Accuracy of sonographic lower segment thickness and prediction of vaginal birth after caesarean in a resourced-limited setting; Prospective study.

OBJECTIVES: To assess the accuracy of ultrasound measurement of the lower uterine segment (LUS) thickness against findings at laparotomy, and to investigate its correlation with the success rate of vaginal birth after one previous caesarean delivery (CD) in a resource-limited setting. DESIGN: Prospective study. SETTING: Obstetrics and Gynaecology department in a tertiary hospital in Ghana. POPULATION: Women with one previous CD undergoing either a trial of labour (TOLAC) or elective CD. METHODS: Myometrial lower uterine segment thickness (mLUS) and full lower uterine segment thickness (fLUS) were measured with transvaginal ultrasound (TVUS). The women were managed according to local protocols with the clinicians blinded to the ultrasound measurements. The LUS was measured intraoperatively for comparison with ultrasound measurements. MAIN OUTCOME MEASURES: Lower uterine segment findings at laparotomy, successful vaginal birth. RESULTS: A total of 311 pregnant women with one previous CD were enrolled; 147 women underwent elective CD and 164 women underwent a TOLAC. Of the women that underwent TOLAC, 96 (58.5%) women had a successful vaginal birth. The mLUS was comparable to the intraoperative measurement in the elective CD group with LUS thickness <5 mm (bias of 0.01, 95% CI -0.10 to 0.12 mm) whereas fLUS overestimated LUS <5 mm (bias of 0.93, 95% CI 0.80-1.06 mm). Successful vaginal birth rate correlated with increasing mLUS values (odds ratio 1.30, 95% CI 1.03-1.64). Twelve cases of uterine defect were recorded. LUS measurement ≤2.0 mm was associated with an increased risk of uterine defects with a sensitivity of 91.7% (95% CI 61.5-99.8%) and specificity of 81.8% (95% CI 75.8-86.8%). CONCLUSION: Accurate TVUS measurement of the LUS is technically feasible in a resource-limited setting. This approach could help in making safer decisions on mode of birth in limited-resource settings.

Localization of Catecholaminergic Neurofibers in Pregnant Cervix as a Possible Myometrial Pacemaker.

In eutocic labor, the autonomic nervous system is dominated by the parasympathetic system, which ensures optimal blood flow to the uterus and placenta. This study is focused on the detection of the quantitative presence of catecholamine (C) neurofibers in the internal uterine orifice (IUO) and in the lower uterine segment (LUS) of the pregnant uterus, which could play a role in labor and delivery. A total of 102 women were enrolled before their submission to a scheduled cesarean section (CS); patients showed a singleton fetus in a cephalic presentation outside labor. During CS, surgeons sampled two serial consecutive full-thickness sections 5 mm in depth (including the myometrial layer) on the LUS and two randomly selected samples of 5 mm depth from the IUO of the cervix. All histological samples were studied to quantify the distribution of A nerve fibers. The authors demonstrated a significant and notably higher concentration of A fibers in the IUO (46 ± 4.8) than in the LUS (21 ± 2.6), showing that the pregnant cervix has a greater concentration of A neurofibers than the at-term LUS. Pregnant women's mechanosensitive pacemakers can operate normally when the body is in a physiological state, which permits normal uterine contractions and eutocic delivery. The increased frequency of C neurofibers in the cervix may influence the smooth muscle cell bundles' activation, which could cause an aberrant mechano-sensitive pacemaker activation-deactivation cycle. Stressful circumstances (anxiety, tension, fetal head position) cause the sympathetic nervous system to become more active, working through these nerve fibers in the gravid cervix. They might interfere with the mechano-sensitive pacemakers, slowing down the uterine contractions and cervix ripening, which could result in dystocic labor.

S. Rao Spiral Suturing (SRSS) of Lower Uterine Segment: An Innovative Hemostatic Technique in the Management of Placenta Previa and Accreta Spectrum.

