The Ultrasonic Evaluation On Healing Condition Of Uterus Scar After Cesarean Section And Analysis Of Its Influential Factors

Objectives To observe uterine cesarean section scar healing of different periods by transvaginal ultrasound, summarize the characteristics of ultrasonic manifestations of previous cesarean scar defects, and analyze its risk factors.Methods 183 cases of maternal during September 2014 to September 2015 who in North China University of Science and Technology Affiliated Hospital for cesarean sections and postpartum 6 weeks, 3 months, 6 months were examined by transvaginal ultrasound in our hospital as the research object. Observed uterine scar and record the related ultrasonographic features and parameters(including uterine position, scar defect size, echo,shape, peripheral blood, uterine incision residual muscle layer thickness, incision healing from cervical mouth distance, cervical length, etc). Divided into scar defect group(41cases) and scar healed well group(142 cases) according to observations. Using a unified questionnaire to collect the clinical data(including age, height, body mass index, gravidity,parity, number of cesarean section, neonatal birth weight, depth of amniotic fluid,pregnancy weight gain and blood pressure, postpartum blood cells, surgeon seniority,length of operation time, postoperative bleeding volume in 24h; whether it was vaginal delivery, selective caesarean section production or emergency cesarean section production;whether exsited fetal distress, preterm premature rupture of membranes, pregnancy hypertension, anemia, puerperal infection and so on).All data was strictly proofread, and database was established by Excel 2007, using SPSS 17 statistical software for statistical analysis. The measurement data of normal distribution to represent, measurement data of skewed distribution with a median(four point interval) representation, and measurement data compared by t test, rank-sum test and one-way repeated measures ANOVA, intra group pairwise compared by Bonferroni test; two groups or multiple sample rate and composition ratio compared with the chi square test; the regression relationship between categorical variables and multiple factors by Logistic regression analysis. There was statistically significant of P<0.05.Results 1 Previous cesarean scar defect ultrasound manifestations and parameters were analyzed of following results:(1) Postpartum 6 weeks, 3 months, 6 months previous cesarean scar defects length, width, depth gradually shortened(P<0.05). The difference of scar defects residual muscle layer thickness and distance from previous cesarean scar defects to the internal cervical os were not statistically significant(P>0.05).(2) 41 cases of cesarean section after 6 weeks of previous cesarean scar defect, 33 cases showed anechoic or hypoechoic area(80.5%), 8 cases showed low echo or middle and low echo(19.5%);postoperative 3 months and 6 months previous cesarean scar defects showed anechoic. It showed no obvious blood flow signal surrounding previous cesarean scar defect by Color Doppler ultrasound.(3) Among previous cesarean scar defect shapes, triangle is the most common, accounted for about 65.9%, wedge about 21.9%, semicircular about 9.8%,irregular shape about 2.4%. 2 The single factor analysis: In multiple single factors analysis(about twenty-eight single factors), there were statistically significant differences between two groups in the eight single factors, including production time(Z=-2.663, P=0.008),number of cesarean section(Z=-2.424, P=0.015), incision distance from the intracervical mouth(Z=-2.458, P=0.014), emergency cesarean section production(2c =7.591, P=0.006),fetal distress(2c =6.553, P=0.010), surgeon seniority(2c =10.945, P=0.001), postpartuminfection(2c =38.742, P=0.000), uterine position(2c =31.239, P=0.000). 3 Analysis of multiple factors: Risk factors of previous cesarean scar defects were repeated cesarean section [OR=92.916, 95%CI(13.705-629.964), P=0.000], surgeon with low seniority[OR=32.823, 95%CI(8.196-131.442), P=0.000], puerperal infection [OR=11.639,95%CI(3.232-41.905), P=0.000], retroposition of uterus [OR=8.788, 95%CI(2.635-29.310),P=0.000] and incision location near the intracervical mouth [OR=8.304, 95%CI(1.863-37.013), P=0.006].Conclusions 1 The ultrasonic features of previous cesarean scar defect: the remaining myometrial thickness become thinner, and the myometrium is discontinuous, while the serosal layer is complete. The defect is anechoic or hypoechoic area, which is connect with uterine cavity. It usually shows no obvious blood flow signal around the defect. The most commonly shape of previous cesarean scar defects is triangular. 2 Early after cesarean section, as the postpartum time prolonging, the size of cesarean scar defect is gradually decreased. 3 Repeatedly cesarean section, puerperal infection, retroposition of uterus, lowcut position and the surgeon inexperience are risk factors for the formation of previous cesarean scar defects.