A sharp drop in barometric pressure sends pregnant women into labor. True or false?

Tuesday's record low pressure was a good opportunity to put that old wives' tale to the test.

As a massive storm moved over the Midwest, the atmospheric pressure plunged to lows usually seen in Category 3 hurricanes.

It coincided with a spike in the number of babies born in four out of five of the busiest maternity hospitals in the western metro.

Whether or not the two were related is a matter of debate.

"Tuesday night really was outrageous," said Dr. Jan Strathy, an obstetrician at Methodist Hospital in St. Louis Park, referring to both the storm and the number of babies born. Methodist typically delivers 10 to 12 babies each day. On Tuesday, it was 18.

Still, she's reluctant to jump to conclusions. The few academic studies out there on the topic are inconclusive, she said: "Some say the stress of anticipating a hurricane may put someone into labor."

On Tuesday evening, atmospheric pressure fell to 955.2 millibars in Big Fork, Minn., breaking the old record of 962.6 millibars set on Nov. 10, 1998, in Austin and Albert Lea, according to WeatherNation.

There's certainly anecdotal evidence that storms or approaching storms can make people feel different.

"A lot of people report having aches and pains, and there is some research supporting the idea that the body can feel the difference in pressure," said Susie Martin, a meteorologist at WeatherNation.

John Eads, a nurse midwife at Fairview Riverside Women's Clinic, thinks the hospital birth numbers simply show normal daily fluctuations.

The clinic currently has 40 patients who are more than 36 weeks pregnant. "If there was a strong correlation, you would expect half of them to go into labor," he said. That didn't happen.

But he concedes the belief is widespread. An East Coast hospital he worked for used to regularly staff up for hurricanes. "I spent many a hurricane sitting in labor and delivery wondering where all the women were," Eads said. "They sure weren't coming to my hospital."

Others are simply unwilling to say either way.

"There is some research that it sometimes happens and sometimes doesn't happen," said Gloria O'Connell, a spokeswoman for Abbott Northwestern Hospital. "This year, it looks like it might have happened."

Chen May Yee • 612-673-7434