The Female Brain (24 page)

Weeks later, after Edith and her husband had been on a month’s vacation, she returned to see me. A pleased grin on her face, she said, “Mission accomplished! He has agreed to keep out of my hair.” They had renegotiated the rules for the next phase of their life.

H
ORMONES IN THE
F
EMALE
B
RAIN
A
FTER
M
ENOPAUSE

Hormones in the brain are part of what makes us women. They are the fuels that activate our sex-specific brain circuits, resulting in female-typical behavior and skills. What happens to our female brains at menopause, when we lose this hormonal fuel? The brain cells, circuits, and neurochemicals that have relied on estrogen soon shrivel. In Canada the researcher Barbara Sherwin found that women who had estrogen replacement therapy right after the removal of their ovaries retained the memory function they’d had before, but women who had no estrogen replacement right after their ovaries were removed had declining verbal memory unless they were soon given estrogen. The therapy restored their memory to nearly premenopausal levels—but only if they began it immediately or soon after the operation. There’s a brief window, it seems, when estrogen provides maximum protective benefits for the brain.

Estrogen may have a protective effect on many aspects of brain functioning, even on the mitochondria—energy centers of cells—especially those in blood vessels in the brain. Researchers at the University of California, Irvine, found that estrogen treatment increased the efficiency of these mitochondria, perhaps explaining why premenopausal women have lower rates of stroke than men their age. Estrogen can help the brain’s blood flow stay strong for years into older age. At Yale University, for instance, researchers treated postmenopausal women with estrogen or a placebo for twenty-one days, then scanned their brains while they performed memory tasks. The women on estrogen had brain patterns characteristic of younger subjects, while those without estrogen had brain patterns typical of much older women. And yet another study, of brain volume in postmenopausal women, suggested that estrogen protects specific parts of the brain. In women who took estrogen, there was less shrinkage in the brain areas for decision making, judgment, concentration, verbal processing, listening skills, and emotional processing.

The protective effect estrogen appears to have on female brain function is one reason scientists are carefully reconsidering the results of the Women’s Health Initiative in 2002, a study that found that women who started taking estrogen after a thirteen-year gap post-menopause didn’t get its protective effects on the brain. Scientists have now shown that a gap of more than five or six years after menopause without estrogen means that the opportunity to reap estrogen’s preventative effects on the heart, brain, and blood vessels is likely gone. Early treatment with estrogen may be especially important to protect brain function as well.

Many women have felt confused and betrayed by the fact that they were told one thing a few years ago by their doctors about hormone replacement therapy (HRT), now called HT, but now hear the opposite based on the results of the WHI study. I myself—as both a doctor and a postmenopausal woman—have been caught in that bind. How and when to start HT and when and if to stop remain burning questions for patients and doctors alike. Until new studies clarify this issue, however, each patient must find her own way—using diet, hormones, activities, exercise, appropriate treatment, and regular input from informed doctors who are specialists in hormone therapy. I now have a complete discussion with each of my menopausal patients about her family genetics, lifestyle, symptoms, health issues, and the risks and benefits of HT for her.

Despite the storms and hormonal adjustments of menopause, most women stay remarkably vigorous, smart, and capable as they age, even without the assistance of estrogen. Not all women need or want hormone therapy. It’s usually not until decades after menopause that the natural process of aging starts affecting the functioning of the female brain. Men’s and women’s brains age differently, with men losing more of the cortex sooner than women.

While every woman’s body and brain react differently in the years after menopause, for many this is a time of increasing freedom and control over our lives. Impulses are less likely to confuse or agitate us. Our survival may no longer depend on a steady paycheck, and there’s less value in pretending about how we feel and more in presenting and living our passionate, real selves. Helping others and being engaged in solving serious problems in the world can energize us. This is also a time when grandmothering can bring new, often uncomplicated joy. Maybe life does save some of the best for last. My sixty-year-old patient Denise, for example, had always been an independent woman focused on her marketing career, even while she was raising her two children. When her daughter gave birth for the first time, Denise was unprepared, she told me, for the waves of love she felt for her grandchild. “I was completely swept off my feet,” she said, “which I never, ever expected. I’ve got a million things going on in my life, but for some reason I can’t get enough of this baby. And my daughter’s letting me into her life in a way that she never has before. She needs me now, and I want to be there for her.”

The special, supportive role that grandmothers play may be one of the reasons that evolution engineered women to live for decades after they can no longer bear children. Grandmothers, according to the University of Utah anthropologist Kristen Hawkes, may actually be one of the keys to growth and survival in ancient human populations. Hawkes argues that in the Stone Age, the extra food-gathering efforts of able-bodied postmenopausal women increased the survival rate of young grandchildren. Grandmothers’ provisioning and help also enabled younger women to produce more children at shorter intervals, increasing the population’s fertility and reproductive success. Even though the life span in hunter-gathering societies is typically less than forty, about a third of all adult women survive past that age, and many go on to live productively into their sixties and seventies. Among the Hadza hunter-gatherer population in Tanzania, Hawkes found, for example, that hardworking grandmothers in their sixties spent more time foraging than did younger mothers, providing food for their grandchildren and increasing their chances of survival. Researchers have found similar positive effects of grandmothers among Hungarian gypsies and populations in India and Africa. In rural Gambia, in fact, anthropologists found that the presence of a grandmother improves a child’s prospects for survival much more than the presence of a father. In other words, women at menopause, the world over, have the option to embrace the life-sustaining role of grandmother, too.

