St. Tammany Parish's growing population, especially of families with children, is drawing the attention of health care providers on the south shore, who are reaching into the north shore market with pediatric subspecialty clinics to serve existing patients and draw new ones.

Last month, Tulane Health System and Children’s Hospital opened pediatric clinics in western St. Tammany Parish within days of each other. Both touted the advantage to young patients and their families of having care closer to home and easier access to doctors like pediatric cardiologists and gastroenterologists.

They're not the first health care companies to pursue this market. When Ochsner Health Systems signed a partnership agreement with St. Tammany Parish Hospital in 2014, expanding clinical services -- specifically pediatrics -- was one of the stated goals.

A quarter of all patients at St. Tammany Parish Hospital's Emergency Department are under 18, Kerry Milton, chief nursing officer for the hospital, said. The hospital, which is expanding its emergency operation, is adding five pediatric specialty beds that will open in late October.

Ochsner began sending pediatric specialists to Covington a year ago, Dr. Mariastella Serrano, head of pediatric gastroenterology with Ochsner, said. In its first year, the Ochsner Health Center for Children Pediatric Subspecialties had 4,500 patient visits. Doctors are increasing the amount of time they spend at the Covington clinic as the need increases, Serrano said.

For parents of sick children, particularly those with serious or chronic health issues, the ability to see a doctor without trekking across the lake is an obvious boon, and one that the hospitals are quick to point out.

Such children must see their doctors more frequently, Dr. John Heaton, senior vice president and chief medical officer for Children's Hospital, said, and some of them need special transport.

But while those patients stand to benefit most, he said the close-to-home model is also important for more routine care, like an orthopedic visit or an appointment with a pediatric surgeon to deal with "a lump or a bump.''

Millennials, who are having children now, demand convenience -- more so than previous generations, Heaton said. The idea of having a central "mother ship" that everyone goes to visit is changing in health care, he said, and Children's Hospital has established other clinics -- similar to the one in Covington -- in Lafayette, Baton Rouge and Metairie.

Dub Lane, a University of New Orleans economist, sees another trend at work: competition among a shrinking number of hospital management companies in the metro area. While there once were a dozen players, he said, the market is now controlled by three: Hospital Corp. of America, or HCA, which has Tulane as well as Lakeview Regional Medical Center; LCMC, which has University Medical Center and other hospitals in addition to Children's; and Ochsner.

All three are represented in St. Tammany's burst of pediatric subspecialty activity.

Lane -- who serves on the board of Slidell Memorial Hospital, which also has a partnership with Ochsner -- sees this as a strategic play. "They are battling for market share,'' he said.

Kim Peters, vice present of service lines with Tulane HCA, said the north shore is one of the areas with highest population growth. She acknowledges there's competition for market share and said Tulane knew that Children's also was establishing a clinic in western St. Tammany.

But the decision to open the Mandeville clinic also grew out of feedback from Tulane's family advisory board, whose members strongly felt St. Tammany was a good place to go. Tulane began making plans last August, she said, including scoping out locations.

A former St. Tammany Parish resident, she said she was struck by the growth on the parish's western end.

Children's Hospital sees the service area for its north shore clinic as covering St. Tammany, Washington and Tangipahoa parishes and southwestern Mississippi, Heaton said. He pegged the population of children ages 0-19 in that area at 120,000, adding that it's expected to see 10 percent growth in five years and another 10 percent in 10 years.

The payer mix is attractive in St. Tammany, Peters said, but she said Tulane takes all levels of payers, especially because it has a teaching mission. She also noted that Medicaid pays better for pediatrics and obstetrics than for other kinds of patients.

As for Children's Hospital, Heaton said its mission is to serve all children.

From a demographic point of view, the north shore will continue to be a good place to find them.

Follow Sara Pagones on Twitter, @spagonesadvocat.