In placenta samples, the greatest difference in the expression pattern of RNAs was found between the rupture-of-membrane group [PPROM + PROM] and the labor-without-membrane-rupture group (FTB + sPTL), as nearly all RNAs were transcribed at different levels with statistical significance (P < 0.05), except for UBE2B mRNA. Here, UBE2B is linked to preterm premature rupture of the membranes.