From the time they are foetuses up through their months first month of life, babies are exposed to a wide range of pollutants. Data remains fragmented, but some are starting to call for greater caution on the part of both parents and industry.
Of its entire existence, a human being never changes so quickly as it does in the uterus and its first year. “Organs are growing fast, and it’s a period of tremendous vulnerability,” says Dr Céline Fischer Fumeaux from the Woman-Mother-Child Department at Lausanne University Hospital (CHUV). Food from the mother – first through the umbilical cord then through breast milk – provide protection, but pollutants can still cross these natural barriers. “Unfortunately, children can develop the effects of any harmful exposure over the course of their entire lives.”
For example, an American study led in 2005 detected more than 287 chemicals in umbilical cord blood in 10 newborns. The substances ranged from pesticides to chemicals used in everyday products, residue from waste incineration and fossil fuel combustion. More recent research has also shown that the placental barrier can be crossed. In 2019, a team from the Centre for Environmental Sciences at the University of Hasselt in Belgium discovered soot particles in the placenta of 28 women. Its close location to a major road increased the amount of particles found.
Exposure to pollutants at birth is more complex, and can be by contact or by air. Switzerland’s neonatal services warn to take caution (see inset “Monitoring medical devices”). Breast milk, often the only food given to infants, is under careful study, because it may contain “lipophilic” chemicals, i.e. substances that attach to fats.
“When the mother draws from her fat stores to create milk, which is particularly high in fats, the pollutants built up in the adipose tissue can pass into the milk,” Dr Fischer Fumeaux says. “They are referred to as ‘persistent organic pollutants’ or POPs.”
Breast milk can also contain certain heavy metals.
But parents should not panic. “The level of POPs in breast milk is on the decline,” Dr Fischer Fumeaux says. “In Switzerland, concentrations of chemical compounds such as PCBs, dioxins and furans were halved between 2002 and 2009. And levels are below the danger threshold set by the WHO.”
In general, the benefits of breastfeeding far outweigh the potential risks. “Through her milk, the mother passes a large number of antibodies to her child,” Raphaël Serreau points out. “Powdered milk – even from organic farming – can contain pollutants.” For several years, the pharmacologist from the University of Burgundy and Institut Léonard de Vinci in Paris has been analysing chemicals present in breast milk, particularly profens. “Anti-inflammatory drugs such as Ibuprofen are commonly prescribed to alleviate pain in childbirth. A 2012 study showed that only a very low amount was passed to and ingested by breastfed babies. However, profens should be considered carefully during pregnancy, as they can affect foetal growth, impacting hepatic, thyroid and endocrine systems.”
More data is needed on the effects of exposure to chemicals, due to a variety of factors.
However, researchers around the world are picking up a cluster of clues and concerns around several substances. But most of the media attention definitely goes to endocrine disruptors, which are chemicals that interfere with hormonal balance. Ariane Giacobino, a geneticist and clinician at the Geneva University Hospitals (HUG), focuses on phthalates. These endocrine disruptors are present in plastic containers, including water bottles, pesticides and cosmetics such as sunscreen. “We exposed pregnant mice to these chemicals and discovered effects on the reproductive system of their offspring up to the third generation, with infertility problems, reduced testes weight or reduced anogenital distance. For this last factor, shorter distances in male subjects are associated with ‘feminisation’.” These results cannot simply be transposed as such to humans, but they do indicate a potential danger.
Researchers are also working to determine the carcinogenic effects of chemicals, meaning that they can cause or increase the frequency of cancer, and their mutagenic effects, meaning that they can cause mutations in the structure or number of chromosomes in cells.
“We’re also studying the neurotoxic effects of certain heavy metals, such as metals that can interfere with cerebral development in infants,” Dr Céline Fischer Fumeaux says. “Other more specific effects, which can alter kidney function or the blood system, are also being examined.”
One step in reducing young children’s exposure to these pollutants involves better informing parents. In September, the CHUV organised a symposium on the subject that brought together paediatricians, gynaecologists, lactation consultants, midwives, and other specialists. “Healthcare professionals must first understand the situation,” says Dr Céline Fischer Fumeaux, who co-organised the event. “They must be able to inform parents, who often need clarification on these topics.”
Parents can take concrete action right from when they decide they want a child. “And they should keep doing that throughout their lives,” Dr Fischer Fumeaux says. For airborne pollutants, you should air out you home once or twice a day, avoiding rush hours in cities, and use cleaning and gardening products with an environmentally friendly label. You should also be careful not to inhale fresh paint.
Other precautions involve substances that can be ingested. You should avoid food in plastic packaging, eat organic foods without pesticides, change Teflon cookware as soon as it is damaged, and so on.” Tap water is recommended. “Large marine fish should also be avoided due to the risk of mercury pollution.” Lastly, you should be careful with contact exposure. “Especially when it comes to cosmetics, less is more.”
Public authorities also play an important role in protecting the youngest children from pollutants. They regularly ban the use of certain chemicals by manufacturers, either as a precaution or as a result of scandals. For example, Bisphenol A has been banned from all childcare articles in Switzerland since 2012.
Chemical exposure is unclear in Switzerland. To change that, the Swiss Federal Office of Public Health launched a test research project in 2020 called the “Swiss Health Study” involving 1,000 people aged between 20 and 69 in the cantons of Bern and Vaud. Three substances known to be potentially harmful are being analysed: perfluorinated chemicals, glyphosate and heavy metals. A risk analysis report will be submitted to the Swiss Federal Council in 2022.
Newborns’ exposure to chemicals is a concern for the Neonatal Service at the CHUV. It monitors levels of DEHP, a phthalate (a group of substances derived from phthalic acid used in plastics) believed to be an endocrine disruptor. “DEHP is used in many plastics because it is flexible and resistant,” says Dr Céline Fischer Fumeaux from the Woman-Mother-Child Department at the CHUV. “It is useful for making small medical devices, such as tubes, for infants in intensive care. However, DEHP can leach into the bloodstream and respiratory tract, and onto the skin.” In 2015, an initial study showed that infants hospitalised at the CHUV could be subjected to multiple and repeated exposure, sometimes exceeding the tolerance thresholds. “Since then, the service has been identifying and minimising materials made with DEHP.”
Pesticides, dioxins and furans from waste incineration or engine combustion, PCBs are chemicals that remain in the environment for a very long time. For example, traces of PCBs can still be found in soil, even though their use (for example in industrial fats) was banned in Switzerland in 1986.
Cadmium, lead, zinc, copper and mercury are released into the atmosphere as a result of industrial activities and then end up in the food chain, both in land and water animals. These metals can be found in large predatory marine fish at the top of the food chain, such as tuna.