Infertility, Hormone Changes
in Women and Breathing


Men and women do breathe differently!

For example, back as far as 1905,  it was discovered that the resting pressure of arterial (blood) carbon dioxide (CO2) was about 8% lower in woman than in men1; and airflow and gas exchange alter during the menstrual cycle 2.

Women breathe less on average as a result in part of a smaller frame and airways, and a shorter diaphragm (by about 9%)3, however did you know that a woman’s ventilation volume and rate varies with her menstrual cycle and during pregnancy and menopausal changes?

Up until recently most medication trials and methods have centred on testing males only – animal and human, and often have not taken into account the time of month nor hormonal changes that occur throughout much of a woman’s life 1, 4

There is now a move to do more studies on women however there are some things we know that can be helpful.

Progesterone, which is produced during the time between ovulation and menstruation (the luteal phase), and also during pregnancy, has been found to stimulate breathing. As a result CO2 levels drop by around 25%. If levels become hypocapnic (lower than healthy arterial CO2)

The follicular phase of the menstrual cycle is when the body is prepping for ovulation and is measured from the first day of your period until ovulation. This is the time that oestrogen production is increasing.

From the mid-follicular phase to the mid luteal phase (at between 10 to about 22 days), breathing issues such as wheeziness, breathlessness, congestion and coughing, worsen 6.

Another interesting study in 2000 indicated that at times when progesterone increases, and breathing ramps up in volume and speed; pain thresh-holds drop 7.

It makes sense therefore that breathing well has the potential to be beneficial in moderating these hormone changes.


Men and women do breathe differently!

Up until recently most medication trials and methods have centred on testing males only – animal and human, and often have not taken into account the time of month nor hormonal changes that  occur throughout much of a woman’s life. There is now a move to do more studies on women      however there are some things we know that can be helpful. 

Did you know that your breathing alters during your menstrual cycle in response to hormonal    changes. The same is true during pregnancy and menopause.

Breathing well is beneficial in moderating these hormone changes.

Fertility is effected by a number of factors some of which are clear and others which are difficult to identify.

What is understood is that infertility causes stress and it may be that stress also contributes to infertility. So far, talking therapies such as Cognitive Behavioural Therapy (CBT), are usually recommended for those suffering from panic attacks and anxiety. What we know is that breathing well will activate the vagus nerve, reduce stress and improve sleep quality. 

Poor sleep has also been identified as a factor which may influence infertility. This was highlighted in a 2015 American study 7: ‘Sleep and sleep disturbances are increasingly recognized as determinants of    women’s health and well-being, particularly in the context of the menstrual cycle, pregnancy, and                 menopause…. Sleep continuity disturbance may influence fertility, and do so in one of the several ways …           if insomnia represents a response to real or perceived life threat, it may be that insomnia serves as a biological cue for less than optimal circumstances for reproduction. From an evolutionary point of view, such an association would be adaptive”

A Taiwanese study in 2017 8 concluded that non-apnoea sleep disorder puts women at a higher risk of developing infertility.

When your nervous system is in Parasympathetic Dominance, (PNS or rest and digest mode), your body is able to rest and repair itself more effectively and your body regulates itself more efficiently, hormones balance and natural immunity is improved. The opposite is true when in Sympathetic  Dominance (SNS or Fight or Flight) mode.


  1. Sex Differences in Breathing  – Luciane H. Gargaglioni,  Danuzia A. Maques and Luis Gustavo A. Patone. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Phsiology (2019): 110543 https://www.sciencedirect.com/science/article/pii/S1095643319303071?via%3Dihub 
  2. Effects of the Menstrual Cycle on Lung Function Variables in Women with Asthma – Farha, Samar, Kewal Asosingh, Daniel Laskowski, Jeffrey Hammel, Raed A/ Dweik, Herbert P. Weidemann, and Serpil C. Erzurum: American Journal of Respiratory and Critical Care Medicine 180, No 4 (2009): 304 – 310 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2731807/
  3. Sex Differences in Respiratory Function – LoMauro, Antonella, and Andrea Aliverti Breathe 14 no.2 (2018):131-140 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5980468/ 
  4. Failure to Consider the Menstrual Cycle Phase May Cause Misinterpretations of Clinical and Research Findings of Cardiometabolic Biomarkers in Premenopausal Women – Schisterman, Enrique F., Sunni L. Mumford, and Lindsey A. Sjaarda: Epidiologic Reviews 36 no 1 (20214): 72-82                                    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3873842/
  5. Changes in Sympathovagal Balance During Menstrual Cycle – Ghildiyal, A.,B. Iqbal, S. Singh, D. Verma: Current Neurobiology 2, no.1 (2011): 49-52 https://pubmed.ncbi.nlm.nih.gov/26557512/  
  6. Respiratory Health in Women: from Menarche to Menopause – Macsali, Ferenc, Cecilie Svanes, Line Bjorge, Ernst R. Omenaas, Rrancisco Gomez Real, Hutchinson, Mathers et al.: Expert review of respiratory medicine 6 No. 2 (2012): 187-202          https://www.tandfonline.com/doi/pdf/10.1586/ers.12.15?needAccess=true
  7. Sleep, Sleep Disturbance and Fertility in Women – Kloss, Jacqueline D., Michael L. Perliss, Jessica A, Zamzow, Elizabeth J. Culnan and Clarissa R. Gracia Sleep Medicine Reviews 22 (2015): 78-87 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4402098/pdf/nihms-636615.pdf 
  8. Non-apnoea Sleep Disorder Increases the Risk of Subsequent Female Infertility – a Nationwide Population-Based Cohort Study – Wang, I-Duo, Yung-Liang Liu, Chung-Kan Peng, Chi-Hsiang Chung, Shan-Yueh Chang, Chang-Huei Tsao and Wu-Chien Chien PhD: Sleep 41, No/1 (2018):zsx186 https://pubmed.ncbi.nlm.nih.gov/29136234/