Brain Rules for Baby (8 page)

 

Clearly, too much stress is not good for pregnant women or their babies. For optimal development of your baby’s brain, you will want to exist in a less-stressed environment, especially in the last few months of pregnancy. You can’t completely upend your life, of course, which could be stressful on its own. But you can reduce your stress, with your spouse’s tender loving care. We’ll say much more about that in the next chapter. You can also begin identifying the areas in your life where you feel out of control, then deliberately form strategies that will allow you to take back control. In some cases, that means exiting the situation that is causing the stress. A temporary helping of courage will translate to a lifetime of benefit for your baby’s brain.

There are plenty of ways to actively practice general stress relief, too. At
www.brainrules.net
,
we’ve listed a number of techniques known from the research literature to reduce stress. A big one is exercise, which has so many benefits that it is the subject of our fourth and final balancing act.

I am always amazed at the life cycle of wildebeests. They are best known for their spectacular annual migrations in the plains and open woodlands of Tanzania and Kenya, thousands upon thousands in hypnotic, constant motion. They move for two reasons. First and foremost, they are looking for new pastures. But they are also 600-pound steaks on legs; they have to keep moving because they are very popular with predators.

Given this urgency, the most interesting part of their life cycle is their pregnancy and birth. The gestation is nearly as long as a human’s, about 260 days, but the similarities end as soon as labor begins. The mother gives birth quickly. Unless there are complications, she also recovers quickly. So do the calves, typically rising to their feet—well, hooves—an hour after they’re born. They have to. Calves represent the herd’s future, but they are also the herd’s most vulnerable population, liable to become leopard food.

We, too, spent our evolutionary adolescence on these same savannahs, and we share many of the wildebeests same predator/prey problems. There are, you might imagine, major differences in birthing and parenting between wildebeests and humans. Women take a long time to recover from birth (it’s that big, overweight brain again, evolution’s secret weapon, forcing itself through a narrow birth canal), and their kids won’t be walking for almost a year. Nonetheless, evolutionary echoes imply that exercise was very much a part of our lives, including during pregnancy. Anthropologists think we walked as many as 12 miles per day.

 

Does that mean exercise should be a part of human pregnancies? Evidence suggests the answer is yes. The first benefit is a practical one, having to do with labor. Many women report that giving birth is both the most exhilarating experience of their lives and the most painful. But women who exercise regularly have a much easier time giving birth than obese women. For fit women, the second stage of labor—that painful phase where you have to do a lot of pushing—lasts an average of 27 minutes. Physically unfit women had to push for almost an hour, some far longer. Not surprisingly, fit women perceived this stage as being far less painful.

And, because the pushing phase was so much shorter, their babies were less likely to experience brain damage from oxygen deprivation. If you are afraid of labor, you owe it yourself to become
as fit as possible going into it. And the reasons are argued purely from the Serengeti.

 

Fit mothers also tend to give birth to smarter babies than obese mothers do. There are two reasons for this. One may have to do with direct effects of exercise—especially aerobic exercise—on a baby’s developing brain. This notion needs more research. More powerful are the data linking aerobic exercise and stress reduction.

Certain types of exercise actually buffer a pregnant woman against the negative influence of stress. Remember those toxic glucocorticoids, the ones that invade neural tissue and cause brain damage? Aerobic exercise elevates a molecule in your brain that can specifically block the toxic effects of those nasty glucocorticoids. This heroic molecule is termed brain-derived neurotrophic factor. More BDNF means less stress, which means fewer glucocorticoids in your womb, which means better baby brain development.

It may sound strange to say, but a fit mom has a much better chance of having a smart baby—or at least one best able to mobilize his or her IQ—than an unfit mom.

 

As usual, though, there’s a balance. A baby can feel and react to the mother’s motion. When her heart rate goes up, so does baby’s. When mom’s breathing rate increases, so does baby’s. But only if the exercise is moderate. During strenuous exercise, especially in the later stages of pregnancy, the baby’s heart rate begins to decline, as does his breathing. Overly strenuous exercise begins to shut off blood flow to the womb, restricting baby’s oxygen supply—not good for the brain. The womb can overheat, too. Elevations of more than 2 degrees Celsius raise the risk of miscarriage and can affect brain and eye development. Your oxygen reserve levels are pretty low by the third trimester anyway, so it’s a good time to wind down strenuous
activities in preparation for labor. Swimming is one of the best forms of exercise in later stages; the water helps dissipate excess heat away from the womb.

