ATLANTA - The price of preventing preterm labor is about to go through the roof.

A drug for high-risk pregnant women that has cost $10 to $20 per injection shoots up next week to $1,500 a dose, meaning the total cost during a pregnancy could be $30,000.

The drug, a form of progesterone given as a weekly shot, has been made cheaply for years, mixed in special pharmacies that custom-compound treatments not federally approved.

But recently, KV Pharmaceutical outside St. Louis won government approval to exclusively sell the drug, known as Makena. The March of Dimes and many obstetricians supported that because it meant quality would be more consistent and it would be easier to get.

None anticipated the dramatic price increase, though - especially since most of the development cost was shouldered by other companies in the past.

"That's a huge increase for something that can't be costing them that much to make," said Roger Snow, deputy medical director for Massachusetts' Medicaid program. "For crying out loud, this is about making money."

"I've never seen anything as outrageous as this," said Arnold Cohen, an obstetrician at Albert Einstein Medical Center in Philadelphia.

"I'm breathless," said Joanne Armstrong, the head of women's health for Aetna, the Hartford, Conn.-based national health insurer.

Doctors say the price increase may deter low-income women from getting the drug, leading to more premature births. And it will certainly be a huge financial burden for health-insurance companies and government programs that have been paying for it.

KV Pharmaceutical chief executive Gregory J. Divis Jr. said the cost was justified to avoid the mental and physical disabilities that can come with very premature births. The cost of care for a preemie is estimated at $51,000 in the first year alone.

"Makena can help offset some of those costs," Divis said. "These moms deserve the opportunity to have the benefits of an FDA-approved Makena." The Food and Drug Administration is not involved in setting the price for the drugs it approves.

Ther-Rx Corp., the KV subsidiary that will market the drug, on Tuesday announced a patient-assistance program designed to help uninsured and low-income women get the drug at little or no cost.

But Snow in Massachusetts and others said the cost would have to be borne by someone. Some of the burden will fall on health-insurance companies, which will have to raise premiums or other costs to their other customers. And some will fall on cash-strapped state Medicaid programs, which may be forced to stop paying for the drug or enroll fewer people.

"There's no question they can't afford this," said Matt Salo, executive director of the National Association of Medicaid Directors.

Aetna will continue to pay for the drug, Armstrong said, but it will be an expensive pill to swallow. Aetna currently covers it for about 1,000 women a year, so the new federal endorsement is likely to cost an estimated $30 million more each year.

In the 1990s, an early incarnation of Makena was withdrawn from the market amid reports it might damage fetuses in early pregnancy.

But the drug got a new life in 2003, with publication of a study that reported it helped prevent early births to women who had a history of spontaneous preterm deliveries.

These very early births produce children who, if they survive, need months of intensive care and often suffer disabilities. The cause of sudden preterm delivery is not understood, but it occurs in black mothers at much higher rates than in whites or Hispanics.