Detector of Pre-Term Labor OKd : Health: FDA approval allows Tokos Medical Corp. to begin marketing a monitoring device developed for women with a history of premature births.

Tokos Medical Corp. said it received federal approval Thursday to begin marketing a device for detecting pre-term labor in pregnant women with a history of premature births.

The device, which is manufactured by Physiologic Diagnostic Service, a small Atlanta firm that Tokos acquired 10 days ago for $31.4 million, is the first of its kind in the nation to receive pre-marketing approval from the U.S. Food and Drug Administration.

Tokos, based in Santa Ana, first announced plans to acquire PDS in June after abandoning a three-year effort to gain federal approval for its own uterine-monitoring device to provide early warning of premature births. Tokos began negotiating the purchase when it appeared that the Atlanta firm was nearing final FDA approval for its device, called the Genesis System.

Industry analysts have praised the move as a strategic coup for Tokos that could make it the leader in a market with an estimated value of $1.5 billion to $3 billion.

About 7,000 obstetrician-gynecologists in the country already prescribe the monitor--a miniaturized version of monitors used in hospitals--for use at home by women with high-risk pregnancies. Tokos has a national network of 64 centers that are staffed by nurses who interpret data transmitted from uterine monitors by telephone lines.

The monitors, which are strapped to patients by a belt, can detect an unusually high incidence of contractions, signaling a need to administer drugs or take other action to prevent premature birth.

Sales of the monitors have been hampered by the refusal of some major insurers, including Medicaid, Blue Cross and Prudential, to reimburse patients for pre-term labor monitoring devices pending FDA approval. Until now, uterine monitoring devices had FDA marketing approval for use only during full-term labor.

Under the FDA’s approval Thursday, Tokos will be allowed to market the device only to women with a history of pre-term labor but not to women with other kinds of high-risk pregnancies, such as those in which the mother is expected to give birth to more than one child.

“We are obviously delighted,” Tokos President Craig T. Davenport said of the FDA’s action. “We anticipate that this pre-market approval will lead to expanded prescriptions for our service.”