What is the proper balance? Four words: moderate, regular aerobic exercise. For most women, that means keeping your heart rate below 70 percent of its maximal rate (which is 220 beats per minute minus your age), then slowing things down as the due date approaches. But you should exercise. As long as you don’t have obstetric or other medical complications, the American College of Obstetricians recommends 30 minutes or more of moderate exercise
per day.

Good advice, even though we are not wildebeests.

Maybe you’re not in the habit of exercising every day. Maybe you’re feeling guilty enough already for drinking that second cup of coffee while pregnant. If so, perhaps you will appreciate some reassurance from the research world: As a species,
Homo sapiens
have been successfully making babies for 250,000 years. We did very well without all this fancy knowledge, thank you, and with such success that we conquered the world. Your best intentions—Morse code belly-tapping notwithstanding—will go a long way toward creating a great environment for your developing baby.

I remember feeling almost completely overwhelmed when we brought our firstborn son, Joshua, home from the hospital. We placed our new baby in the car seat for the first time, praying that we were buckling him in correctly. I drove home from the hospital at a snail’s pace—miraculous, for me. My wife was in the back seat, just to keep an eye on things. So far, so good.

When the little guy entered our house, his tiny face suddenly corrugated into annoyance. He started screaming. We changed his diaper. Still he screamed. My wife fed him. He took one or two gulps, then resumed screaming, tried to wiggle out of my wife’s arms, tried to get away. This didn’t happen in the hospital. Were we doing something wrong? I held him. My wife held him. Eventually, he calmed down. Then he seemed to go to sleep. We were so relieved.“We can do this”, we kept telling ourselves. It was late, and we decided to follow his lead. No sooner did our heads hit the pillow than Joshua started crying again. My wife got up, fed him, then handed Josh to me. I burped
him, changed him, laid him back down. He was calm and settled, and we went back to bed. I didn’t even get to feel the warmth of the sheet before the crying and screaming resumed. My wife was exhausted, recovering from a 21-hour labor, in no shape to help. I got up, held the baby, then set him back into his crib. He calmed down. Success! I crept back to bed. I got only as far as the pillow before the crying began again. I tucked my head under the blankets, hoping it would stop. It didn’t. What was I supposed to do?

This bewildering routine, and my reactions to them, recurred day after day. I had deep feelings for my son—always will—but I wondered at the time what ever made me decide to have a baby. I had no idea that something so wonderful was also going to be so hard. I learned a difficult but important lesson: Once a kid comes into the world, the calculus of daily living coughs up new equations. I am good at math, but I was no good at this. I had no idea how to solve these problems.

For most first-time moms and dads, the first shock is the overwhelmingly relentless nature of this new social contract. The baby
takes.
The parent
gives.
End of story. What startles many couples is the excruciating toll it can take on their quality of life—especially their marriages. The baby cries, the baby sleeps, the baby vomits, gets held, needs changing, must be fed, all before 4 a.m. Then you have to go to work. Or your spouse does. This is repeated day after day after ad nauseam day. Parents want just one square inch of silence, one small second to themselves, and they routinely get neither. You can’t even go to the bathroom when you want. You’re sleep-deprived, you’ve lost friends, your household chores just tripled, your sex life is nonexistent, and you barely have the energy to ask about each other’s day.

Is it any surprise that a couple’s relationship suffers?

It’s rarely talked about, but it’s a fact: Couples hostile interactions sharply increase in baby’s first year. Sometimes the baby brings a hormone-soaked honeymoon period. (One couple I know constantly
quoted Tagore to each other: “Every child comes with the message that God is not yet discouraged of man!”) Even then, things quickly deteriorate. The hostility can be so severe that, in some marriages, having a baby is actually a risk factor for divorce.

Why do I bring this up in a book about baby brain development? Because it’s serious for the baby’s brain. We learned in the Pregnancy chapter how exquisitely sensitive a baby in the womb is to outside stimuli. Once baby leaves his comfortable, watery incubator, his brain becomes even more vulnerable. Sustained exposure to hostility can erode a baby’s IQ and ability to handle stress, sometimes dramatically. An infant’s need for caregiver stability is so strong, he will
rewir
e his developing nervous system depending upon the turbulence he perceives. If you want your child to be equipped with the best brain possible, you need to know about this before you bring home your bundle of joy.

When I lecture on the science of young brains, the dads (it’s almost always the dads) demand to know how to get their kids into Harvard. The question invariably angers me. I bellow, “You want to get your kid into Harvard? You
really
want to know what the data say? I’ll tell you what the data say! Go home and love your wife!” This chapter is about that retort: why marital hostility happens, how it alters a baby’s developing brain, and how you can counteract the hostility and minimize its effects.