Can a full moon bring on labor?

It’s official! The Royal baby is here and both mom and baby are doing quite well according to palace officials. The Duchess of Cambridge ended the long anticipated wait and media frenzy over her bump after delivering a healthy baby boy at St Mary’s Hospital in West London on Monday.

Kate Middleton and her baby bump in April.

Earlier reports said Prince William’s wife was actually due to give birth last weekend, but the little heir-to-the-throne didn’t budge right away— leaving some to speculate whether a full moon on Sunday played a part in the delivery date.

For years, many have heard the old Wives’ Tale that, “if you’re a nurse on call and it’s a full moon, there will likely be a surge in births.” The reason behind the cliché is the thought that the moon’s gravitation affects amniotic fluid in the same way it affects water. The idea is that because babies are surrounded by water, the timing of a full moon and the high tide can cause mommies’ waters to break.

But it turns out there is not much science to back up this theory. Many studies dating back to the 1950s have dis-proven this myth time and time again.

Earlier research actually showed only a 1 percent increase in births during the two weeks following a full moon. There’s also research that shows only a 1 percent increase in births in the weeks leading up to a full moon.

In fact, in the largest study published in 2001, by astronomer and physicist, Daniel Caton, he found no correlation between the full moon and deliveries after pouring over 20 years of data from the National Center for Health Statistics—approximately 70 million U.S. births.

And if you’re thinking French births may be different. Well, researchers there also looked at about 14.5 million births and found no link between births and a full moon either.

As with tradition, nothing is likely to change the mind of conspiracy theorists and those who are full believers in Old Wives’ Tales. But according to science, if you are playing the odds, don’t bet on giving birth when it’s a full moon, unless of course that’s already your due date.

And even then your odds may be slim. According to the Centers for Disease Control and Prevention, there are nearly 4 million births annually in the U.S. and of those only about 5 percent are actually born on their due date. Experts say that’s because predicting due dates is not always an exact science.

“The traditional way of calculating the due date by LMP (or last menstrual period) is not very accurate because some women do not have a regular 28-day period cycle,” said Dr. Vibha Thaker, neonatologist at Advocate Good Samaritan Hospital in Downers Grove, Ill.

But Dr. Thaker says there are ways to predict an accurate due date. “We can get an early HCG (Human Chorionic Gonadotropins-a pregnancy hormone ) measurement or another way is by knowing the actual date of conception, such as when Invitro fertilization is performed.”

The good news Dr. Thaker added is that typically 80 percent of women deliver somewhere within a two week window of their due dates.