In a sport that seems to have labor problems every nine months, maybe "Birth Night" isn't such a strange idea after all.

In the latest twist on old-time ballpark promotions, the Class A Lowell Spinners invited expectant mothers to Thursday night's game and offered a year's supply of diapers to the woman who delivered first. None went into labor during the game, but the Spinners are in contact with local hospitals so that the winner will eventually get her prize.

"I must say there were a couple that were very low when they came in," said Linda Jezek, a childbirth educator who led the packed house in breathing exercises between innings. "One of them is overdue, so I think she's the favorite. I'd definitely be betting on her."

The crowd of 5,000 -- and threatening to expand at any minute -- cheered the mothers along, voted on potential names and tried to guess the time of the first delivery. But by the time Lowell had finished beating the Vermont Expos 7-2, none of the women reported so much as a contraction.

"Nobody's even warming up at this point," said physician Ed Lipman, who was standing by along with four paramedics and a fleet of ambulances. "The most we've seen is some discomfort.

"No woman at full term is comfortable for more than seven minutes in any one position. There have been a lot of trips to the bathroom," he said. "And maybe the [ice cream] line is a little longer tonight."

Although 40 couples called the team to inquire about the promotion, 30 showed up and registered for the contest. As they checked in, they were told what to do in case they went into labor: call an usher and he'll summon the doctor.

Team owner Joann Weber said one man called Thursday morning while his wife was in labor in the next room.

"He said, `If she hasn't given birth by then, can I wheel her in in a wheelchair?' " Weber said.

"I said, `This is your first baby, right?'

"He said, `Yes.'

"I asked him if he discussed it with his wife, and he said, `No.'

"I said, `You talk to your wife. If she thinks this is as good an idea as you do, it would be our pleasure to have you.' I'd like to be a fly on the wall for that one."

He did not call back.

The original guru of the giveaway day was former White Sox, Indians and St. Louis Browns owner Bill Veeck, who used prizes to lure children to the ballpark, then made his money back on all the peanuts and hot dogs they ate while waiting for the game to start.

Veeck gave away bats, balls and caps. As the idea spread, the gifts expanded to beach sandals, Beanie Babies and even haircuts.

In recent years, though, publicity-starved teams have taken the idea to new heights -- or lows -- like the Tampa Bay Devil Rays' "Lawyer Appreciation Night," when attorneys were charged double and billed by the third of an inning. On Conversion Day, Tampa Bay fans were rewarded for getting rid of New York Yankees caps.

For the Spinners, it's promotions such as this that make minor league baseball a fun, inexpensive alternative to the big leagues.

"We try sometimes to make people enjoy baseball who might not be the consummate baseball fans," owner Drew Weber said. "I see a lot of kids smiling, and that's what it's all about to me."