hormones and our period

hormones and our period

Written by: Dr Sophie Scandrett

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Time to read 3 min

back to basics

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.

five key hormones to focus on

  • 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.

menstrual cycle

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!

Dr Sophie Scandrett

Dr Sophie Scandrett MBBS BSc Hons MRCOG

Dr Sophie qualified in 2017 with a full medical degree and Bachelor of Science in Anatomy & Reproduction. She now works as an Obstetrics & Gynaecology doctor for the NHS.

period mythbuster

Menstrual cycles sync up when you are working or living together

FALSE. This was a theory in the 1970s, but actually there is no evidence for this and actually it is much more likely to be related to slightly different cycle lengths meaning that for a couple of months of the year you are on your period at the same time as your flatmate, but then other months you diverge again.

Period blood is dirty

FALSE. Period blood is just normal blood and womb lining tissue that comes away and definitely is not dirty! There is no need to wash inside the vagina during your period or at any other time; in fact this can be harmful and wash away the good bacteria in the vagina. More on this another time.

You shouldn’t swim on your period

FALSE. It is safe to swim on your period if you want to, you just have to figure out what works for you - whether it’s a tampon, menstrual cup or period pants in the swimwear range!