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169: Short cervix is not characterized by placental apoptosis: Examining the maternal plasma free fetal DNA (ffDNS) in patients at risk for preterm labor

      Objective

      The association between apoptotic and degenerative changes in the syncytiotrophoblast and the release of ffDNA to the maternal circulation has been demonstrated by in vitro studies under hypoxic conditions. Ischemia is one of the etiopatogenic conditions leading to spontaneous preterm delivery. The objective of this study was to evaluate the capability of ffDNA to increase the accuracy of cervical length in the prediction of preterm labor

      Study Design

      Fifty-seven women with cervical length assessment at 22-24 weeks were included in the study, and divided in 3 groups: 1) Short cervix (<15 mm) delivered at term (T=20); 2) Short cervix delivered before 37 weeks (PT=15); and 3) Patients who delivered at term with normal cervical length (N=22). Maternal plasma samples were collected between 18 to 24 weeks of gestational age. Real-time polymerase chain reaction (PCR) using TaqMan primers and probes directed against DYS14 gene sequences were used to quantified ffDNA in the maternal plasma. Statistical analysis was done using ANOVA test and Pearson′s correlation

      Results

      ffDNA was detectable in almost all cases (56/57). The median gestational age at delivery for group PT and T were 26+1 (range 22-33) and 39+3 (range 37-41) weeks. There was no significant difference between the 3 groups (PT= 11.06 ge/ml; T= 8.24 ge/ml; N=6.71 ge/ml p=0.27). Similarly, no correlation was observed between ffDNA and gestational age at delivery (r= −0.23; p=0.07)

      Conclusion

      ffDNA is not increased at midtrimester in patients at risk for preterm delivery determined by a short cervix. These findings do not support the role of apoptotic and degenerative changes in the syncytiotrophoblast as a main factor in the triggering of spontaneous preterm delivery