Because Mom Likes Valentine's Day and Hates Halloween

A hugely pregnant woman and her OBGYN walk into a bar. The woman says, "When will this baby ever come?" And the OBGYN says, ....

It's a joke waiting for a punchline--that's been delivered (ba-da-bum) in the October 2011 issue of Social Science and Medicine. And here's the punchline: The baby's arrival may be either delayed or hurried along by Mom's emotions.

Researchers at the Yale University School of Medicine's School of Public Health analyzed birth certificate information for all births in the United States for the weeks before and after Valentine's Day and Halloween across 11 years. They determined that on Valentine's Day there was a 3.6% increase in spontaneous births and a 12.1% increase in cesarean births. On Halloween, however, there was a 5.3% decrease in spontaneous births and a 16.9% decrease in cesarean births.