Parabens are antimicrobial preservatives added to personal care products, pills and processed foods, and the focus on the harm they cause had diminished somewhat. However, a new study shows that the threshold for adverse estrogenic effects was exceeded in the urine of 10% of women, and this directly affected their newborn children. The researchers measured the distance from the anus to the genitals in newborns and found that the parabens have harmful effects and may affect future fertility.
We may appreciate the convenience of expensive skin cream not turning mouldy and chewing gum not being colonized by bacteria before we chew it. However, the cost of extending the shelf life of products by adding preservatives such as parabens seems to be higher than previously thought. A new major study shows that these chemicals affect pregnant women and their children.
“The concentration of parabens in the urine of pregnant women was associated with the effects on the genitals of their children. The threshold for unwanted estrogenic effects was exceeded for one in ten women.
Boys exposed to parabens prenatally had a reduced distance from the anus to the scrotum – a recognized sign of endocrine disorders that may affect future sperm quality and testosterone levels. The girls had shorter distance and changes in their reproductive hormones, but we do not yet know the long-term impact of these changes,” explains Tina Kold Jensen, Professor, Research Unit for Clinical Pharmacology, Pharmacy and Environmental Medicine, University of Southern Denmark and Research leader, Odense Birth Cohort, Odense University Hospital.
The study of paraben concentrations among the 536 pregnant women dates back to 2010–2012, when the researchers measured various chemicals in pregnant women’s blood. The paraben levels did not cause much concern, because on average they looked reasonable. The data were therefore put away for later examination but there was a surprise in store.
“Most pregnant women had low concentrations of parabens in urine, but 10% exceeded the threshold for adverse estrogenic effects” says Tina Kold Jensen.
The researchers then compared the levels of parabens with the anogenital distance of the children and found that this was significantly shorter in boys who had been exposed to high concentrations of these endocrine-disrupting parabens inside the womb. The girls were also affected, although not as much, with the anogenital distance becoming longer.
“Previous research has linked this distance to a higher incidence of polycystic ovary syndrome, which affects 5–10% of women of childbearing age and is the most common cause of involuntary infertility,” explains Tina Kold Jensen.
Following up the children
Parabens bind to the same receptor as the sex hormone estrogen – a hormone normally only associated with girls and women, although boys and men also have some.
“We believe that this may explain the change in anogenital distance and the fact that the 3-month-old girls had lower serum concentrations of follicle-stimulating hormone, luteinizing hormone, dehydroepiandrosterone-sulfate and 17-hydroxyprogesterone. However, the long-term consequences of these findings are still unknown,” says Tina Kold Jensen.
The new study is the first to find a link among girls, and the findings therefore need to be confirmed. Another interesting aspect was that the children with the highest paraben exposure weighed less at 3 months old.
“This could not be explained by differences in breastfeeding. This suggests that parabens may also affect fetal and infant growth,” explains Tina Kold Jensen.
Although the European Union banned several parabens in 2015, methyl and ethyl parabens are still widely used in cosmetics, and propyl paraben is used in wet wipes. This continued use worries Tina Kold Jensen, who fears that we can only see the tip of the iceberg.
“The change in the anogenital distance is of concern since it suggests that the children are affected, and the effects on reproduction may just be the tip of the iceberg. Exposure to endocrine-disrupting chemicals, including parabens, may also be linked to neuropsychological development. We are currently investigating this to determine whether fetal exposure to parabens causes long-term adverse effects not only on the reproductive system but also on nervous system development,” concludes Tina Kold Jensen.