An alarming new study in the journal Environmental International documents the first ever detection of microplastics inside the human placenta. While more research will be needed in order to determine if this directly harms the developing fetus, the revelation that these particles can penetrate the placenta raises a number of concerns.
Microplastics are particles measuring less than five millimeters, which are produced as larger plastic objects degrade. They have become a major environmental hazard over the past few decades, and are now present in huge numbers throughout the world’s oceans and in the soil and rivers of all seven continents.
Their presence inside the human body is nothing new, although given the role of the placenta in policing the transfer of material between a fetus and its mother, it is essential that pollutants such microplastics don’t breach this barrier.
To conduct their study, researchers collected small sections of placentas from six women. After dissolving and filtering these samples, the study authors were left with 12 microplastic particles, originating in four of the six placentas.
This may seem like a small number, but it’s important to note that the researchers only analyzed about four percent of each placenta, so it’s likely that many more particles may be present in these organs.
All 12 microplastics measured less than ten micrometers in diameter, with two being smaller than five micrometers, meaning they could easily be transported in the blood. However, the study authors are unsure exactly how these particles might have entered the mothers’ bloodstream to begin with, as it’s impossible to tell if they came through the respiratory system or the gastrointestinal system.
What they do know, however, is that once inside the body, microplastics can reach all levels of placental tissue. Indeed, of the 12 particles, five were found on the fetal side of the placenta, four were located on the maternal side and the remaining three were found in the membranes that protect the amniotic fluid.
All of these particles were pigmented using compounds that are typically used to color plastics, paints and cosmetics. For example, one of the microplastics was stained with iron hydroxide oxide yellow, which is often used for the coloration of polymers and make-up, while several contained copper phthalocyanine, which is used in finger paints.
Fortunately, all of the mothers in this study gave birth to healthy babies, although that’s not to say that the presence of microplastics in the placenta should be considered completely safe. Research has shown that such particles can disrupt immune signaling and the utilization of energy stores once inside the body, leading the study authors to suggest that fetuses exposed to microplastics may develop complications.
“Due to the crucial role of placenta in supporting the foetus development and in acting as an interface between the latter and the external environment, the presence of exogenous and potentially harmful (plastic) particles is a matter of great concern,” they explain.
“Further studies need to be performed to assess if the presence of [microplastics] in human placenta may trigger immune responses or may lead to the release of toxic contaminants, resulting harmful for pregnancy.”