Microplastics in maternal blood, fetal appendages, and umbilical vein blood.

Microplastics (MPs) have been detected in placenta and amniotic fluid, but there is no research on whether MPs exist in the other two fetal appendages: fetal membrane and umbilical cord. Additionally, the existence of MPs in umbilical vein blood remains unexplored. Furthermore, it is unclear whether MPs in maternal blood are associated with those in umbilical vein blood and fetal appendages. In this study, we selected 12 full-term pregnant people who delivered by cesarean section, and finally detected 16 kinds of MPs from maternal blood, fetal appendages, and umbilical vein blood by laser direct infrared (LDIR). Polyamide accounted for the highest proportion in the six kinds of samples, followed by Polyurethane. The total MPs median abundance in six kinds of samples were umbilical cord, maternal blood, fetal membrane, amniotic fluid, placenta and umbilical vein blood from high to low, and the specific values were 10.397 particles/g, 8.176 particles/g, 6.561 particles/g, 4.795 particles/g, 4.675 particles/g, and 2.726 particles/g respectively. Moreover, more than 90 % of MPs measured between 20 and 100 μm in diameter. We also found that MPs abundance in amniotic fluid increased with the increase of maternal age (R=0.64, p=0.025) and body mass index before pregnancy (r = 0.59, p= 0.049). However, no statistically significant association was found between lifestyle factors and MPs abundance. Future studies should aim to expand the sample size for further investigation.