The moment you have your little one in your arms, your life changes forever. As cliché as that sounds, it’s true. And not just because there’s now a tiny human to keep alive and who's essentially your new boss, but because your brain goes through some pretty crazy changes. This rewiring can explain the love that feels like it bubbles up from nowhere (and you thought you adored your dog before…) and why anxieties and irrational fears suddenly pop up.

“We know that evolutionarily it’s so important to support our children to grow up and be productive. Because of that and the physical changes a woman goes through during pregnancy, it’s not surprising that a significant transformation in the brain happens after having kids — and that’s what we see in our research,” says Pilyoung Kim, Ph.D., associate professor in the department of psychology at the University of Denver.

She’s talking about a core neurocircuitry in the brain that is designed to support parenting and caregiving of your offspring. “These brain changes start in pregnancy and continue into the post-partum period,” says Kim.

First, you have the reward circuits in your brain. As Kim explains, there are a number of regions in your noggin that are connected to each other and communicate through levels of the feel-good neurotransmitter dopamine. Those same areas illuminate when you bite into a big juicy burger or have sex with your partner. “For parents, these circuits are particularly sensitive to their baby,” she explains.

Brain changes start in pregnancy and continue into the post-partum period.

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And your baby can do anything — positive or negative — and these rewarding regions light up. She could squeal and coo and look adorable in her headband. She could cry and fuss and scream, and you’ll reach out to her without thinking twice. In either scenario, you experience an intense emotional response. “That’s why you will do anything for your baby,” says Kim. “All of these moments are highly rewarding and serve to strengthen your emotional bond,” she continues.

That’s not to say that hearing your baby cry is fun. For anyone who’s had a newborn who prefers screaming in your arms to chilling in a swing knows that their wails are particularly distressing. And if you don’t have children but have been to a friend’s house who just had a baby and thought “yikes, this crying would drive me up a wall,” know that your brain would change to help you out there, too. A bawling babe activates those reward circuits as well as other regions that help support emotional control, empathy and decision making. Meaning, “it helps moms regulate their own distress,” explains Kim, even when a mom is struggling with a lack of sleep. “We seem to manage when our baby needs us,” she says.

A bawling babe activates those reward circuits as well as other regions that help support emotional control, empathy and decision making.

Finally, there’s the fact that every new cough or “could that be a rash?” red mark might send you straight to the ER. Kim notes that in their research when they’ve surveyed parents, new moms and dads report higher levels of concern and worry about their baby’s health and their ability as a parent. Happily, these alarm bells gradually decline, especially with the second or third child.

These brain changes last far beyond the baby stage

Another cliché: after you become a parent, you’re changed forever. And in many ways, that’s totally true. “The high intensity of this emotion during the post-partum period in parents is crucial for building a long-term emotional bond,” says Kim. Hence why when they go off to kindergarten or pack up for college and you ball your eyes out, but really, could they just live with you forever?

Recently, Kim has put her focus on examining moms that are exposed to high levels of stress in the post-partum period. She points out that stress levels may be associated with a parent’s ability to respond to her baby’s cues. The takeaway: “We need to be more supportive to pregnant women and new mothers so that they don’t experience as high levels of stress,” she says.

And that may be one reason why levels of happiness tend to plummet in US parents, per research. The study looked at 22 countries and found that US has the largest happiness gap between parents and nonparents. That probably makes sense to parents who love their kids and don’t regret their decision to have them, but find themselves envying a child-free life.

“Parents are both squeezed for time and money. What could be a joyful and messy experience that will always have its challenges turns into something that feels insurmountable,” says the co-author of that paper, Jennifer Glass, Ph.D, the executive director of the non-profit organization the Council on Contemporary Families at the University of Texas at Austin. Missing in the equation that’s present in other, happier countries is the support of parents through programs like subsidized high-quality early childhood education and parental leave policies, including sick and vacation time. “We are the only industrialized country in the world that expects parents to shoulder this all. It raises the cost and lowers the benefit of parenthood,” she continues.

If you want to boost your happiness quota at a parent, there are a few solutions that don’t have to do with re-wiring your brain to find more joy in small moments or soak up the time you have with your kids. They’re entirely practical. If you have babies on the brain or on the way, maximize all the good will you can at work, says Glass. Get great performance evaluations over the years and then call in those chips when the time comes — and you need paid time off to spend building all those important neural connections that bond you with your child for life.

“It’s always scary to raise your voice, but this is the most important time. The wellbeing of your family is an important risk worth taking,” adds Glass.Want more tips like these? NBC News BETTER is obsessed with finding easier, healthier and smarter ways to live.

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