Objective: The study aimed to demonstrate the efficacy and safety of an innovative hemostatic technique in managing Placenta Previa and Accreta Spectrum by S. Rao Spiral Suturing (SRSS) of a lower uterine segment. Method: In this retrospective study conducted at Department of Obstetrics & Gynecology Unit-II of Nishtar Medical University, Multan between December 2018 to January 2021, one hundred and thirty consenting patients' clinical records were reviewed with major degree placenta previa/placenta accrete spectrum, either operated electively or presented in an emergency, with or without a history of previous cesarean section. The enrolled patients underwent SRSS, procedure's efficacy and safety were measured by the number of obstetrical hysterectomies, the time required for the procedure, estimated blood loss, blood transfusion volume, need for any other hemostatic technique, bladder trauma, pelvic infection, scar site hematoma or abscess, sepsis, duration of hospital stay and maternal mortality. Results: Out of 130 patients, 17(12.6%) had Placenta Accreta, 86(66.3%) Increta, and 27(21%) Percreta. The Placenta location was anterior dominant in 102(78.4%) cases and posterior in 17(8.4%). Of the patients who underwent surgery, only two required obstetrical hysterectomy due to uncontrolled bleeding. The procedure took three to five minutes in 127 patients and five to seven minutes in three patients. Regarding intraoperative blood transfusion, 54.6% of patients were transfused 1000-2000 ml blood, and 5.38% required > 3000 ml. No blood transfusion was required postoperatively in any patient. Postpartum hemorrhage, infection, fever, and sepsis were not observed in any patient postoperatively. None of the patients suffered bladder injury. All patients were discharged as per routine. Conclusion: SRSS is an innovative, safe, effective, and simple suturing technique for patients with Placenta Previa and Accreta spectrum.

The role of transvaginal ultrasound in the third-trimester evaluation of patients at high risk of placenta accreta spectrum at birth.

BACKGROUND: Transvaginal ultrasound imaging has become an essential tool in the prenatal evaluation of the lower uterine segment and anatomy of the cervix, but there are only limited data on the role of transvaginal ultrasound in the management of patients at high risk of placenta accreta spectrum at birth. OBJECTIVE: This study aimed to evaluate the role of transvaginal sonography in the third trimester of pregnancy in predicting outcomes in patients with a high probability of placenta accreta spectrum at birth. STUDY DESIGN: This was a retrospective analysis of prospectively collected data of patients presenting with a singleton pregnancy and a history of at least 1 previous cesarean delivery and patients diagnosed prenatally with an anterior low-lying placenta or placenta previa delivered electively after 32 weeks of gestation. All patients had a least 1 detailed ultrasound examination, including transabdominal and transvaginal scans, within 2 weeks before delivery. Of note, 2 experienced operators, blinded to the clinical data, were asked to make a judgment on the likelihood of placenta accreta spectrum as a binary, low or high-probability of placenta accreta spectrum, and to predict the main surgical outcome (conservative vs peripartum hysterectomy). The diagnosis of accreta placentation was confirmed when one or more placental cotyledons could not be digitally separated from the uterine wall at delivery or during the gross examination of the hysterectomy or partial myometrial resection specimens. RESULTS: A total of 111 patients were included in the study. Abnormal placental tissue attachment was found in 76 patients (68.5%) at birth, and histologic examination confirmed superficial villous attachment (creta) and deep villous attachment (increta) in 11 and 65 cases, respectively. Of note, 72 patients (64.9%) had a peripartum hysterectomy, including 13 cases with no evidence of placenta accreta spectrum at birth because of failure to reconstruct the lower uterine segment and/or excessive bleeding. There was a significant difference in the distribution of placental location (X2=12.66; P=.002) between transabdominal and transvaginal ultrasound examinations, but both ultrasound techniques had similar likelihood scores in identifying accreta placentation that was confirmed at birth. On transabdominal scan, only a high lacuna score was significantly associated (P=.02) with an increased chance of hysterectomy, whereas on transvaginal scan, significant associations were found between the need for hysterectomy and the thickness of the distal part of the lower uterine segment (P=.003), changes in the cervix structure (P=.01), cervix increased vascularity (P=.001), and the presence of placental lacunae (P=.005). The odds ratio for peripartum hysterectomy were 5.01 (95% confidence interval, 1.25-20.1) for a very thin (<1-mm) distal lower uterine segment and 5.62 (95% confidence interval, 1.41-22.5) for a lacuna score of 3+. CONCLUSION: Transvaginal ultrasound examination contributes to both prenatal management and the prediction of surgical outcomes in patients with a history of previous cesarean delivery with and without ultrasound signs suggestive of placenta accreta spectrum. Transvaginal ultrasound examination of the lower uterine segment and cervix should be included in clinical protocols for the preoperative evaluation of patients at risk of complex cesarean delivery.

