Hollywood’s below-the-line unions and the conglomerates have suspended negotiations, three weeks after starting talks on a new master contract — with four months to go before the current master contract ends July 31.

In a joint announcement Monday, the Intl. Alliance of Theatrical Stage Employees the Alliance of Motion Picture and Television Producers said they had not completed their negotiation for a new basic agreement covering West Coast employees.

“The parties need additional time to review data before resuming talks at a later time,” the statement said. “In the meantime, the parties will continue to maintain a formal news blackout. We will have no further comment at this time.”

It’s likely that the complexity of healthcare issues caused the talks, which had started March 7, to be suspended. For the first time, the IATSE West Coast locals were negotiating jointly with Local 399 of the Intl. Brotherhood of Teamsters and four other Basic Crafts unions on healthcare and retirement issues while holding separate bargaining on the remainder of their contracts.

Healthcare costs have become a dominant component in negotiations in late 2010 and early 2011 with the Screen Actors Guild, the American Federation of Televison & Radio Artists, the Directors Guild of America and the Writers Guild of America. Those deals included 2% hikes in minimums, while the chief gain in each was an increase of 1.5¢ per dollar in employer contributions to the pension and health plans.

Both IATSE and the Teamsters have been scaling up activity since last fall to heighten membership awareness on the specifics of rising healthcare costs with a series of explanatory sessions for members, which included presentations by healthcare expert and consultant John Garner and David Wescoe, exec administrative director with the Motion Picture Industry Pension and Health Plan.

Teamsters Local 399 secretary-treasurer Leo Reed said in a message to members earlier this year that the cost of healthcare benefits had become one of the most important issues facing members.

“Costs of care and insurance coverage have been going up at an alarming rate for the last decade or more,” Reed said. “Indications are that costs will rise an average of 9% to 10% a year for the next five years.”

The Teamsters Local 399 covers about 3,200 drivers in 13 Western states and about 1,000 basic craft workers, while the IATSE deal covers 15 locals on the West Coast encompassing more than 20,000 members. The two unions entered into a formal alliance in August 2010 — two weeks after Teamster Local 399 drivers reached a deal with the AMPTP and synched up its contract expiration with the IATSE deal.