Living With Your Mother-In-Law May Affect How Many Kids You Have, New Study Says

It might seem like a plot from a TV show, but according to new research out of the University of Vienna in Austria, living with your mother-in-law may affect the number of kids you have. This might not come as a total surprise to anyone with close, extended family living nearby. Although one might assume that living with a mother-in-law means having grandma on-call all day, every day to help out might ease some parental stress. But according to this new research, people who live with their in-laws tend to have less children.

A woman's fertility can be also be affected by her own mother's presence, according to Medical News Today. This is different from what was previously believed, as prior research had suggested that living with a mother-in-law or one's own mother can increase a woman's fertility, prompting this new research.

To get to the bottom of what happens when a woman lives with her mom or mother-in-law, the researchers examined over 2.5 million medical records of women who were of reproductive age, between the ages of 15 and 34 years old, in 14 countries, according to the study. They considered a few things, such as the number of children women already had, a woman's age, and how much longer she would be fertile, and whether or not the mother or mother-in-law was living in the household during the reproductive period.

The researchers found that across the board, according to the Royal Society Open Science journal, the "absence of a mother" in the household means more children for a family — in all cases, a spouse was also present in the home. And it doesn't really matter whether it's a woman's mom or her mother-in-law. Having any grandmother figure around is bad news if you want more kids.

This disputes existing theories that living with extended family would encourage women to have more kids, according to the study published in Royal Society Open Science.

The researchers noted that the grandmothers living with their adult children tend to be younger, which also defies some logic. This means that the grandmother might also have more children of her own to handle or even a job in some cases, so they're not there to strictly help out with child care.

The researchers suggested that perhaps the women felt like they wouldn't have enough support for more children if the grandmothers were otherwise disposed. Or maybe it's just the mayhem that comes with living close to a maternal figure or that the grandmother makes the home feel more "full," negating a longing for more children. It could be any number of things, according to what the researchers told the Daily Mail.

As you can imagine, letting your mother or mother-in-law into the home varies from region to region. For example, in the United States, only 1.74 percent of women lived with their moms or mother-in-law, but in Iraq that jumps up to 53 percent of women who live with their extended families, according to the University of Vienna's data.

Living with in-laws can affect women in other ways, too. A 2008 study out of Osaka University in Japan found that women who live with their mother-in-law have higher rates of different kinds of heart diseases. The study examined the living arrangements and health of 91,000 healthy middle-aged women and men over 14 years and found that women were three times as likely to die of heart disease if they lived with in-laws, according to the Daily Mail.

It all comes down to stress. Being a mom, a partner, and a daughter-in-law is not easy work, the researchers from the 2008 study concluded. Likewise, a 2012 study from the University of Michigan's Institute for Social Research found that living with in-laws can also affect your marriage.

Terri Orbuch, who led that study, told CNN at the time that, "If women are close to their in-laws, especially early in marriage, this interferes with or prevents them from forming a unified and strong bond with their husband."

She added, "Also, since women are constantly analyzing and trying to improve their relationships, they often take what their in-laws say as personal and can't set the clear boundaries." Yikes, right?

So if you're considering moving in with family, or letting them come live with you, make sure you're practicing some self-care. And maybe think about having as many babies as you want beforehand.

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