In a 4-to-3 ruling, the Supreme Judicial Court said the 1972 law guarantees full-time employees eight weeks off to give birth or to adopt a child, after which they are entitled to return to the same job or a comparable one. Beyond that, however, the law does not protect them.

“Once a female employee is absent from employment for more than eight weeks, she is no longer within the purview of the [Massachusetts Maternity Leave Act] and, consequently, is not afforded the protections conferred by the statute,’’ Justice Francis X. Spina wrote for the majority.

The decision, which affirmed how the law has generally been applied, was a victory for business interests, according to John J. Barter, a Boston lawyer who represented Global NAPs Inc., a telecommunications company.

Five years ago, the firm was ordered to pay more than $1 million to a housekeeper whom the company president fired after the housekeeper returned about 10 weeks after her maternity leave started.

The ruling is limited to women whose maternity leave falls under state law, typically those who work at smaller companies but with at least six employees. People who work for employers with 50 or more employees are covered by the federal Family and Medical Leave Act of 1993, which provides up to 12 weeks of unpaid leave and job protection. The ruling does not affect the federal protections.

Barter said he was familiar with only one other lawsuit in Massachusetts filed by a woman who contended her rights under the state maternity leave law were violated because she was fired for taking too much time.

Yesterday’s decision clarifies some uncertainty over the application of the law.

The New England Legal Foundation, a pro-business legal advocacy group, had contended in a friend-of-the-court brief that the Massachusetts Commission Against Discrimination, the state agency that enforces the maternity law, had recently given workers more leeway, exposing businesses to lawsuits.

“Employers in general feel as though they are sometimes not getting a fair shake in front of the Massachusetts Commission Against Discrimination,’’ Barter said. “They feel the commission is creating new laws and new protections for employees that the Legislature didn’t intend.’’

He said, for example, that MCAD had adopted the position that women could take eight weeks of medical leave for each child they give birth to or adopt, enabling workers with twins or triplets to be out 16 or 24 weeks. MCAD officials also said a couple of years ago that they would apply the maternity law to men, even though the law mentions only women.

The MCAD filed a friend-of-the-court brief arguing that drawing the line at eight weeks would enable unscrupulous employers to promise women longer leaves, only to fire them for violating the law after they returned. The majority rejected that interpretation, in what amounted to a rebuff to MCAD.

Justice Margot Botsford dissented with parts of the decision. She agreed with MCAD that some employers could use the law to employ a bait-and-switch with workers. Also dissenting with parts were Chief Justice Margaret H. Marshall and Justice Ralph D. Gants.

But Spina said that if an employer promised a maternity leave exceeding eight weeks and reneged on it, the employee had legal options, including suing for breach of contract.

The MCAD plans to review the decision and take appropriate steps to “ensure that the discrimination laws of the Commonwealth give the greatest allowable protection to employees across Massachusetts,’’ said its chairman, Malcolm Medley.

Sandy Stephens, a personal housekeeper for Frank Tiberius Gangi, president of Global NAPs Inc., contended that she got permission to take about 2 1/2 months of maternity leave and return to her job on Oct. 2, 2000. But when she called her employer on Sept. 27 that year, she learned that she had been fired, according to the SJC ruling. Stephens was earning about $43,000 a year, Barter said.

Stephens sued in Superior Court, citing an MCAD guideline that says employers should notify employees in writing if they do not plan to guarantee maternity benefits beyond eight weeks.

The jury sided with Stephens in 2004, awarding her more than $2.3 million in compensatory and punitive damages. A judge later reduced the award to more than $1 million. The following year, Global and Gangi sought an appeal with the state Appeals Court, but the court dismissed most of the case, saying it had been filed too late.

That prompted Global to sue its lawyers, Martha Awiszus and David Kerman, for alleged legal malpractice. But another Superior Court judge dismissed the suit without a trial and concluded that the lawyers could not have won their appeal even if they filed it on time.

Yesterday, the SJC reversed that judge’s ruling, found that the lawyers did commit professional malpractice, and sent that case back to a lower court to determine what damages the lawyers should pay their former client. In the course of that decision, the court also clarified that the maternity law guarantees jobs only up to eight weeks.

The ruling does not affect the award to the housekeeper. But Barter said Global hopes to recoup some money from their former lawyers and believes the decision restores the company’s reputation.

Saltzman can be reached at jsaltzman@globe.com.