The Female Brain (17 page)

The maternal brain circuits change in other ways, too. Mothers may have better spatial memory than females who haven’t given birth, and they may be more flexible, adaptive, and courageous. These are all skills and talents they will need to keep track of and protect their babies. Female rats, for example, that have had at least one litter are bolder, have less activity in the fear centers of their brains, do better on maze tests because they are better at remembering, and are up to five times more efficient in catching prey. These changes last a lifetime, researchers have found, and human mothers may share them. This transformation holds true even for adoptive mothers. As long as you’re in continuous physical contact with the child, your brain will release oxytocin and form the circuits needed to make and maintain the mommy brain.

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Expectant dads go through hormonal and brain changes that roughly parallel those of their pregnant mates. This may explain the strange experience of my patient Joan. She and her husband, Jason, were ecstatic when their pregnancy test came back positive. Three weeks into the pregnancy, however, Joan began to have violent morning sickness. By her third month, she’d gradually improved—but then, to his surprise, Jason started feeling so nauseated in the morning that he couldn’t eat breakfast and could barely drag himself out of bed. He lost five pounds in three weeks and was worried that he had a parasite. But what Jason actually had was Couvade Syndrome, a common complaint of expectant dads (up to 65 percent worldwide) who share some of the symptoms of pregnancy with their partners.

In the weeks before birth, researchers have found, fathers have a 20 percent rise in their level of prolactin, the nurturing and lactation hormone. At the same time, their level of the stress hormone cortisol doubles, increasing sensitivity and alertness. Then, in the first weeks after birth, men’s testosterone plummets by a third, while their estrogen level climbs higher than usual. These hormone changes prime their brains for emotionally bonding with their helpless little offspring. Men with lower testosterone levels actually hear the cries of babies better. They don’t hear quite as well as moms, however, when babies whimper, for example, fathers are slower than mothers to respond, although they tend to react just as quickly when a baby screams. Men’s lower testosterone levels also decrease their sex drive during this time.

Testosterone suppresses maternal behavior, in females as well as males. Fathers who have Couvade Syndrome have higher levels of prolactin than other fathers do and steeper drops in testosterone when they interact with their babies. It may be, scientists think, that pheromones produced by a pregnant woman can cause these neurochemical changes in her mate, preparing him to be a doting father and equipping him—secretly, through smell—with some of the special nurturing mechanisms of the mommy brain.

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Unlike sheep, most human females take longer than five minutes to bond with their newborns, but the window doesn’t close that fast for humans. This is good news for women like me, who had less than ideal birth experiences, involving anesthesia, C-sections, or premature labor and delivery. By the time my son was born—after thirty-six hours of contractions, epidural anesthesia, and morphine—I was feeling a little dazed and only mildly curious to see the little guy. It wasn’t the warm wave of gooey maternal love I had expected to feel immediately for my baby, partly because anesthesia and morphine mute the effects of oxytocin. Only after I emerged from my drugged state did I feel alert and protective. And I soon fell addictively, hopelessly in love with my new son, with all my maternal wiring and sensitivities fully firing.

“In love” is a phrase, in fact, that many mothers use to describe their feeling for their babies. And, not surprisingly, mother love looks a lot like romantic love on a brain scan. Researchers hooked new mothers up to brain-monitoring equipment and showed them photographs of their own children, then pictures of their romantic partners. The scans revealed that the same oxytocin-activated regions of the brain lit up in response to both photos. Now I know why I felt so passionately about my child, and why my husband was sometimes jealous. In both types of love, surges of dopamine and oxytocin in the brain create the bond, switching off judgmental thinking and negative emotions and switching on pleasure circuits that produce feelings of exhilaration and attachment. Scientists at University College in London found that the parts of the brain usually available for making negative, critical judgments of others—for example, the anterior cingulate cortex—are turned off when one is looking at a loved one. The tender nurturing response of the oxytocin circuits is reinforced by the feeling of pleasure created by bursts of dopamine, the pleasure and reward chemical. Dopamine is jacked up in the mommy brain by estrogen and oxytocin. This is the same reward circuit set off in a woman’s brain by intimate communication and orgasm.

