Seems unlikely that the use of painkiller during pregnancy should affect fetal testosterone levels. But a study conducted in the University of Edinburg has shown a direct effect between dip in testosterone levels and acetaminophen.
Acetaminophen is a commonly used painkiller which is considered safe to use during pregnancy. It is also known by the name paracetamol, and is available in the United States under the trade name Tylenol. It is classified under the COX2 inhibitors and acts as an antipyretic as well.
But prolonged use of this drug during pregnancy can significantly reduce the amount of testosterone produced by the fetal tissues.
The research conducted in the University of Edinburg was performed on mice. These mice were grafted with a sample of human fetal testicular tissue. They were then administered a daily recommended dose of acetaminophen and the levels of testosterone produced by the graft tissue was measured after 24 hours.
The subjects were gradually given the dose for up to 1 week and the testosterone levels were checked at each stage. This was done to measure the results of intermittent and regular exposure to acetaminophen with respect to testosterone levels.
The results of the study
It was found that those mice which received only a 24 hour dose of acetaminophen did not show any significant alterations in testosterone levels. This showed that short term exposure to the drug was relatively safe.
But the mice that had been given acetaminophen for 7 days or more showed the maximum changes in testosterone levels. About 72 % of the subjects showed a 45 % drop in testosterone levels.
This is quite a large number and the percentage of testosterone decrease is also quite substantial. Such a reduction can create a marked hormonal imbalance in the fetus.
The interpretation of the results
The results of the Edinburg study can be interpreted without much debate and disagreement. They show that intermittent or infrequent doses of acetaminophen do not interfere with the production of testosterone. This would mean that sporadic use of the drug by pregnant women should not affect testosterone levels in the fetus.
However, if women consume this drug for longer periods of time during pregnancy, this can drastically affect fetal testosterone levels. So the study establishes without a doubt that acetaminophen should not be taken regularly during pregnancy. But the studies were after all performed on laboratory animals and they may not extrapolate well to human beings.
It has to be pointed out, however, that the evidence establishing the safety of short term use of the drug has been proved by only one single study, so this fact may also need further investigation.
Why is fetal testosterone production important?
A reduction in the production of testosterone by the fetal testicular tissue can lead to many disorder, improper descent of testes being the most significant of them. Testes require a temperature slightly lower than that of core body temperature for the production on sperms. Abdominal testes can lead to infertility.
Apart from the above mentioned disorder, it is also possible that low testosterone during fetal development can also affect the development of reproductive organs and cause many disorders during future life. This may also lead to lifelong problems, something that should be avoided at all costs.
Does this mean acetaminophen is contraindicated during pregnancy?
Not really. The general safety of the drug during pregnancy has established. As regards effects on testosterone levels, the researchers in Edinburg have stated that it is acceptable to consume paracetamol during pregnancy. But the drug should be taken in the least effective dosage and for the least possible duration to avoid any disturbances in testosterone production in male fetuses.