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How Hormones Change the Female Brain Daily, Monthly, and Over a LifetimeDid you know that every brain starts out as female?

At eight weeks of development, either a testosterone surge kills off cells in the communication center of the brain, and grows more cells in the sex and aggression areas — making a male brain —  or a surge of estrogen promotes brain growth in parts specializing in communication, feelings, emotional memory, and anger-suppression –making a female brain.

In her book The Female Brain, Dr. Laura Brisendine M.D. explores the relationship between female hormonal fluctuations and the female brain. Dr. Brisendine explains that after girlhood, because of hormone fluctuations that continue until after menopause, the female brain actually changes daily, monthly and over a woman’s lifetime. These fluctuations heavily influence her thoughts, desires, emotions, and behavior.

The Maturing Girl Brain

For up to two years after birth, a girl’s brain is flooded with massive amounts of estrogen, and at around 24 months, hormones are turned off for a juvenile pause. As a girl ages, however, estrogen, progesterone, and testosterone gradually increase in a monthly cycle.

Once her monthly menstruation cycle begins, the female brain changes a little bit every day throughout the month, with some parts differing as much as 25 percent. From a biological standpoint during this phase of puberty, a girl’s primary focus is to become sexually desirable and attractive with her attention on relationships, choosing a life path, and finding a mate compatible to raise a family.

The Mommy Brain

There really is such a thing as “mommy brain.”

The mommy brain transformation starts at conception when a woman’s brain gets inundated with neurohormones manufactured by the fetus and placenta. Even the most career-oriented woman’s brain circuits are changed during the process of motherhood, radically altering the way she thinks and feels and what she finds important.

During those nine months, women experience a flood of estrogen which is greater than at any other time in their lives. Research has discovered that pregnancy reduces grey matter in specific parts of a woman’s brain, to help her bond with her baby and prepare for the demands of motherhood. The brain remodeling of pregnancy was found to last for about two years after giving birth.

After childbirth, new neurochemical pathways are formed in a mother’s brain to reinforce maternal behavior, new responses, and priorities. Her brain and reality are transformed. The mother gets continual rewards of oxytocin, the bonding hormone, from physical touch with her child and partner. This helps keep her brain focused on tending to and caring for her family and avoiding conflict to keep the family together. Mothering behavior is coded deep in her genes and brain. Because of regular oxytocin rewards,  even fathers, adoptive parents, and caregivers can experience similar differences when in close daily contact with an infant.

For about six months after giving birth, the parts of the mommy brain responsible for focus and concentration are preoccupied with protecting and tracking the baby. This can result in what feels like decreased brain power, and increased stress and anxiety when separated from the child — especially if nursing.

The Peri-menopausal Brain

After the mommy brain stage, the female brain goes through a second major change, similar to adolescence called perimenopause, which can make a woman as moody as when she was a teenager. Her brain becomes less sensitive to estrogen, and her ovaries make erratic amounts of it before eventually stopping causing the well-known hot flashes and irritability as well as erratic sleep, fatigue, joint pain, decreased sex drive, and anxiety.

This leads to menopause, which starts, on average, at 51. Since estrogen also affects the brain’s neurotransmitters controlling mood and memory, many perimenopausal women suffer from depression and memory lapses.

Peri-menopause isn’t all bad news. Because female brain circuits fueled by estrogen, oxytocin, and progesterone become less active, the mommy brain begins to unplug, and a woman’s interests start to expand with her focus shifting to herself: staying healthy, improving well-being, and embracing new challenges which can result in positive life changes.

The Post-Menopausal Brain

Once estrogen levels drop and the kids leave home, oxytocin also declines and the mature female brain gets a second wind. What had been hardwired to be important to women earlier in their lives, connection, communication, approval, children, making sure the family stayed together, is no longer their biological priority.

Her brain circuits are now free to entertain new thoughts, ambitions, and ideas. Many women may feel sad, lost, and disoriented because the changing chemicals in their brains literally shift their realities — again. After the transition period, the twilight years for many 50+ women are characterized by an increased zest for life and appetite for adventure.

At this point, many women may leave a marriage or make drastic changes in their lives. Women now want their turn. They want to find and pursue their passions and step out in the world in a more independent way. Their top concern isn’t taking care of everyone else anymore. (A cruel joke of nature is that men start to show increased interest in relationships as they age.) Whether the mature female sows her newly wild oats by traveling, picking up hobbies, going back to school, or playing the field depends on the person, of course.

But for many women in mid-life, the twilight years are characterized by a renewed energy for life and appetite for adventure. The female brain actually becomes more stable now with lower, steadier hormones which translate into a calmer, less emotional brain not as reactive to stress.

The Mature Female Brain And Alzheimer’s and Dementia

I would encourage post-menopausal women to follow their brain’s thirst for novelty and challenge and to keep active because dementia hits the mature female brain the hardest.

According to a 2014 report from the Alzheimer’s Association, two-thirds of Americans with the disease are women. A UK study found that women over the age of 60 were twice as likely to get dementia as breast cancer, and dementia surpassed heart disease and cancer to become the most common cause of death in women.

The reasons are not exactly clear, but possible explanations are that women live longer and have different brain structure, physiology, genetics, and sex-specific hormones.  The best prevention for the disease is a brain-healthy diet and lifestyle.

My Mature Female Brain

As a 50 something-year-old woman, I can attest to living every one of the female brain stages to the letter.

Upon graduating from college, I chose to get married at the ripe old age of 21. After being a stay-at-home Mom to two sons and married for 18 years, I left the marriage and found myself completely lost, depressed, without any idea who I was. At the age of 43, I tried to commit suicide by downing a bunch of pills resulting in a serious brain injury and losing custody of my sons who moved out-of-state with their father.  (Read the story here.)

Because the brain injury affected my hormones, I went through menopause early in my forties and maybe a little bit because the kids weren’t around anymore.

Now that I am years into my post-menopausal brain, I take comfort in knowing that my lack of maternal focus and disinterest in nesting is partly due to hormones. I’ve never let my home get as messy as it does now, and I find it really odd that it’s OK with me. I have no interest in cooking, fashion, or decorating, and hardly ever wear makeup, but I do feel totally motivated in investing in my future.

My mature brain and I are enjoying ourselves and looking forward to the years ahead without being jerked around by hormones!

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  1. Fascinating. I missed the mommy brain stage! I’m glad to hear this although probably due to trauma my own brain isn’t quite so settled: “The female brain actually becomes more stable now with lower, steadier hormones which translate into a calmer, less emotional brain not as reactive to stress.”

    • A reader asked, “What if you don’t do the Mommy brain stage?” That’s a good question I had not considered. I’ll look into it, but I would assume you just go straight to perimenopause. At least your brain isn’t also dealing with all the hormone fluctuations anymore! 🙂

  2. A fascinating read Debbie. I remember reading some of this many years ago and was equally fascinated then. I can pretty much relate to some degree or other to all these phases. Each one of which has brought me great joy and sometimes a bit of sadness. <3

  3. This is so interesting, Debbie. I do remember the mommy brain stage. I find it fascinating how the brain initially forms into the female or male brain. I haven’t read the book, but will definitely add it to my list.

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