Lower uterine segment thickness assessed by transvaginal ultrasound before labor induction: reproducibility analysis and relationship with delivery outcome.

OBJECTIVES: To evaluate the reproducibility of lower uterine segment (LUS) thickness measurement before induction of labor (IOL), and to assess the relationship between LUS thickness and IOL outcomes. METHODS: This was a prospective cohort study of pregnant women undergoing IOL at term, conducted in a single tertiary hospital between July 2014 and February 2017. Women with a singleton pregnancy at ≥ 37 weeks' gestation, with a live fetus in cephalic presentation and a Bishop score of ≤ 6, were eligible for inclusion. Both nulliparous and parous women, and those with a previous Cesarean section (CS), were eligible. All women underwent transvaginal ultrasound assessment before IOL admission, and cervical length and LUS thickness were measured offline after delivery. Maternal and obstetric characteristics and Bishop score were recorded. The main outcome was the overall rate of CS after IOL, and secondary outcomes were CS for either failure to progress in the active phase of labor or failed IOL, and CS for failed IOL only. Interobserver agreement for measurement of LUS thickness between two operators was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis with the ANOVA test to evaluate systematic bias. Univariable and multivariable analysis were employed to evaluate the relationship between clinical and sonographic characteristics and IOL outcomes. RESULTS: Of 265 women included in the analysis, 195 (73.6%) had a vaginal delivery and 70 (26.4%) required a CS after IOL. Reproducibility analysis showed excellent interobserver agreement for the measurement of LUS thickness (ICC, 0.96 (95% CI, 0.93-0.98)). On Bland-Altman analysis, the mean difference in LUS thickness between the two operators was 0.15 mm (95% limits of agreement, -1.84 to 2.14 mm), and there was no evidence of systematic bias (ANOVA test, P = 0.46). Univariable analysis showed that LUS thickness was associated significantly with overall CS (P = 0.002), CS for failure to progress in the active phase of labor or failed IOL (P = 0.03) and CS for failed IOL (P = 0.037). On multivariable logistic regression analysis, LUS thickness was an independent predictive factor for overall CS (odds ratio (OR), 1.149 (95% CI, 1.031-1.281)) and CS for failure to progress in the active phase of labor or failed IOL (OR, 1.226 (95% CI, 1.039-1.445)). CONCLUSIONS: In women undergoing IOL at term, measurement of LUS thickness is feasible and reproducible, and is associated significantly with IOL outcome. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Evaluation of the usefulness of ultrasound measurement of the lower uterine segment before delivery of women with a prior cesarean delivery: a randomized trial.

BACKGROUND: The main reason to avoid trial of labor after cesarean delivery is the possibility of uterine rupture. Identifying women at risk is thus an important aim, for it would enable women at low risk to proceed with a secure planned vaginal birth. OBJECTIVE: To evaluate the impact of proposing mode of delivery based on the ultrasound measurement of the lower uterine segment thickness on a composite outcome of maternal-fetal mortality and morbidity, compared with usual management, among pregnant women with a previous cesarean delivery. STUDY DESIGN: This multicenter, randomized, controlled, parallel-group, unmasked trial was conducted at 8 referral university hospitals with a neonatal intensive care unit and enrolled 2948 women at 36 weeks 0 days to 38 weeks 6 days of gestation with 1 previous low transverse cesarean delivery and no contraindication to trial of labor. Women in the study group had their lower uterine segment thickness measured by ultrasound. Those with measurements >3.5 mm, were encouraged to choose a planned vaginal delivery, and those with measurements ≤3.5 mm, were encouraged to choose a planned repeat cesarean delivery. This measurement was not taken in the control group; their mode of delivery was decided according to standard management. The primary outcome was a composite criterion comprising maternal mortality, uterine rupture, uterine dehiscence, hysterectomy, thromboembolic disease, transfusion, endometritis, perinatal death, or neonatal encephalopathy. Prespecified secondary outcomes were repeat cesarean deliveries, elective or after trial of labor. RESULTS: The study group included 1472 women, and the control group included 1476 women. These groups were similar at baseline. The primary outcome occurred in 3.4% of the study group and 4.3% of the control group (relative risk, 0.78; 95% confidence interval, 0.54-1.13: risk difference, -1.0%; 95% confidence interval, -2.4 to 0.5). The uterine rupture rate in the study group was 0.4% and in the control group 0.9% (relative risk, 0.43; 95% confidence interval, 0.15-1.19). The planned cesarean delivery rate was 16.4% in the study group and 13.7% in the control group (relative risk, 1.21; 95% confidence interval, 1.00-1.47), whereas the rates of cesarean delivery during labor were 25.1% and 25.0% (relative risk, 1.01; 95% confidence interval, 0.89-1.14) in the study and control groups, respectively. CONCLUSION: Ultrasound measurements of lower uterine segment thickness did not result in a statistically significant lower frequency of maternal and perinatal adverse outcomes than standard management. However, because this study was underpowered, further research should be encouraged.

