Cervical stroma apoptosis in pregnancy

Objective: To determine whether the percentage of apoptotic nuclei is diffe rent in cervical stroma of pregnant laboring women compared with nonpregnan t women and pregnant nonlaboring women. Methods: We took cervical stromal biopsies during cesarean delivery at the level of the lower uterine segment from ten women in active labor and 13 wo men before labor. In addition, we took biopsies of cervical stroma at the l evel of the internal cervical os from hysterectomy specimens in ten reprodu ctive-aged women. Cryosections were then analyzed using terminal deoxynucle otidyl transferase-mediated deoxyuridine triphosphate nick-end labeling sta ining. Tissue specimens were analyzed with ligation-mediated polymerase cha in reaction to visualize nucleosomal ladders characteristic of apoptosis. T o detect a 10% difference in the percentage of apoptotic cells per subject between study groups assuming a power of 0.90, an alpha of .05 in approxima tely ten subjects per group was needed. Results: The median percentage of apoptotic nuclei was 0.7 (interquartile r ange 0.4, 1.4) for the nonpregnant group, 7.5 (interquartile range 6.6, 11. 2) for the pregnant nonlaboring group, and 11.6 (interquartile range 8.3, 1 6.7) for the pregnant laboring group (P < .001). The percentage of apoptoti c nuclei differed significantly across the three study groups. Using ligati on-mediated polymerase chain reaction, nucleosomal ladders were seen in the specimens from pregnant women but not in the specimens from nonpregnant wo men, confirming the increase in stromal apoptosis seen with pregnancy. Conc lusion: Apoptosis of cervical stromal cell's may play a role in the remodel ing of the cervix during pregnancy and contribute to cervical changes durin g labor. (C) 2001 by The American College of Obstetricians and Gynecologist s.