Pregnant mothers to be may have control over birth timing, as a study found mothers to be prefer Valentine’s Day over Halloween births.

Researchers from the Yale School of Public Health found expectant mothers treated a Halloween day birth, as unfavorable, seeing it as being symbolic of witches and death. They preferred Valentine's Day birth, symbolic of love and flowers.

Researchers found that on Halloween there was a 5.3 percent decreased in spontaneous births and 16.9 percent decrease in cesarean births. On Valentine's Day they found a 3.6 percent increase in spontaneous birth and 12.1 percent increase in cesarean births.

The study accumulated 11 years of birth-certificate information for all births in the United States and found decreased childbirth on Halloween and increase birth on Valentine's Day, according to a study published in the journal Social Science and Medicine.

“The study suggests that beliefs arising from our culture can have a greater impact on physical functioning than we might suspect,” says Becca Levy, lead author and associate professor of epidemiology and psychology at Yale.

The finding results show pregnant mothers to be may have some control over the timing of spontaneous births - traditionally believed to be beyond their control.