Oct. 30, 2011 at 8:19 AM ET
Fewer women give birth on Halloween than on Valentine's Day, finds a new study. But this may not be a mere calendar coincidence. Researchers at the Yale School of Public Health suggest that pregnant women appear to be swayed by the cultural symbolism of the two holidays -- skeletons versus cherubs -- and this might influence their baby's arrival date.
They speculate that mothers-to-be may avoid delivering on the October holiday associated with death and witches. But scientists suspect that women have a more favorable view of Valentine's day, which is linked with love and romance, and may try for a Feb. 14 delivery.
Researchers raise the possibility that pregnant women may have some control over the timing of childbirth. Their findings suggest that a spontaneous birth (giving birth naturally) may be less spontaneous than doctors previously thought.
"The positive connotations of Valentine's Day may increase a pregnant woman's will to initiate birth and the negative connotations of Halloween may precipitate her will to resist giving birth," write the researchers. In other words, maybe a woman's mind is consciously or unconsciously influencing her hormonal mechanisms, and telling her body to speed up or slow down her baby's birth.
In the study, published in the journal Social Science & Medicine, researchers reviewed more than three million U.S. birth records. They looked at the number of babies born in the two-week period surrounding Halloween and Valentine's Day between 1996 and 2006, and considered the mother's delivery method.
Researchers selected cultural holidays with widespread participation, like Halloween and Valentine's Day, because unlike religious or national holidays, these would not affect hospital staffing rates. They found that births -- both scheduled and unscheduled -- increased on the holiday associated with hearts and flowers but dropped on trick-or-treat.
On Valentine's Day, they observed a 3.4 percent increase in induced births, a 3.6 percent lift in spontaneous births, and a 12.1 rise in cesarean deliveries compared to the seven days before and after the heart-themed holiday.
And there was a noticeable decline on Halloween. There was an 18.7 percent drop in induced births, a 16.9 percent dip in cesarean deliveries, and a 5.3 percent fall in spontaneous births compared to the other days in this two-week timeframe.
During this 11-year period, a woman's odds of giving birth on Valentine's Day went up by 5 percent overall, but it went down by 11.3 percent on Halloween. Although researchers admit they don't know the exact mechanisms behind this birth-timing pattern, they suspect that psychological factors and cultural beliefs can impact when women go into labor.
Of course, birth records don't reveal what may have been going on in couples' minds or lives nine months earlier.
Halloween and Valentine's babies, let's hear from you. Is it fun to share your birthday with pumpkins and costumes or hearts and romance? Others who have holiday birthdays feel free to add your comments.