Macroscopic and microscopic analysis of placentas and embryos after maternal exposure to PEG-SWCNTs. A. A Fetus showing abnormal development (left) is compared to one from a control female (right). B. The placenta nourishing the abnormal fetus (left) appeared abnormally vascularised and slightly smaller than the one from the control fetus (right). C-F. Reduced vascularisation in abnormal placentas (C) compared to normal ones (D) was demonstrated in Azan-Mallory stained sections; similar results were obtained by immunostaining, using the anti-CD31 antibody: (E) placentas nourishing abnormal fetuses displayed reduced CD31 expression, compared to normal tissue (F).