(CBS Atlanta) – Laughing is contagious, and so is yawning, but it looks like pregnancy could be added to that list too.
In a new study, researchers have found that women are twice as likely to have a child two years after their high school friends have their first child.
More specifically, the study reports that after a high school friend has her first baby, the probability of her friends having one gradually increases before peaking two years after the birth and then recedes in the years after.
“Friendships that were formed a long time ago have a big influence on the decision to have a child,” study co-author Nicoletta Balbo, a sociologist at Bocconi University in Italy told Live Science.
The longitudinal study examined 1,726 American women who participated in a 1996 survey called the National Longitudinal Study of Adolescent Health (Add Health) at the age of 15. During that survey, the teens answered numerous questions regarding their closest friendships, health, family, and life courses.
Those same teens were surveyed again from 2008-2009 at the age of 30, and the study found that half of the women who had children had given birth by age 27.
While no concrete explanation has been given, researchers believe that the timing of having a child seems to be closely influenced by friends.
“You see your best friend having a child. You start meeting her with the baby, and you see what being a parent looks like,” Balbo suggests. In turn, this may make women more comfortable with the idea of having their own child.
The theory of pregnancy being contagious could also add to recent claims that the “baby recession” is over in the U.S. with pregnancy rates at their highest in the last five years.
The Centers for Disease Control and Prevention, based in Atlanta, reported that the number of babies born in 2013 rose by about 4,700, the first annual increase since 2007.
One other connecting factor in contagious pregnancy and the increase in U.S. birth rate could be the economy. Researchers in Balbo’s study stated that having a baby around the same time as friends was also cost-effective, prompting many women to have a baby shortly after a best friend’s pregnancy.
Additionally, the CDC cited an improved economy as a possible factor in the increased birth rate.
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