First-trimester ultrasound diagnostic features of placenta accreta spectrum in low-implantation pregnancy.

OBJECTIVE: Low-implantation pregnancy (LIP) is an important marker for the diagnosis of placenta accreta spectrum (PAS) in the first trimester. Many grayscale and color Doppler ultrasound markers of PAS have been defined in the second and third trimesters of pregnancy, but have not been studied in the first trimester. The aim of this study was to determine whether PAS sonographic markers could be used in the first trimester to differentiate patients with LIP who develop PAS from those who do not. METHODS: This was a retrospective case-control study of women who delivered at our institution between 2009 and 2019. Cases were women with PAS who delivered by Cesarean hysterectomy and who had undergone first-trimester ultrasound demonstrating LIP. Controls were women with persistent placenta previa without PAS who delivered by Cesarean section without postpartum hemorrhage and who had undergone first-trimester ultrasound demonstrating LIP. Sonographic images were reviewed by an investigator blinded to pregnancy outcome and ultrasound reports. Images were reviewed for presence of abnormal uteroplacental interface, increased lower uterine segment hypervascularity and placental lacunae, with or without swirling on grayscale or color Doppler ultrasound. RESULTS: Following review of the electronic health records, 21 cases and 46 controls met the inclusion criteria. Placental lacunae were present in 18/21 (85.7%) cases and 7/46 (15.2%) controls (odds ratio (OR), 33.4; 95% CI, 7.7-144.4; P < 0.001). The number of lacunae was significantly higher in cases compared with controls, with a median of five lacunae present in cases compared with a median of one lacuna in controls (P < 0.001). The median size of the lacunae was also significantly larger in cases compared with controls, measuring 10.03 (interquartile range (IQR), 7.3-12.05) mm and 4.15 (IQR, 4.05-5.05) mm, respectively (P = 0.001). Lacunae swirling on grayscale or color Doppler ultrasound was noted only in PAS cases, with 10/12 (83.3%) having swirling on grayscale ultrasound and 12/12 (100%) having swirling on color Doppler (P < 0.001). Presence of an abnormal uteroplacental interface was also observed only in PAS cases, at a rate of 17/20 (85.0%) (P < 0.001). Lower uterine segment (uterovesical, subplacental and/or intraplacental) hypervascularity was present in 14/14 (100%) cases and only 1/12 (8.3%) controls (P < 0.001). CONCLUSION: In women at risk of PAS, ultrasound markers of PAS can and should be assessed as early as in the first trimester. The use of a first-trimester prenatal ultrasound screening protocol and standardized approach to ultrasound examination in at-risk mothers may help increase detection of PAS and enable planning for optimal management of affected pregnancies. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Intrapartum ultrasound measurement of the lower uterine segment thickness in parturients with previous scar in labor: a cross-sectional study.

