UNASSIGNED: After caesarean section a uterine niche can be detected in 42-84% of all women and in 11-45% large defects with a residual myometrium < 2.2 mm occur. If the niche compromises > 50% of myometrial thickness, risk of uterine rupture during birth increases. The suturing technique might contribute substantially on pathogenesis of niches. The objective of this study is to investigate the effect of the suturing technique on niche prevalence by using a standardized two-layer surgical technique.
UNASSIGNED: Women with one previous caesarean section were examined within 6-23 months after caesarean section using contrast medium-supported transvaginal sonography regarding the prevalence, sonomorphological aspect and clinical symptoms of a uterine niche. The surgical technique used was: dilatation of the cervix, interrupted suture of the first layer (excluding the endometrium), continuous closure of the visceral and parietal peritoneum.
UNASSIGNED: Using native vaginal sonography, no niches were visible in the whole cohort. In three cases, there was a small niche detectable with a depth between 2.3 and 3.9 mm by contrast hysterosonography. Regarding the total myometrial thickness, the niche depth compromised less than 50%. All patients were symptom-free.
UNASSIGNED: In our study population, there were only three cases (9.1%) with a small uterine niche. Residual myometrium and niche percentage on myometrial thickness were excellent in all three cases. Thus, our results show that the uterotomy closure technique used in the study cohort might be superior with respect to the development of uterine niches compared with the expected prevalence.
UNASSIGNED: Nach einem Kaiserschnitt lässt sich bei 42–84 % aller Frauen eine Uterusnische nachweisen, und bei 11–45 % treten große Defekte mit einem Restmyometrium < 2,2 mm auf. Wenn die Nische > 50 % der Myometriumdicke einnimmt, steigt das Risiko einer Uterusruptur während der Geburt. Die Nahttechnik könnte wesentlich zur Pathogenese von Nischen beitragen. Ziel dieser Studie ist es, den Einfluss der Nahttechnik auf die Nischenprävalenz mithilfe einer standardisierten zweischichtigen Operationstechnik zu untersuchen.
UNASSIGNED: Frauen mit einem vorangegangenen Kaiserschnitt wurden innerhalb von 6–23 Monaten nach dem Kaiserschnitt mittels kontrastmittelgestützter transvaginaler Sonografie auf die Prävalenz, den sonomorphologischen Aspekt und die klinischen Symptome einer Uterusnische untersucht. Die angewandte Operationstechnik war: Dilatation der Zervix, Einzelknopfnaht der ersten Schicht (ohne Endometrium), kontinuierlicher Verschluss des viszeralen und parietalen Peritoneums.
UNASSIGNED: Bei der nativen Vaginalsonografie waren in der gesamten Kohorte keine Nischen sichtbar. In 3 Fällen war eine kleine Nische mit einer Tiefe zwischen 2,3 und 3,9 mm in der Kontrast-Hysterosonografie nachweisbar. Bezogen auf die Gesamtdicke des Myometriums betrug die Nischentiefe weniger als 50 %. Alle Patientinnen waren symptomfrei.
UNASSIGNED: In unserer Studienpopulation gab es nur 3 Fälle (9,1 %) mit einer kleinen uterinen Nische. Sowohl das Restmyometrium als auch der prozentuale Anteil der Nische bezogen auf die Myometriumdicke war in allen 3 Fällen ausgezeichnet. Somit zeigen unsere Ergebnisse, dass die in der Studienkohorte angewandte Uterotomie-Verschlusstechnik im Hinblick auf die Entstehung von Uterusnischen im Vergleich zur erwarteten Prävalenz überlegen sein könnte.