Being hopelessly in love with my baby soon became for me a permanent state of mind, reinforced daily. This is not to say the trials and tribulations of taking care of a new baby—such as having a whole day go by without having time for a shower and having gotten no sleep the night before—didn’t get to me, too. (New mothers lose an average of seven hundred hours of sleep in the first year postpartum.) As Janet, one of my best girlfriends, who had just had a baby, too, commented, “Now you know why they say one kid and your life changes, two kids and your life is over.” It’s a good thing that in most cases the maternal pleasure button gets pushed over and over again, and the bonds grow tighter the longer the baby is close physically.

This increased bonding includes the effects of breast feeding. Most women who nurse their babies have an extra benefit: regular stimulation of some of the most pleasurable aspects of the mommy brain. In one study, mother rats were given the opportunity to press a bar and get a squirt of cocaine or press a bar and get a rat pup to suck their nipples. Which do you think they preferred? Those oxytocin squirts in the brain outscored a snort of cocaine every time. So you can imagine what a reinforced behavior breast feeding is. It had to be good to guarantee the survival of our species. When a baby grasps its mother’s breast with tiny hands and suckles on her nipple, it triggers explosive bursts of oxytocin, dopamine, and prolactin in the mother’s brain. Breast milk then begins to flow. At first, all that tugging at your sore, bleeding nipples can make you think it will be impossible to get through another day of breast-feeding torture. But after a few weeks—if you haven’t been driven to hara-kiri—you’ll be able to quiet your screaming infant and calm yourself down by breast feeding. Within three or four weeks, the experience begins to become downright pleasurable. And not just because the pain has stopped. You start to look forward to breast feeding—unless you are so sleep-deprived that you can only go through your day in a dreamlike state. But at some point in the first few months, you may realize that breast feeding has become easy and you really, really enjoy it. Your blood pressure drops, you feel peaceful and relaxed, and you’re basking in waves of oxytocin-inspired loving feelings for your baby.

Often mother love and breast feeding replace or interfere with a new mother’s desire for her partner. Lisa came to see me a year after the birth of her second child. “Having sex,” she told me matter-of-factly, “is no longer on my list of top ten things to do. I’d much rather catch up on sleep or the million different chores I can never finish. But my husband is getting very irritable, even angry, that sex isn’t a priority for me.” When I asked Lisa how other things in her life were going, she described the wonderful feeling she got being physically close and skin to skin with her young children. Tears, in fact, welled up in her eyes when she told me how much she loves and feels “in love with” her youngsters. Her one-year-old was still breast feeding two or three times a day, and she said she could never have imagined such a complete, selfless sense of connection with another. “I love my husband,” Lisa assured me, “but a lot of things are more important right now than taking care of his sexual needs. Sometimes I wish he’d just leave me alone.”

Lisa’s experience isn’t unusual, and it’s based on hardwired responses in her maternal brain. Lisa—like all women who are in skin-to-skin contact with babies and breast feeding—has a brain that’s marinating in oxytocin and dopamine making her feel loved, deeply bonded, and physically and emotionally satisfied. It’s no wonder that she has no need for sexual contact. Many of the positive feelings she usually gets from sexual intercourse are evoked, several times daily, by meeting the basic physical needs of her young children.

