(C-F) Sections of human normal third-trimester placentas post-partum (n=4 normal placentas) and IUGR-complicated placentas of the same gestational age (n=4 IUGR placentas) were stained for senescence-related markers of p15 (C), p16 (D), p21 (E), and p53 (F) in the syncytiotrophoblast (n=3 sections, derived from each normal and IUGR placenta). Percentages of positively stained syncytia were quantified (n= at least 12 fields of view from all sections). Scale bar, 100 µm. Arrowheads indicate syncytiotrophoblast cells. Data information: Values are means + SEM of at least three experimental repeats. Statistical significance was determined by unpaired two-tailed Student's t-test (*) p < 0.05; (**) p < 0.01; (***) p < 0.001. 