Study On The Prediction Of Spontaneous Preterm Delivery By Ultrasound During The Second Trimester Of Pregnancy

Objective: To evaluate the value of cervical length(CL),uterocervical angle(UCA)and cervical consistency index(CCI)measured by transvaginal ultrasound in predicting spontaneous preterm birth(s PTB),and to provide diagnostic basis for clinical diagnosis.Methods: The pregnant women with gestational cycle of 20-23 + 6 weeks were selected.The cervical diameter before and after pressure was applied to the cervix was calculated by using the color Doppler ultrasound diagnostic instrument of General Electric Company(GE)voluson E10,equipped with a probe frequency of5-7.5m Hz,and the sagittal plane of the cervix was obtained through vagina or the length and angle of cervix were measured.After tracking the pregnancy outcome,it was divided into premature group and non premature group.The statistical analysis obtained the above three methods to predict the efficacy of spontaneous premature delivery among the groups,and established the dual logistic regression model.Results: In this study,126 effective cases were included,with an average age of 29 years old.The number of preterm delivery was 45,and the number of non preterm delivery was 81.The average cervical length and average cervical angle of preterm delivery group were 25.33 mm and 113.42 respectively.The average cervical consistency index was 57.00%.The average cervical length and angle of non preterm labor group were 34.10 mm and 84.46 respectively.The average cervical consistency index was 74.41%.When the cutoff value of CL was set at 26 mm,the sensitivity and specificity were the best,which were 0.80,0.79,0.68 and 0.88 respectively.When the cut-off value of UCA is equal to 96。.The area under the curve was 0.86,the sensitivity was 0.84 and the specificity was 0.82.When the cut-off value of CCI was65%,the sensitivity and specificity were 0.93 and 0.85,respectively.Logit(P)=0.97+4.37 x UCA-3.52 x CL-4.59 x CCI.The sensitivity and specificity of the equation in predicting spontaneous preterm birth were 0.95 and 0.93,respectively.Conclusion: The use of cervical length,uterocervical angle and cervical consistency index in the middle pregnancy can predict the occurrence of spontaneous premature labor in pregnant women.CCI is the best diagnosis efficiency in preterm group in each period,and it can find the changes of cervical tissue in pregnant women earlier in theory,and provide a new method for early diagnosis and early treatment.