Observation And Prediction Of Migration Of Placenta Previa In Early Pregnancy

Objective: Using two-dimensional and three-dimensional ultrasound,According to the ultrasound image at 38 weeks as the diagnostic standard,the pregnant women with placenta covering the inner cervix or the lower edge of the placenta to the inner cervix during the first trimester were followed up continuously,related clinical data were collected and the characteristics of ultrasound images.summarize the characteristics of placenta migration in the placenta previa state during the first trimester,and retrospectively analyze the relevant sonographic features of ultrasound that can predict the placenta migration,in order to assess the abnormal placental position in the first trimester.Methods: From April 2018 to June 2019,11 to 14 weeks of pregnancy,the prenatal ultrasound examination was performed at the Shengjing Hospital Department of Ultrasound,and the ultrasound performance measured by abdominal or perineum examination showed that the placenta completely covered the cervix.A total of 300 pregnant women were followed up with ultrasound results at 38 weeks.Among them,83 patients have a total of 7 ultrasound examinations once every 4 weeks.Twenty-one pregnant women with the placenta covering the inner cervix consistently as the case group,and 62 cases with the placenta returning to the normal position as the control group.Ultrasound examination uses GE Voluson E8 and E10 three-dimensional ultrasound diagnostic equipment to collect and store two-dimensional and three-dimensional images of eligible persons,post-processing the images,and collect relevant clinical medical history of the patient(including age,pregnancy history,cesarean section history and myoma of uterus,adenomyosis).According to the 38-week ultrasonography showing the distance between the lower margin of the placenta and the cervix.In the case group,21 patients with the lower margin of the placenta still reached or covered the cervix at 38 weeks.The control group :62 cases with complete clinical data were >2 cm,from the inner cervix at 38 weeks gestation and followed up every four weeks.Statistical analysis using SPSS 24.0 software,using the mean ± standard deviation to describe the analysis and assessment of the relationship between the gestational week and placenta previa;use t test or chi-square test to test whether each variable is related to the results of placenta previa,Calculate the total score of the risk of placenta previa in each pregnant woman,use the ROC curve to calculate the score to predict the AUC of PP,determine the best cut-off point,and get the sensitivity and specificity.P <0.05 is considered statistically significant.Results:(1)The proportion of pregnant women who showed a placenta previa state in the first trimester and migrated to the normal position during the late pregnancy was 93%.(2)From 15w0 d to 18w6 d,14 people(22.58%)migrated to the normal position,and the average distance between the lower edge of the placenta and the cervical ostium was 0.44 ± 0.90cm;35 people(56.45%)The placenta migrated to the normal position,and the average distance from the lower edge of the placenta to the cervix was 1.65 ± 1.66 cm;23 people(93.55%)migrated to the normal position from 23 weeks 0 days to 26 weeks 6 days.The average distance from the mouth was 4.60 ± 2.29cm;27 weeks,0 days,and 30 weeks and 6 days all migrated to the normal position,and the average distance from the lower edge of the placenta to the inner cervix was 5.81 ± 2.00 cm.The average value of the distance from the lower edge of the placenta to the inner cervix of the cervix is 6.31 ± 1.53 cm from week 0 to 31 of week 31;the average value of the distance from the lower edge of the placenta to the inner cervix of the cervix is 6.52 ± 1.25 cm.(3)The type of placenta previa(completely covers the inner cervix),the placenta position(posterior wall),the type of full placenta previa(main body cover),and umbilical cord entrance position(The lower parts)and the placenta fluid zone,each of these rise factors is given a score of 1.If the total score is greater than 3,the sensitivity is 76.2% and the specificity is 85.5%.The Youden index is 0.671.Conclusion:(1)Placenta previa state in the first trimester will gradually move to the normal position passively,and most of them will return to normal in the late pregnancy.(2)The distance between the lower edge of the placenta and the cervix is about 23 weeks to 27 weeks of pregnancy have the biggest change.(3)According to the type of placenta completely covers the cervix,the position of the umbilical cord entrance,the placenta position,the fluid area in the placenta,and whether the placenta is implanted,it is possible to predict whether the placenta can migrate to the normal position,and according to whether the placenta previa occurs The relevant ultrasound image features score the risk of placenta previa,and it is highly likely that it will migrate to a normal position if it is greater than 3 points.