Genital defect in baby boys linked to moms’ chemical exposure
Mothers around a lot of endocrine disrupting chemicals at home or in jobs such as cleaners, hairdressers and laboratory workers during pregnancy are more likely to have baby boys with a genital defect, according to a new study in the south of France.
The study adds to mounting evidence that fetal exposure to chemicals that mimic people’s natural hormones may cause hypospadias, a condition where the opening of the urethra is on the underside of the penis rather than at the tip.
French researchers examined more than 600 children in the south of France and found that babies exposed to endocrine disrupting chemicals while their genitals were developing were more likely to suffer from hypospadias.
Half the boys had hypospadias and half did not. The risk for those exposed was 68 percent higher than the unexposed boys. The researchers ruled out baby boys with known genetic risks for such defects.
“This study is well-crafted and supports the thought that chemicals in the environment are affecting our genital well-being,”
said Dr. George Steinhardt, a pediatric urologist at the Helen DeVos Children’s Hospital in Grand Rapids, Michigan, who was not involved in the study. He added
“This is another little piece of the puzzle that says we are affected by these exposures,”
The defect, which can be minor or quite severe depending on how far the opening is from the tip, can lead to problems with urination and, later in life, sexual difficulty.
About 70 percent of deformities are relatively mild, Steinhardt said.
It is one of the most common genital defects in baby boys, and most cases require surgery, often done before they reach two years old. In the United States, an estimated five out of 1,000 boys are born annually with hypospadias, while Europe’s rate is slightly less than two out of 1,000.
The researchers estimated the unborn babies’ exposure by looking at their parents’ jobs and where they lived. Working with hormone disrupting chemicals and living in homes near heavy polluters were both linked to more baby boys having the defect. However, the researchers did say a limit of the study was attempting to estimate fetal exposure to such chemicals.
Mothers were most likely to have boys with hypospadias if they worked as a cleaner, hairdresser or beautician.
Some of the endocrine disrupting chemicals linked to the professions involved in the study were bisphenol-A (BPA), phthalates, polychlorinated compounds, alkylphenolic compounds and organic solvents.
Most exposures—78 percent—occurred in the window of development when babies’ genitals are forming.
“We found that fetal exposure to [endocrine disrupting chemicals] was a significant risk factor for hypospadias in our series. The types of substance having an impact on the phenotype were heterogeneous, but detergents, pesticides, and cosmetics accounted for 75 percent of the cases,”
the authors wrote in the study published in the European Urology journal this month.
The authors were not available for an interview.
The study doesn’t prove that the exposure caused hypospadias, as chemical exposure isn’t the only possible cause. However, it is plausible since such chemicals impact the developing endocrine system,
said Dr. Laurence Baskin, professor of urology and chief of pediatric urology at University of California, San Francisco, who added that it would be most likely due to a disruption in the boys’ androgen hormones while their penis was developing.
Other possible causes of the birth defect include older, obese mothers, and fertility or hormone treatments during pregnancy, according to the U.S. Centers for Disease Control and Prevention.
In reviewing potential causes of hypospadias, European and Australian pediatric researchers found that “having an affected family member is the highest identified risk factor so far.” In the European and Australian researchers’ report, which examined recent science of hypospadias causes, they also concluded that mothers’ chemical exposure might also cause the defects or raise the risk for those boys already predisposed through their genes.
One of the major strengths of the current study was the exclusion of a lot of children with known genetic risk factors for hypospadias, Baskin said.
“It’s an outstanding study with both age and culturally matched children,”
This wasn’t the first time scientists have found a link between certain chemicals and hypospadias. Mothers in southeast England who were heavily exposed to endocrine disrupting phthalates on the job were about three times as likely to have a baby boy with hypospadias. Phthalates are used in some cosmetics, fragrances, food packaging and PVC plastics.
In 2010, Italian researchers found that among 160 mothers, those who worked with more than one group of endocrine disrupting chemicals were four times as likely to have a baby boy with hypospadias.
Baskin said the French study could help stem hypospadias prevalence. He added :
“Nobody dies from hypospadias, most are cured with surgery, but if we can come up with some kind of prevention protocol, it could prevent a lot of surgeries and anxiety for families,”