Least Square Means (LS Mean) of Chorion Thickness by Gestational Age, excluding Histologic Chorioamnionitis, where all preterm and term subjects have been grouped and compared to PPROM subjects once all samples with histologic chorioamnionitis have been excluded.

P less than 0.01 at the Rupture site; P less than 0.004 at the Distant site.
PPROM =  Preterm, premature rupture of membranes (subjects between 24 and 34 weeks following confirmation of rupture of membranes by physical exam).
Preterm Labor  =  subjects between 24 and 34 weeks of gestation with spontaneous preterm labor.
Preterm, No Labor  =  subjects between 24 and 34 weeks of gestation delivered preterm without labor exposure.
Term  =  subjects between 37 and 41 weeks with labor.
Term, No Labor  =  subjects between 37 and 41 weeks without exposure to labor.
Rupture  =  sample of membrane collected at site of rupture.
Distant  =  sample of membrane collected from an area distant to rupture site, most commonly near the placenta.