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Every benefit has a cost, however, and one downside of breast feeding can be a lack of mental focus. Although a fuzzy-brained state is pretty common after giving birth, breast feeding can heighten and prolong this mellow, mildly unfocused state. Kathy, age thirty-two, came to see me frightened about the state of her memory. She was becoming increasingly absentminded and had even “forgotten” to pick up her seven-year-old son from school. She was still breast feeding her eight-month-old daughter and had noticed that she was getting more “ditsy” by the day. She told me, “What really worries me is that I’ll go into a room to get something and forget what I was looking for—not once but up to twenty times a day.” Kathy was particularly alarmed since her mother had Alzheimer’s and she thought that these could be early symptoms of the illness. As we talked, Kathy remembered that she’d also been forgetful after the birth of her first child, and that the confusing state had passed soon after she she’d weaned her son.

The parts of the brain responsible for focus and concentration are preoccupied with protecting and tracking the newborn for these first six months. Remember, too, that besides lack of sleep, a woman’s brain size returns to normal only at six months postpartum. Until then, as Kathy discovered, the level of mental fog can be alarming. A distinguished scientist I know was stunned, ten days after giving birth, to find that she couldn’t even summon the basic words and phrases to hold an intelligent conversation. Several months later, however, once she had stopped breast feeding, she was as sharp as ever.

For most women, a little ditsiness may be a small price to pay for the benefits of nursing. And babies share the rewards. In fact, they’re crucial partners in the neurological act of breast feeding. The hormones released by breast feeding and skin-to-skin contact spur the maternal brain wiring to forge new connections. The longer and more often a baby suckles, the more it triggers the prolactin-oxytocin response in the mommy brain. Pretty soon, a mother may feel her breasts tingling and leaking at the sight, sound, touch, or merely passing thought of nursing her baby. The immediate payoff for the infant is food and comfort. Oxytocin dilates blood vessels in the mother’s chest, warming her nursing child, who also gets doses of feel-good compounds in the breast milk. The milk stretches the baby’s stomach as it is fed releasing oxytocin in the baby’s brain, too. This quiets and calms the baby—not just from the meal but from those relaxing waves of hormone.

Many mothers suffer “withdrawal” symptoms when they’re physically separated from their babies, feeling fear, anxiety, and even waves of panic. It is now recognized that this is more than a psychological state but is a neurochemical state. I can remember returning to work when my son was five months old and packing my breast pump with me. The mommy brain, it turns out, is a finely tuned instrument, and separation, especially from a nursing baby, can upset a mother’s mood, perhaps through a decline in the stress-regulating brain levels of oxytocin. I was a wreck on most days, but I thought it was just the stress of working at a full-time job at the hospital and trying to run a household, too.

Nursing mothers also go through withdrawal symptoms when they wean their babies. Since weaning often occurs in conjunction with returning to a stressful workplace, mothers may be flipped into an agitated, anxious state. Can you imagine how most breast-feeding mothers must feel at the end of eight hours or more at work? At home, they had oxytocin rushes flooding their brains every few hours from nursing their babies. At work, their usual supply is cut off, since oxytocin lasts only one to three hours in the bloodstream and brain. I can remember the intense desire I had by three o’clock most days to go home to my baby. Many mothers find they can ease these symptoms by pumping their breast milk at work for as long as possible. Then they can slowly taper off breast feeding and continue to nurse on evenings and weekends to maintain their breast milk supply. This allows them to still get the pleasurable oxytocin and dopamine boosts and to stay connected with their babies.

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The flip side of the warm, nurturing mommy experience is also common. In my practice it is not unusual to hear complaints about mothers. My thirty-two-year-old, newly pregnant patient Veronica immediately comes to mind. As she talked, it became apparent to me that her blistering anger toward her mother was directly linked to her busy mother’s inattentive nurturing when Veronica was a child. Her mother would take off on business trips, leaving Veronica with a nanny for a week at a time, and whenever Veronica was upset, her mother seemed to shut down emotionally instead of offering warm support. She would say that she was too busy with work and tell Veronica to go play in the other room. Now that Veronica was pregnant with her first child, she was expressing fear that she might be the same kind of mother, given her busy, high-pressure job as an art director at a magazine. Two generations of working mothers unable to spend time with their children. Should she worry? Maybe.