BACKGROUND: There is a lack of reliable methods to estimate the risk of uterine rupture or dehiscence during a trial of labor in women with previous cesarean sections. This study aimed to assess the lower uterine segment and myometrial thickness by ultrasonography in women with previous cesarean sections during labor and assess their association with the uterine defect. METHODS: A cross-sectional study was conducted on 161 women in the active phase of labor having one previous cesarean section. The study was conducted et al.-Azhar University Hospital, Assiut City, Egypt, from March 2018 to March 2019. Ultrasound measurements of lower uterine segment thickness and myometrial thickness were conducted by vaginal and abdominal ultrasound by two observers. The correlation of both thicknesses with the uterine defect was analyzed. RESULTS: Uterine defects were reported in 42 women (25.9%), uterine rupture in four women (2.5%), and dehiscence in 38 women (23.5%). The uterine defects were not associated with maternal factors (maternal age, gestational age at labor, body mass index, birth weight, interpregnancy, and inter-delivery interval). Receiver operating curve analysis demonstrated that lower uterine segment thickness was linked with uterine defect, with an area under the curve of 60% (95% CI, 51-70%, P = 0.044). Myometrial thickness was also linked to the uterine defect, with an area under the curve of 61% (95% CI, 52-71%, P = 0.025). Full lower uterine segment thickness of 2.3 mm and myometrial thickness of 1.9 mm were the cutoff value with the best combination of sensitivity and specificity for the uterine defect. Lower uterine segment thickness (OR = 0.49, 95%CI 0.24-0.96) and myometrial thickness (OR = 0.44, 95%CI 0.20-0.94) were significantly associated with the uterine defect. Lower uterine segment thickness (OR = 0.41, 95%CI 0.22-0.76) and myometrial thickness (OR = 0.33, 95%CI 0.16-0.66) were also significantly associated with cesarean section delivery. CONCLUSION: A lower uterine segment thickness of 2.3 mm and myometrial thickness of 1.9 mm during the first stage of labor are associated with a high risk of uterine defects during a labor trial. These measurements during labor can have a practical application in deciding the mode of delivery in women with previous cesarean sections and might reduce uterine rupture.

Transvaginally surgically treatment of early postpartum hemorrhage caused by lower uterine segment atony.

OBJECTIVES: Prove the success of transvaginal hemostatic procedures in treatment of the early postpartum hemorrhage caused by lower uterine segment atony. METHODS: We have conducted a retrospective, clinical study during a 10-year period (2010-2019) in our institution that is tertiary perinatal university center. RESULTS: This particular study enrolled total number of 29,543 deliveries with 215 cases of early postpartum hemorrhage (0.72%). Lower uterine segment atony was diagnosed in 44 cases (29.93%) in all uterine atony cases of early postpartum hemorrhage. Hemostatic ligation procedures according to authors: Losickaja in two cases, Hebisch-Huch in 13 cases, Habek in seven cases, Hebisch-Huch + Losickaja in 10 cases. According to our results, hemostatic ligation procedures alone (32 cases; 72.72%) or combined with gauze or ballon tamponade (five cases, 11.36%), have shown to be highly effective in 37 cases (84.09%). CONCLUSIONS: Lower uterine segment atony should definitely be identified and understood as a clinical entity. Transvaginal hemostatic approach for surgical treatment of lower uterine segment atony is accessible, minimally invasive, feasible, successful and lifesaving. All of the above-mentioned methods are of great importance in the prevention and treatment of obstetric shock, multiorgan failure, postpartum hysterectomy and finally vital for fertility preservation.

The Overlooked Impact of Lower Uterine Segment Contractions on Second Trimester Cervical Assessment.

INTRODUCTION: Asymptomatic contractions in the lower uterine segment (LUS) may affect uterocervical angle and cervical length (CL); however, this has never been investigated. Therefore, the aim of this study was to evaluate the effect of LUS contractions on uterocervical angle, CL, and LUS thickness. MATERIALS AND METHODS: This was a prospective, observational, single-cohort study conducted on 102 asymptomatic singleton pregnancies between 19.0 and 22.6 weeks of gestation. Uterocervical angle and CL were measured by transvaginal ultrasound at two different time points with an interval of at least 20 min. LUS thickness was also measured as an indirect marker of myometrial contraction. A linear and curvilinear regression were performed to explore a potential association between LUS contractions, measured as increments in LUS thickness, and changes in CL and uterocervical angle. RESULTS: The linear regression between changes in LUS thickness and changes in CL showed that LUS contractions impact CL; for every 1-mm increase in LUS thickness, CL increased by 0.909 mm, when the isthmus was included in the CL measurement (R2 = 0.358; ß = 0.909; p < 0.001). By contrast, when the isthmus was not included in the measurement, a curvilinear relation between changes in LUS thickness and changes in CL was found (R2 = 0.077; ß1 = 0.575, ß2 = 0.038; p = 0.018). The relation between changes in uterocervical angle and changes in LUS thickness was not significant. DISCUSSION/CONCLUSION: LUS contractions can be observed in many asymptomatic women during the second trimester of pregnancy. LUS contractions lead to an increase in CL and LUS thickness, thus impacting ultrasound cervical assessments. These contractions do not affect the uterocervical angle.