Women’s bodies change during their lifetime. They also change over the course of every month during their fertile years. This is mostly due to the fluctuation in sex hormones over different life phases and the menstrual cycle. Obviously, there are other factors that change us as we age but bear with me, I am talking about hormones here! Speaking for myself as a 40-something-year-old female, I still have not come to grips with understanding the impact that hormones have and continue to have on me. Our hormones can impact on our moods, skin, sleep and the list could go on. So, here I wanted to gather some information to try and learn the language of my hormones.

Let’s start with how our hormones change during our lifetime and the impact this can have on us.

Sex (yes please) hormones (no thanks)

Hormones are natural substances or chemicals that are produced in our bodies. Well, there are synthetic hormones but let’s focus on the ones that we make ourselves for starters. Hormones can be described as chemical messengers. They circulate around our bodies and talk to different parts of our body to regulate various things l sleep, appetite, and growth.

Sex hormones are vital in sexual development, reproduction, and in general health. These hormones are produced in the adrenal glands and the gonads, for women this is in the ovaries (at least until menopause), for men it’s the testes.

The levels of sex hormones in our body changes over time; the largest variations for women are during puberty, pregnancy, and during perimenopause to menopause. Sex hormones have a huge impact on how we feel, look, and how we function. They can impact on our mood – whether we feel calm or anxious.

The two main female sex hormones are oestrogen and progesterone.  The major sex hormone in males is testosterone. Women have testosterone too but in much lower levels.

How do our hormones change during our lifetime?

Variation in oestrogen over a woman’s lifetime.


Early in puberty, levels of luteinizing hormone (LH) and follicle-stimulating hormone (produced by the pituitary gland) increase. This stilumates the production of sex hormones. In girls, levels of oestrogen start to increase. This results in physical changes in the body associated with puberty in girls, including development of breasts, ovaries, uterus, and vagina, as well as a girl’s first period.

During puberty, a monthly menstrual cycle is established. At mid-cycle oestrogen and LH levels suddenly spike, triggering the release of an egg (ovulation). They then fall just as quickly. During the rest of the month, oestrogen levels climb and fall gradually. A normal menstrual cycle is around 28 days, but there is a big range across individuals! The four phases of the menstrual cycle are the follicular phase, ovulation or the fertile window, followed by the luteal phase. Then the period or menstrual phase. It’s useful to keep track of your menstrual cycle so that you can understand what’s happening in your body. There are lots of tools in this area, like the Bellabeat apps ‘My Diary’ function, or Clue, Flo, or the Natural Cycles app. Natural Cycles is actually an FDA approved birth control app!

Menstrual cycle diagram. Menstruation phases.


During pregnancy there is a huge increase in oestrogen and progesterone. In fact, a woman will produce more oestrogen during one pregnancy than throughout her entire life when not pregnant.

Oestrogen is produced by the ovaries and later by the placenta. It helps the uterus grow, maintains uterine lining, regulates other key hormones, and triggers the development of baby’s organs. And when it’s time to breastfeed, oestrogen supports the growth of breast tissue and helps milk flow.

Progesterone helps to create the placenta and strengthens the pelvic wall muscles for labour, amongst other things.

Changes in hormone levels during pregnancy.

There are lots of other hormones flying around during pregnancy, each with their own job to do. Here’s a list of the main ones (on top of oestrogen and progesterone):

But don’t worry, we’re not going to go into detail on those for now. This cocktail of hormones aid in the development both of the baby and in changes to the mother’s body to support pregnancy, birth, and beyond.

Perimenopause / menopause

More big changes arise in the hormone balance when women approach menopause. This phase is called perimenopause which means ‘around menopause’. It can last for several years and typically begins when a woman is in her mid to late forties, although it can start earlier in some.

During perimenopause oestrogen and progesterone decrease. And a woman’s ovaries will stop releasing eggs. These changes result in periods becoming less regular. Plus women can experience night sweats, trouble sleeping, hot flashes, vaginal dryness, and mood problems. You can read more about different symptoms here.

Menopause officially begins 12 months after a woman’s last period. After that, a woman is considered to be in the “post menopause” phase of her life.

After menopause, the ovaries stop making female hormones, including oestrogen. But the body still makes small amounts of oestrogen. It does this by changing hormones called androgens into oestrogen. Androgens are produced by the adrenal glands.

Progesterone is mainly secreted by the corpus luteum in the ovary, after ovulation. So, when ovulation stops in menopause, progesterone levels are low.

How do changes in oestrogen impact on us?

There is a clear link between hormones, especially oestrogen, and a woman’s mood or emotional well-being. 

Oestrogen is thought to be a “protective” agent in the brain. This may in part explain why some women feel worse, in terms of their mental state, in the low-oestrogen phase of their monthly cycle. Oestrogen is also linked to mood disruptions that occur only in women. Things like premenstrual syndrome (PMS), premenstrual dysphoric disorder (PMDD), and postpartum depression.

During puberty, when hormones are changing a lot, many girls experience mood swings and other changes in mental health. Certain types of oral contraceptives can also lead to depressive symptoms in some women.

During the transition to menopause, women experience big hormonal shifts. At this time, they are 14 times more likely than usual to experience depression. As well as mood, the hormonal changes associated with menopause can impact a woman’s quality of life or even lead to chronic health issues. Postmenopausal women lose an average of 25 percent of their bone mass by age 60, largely due to the loss of oestrogen. The loss of oestrogen can also result in a higher risk for coronary artery disease.

How do changes in progesterone impact us?

Progesterone has a calming effect for most women. This is why times of high progesterone (luteal phase and pregnancy) can cause sleepiness.

A low progesterone level also has a range of effects on the body, most commonly psychological and emotional issues: irritability, rage, depression, tension, anxiety, confusion, fatigue, memory lapses and loss, inability to concentrate, and decreased stress tolerance.

If progesterone is absent or levels are too low, irregular and heavy menstrual bleeding can occur. A drop in progesterone during pregnancy can result in a miscarriage and early labour. Mothers at risk of giving birth too soon can be given a synthetic form of progesterone to delay the onset of labour.

Lack of progesterone in the bloodstream can mean the ovary has failed to release an egg at ovulation, as can occur in women with polycystic ovary syndrome (PCOS).

Sync with your body!

But it’s not all doom and gloom. If we can understand the fluctuations in our hormones, we can use them to harness energy and productivity. We need to learn to work with our hormones, assuming they are in the healthy balanced range of course, and work with them.

Products like Bellabeat and Wild are helping women to get in sync with their natural cycle. By tailoring workout intensities, making nutritional adjustments, and scheduling recovery/relaxation based on your hormonal fluctuations we can work in sync with our cycles. By tracking your cycle, you can also find patterns in your data and learn how to mitigate and understand any changes in your body and mind.

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