heartbeat? Big wooden funnels that they hold up to their ears,” he said.

He explained that Zambians have enjoyed years of peace and democratic elections (the most recent was held during Dr. Lew’s last visit), with smooth governmental transitions. “The only problem is that Zambians for the most part are very poor,” he said. The country has abundant natural resources, including lead and copper, fertile soil, and wildlife preserves.

But it also has all the illnesses endemic to the continent: malaria, tuberculosis, snake bites, malnutrition, and H.I.V. and AIDS. “One third to one-half of patients in hospitals are infected with H.I.V.,” Dr. Lew said.

These public health problems contribute to the high infant mortality rates. Dr. Lew noted that a typical expectant mother’s prenatal record, written on a document the size of an index card, will show several stillborn births. Asked if he thought his Boston-based group was making a difference, he replied: “Sometimes I think we are. Other times I feel our work is less than a drop in the bucket — it’s a drop dissolving before it even hits the bucket.”

But the resilient, upbeat physician recalled his last visit to Zambia with fondness for the daily routine. “I walked from my lodgings in the center of Nkole, through the marketplace, with all its fruits and vegetables, bright textiles, past trees with amazing orange blossoms, to the hospital,” he said. During his visit he befriended a tailor who stitched handsome brown and cream-colored cushion covers for the Lews’ breakfast nook back home. The tailor was Muslim and one morning he took Dr. Lew to his mosque.

Most of the country is Christian, and Dr. Lew often passed open houses of worship from which heavenly voices erupted in choir practice. He recorded a couple of the choirs on video, one of them singing a classic Bach cantata, another group, standing outdoors, jiving to an upbeat, Baptist-inflected hymn.

The most memorable moment in this past visit occurred when Dr. Lew and a Scots physician and ultrasound expert, Dr. Alice Murray, paid their formal respects to the district’s tribal chief. A sign outside the chief’s compound announced, “Welcome to His Royal Highness, Chief Nkole’s Palace Kapiri-Mposhi.” He said the imperial dwelling was set inside a thatched fence. The compound held a wealth of mud huts with thatched roofs, while the chief himself occupied a modest single-story bungalow. Dr. Lew and Dr. Murray had been instructed in proper protocol: When the chief entered, clad in a shirt resembling a red choir robe, the physicians stood and clapped, then knelt at the chief’s feet. His royal highness regaled them with solemn words in his native Bemba dialect. Dr. Lew turned slightly to Dr. Murray, and whispered, “I think we’ve just been married.”

Dr. Lew opened up his laptop and showed pictures of long lines of women waiting outside clinics, the colorful marketplace in Nkole, political rallies, old and new surgical units, exquisite orange-blossomed trees and an African menagerie of giraffes, elephants, hippopotami and lions. One of the photographs was taken during his trip to Kapiri Mpochi last March, when his daughter, Olivia, accompanied him to help out both at the hospital and at a nearby school. The photograph shows Olivia seated outdoors with a newborn in her arms, the sun shining on both their faces.

“When babies are born with jaundice in America, we put them under special lamps. In Africa they expose them to sunshine,” Dr. Lew said.

The picture of Olivia Lew with a Zambian infant in her arms was another drop hitting the bucket.