N
OW
W
HAT
D
O
I D
O?

A century ago, menopause was relatively rare. Even in the late nineteenth and early twentieth centuries, the average age of death for women in the United States was forty-nine—two years before the typical woman ends her menstrual cycle. Women in the United States can now expect to live many decades after their periods stop. Science, however, hasn’t fully caught up with this change in demographics. Our knowledge about menopause is relatively new and incomplete, though it’s advancing rapidly as large populations of women are moving through this once rare transition. Forty-five million American women are now between ages forty and sixty.

Planning for the many years after menopause is historically a new option for women. Being able to visualize exciting projects of their own choosing can be one of the most delightful parts of women’s lives in the new century. They may have attained personal and economic power by this time. They may have a broad knowledge base, and for the first time in their lives they may have more exciting options than they ever imagined possible. One scientist friend of mine, Cynthia Kenyon, an expert in aging, believes that in the future women will likely live to be more than 120, a lot of years to imagine.

For Sylvia, imagining her postmenopausal years meant rediscovering Robert. When she came to see me again two years after she and Robert broke up, she told me that after she got back to the girl she once was, felt the joy of rediscovering who she really was, and had dated enough disillusioning older men, she realized she missed Robert. He was the only one she could talk to about certain things—including their wonderful children. One day he invited her to dinner and she decided to accept. They met at a romantic restaurant, talked calmly about what had gone wrong, and ended up apologizing for the unhappiness they had caused each other. They also had new experiences to share—her job, her painting, his new interest in antiques, and even their funny adventures in dating. Over time they rediscovered their friendship and respect for each other and realized that they had already found their soul mates. They just needed to rewrite the contract.

T
HE MATURE FEMALE
brain is still relatively unknown territory, but it’s a wide open place for women to discover, create, contribute, and lead in positive ways for future generations. And maybe even have the most fun years of their lives. The postmenopausal years can be a time for both men and women to redefine their relationships and roles, and take on new challenges and adventures independently and together.

I know for myself that having raised my son, discovered passion in my work, and finally having found my soul mate makes me feel very grateful for my life. The struggles along the way have certainly been painful as well, but they have also been my greatest teachers. The reason I wrote this book was to share my knowledge about the inner workings of the female brain with other women who are traveling their own similar paths, trying to be true to themselves and understand how their innate biology affects their reality. I know it would have helped me to know more about what my brain was doing during many of the craziest times in my life. At each step of the way we can better understand our world if we can have a vision of what our brains are doing. Learning how to harness the female brainpower we have will help us each become the woman we ought to be. As a postmenopausal woman, I find myself excited and more determined than ever to try to make a difference in the lives of the girls and women I touch. Of course, I still can’t see around the corner for myself—but the many decades ahead seem full of hope, passion, and outward momentum. I hope this map will help guide you through the incredible journey of the female brain.

EPILOGUE

The Future of the Female Brain

I
F I HAD
to impart one lesson to women that I learned through writing this book, it would be that understanding our innate biology empowers us to better plan our future. Now that so many women have gained control over their fertility and achieved economic independence, we can create a blueprint for the road ahead. That means making revolutionary changes in society and our personal choices of partners, careers, and the timing of our children.

Since women are now taking their twenties to get educated and establish their careers, more career women are pushing the boundaries of their biological clocks and having children in their mid-to late thirties—even early forties. A large percentage of my residents in their mid-thirties haven’t yet even found the men with whom they want to start families because they have been so busy building their careers. This doesn’t mean that women have made bad choices. It means that the phases of women’s lives have drastically expanded. In early modern Europe, women became fertile at age sixteen or seventeen and had all their children by the time they were in their late twenties. Now, by the time the mommy brain takes over, women are fully entrenched in careers, and that means an inevitable tug-of-war because of overloaded brain circuits. Then women find themselves facing the ups and downs of perimenopause and menopause with toddlers and preschoolers running around the house. At the same time, they are managing busy careers. If a woman hasn’t come to see me in her mid-thirties to talk about the challenges of her fertility and career, then she will come in her mid-forties, saying that she just doesn’t have time for perimenopause. She can’t afford to lose her memory and focus from moods that make her miserable because her hormones are out of sync.

What does all this mean in terms of women’s innate brain biology? It doesn’t mean that women should get off the path of motherhood combined with career; it just means they may benefit from getting a glimpse of all the balls they will need to juggle starting in their teen years. Obviously, there is no way that any of us can see around the corners in our lives and anticipate every type of support we will need. Understanding what is happening in our brains at each phase, however, is an important first step in controlling our destiny. Our modern challenge is to help society better support our natural female abilities and needs.