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Hormonal Changes Across the Lifespan: What Happens During Pregnancy, Postpartum and Menopause?

Ok, so hopefully you all have gotten a bit of an understanding of the basic female hormones and how they work. If you haven’t yet read my last 2 posts, I’d encourage you to do so! As a pelvic floor physical therapist, I work with women throughout their lifetimes: through pregnancy, after pregnancy and through menopause. It’s remarkable how much a woman’s body will change throughout the course of her lifetime. And what drives all of these changes? You guessed it: hormones. So let’s talk a little bit about how things change hormonally throughout a woman’s life.

Let’s start with pregnancy. Of course, a woman’s body goes through SO many changes during this time, but I am just going to focus on the endocrine (hormone) changes for this post:

  • The pituitary gland increases in size at a rate of 0.08mm/week during pregnancy. The pituitary gland releases the following:
    • Adrenocorticotropic hormone: Stimulates appetite and also stimulates the release of melanin, thereby causing the linea negra (the dark line along a woman’s midline during pregnancy)
    • Growth hormone: No surprise here, it stimulates fetal growth.
    • Thyroid-stimulating hormone (TSH): Stimulates the thyroid to release T3 and T4; this may be reduced slightly during the first trimester, hence the fatigue associated with the first trimester.
    • Prolactin: Causes milk production in the breast tissue. Prolactin can inhibit luteinizing hormone (LH) and follicle stimulating hormone (FSH), which can prevent ovulation. This is why some women do not become pregnant while they’re still breastfeeding. But, this is NOT a sure-fire way to prevent pregnancy, so don’t rely upon this as your sole form of birth control if you are in the postpartum period.
    • Oxytocin: Involved in uterine contractions during delivery. and enhances mother/infant bonding during breastfeeding.
  • The thyroid releases more T3 and T4  due to increased levels of TSH.
  • Recall that the corpus luteum is formed a temporary gland made after ovulation during the second half of the menstrual cycle. It will last up to 3 months if you do become pregnant (until the placenta takes over).
    • Relaxin: This hormone can be the bane of a pregnant woman’s existence, especially if she is hyperflexibile at baseline. Relaxin limits collagen production and reorganization and also stimulates the breakdown of collagen. Its role is essentially to relax a woman’s ligaments and connective tissue so that her body may change in shape in order to accommodate the growing baby. Relaxin can also lead to development of diastasis recti. I’d like to point out that relaxin peaks at 12 weeks gestation, declines until week 17 and then stabilizes for the duration of pregnancy. Your body is no longer making relaxin by 3 days postpartum. This is one reason that women should be mindful of not pushing themselves in terms of stretching while they’re pregnant – they are already more flexible than they were before becoming pregnant and can risk injury by pushing into deep stretches.
  • The placenta starts to form within 2 weeks of conception and as it grows, it starts to secrete several hormones:
    • Progesterone secretion comes solely from the placenta during pregnancy and is necessary to maintain pregnancy.
    • Estrogen in the form of estriol (E3) is produced in large quantities during pregnancy. Recall that estriol is often undetectable in women who are not pregnant.
    • Human chorionic gonadotropic (hCG) is the hormone that confirms pregnancy on a pregnancy test. It suppresses the mother’s immune system and helps with fetal brain development. It is worth noting that it increases the demand for iodine uptake (iodine is needed for the production of thyroid hormone).  It is also responsible for morning sickness.
    • Placental growth hormone is also released from the placenta to, you guessed it, support fetal growth.
    • Placental hormones can act to block insulin, which can make women predisposed toward insulin resistance, and subsequently gestational diabetes, during pregnancy.

Here is my main takeaway for my pregnant ladies (especially from a PT standpoint): Your hormones have made your body much more lax than it normally is. What this means for you is that your joints are inherently less stable and are also more taxed as your body changes with the growing baby. Be mindful of any increased flexibility and do not push into end-range stretches. Focus on maintaining the strength of your core and hip girdle muscle throughout your pregnancy, rather than focusing on increasing your physical fitness during this time. Also, do your best to limit your sugar intake in order to prevent insulin spikes during this time.

Ok, so let’s chat about what goes on in the postpartum period:

  • Progesterone levels drop when you deliver the placenta. Big time. You won’t have another increase in progesterone until you start to ovulate again.
  • Estrogen levels also drop in a big way, and rightly so, because estrogen can interfere with a woman’s ability to make breastmilk.
    • Keep in mind that a drop in estrogen and progesterone is what contributes to PMS symptoms. That said, this major drop of estrogen and progesterone in the postpartum period is much more drastic and can certainly contribute to feelings of postpartum depression and mood changes.
  • Oxytocin is also being released by the pituitary in response to suckling; this enhances mother/infant bonding during breastfeeding. This is another one of our “feel-good” hormones and can help to combat postpartum mood changes.
  • Prolactin is still being produced by the pituitary. But here’s the thing: Dopamine (one of our feel-good hormones) inhibits prolactin release. So, it stands to reason that this can contribute to some mood changes in the early postpartum period.
  • A note on relaxin: While our body is no longer making relaxin in the postpartum period, there is some evidence that the female body can still feel the effects of relaxin up to 5-6 months postpartum.

