Oestrogen dominance is also called unopposed oestrogen and it’s a situation that occurs when your body doesn’t make progesterone half way through the menstrual cycle, which leaves oestrogen alone to dominate the entire cycle.
Being oestrogen dominant doesn’t necessarily mean having elevated levels of oestrogen in your body.
However, if you’re always oestrogen dominant, it can be just as bad as having high levels of oestrogen and become a risk factor for growth of fibroids, cysts and oestrogen driven cancers.

NOTE: In perimenopause oestrogen is on a rollercoaster and does NOT look as gentle as it does in this diagram but for the sake of this blog I am using this diagram to illustrate that progesterone is always low in the follicular phase (first half of the cycle), which makes oestrogen the dominant hormone in that first half.
Then, about half way through the cycle, once you ovulate, one of your ovaries releases a load of progesterone into your system.
You make oestrogen almost every day but progesterone for only the final ten to 14 days after you ovulate and progesterone is the dominating hormone in the second half of your cycle.
Unopposed oestrogen or ‘oestrogen dominance’ occurs when you don’t ovulate and therefore don’t go on to make progesterone, which leaves oestrogen alone (unopposed) in the second half of the cycle and therefore ‘dominant’ for the entire cycle.
Symptoms of unopposed oestrogen include:
- Miserable periods (heavy, painful)
- Breast pain
- Mood swings, rage, irritability
- Water retention (‘puffy’)
- Headaches
- Cysts
- Histamine or mast cell reactions
There are oestrogen receptors on every cell in your body, which means it has far-reaching effects on all body systems, such as metabolic health, skin, bones, heart and even the gut. All systems feel the effects, whether it’s high, dominant or low.
What can you do?
One of the most important things you can be doing to support your body through perimenopause and the oestrogen dominant situation is supporting your body to ovulate as many months as possible.
Without doing this, you’re likely to ovulate much less in your 40s than you would have if you put habits in place that can give your body the best chance at ovulating.
Ovulation is only ever really talked about in terms of fertility, but trust me, you want to know about it if you want a MUCH smoother, happier hormonal ride in perimenopause and transition into menopause when the time comes.
Read my blog here where I explain how to support ovulation and how to know if it’s occurred (how you can track it).
I personally take my baseline body temperature each morning when I wake up, which gives me an indication of whether or not I’ve ovulated. The cycles when I haven’t (which luckily are few and far between at the moment), I really notice it, mostly in my mood, sleep and tolerance levels!
Make sure you have a read of my blog for 5 key ways to support your body to ovulate as many months as possible throughout your 40s.