Objective: While the association between infection and inflammatory response in preterm labor (PTL) is well establish, the role of poor utero-placental perfusion and the fetal component in this condition is less clear.
Methods: Placentas from pregnancies complicated by PTL with premature rupture of membranes (P-PROM) and without (spontaneous PTL, S-PTL), were analyzed and compared to placentas retrieved from women who delivered >34 weeks of gestation (control) that were divided into spontaneous ruptured membrane (ROM) and spontaneous labor (S-Labor) sub-groups. Placental lesions were classified as lesions consistent with loss of integrity in the maternal circulation (M), maternal underperfusion, vascular (M1) and villous (M2) lesions, lesions consistent with fetal thrombo-occlusive disease, vascular (F1) and villous (F2) changes, and lesions consistent with maternal or fetal origin inflammatory responses (MIR and FIR, respectively).
Results: A significant increased rate of vascular lesions classified as M were detected in placentas from the PTL group (26.5%, n=68) as compared with the control group (11.1%, n=135), p=0.005. Inflammatory lesions, maternal and fetal origin, were significantly more common in the PTL group compared with the control group, p<0.001, and more common also in the P-PROM sub-group as compared with the S-PTL sub-group, p< 0.001.
Conclusion: Placentas from women with PTL demonstrate combined maternal vascular compromise in addition to maternal and fetal origin inflammatory changes. P-PROM is associated with increased rate of maternal and fetal origin inflammatory lesions, compared with spontaneous PTL, all suggesting involvement of different mechanisms in PTL.
Michal Kovo 1, Letizia Schreiber 2, Avi Ben-Haroush 3 , Lina Asli1 , Sarit Seadia 1, Abraham Golan 1, Jacob Bar 1
Departments of Obstetrics & Gynecology 1 and Pathology 2, the Edith Wolfson Medical Center, Holon and the Rabin Medical Center 3, Petah-Tikva,
Sackler Faculty of Medicine , Tel Aviv University, Tel Aviv, Israel