PREDICTION OF PRETERM LABOR FROM THE IDENTIFICATION OF THE MOST SIGNIFICANT RISK FACTORS

Objective. To develop and introduce a new preterm labor-predicting system that is based on the identification of the most significant risk factors. Subjects and methods. The labor histories of 25297 puerperas who had given live births in the obstetric facilities of the Tula Region in 2006 to 2008 were retrospectively analyzed. Groups 1a and 1b comprised 149 and 1243 puerperas whose delivery occurred at 22—31 and 32-36 weeks gestation, respectively; Group 2 (control) included 23905 women who had full-term pregnancy. The pregnant women who had been registered at 20—24 weeks gestation in the maternity consulting centers of the Tula Region and whose pregnancy ended in delivery in 2009 were prospectively examined. Results. Most risk factors increase the probability of preterm labor (PL) after 32 weeks gestation. Medical risk factors have a stronger influence on early PL than on late ones. The major risk factors of early PL are multiple pregnancy (75.8%) and isthmic-cervical insufficiency (54.9%). A significantly increased risk is observed when the cervical canal is 25 mm or less in length in combination with V- and U-shaped form of the internal pharynx. PL with preterm rupture of fetal membranes occurred irrespective of the state of the cervix uteri. Conclusion. The main direct cause of PL in the Tula Region is the spontaneous onset of labor, the leading risk factors of which were multiple pregnancy and incompetence of the cervix uteri. A pathological change in the (V- and U-shaped) form of the internal pharynx in combination with the shortening of the cervical canal to 25 mm or less is a prognostically poor ultrasound criterion for PL.

preterm labor, risk factors, multiple pregnancy, isthmic-cervical insufficiency