Hormones And Our Period

This blog is not meant to be read in any particular order but I thought it best to start with a quick overview of the menstrual cycle because it underpins everything related to women’s health. The idea is you can refer back to this info when you are reading later posts to help you understand the basics. If you want less basic science and more practical bits, stay tuned...

Please note that everything described here initially will be “typical”, so that we can then understand what is “normal” and what is not, whilst acknowledging the huge variations between women as we are all unique!

I spent some time trying to think of an example of something not affected by the hormones that drive the monthly cycle - and I couldn’t! Take a bone fracture: the strength of your bones is influenced by many factors, but one is oestrogen; more oestrogen = stronger bones in simplistic terms. How about your skin? Well, oestrogen helps maintain your skin collagen, elasticity and hydration. Your mental health, gut, bones, skin, heart; all are influenced so strongly by our female sex hormones.

Also known as low sex drive, it is a reduced desire intensity (i.e. you want to less) or a reduced frequency (i.e. you still want to, but less often). It can be temporary or long term. It might be related to reduced desire, reduced ability to orgasm, pain during sex or all three. You might also hear the term “female sexual dysfunction”. This is the newer umbrella term for any and all of the above. I don’t personally love the word “dysfunction” but it can be helpful to know how others may refer to it.

• Oestrogen: a powerhouse, released in huge amounts by the ovary in the first half of your cycle. It thickens the womb lining before ovulation. It also affects your skin, bladder, heart, brain, breasts and bones as above. This needs a separate blog post!
• Progesterone: dominant in the second half of your cycle. Vital to balance out the oestrogen and to support early pregnancy (think Progesterone for Pregnancy) and lots of the effects of progesterone can be understood by thinking about those symptoms just before your period, or in early pregnancy - bloating and breast tenderness for example.
• FSH (follicle-stimulating hormone): a hormone released from the brain which is responsible for activating some eggs each month.
• LH (luteinizing hormone): a hormone released from the brain which is responsible for ovulation. If you try ovulation kits at home, you are measuring this in your urine!
• Prostaglandins: much less well known but essentially a local hormone involved in inflammation - so it not only triggers the bleed but is responsible for some of the pain associated with your period, so blocking prostaglandins (how ibuprofen works!) generally reduces period pain.

A woman will typically have a period every month, 21-35 days between periods. From the first day of your period, your “cycle” has started. The brain releases FSH which kick the ovaries into gear to start some eggs developing. The growing eggs produce lots of estrogen which helps thicken the womb lining. By the middle of your cycle, your estrogen peaks, signaling back to the brain which releases lots of LH. The LH surge prompts the ovary to ovulate - release an egg - which is scooped up by the tube to wait for a sperm. The ovary then begins producing progesterone in the second half of your cycle, which prepares the womb lining further for a pregnancy to implant if the egg is fertilised by a sperm. If this doesn’t happen, local hormones called prostaglandins in the womb rise, which causes the womb lining to shed. This is day one of your bleeding, which typically lasts 3-7 days. And the cycle starts again.

The rise and fall of all of these hormones is an incredible, finely balanced system. No wonder then that so many factors can throw it off and result in irregular cycles, with irregular or no ovulation, whether from jet lag, stress, lack of sleep, change in diet or exercise, or a micronutrient or vitamin deficiency. The most important message to understand with women’s health is this: there is rarely one solution for a symptom. It is often “multifactorial” = doctor speak for many factors contributing to the problem!

• Menstrual cycles sync up when you are working or living together
• Period blood is dirty
• You shouldn’t swim on your period

• Kershaw V, Jha S. Female sexual dysfunction. The Obstetrician & Gynaecologist 2022;24:12-23
• Avis NE et al, Correlates of sexual function among multi-ethnic middle-aged women: results from the Study of Women’s Health across the Nation (SWANN).
• Menopause 2018;25:1244-55

  Shifren JL. Androgen in the oophorectimised women. Fertil Steril 2022;77 Suppl 4:S60-2