For me, giving birth to each of my three children has been a jarring and disruptive experience. I carried them around inside of my body for more than nine months and then suddenly, over the course of 10 hours or so of labor, we became two separate people.
At least that’s how it felt—that when I celebrated the birth of my children, I also let go of another season of our life together, our amazing interdependence. Even so, I have always felt that my babies are still a part of me.
Whenever I pull my infant in close to my chest to nurse, I chase down my toddler to smother her in kisses, or I snuggle my preschooler in close to read books before bed, I know we are still connected to one another.
I have always assumed the mother–child bond I was experiencing was just an emotional connection. But recent research has provided an explanation for a deeper connection between mother and child. During pregnancy the growing fetus has a lasting impact on the mother’s body.
The placenta, which has long been known to provide essentials to the growing baby, also serves as an avenue for transfer of fetal cells into the mother’s body, according to Smithsonian magazine.
Over time, the mother’s immune system gets rid of many of those cells, but some adapt to the mother’s body in a way that allows them to fly under the radar and remain inside of her for years to come.
Amazing, isn’t it? The grade-schooler who sits across from you at the table or the baby you said a difficult goodbye to early in your pregnancy could still be influencing your cellular makeup today.
Of course, research has a ways to go before we can figure out the exact implications of how fetal cells manipulate their mother’s body. We certainly have made a lot of progress in recent years in our quest to explain why humans do the things we do.
More than ever, we can observe specific parenting behaviors and point to an explanation for these habits. In short, science can explain why you parent the way you do.
Here’s why so many moms hold their baby the same way.
Have you ever noticed that most moms hoist their baby onto their left hip and hold them there, instead of switching from side to side?
This isn’t merely a coincidence. This habit of holding a baby on your left side is observed in a large percentage of human mothers and even in other mammals, according to the journal Developmental Science.
Left-cradling bias, as this behavior is called, is believed to be explained by the way humans process social and emotional interactions, according to the journal Nature Ecology & Evolution. Some of the functions performed by the brain are worked out in one hemisphere or the other; this is called lateralization.
Specifically relevant to left-cradling bias is that fact that the right hemisphere of the brain, which receives information from the left side of the body, is the dominant location for processing emotional and social experiences.
To put it simply—when Mom holds Baby on her left side, she is more adept at interpreting their emotional cues. Scientists don’t believe this is coincidence. Instead they are confident this is an evolutionary behavior adopted by mothers whose main priority early on is meeting their child’s emotional and physical needs.
Here’s why you scrubbed your kitchen floor when you were nine months pregnant.
At the end of each of my pregnancies, I found myself obsessing over the most seemingly insignificant things. With my second baby, for instance, I spent two weeks searching our home from top to bottom, intent on finding handful of missing pieces from my toddler’s puzzle collection.
When I neared the end of my third pregnancy, I grew fixated on keeping laundry going non-stop because I was determined I wouldn’t have dirty laundry in the house when the baby was born.
These kinds of behaviors are so common among expectant mothers, we joke about with our pregnant friends. We typically assume a mother who is cleaning, organizing, or cooking is getting ready to give birth.
This phenomenon, called nesting, isn’t simply a social norm or an old wives’ tale. There is actually a scientific explanation for why women adopt nesting behaviors near the end of their pregnancies, according to the journal Evolution & Human Behavior. It’s all about controlling the environment the baby will be born into.
Anthropologists report that this behavior was observed in our ancestors and is now repeated by modern mothers. Nesting tends to peak during the third trimester, when expectant mothers focus their energy on creating a safe environment for their new child.
Women don’t just reorganize their belongings; they tend to focus some of their energy on their relationships too. According to this study, expectant mothers are driven to consider whom they want near their child after birth, too.
A natural desire to protect their baby from unknown dangers or foreign pathogens compels an unconscious drive to steer clear of strangers during late pregnancy.
Here’s why you turn into a hermit right before birth.
At the end of a pregnancy, it is fairly typical for expectant moms to feel compelled to hunker down and stay home until the arrival of their new baby.
Turning into a hermit during the third trimester isn’t just because it is too much work to get your aching and swollen body off the couch. There is an evolutionary explanation for why women turn into homebodies late in their pregnancies.
It seems that in pregnant women there is an innate knowledge that home is the safest place to be. Research suggests that pregnant women prefer to stay home because they know it is the most comfortable place to give birth and likely to be the most danger free place for a vulnerable newborn.
This is an evolutionary behavior and is believed to have been passed down from ancestors who had more immediate dangers in the environment surrounding their homes, according to Evolution & Human Behavior.
Here’s why you like cute babies so much.
There’s no denying it: Human beings have a strong preference for really cute babies. When it comes to what is and isn’t considered cute, there are some objective principles that influence this preference.
Babies with large eyes, small mouths and noses, and a symmetrical face tend to be seen as more attractive, according to Dr. Jeffrey Kurland, professor of anthropology and development at Penn State.
There are perks to being cute, too. As embarrassing as it may be to acknowledge, both men and women tend to show preferential treatment to cute kids. Don’t beat yourself up too much; there is an evolutionary explanation for such favoritism.
The same characteristics that are commonly associated with cuteness in babies have also been associated with a perception of overall well-being. So the belief is that the preference for cute babies is really just a byproduct of preferring and promoting the growth of babies who appear to have a survival advantage over less-cute babies.
We might not realize it at the time, but it seems that a lot of the automatic behaviors we engage in as mothers are all about survival of our children and our family line.
From the way we hold our babies to that irresistible urge to straighten the linen closet for the tenth time in a week, we’re just following an unconscious drive set in motion long before our own mothers were expecting our arrival.