A file image shows a 4-month-old fetus in an ultrasound image. (Photo by: BSIP/Education Images/Universal Images Group via Getty Images) Researchers have discovered microplastics in human placentas for the first time, shedding new light on the level of human exposure to such materials and giving rise to concern about its potential to interfere with fetal development.The study, published this month in the journal Environment International, found particles in the placentas of four healthy women who had normal pregnancies and births in Italy.