What's almost as unpopular as a Leap Day birthday?

Turns out, major holidays.

Alison Church/Special (ENLARGE)

Aimee Christian stands in the nursery of her unborn son Andrew Joseph Christian's room in her Marietta home. Christian will deliver by C-section on February 29th, making her child a rare Leap Day baby.

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While Feb. 29 is a rare birthday, expectant mothers avoid the delivery room in great numbers on Christmas, New Year's, Fourth of July, Thanksgiving and Memorial Day.

Birth is a natural process, but not fully random. Nature gets a nudge from doctor's schedules and expectant parents' preferences. It's enough to create visible dips in birth data near certain days.

"Not many people want their C-section Christmas Eve," said Dr. Stuart Pancer, an OB/GYN at DeKalb Medical Center.

While every day produces a good number of babies in Georgia – roughly 200 to 500 – birth days follow some patterns, including significant drops on holidays and weekends. There's no noticeable uptick in births on days with a full moon, contrary to popular opinion.

Leap Day, however, is not a day that mothers — or the health care system — take great pains to avoid.

That's according to 16 years of data on Georgia births analyzed by the Atlanta Journal-Constitution. Every four years during this period, the number of Leap Day births has been consistent with other February days.

Medical technology is one of the primary factors determining birth patterns.

Cesarean sections make up about 30 percent of births, so more mothers schedule births compared to past decades. Doctors also induce births when medical conditions require it, or if there's a compelling reason to spur a birth along.

That was the case earlier this year when a soldier needed to report to duty in Iraq but hoped to see his baby born. Pancer induced the mother and the soldier was able to hold his baby.

"A day or two later, the poor guy's off to Iraq," Pancer said.

On weekends, the number of births in Georgia drops. There's fewer hospital staff working and doctors don't schedule C-sections or inducements.

Tuesdays are the busiest birthing days in Georgia, likely because many floating holidays fall on Mondays. Also, after a weekend, it can take a day to get an expectant mother into the doctor's office and get the ball rolling, doctors say.

Aimee Christian, 37, of East Cobb, scheduled her C-section today, which is close to her due-date.

"It'll make him special and unique," Christian said of her expected son's Leap Day birthday.

She chose Friday because her father will be taking care of her two children. She did not want her dad to have to take three days off from work next week.

"My whole family thinks I'm crazy," Christian said.

Another day parents don't appear to avoid is the anniversary of the terrorist attacks on New York and Washington. The number of births on Sept. 11 have been in the 400-plus range since 2001, dipping only when Sept. 11 fell on a Saturday or a Sunday. Dr. Genevieve Fairbrother, head of OB/GYN at Northside Hospital, has been on call several times on Sept. 11.

"No one said anything," Fairbrother said. "I didn't have anybody make a comment."

A big push happens Dec. 29 and Dec. 30, as well as Sept. 9, which is close to, um, Labor Day.

The year-end rush could be because mothers want to schedule births between Christmas and New Year's to avoid those holidays.

"Everybody wants their child to have a special day," Fairbrother, said. It's hard to compete with Christmas.

There can also be a tax advantage to giving birth before the end of the year. The Child Tax Credit can put as much as $1,000 in a parent's pocket, even if they had the child only one day that year. "Meanwhile, you have not had the expense of raising the child," said Don Whalen, of Versailles Financial planning.

The busiest birth months are routinely July, August and September, doctors say.

"When you're cold in the winter, you like to snuggle," Pancer said. "If you calculate nine months from Christmas-time, guess where you are?"