The relationship between prior cervical conization, cervical microbial colonization and preterm premature rupture of the membranes

The occurrence of prior cervical conization and the cervical microbial colonization was investigated in 38 women with idiopathic preterm labor, 35 women with preterm premature rupture of the membranes (PPROM) and 75 normal pregnant women at 26–34 weeks of gestation. Data were analyzed by Fisher's exact test (two-tailed). The frequency of prior cervical conization was significantly higher in PPROM patients compared to normal pregnant women ( P < 0.001) and to patients in preterm labor ( P < 0.01). Lactobacilli occurred with a lower frequency in patients with PPROM compared to patients in preterm labor ( P < 0.05) and control patients ( P = 0.0543) — and with a lower frequency in patients with prior cervical conization ( P < 0.05). All other microorganisms occurred with the same frequencies in all groups. The absence of lactobacilli may indicate changes in the cervical flora, which could increase the risk of PPROM. Prior cervical conization may impair the antimicrobial defense-mechanisms in the cervix, which could facilitate ascending microbial colonization. This may lead to a release of prostaglandins and proteolytic enzymes and subsequently preterm labor and rupture of the membranes.