Painkillers, pregnancy and problems of procreation

Mums using painkillers, such as paracetamol, aspirin or ibuprofen, during pregnancy are putting their sons at risk of reproductive problems.

A study in Reproduction Today looked at two groups of pregnant women, 834 in Denmark and 1,463 in Finland, who were asked about their use of painkillers. The study found that women, who took mild painkillers during the second or third trimester of pregnancy, were at increased risk of giving birth to sons with undescended testicles, a condition known as cryptorchidism. Use of any one painkiller is enough to cause problems, but the risk is increased in women who simultaneously use multiple painkillers.

The painkillers disrupt the production of androgens, a group of hormones including testosterone, required for the development of male sex organs. In the mild form of cryptorchidism the testis is merely located high up in the scrotum. In the more severe form the testis is so high up in the belly that they cannot even be felt. Undescended testicles are a risk factor for poor semen quality and sperm stem cell cancer in later life.

Until now researchers had looked at so-called ‘environmental’ hormone disruptors, which can also disrupt normal testosterone supplies. Among these are phthalates, a family of chemical compounds used in the manufacture of plastics such as PVC. It is considered somewhat inevitable that today’s western women are exposed to low levels of these chemical compounds.

This new research has highlighted that the fears associated with such chemical environmental disruptors may be negligible compared to the effect of painkillers. Dr Leffers, a senior scientist leading the research, said: “A single paracetamol tablet (500 mg) contains more endocrine [hormone] disruptor potency than the combined exposure to the ten most prevalent of the known environmental disruptors during pregnancy…a single tablet will, for most women, be at least a doubling of the exposure.”

The fact that painkillers are now much more widely available than in the past, might explain the marked increase in the incidence of cryptorchidism in recent decades. In Denmark the prevalence of cryptorchidism has increased from 1.8 per cent in 1959-1961 to 8.5 per cent in 1997-2001.

References

Kristensen, D., Hass, U., Lesne, L., Lottrup, G., Jacobsen, P., Desdoits-Lethimonier, C., Boberg, J., Petersen, J., Toppari, J., Jensen, T., Brunak, S., Skakkebaek, N., Nellemann, C., Main, K., Jegou, B., & Leffers, H. (2010). Intrauterine exposure to mild analgesics is a risk factor for development of male reproductive disorders in human and rat Human Reproduction, 26 (1), 235-244 DOI: 10.1093/humrep/deq323