Bottom line for postpartum women: your recovery is individual to you. Every single body is different, and each pregnancy may be different in terms of how long it takes to feel “normal” again. Keep in mind that breast feeding does alter your hormonal profile, which may delay your return to your prior level of function, especially from a physical standpoint (low estrogen and persistent effects of relaxin can perpetuate ligament laxity and weakness).

Take plenty of time to focus on supporting your adrenal system, which is taking a hit inherently with the increased stress associated with being a new mom. Think about it: every time you hear your baby cry your body has a stress response – it’s a survival mechanism, and it can be very taxing to your body. Couple that with a lack of sleep and you have a perfect recipe for adrenal disaster. That said, I recommend taking adequate vitamin B5 (it’s also found in organ meats), vitamin C, and magnesium. I also recommend taking DHA during this time to support brain health.

What I want every woman to remember is that you know your body. You do. If something isn’t right, advocate for yourself. Seek treatment from a practitioner that listens to you. Know that autoimmune conditions can develop during pregnancy, serious changes to your physical structure can occur (I promise to discuss this more in a future post) and mood changes are very real during this time frame. Do not let a provider discredit what you are feeling. Advocate for the treatment you need to feel your best!

So, before we delve into menopause, let’s define this a bit more. Perimenopause is the time frame leading up to menopause (it can last 10 years!) and this is the time that women experience symptoms due to changes in hormone levels. Menopause itself begins when you have not had a period for one year.  Signs of perimenopause include: heavier/longer flow, shorter cycles, worsening menstrual cramps, waking at night, night sweats, mood swings, weight gain and migraine headaches. Now, let’s talk a little bit about what is happening to female hormones during perimenopause:

Estrogen experiences huge fluctuations. When estrogen is high women experience breast pain, heavy periods, fluid retention and mood swings. Surges of estrogen can also result in development of uterine fibroids. When it drops women experience depression, hot flashes and night sweats. As estrogen drops our risk for heart disease increases (LDL increases and HDL decreases), we lose bone density, we experience vaginal dryness, vaginal atrophy and fat distribution changes (women start to gain weight around their midsection).  In my practice, I see a fair amount of women who develop pelvic organ prolapse and urinary incontinence in the perimenopausal period due to pelvic floor weakness that is perpetuated by vaginal atrophy associated with a drop in estrogen.

You may also recall from my earlier blog post that we have 3 types of estrogen. Young women’s ovaries have the ability to convert estrone (E1, the estrogen made by our fat cells) into estradiol (E2), but as our ovaries age, they lose this ability. What this means for women in their 40’s is that they have more estrone.

I’d like to emphasize the fact that adiposity increases the risk for estrogen-receptive breast cancer as well as non-estrogen-dependent cancers. If you care to know the nitty-gritty, here’s what happens: Fat cells secrete a hormone called leptin (its purpose is to signal satiety to the brain, thereby decreasing food intake; however, we often become leptin-resistant and that warrants a separate conversation!). So, more body fat = more leptin. Leptin then leads to expression of an enzyme called aromatase, which then stimulates androgens to be converted to estrogen. It’s also worth stating that estrogen increases insulin sensitivity, so as your insulin drops you are more likely to become insulin-resistant, which can contribute to weight gain.

A final note about estrogen: we want to ensure appropriate liver health in order to appropriately metabolize and eliminate estrogen. The best way to do this: eliminate or limit alcohol intake. Furthermore, alcohol consumption is correlated with an increase in estrogen. If you’re having hot flashes at night, skip alcohol until this is better controlled.

Progesterone gradually decreases. Don’t forget that it’s the ratio of progesterone and estrogen that determines how you feel, so as progesterone drops it isn’t able to counteract high estrogen levels. Why does progesterone drop with age? Well, your follicles are aging. Recent research has suggested that we don’t run out of eggs, like we once thought we did.

Testosterone continues to decline (it peaks in our 20’s), which contributes to our inability to synthesize muscle at a rate that exceeds muscle breakdown. What that means for us, is a tendency toward atrophy of muscle tissue.

As we age, there is also a decrease in dehydroepiandrosterone (DHEA), which is released by the adrenals and is a precursor for testosterone and estrogen.  However, there is an initial attempt to increase DHEA, which can stress our adrenal system.

So what should women be thinking about in their early 40’s? Well, I focus on forming good nutrition habits; as we age will become more insulin resistant and require less carbohydrates. Ensure adequate protein intake in order to prevent muscle breakdown and limit your sugar and alcohol intake. Women also benefit from getting adequate Vitamin D (2000-4000 IU/day) and calcium (1500mg/day) to promote bone health. Perimenopausal women should participate in daily weight-bearing activity; this will also promote healthy body composition and bone density. During this time, focus on getting good, quality sleep and managing your stress levels.

It is not within my scope of practice to give advice re: hormone replacement therapy, but I will say this: I encourage you to consider bioidentical hormones versus synthetically derived hormones or hormones derived from horses (e.g. premarin). Bioidentical hormones are identical to our own hormones Be sure to do your research when it comes to bioidentical hormone therapy, as there are risks associated with their use.  

I hope that this gives you even more insight into how our hormones changes throughout our lifespan. Please feel free to ask me any questions that you may have.

Thank you so much for visiting and I invite you to come back next week for a discussion about endometriosis, PCOS and fibroids!

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