Paracetamol and pregnancy

Henrietta Norton BSc, Dip NT, MBANT, AFMCP Co-founder of Wild Nutrition and Nutritional Therapist.

Can paracetamol use in pregnancy lower testosterone levels in boys?


In May 2015, information on a study was released which looked into the potential effects of paracetamol use and testosterone levels in baby boys during gestation (pregnancy). Paracetamol is routinely recommended by midwives and doctors for pregnant women to relieve pain relief and minimise fever. The study concluded that after just 7 days of paracetamol administration; testosterone levels had fallen by 45 %. This was a landmark study and more studies will no doubt be put in place since testosterone is essential for the development of healthy adult males.


What is the new research?


The research was conducted on laboratory mice, which were skin grafted with human testicular tissue, to mimic how testes develop and function in pregnancy. The mice were given a normal dose of paracetamol over a 24 hours or a 7-day period. The amount of testosterone produced by the human tissue was measured an hour after the final dose of paracetamol (in both durations). Interestingly there was no adverse effect after 24 hours but after as little as 7 days, there was a close to half drop in testosterone levels. This has raised questions for the medical community. Sadaf Ghaem-Maghami, who is the chair of the Royal College of Obstetricians and Gynecologists’ scientific advisory committee, said the research was "robust".  She welcomed more research but that since it was in animals with human tissues, it was difficult to extrapolate its meaning for humans. Ghaem-Maghami added that women should continue to follow guidelines but try to take paracetamol for the shortest time possible. This new evidence does open up a larger discussion on how medication or chemicals may affect hormones.


Physical effects of testosterone


Testosterone is produced by the testes and in smaller amounts, in the adrenal glands.  It is required for genital formation, sperm formation, development of male attributes like a deeper voice and body hair. It is also needed for male sex drive and muscle mass. Testosterone is what gives men natural ‘drive’ and energy, a tendency towards dominance and in some a more competitive nature. Low testosterone has been shown to result in a low sexual drive, pre-mature ejaculation, low sperm count, a lack or drop in self-confidence, poor concentration, low mood or depression, lack of energy and sleep disturbances. So while this research is preliminary; it does raise concern around the entire subject of testosterone levels in early developmental years when we are already so aware of the significance of healthy testosterone. At the end of this article we discuss simple steps and recommendations to gently support normal testosterone.

Although the study didn't look at the effect on female fetus testosterone levels; testosterone in females is required for muscle mass, bone health and sex drive. Women only need a small amount in comparison to men but that small amount is still crucial.


Testosterone for mental wellbeing


Decline in testosterone effects male physiology but let's also look at the social-psychological behaviour in males in response to changes in testosterone levels. Melissa Hines from the Department of Psychology at City University wrote in The European Journal of Endocrinology (2006): “Testosterone plays an important role in mammalian brain development. In neural regions with appropriate receptors testosterone, or its metabolites, influences patterns of cell death and survival, neural connectivity and neurochemical characterization. Consequently, testosterone exposure during critical periods of early development produces permanent behavioural changes”.

Male and female hormones provide us with necessary support for biochemical reactions and reproductive purposes but they also somewhat dictate our emotions and preferences in life. In more recent times we have begun to examine the idea of what makes us ‘male’ or ‘female’ beyond the obvious physical features and conventional human biology. There has been a trend to move away from the stereotyping of male and female children in terms of play and social activities e.g. dolls and netball for girls, or an action hero and football for boys.

However research has shown that boys with healthy levels of testosterone are more likely to engage with gender typical specific social behaviour. Therefore while we are not saying boys should only be playing with 'masculine' toys, it seems right to allow masculine traits that are typically formed from normal biochemistry. It seems that allowing boys to indulge in ‘rough and tumble” may support healthy testosterone production and their ability to socialise. Conversely, there are other studies, which show high fetal testosterone levels are linked to negative behaviour and issues with learning and cognition.  Therefore we should always be looking for a state of balance when testosterone plays such a vital role in male health, including the development of muscle mass, transformation of genitals and sperm production in the appropriate amount.


Environmental factors and testosterone


What about the hormones in our external environment? A group of xenoestrogens found in products such as plastic bottles or unfiltered tap water also have the ability to disrupt hormone balance in men and women. This group of manmade industrial chemicals are also aptly called endocrine-disrupting hormones. If we look to the animal kingdom, zoologists and nature experts have been commenting on fish population becoming either asexual (neither one sex nor the other) or male species becoming feminised. Thereby their reproduction capacity dwindles and general fish populations decrease.

One study looked at elevated oestrogen levels in male and female alligators. Male alligators were found to have 3 times lower than normal the average levels of testosterone. More alarmingly, a study from 1998 demonstrated how these endocrine-disruptors on sperm development and testicular cancer rates.  This raises the point that we should do what we can to protect men from not only drops in natural levels of testosterone but also environmental oestrogens and xenoestrogens (chemicals that have an oestogen-like effect or mimic oestrogen).


What can you change in your lifestyle to support a healthy foundation for male hormonal health?


  1. Cut down on the use of plastic in your life – especially heated plastic. Plastics when heated can release chemicals, which disrupt hormones. Swap plastic cooking utensils for wood or steel, avoid putting hot food directly into plastic containers (allow food to cool beforehand), never heat food in a plastic container (use glass or ceramic) and avoid leaving plastic water bottles in direct sunlight (windowsill or back of car window).
  2. Research shows that the stress hormone cortisol has been shown to lower testosterone levels in males. Therefore looking into lifestyle and nutritional changes that support stress is a positive step. Including good levels of healthy proteins (meat, fish, eggs, beans, legumes and nuts or seeds) and vegetables supports a diet rich in B vitamins, minerals like magnesium and vitamin C which all support energy and relief from the ups and downs of a busy and intense life.
  3. The mineral zinc is required for the maintenance of normal serum testosterone concentrations.
  4. Since ancient times in India, the wonderful herb ashwagandha (withania) has been used to help men and women ‘adapt’ to life’s challenges. Ashwagandha supports the health of all organs including the health of the testes and adrenal glands (where testosterone is secreted from). It has also been shown to aid sleep and support a feeling of calm, which is critical for any busy man who may have fluctuating cortisol levels.
  5. Both men and women may benefit from regular general cleansing and specific liver support. ‘Waste’ hormones are detoxified by the liver and go into the bowel. This is why we should also be eating well to encourage healthy routes of elimination to avoid unwanted hormonal build up.

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