A team at Lanzhou University which discovered several years ago that PM2.5 carbon nanoparticles affect the number of pregnancies has estimated that the risk for miscarriage at the first pregnancy may be up to 70 %. The 2 years study, based on isotope tracer experiments in mice, found damage to the placenta, to progesterone and estradiol secretion and to the number and quality of blood vessels in the placenta.
China Bio news release, April 21, 2014