Background Isthmocele or a scar defect is a relatively common consequence of cesarean section resulting in menstrual disturbances and infertility and may compromise the myometrial integrity of the uterus in women contemplating subsequent vaginal birth. Several preventive measures have been suggested, including the modification of surgical techniques used for the closure of the uterine incision. The current study aimed to compare the incidence of isthmocele and assess residual myometrial thickness in women who underwent single versus parallel layered closure to approximate the endo-myometrial layer during cesarean section. Methodology This retrospective study evaluated data of women undergoing their first cesarean section under elective conditions (n = 497) where the uterine incision was closed using a single (n = 295) or a parallel layer (n = 202) technique. Patients were evaluated twice, at 3-6 months and 18 months postpartum, with a transvaginal ultrasound noting the presence or absence of an isthmocele and measurement of the residual myometrial thickness. Results Regardless of the closure technique, 64 (12.9%) women had an ultrasound-diagnosed isthmocele. Significantly fewer patients in the parallel-layer closure group presented with an isthmocele both at 3-6 (13.6 vs. 6.9%; p = 0.019) and 18 months (16.3 vs. 7.8%; p = 0.009) postpartum. Residual myometrium was significantly thicker in the parallel-layer closure group (8.0 vs. 13.2 mm at 3-6 months postpartum; p = 0.000 and 7.2 vs. 12.3 mm at 18 months postpartum; p = 0.004). For all patients, a retroverted position of the uterus at 3-6 months follow-up examination significantly increased the frequency of isthmocele (36/395 (9.1%) with an anteverted uterus and 18/102 (17.6%) with a retroverted uterus; p = 0.002). In patients with a single-layer closure, a retroverted uterus at the 3-6-month follow-up was associated with an isthmocele in 29.5% (18/61) of patients, while no isthmocele was recorded when the uterus was retroverted in the parallel-layer closure group (0/41) (p = 0.001). At 18 months postpartum, of the 64 patients with an isthmocele, 26 (40.6%) presented with abnormal uterine bleeding mainly in the form of postmenstrual spotting. Of the 26 patients with abnormal bleeding, 23 were in the single-layer and three were in the parallel-layer closure group. Conclusions The parallel-layer closure when compared to a single-layer closure of the uterine incision in patients undergoing primary cesarean section decreased the incidence of isthmocele formation and increased residual myometrial thickness. More patients in the single-layer closure group had menstrual cycle disturbances at 18 months postpartum.

OBJECTIVE: The primary objective was to detect the number of women developing isthmocele following lower segment caesarean section. The secondary objectives included analysing the risk factors associated with developing isthmocele and measuring the agreement between Transvaginal Ultrasonography (TVS) and Saline infusion Sonohysterography (SIS) in diagnosing Isthmocele.
METHODS: This study was conducted in the Department of Obstetrics and Gynecology and focused on women who had undergone Lower Segment cesarean Section (LSCS). The study aimed to detect any indentation of at least 2 mm in the scar site, known as isthmocele, using Transvaginal Ultrasound (TVS) and Saline Infusion Sonography (SIS) between 6 weeks and 6 months after delivery. Along with the primary objective, the study also evaluated several secondary outcomes such as maternal comorbidities, closure techniques, and labor details. The evaluation of isthmocele followed the 2019 modified Delphi consensus approach.
RESULTS: In our study, we found that 30% of our study population had isthmocele. We also observed that the number of previous caesarean deliveries, maternal BMI, duration of surgery, and characteristics of the previous CD scar were significantly associated with the development of isthmocele. When we compared the diagnostic methods, we found that TVS and SIS had similar limits of agreement for clinically important isthmocele parameters. However, we noticed a difference in the length and distance of isthmocele from the internal os, which we observed through Bland Altman plots.
CONCLUSIONS: Our research has shown that women who have undergone multiple caesarean deliveries, have a higher maternal body mass index (BMI), and experienced longer surgery duration are at a significantly higher risk of developing isthmocele. To prevent its development, it is recommended to promote vaginal birth after caesarean delivery whenever feasible, manage maternal obesity early on, and provide adequate surgical training to medical professionals. Additionally, transvaginal ultrasound (TVS) is an effective method for detecting isthmocele and can be used interchangeably with saline-infused sonography (SIS).

BACKGROUND: Cesarean delivery rates are increasing globally, raising concerns about associated complications such as isthmocele. Isthmoceles are pouch-like defects in the anterior uterine wall at the site of a prior cesarean delivery scar.
OBJECTIVE: This study aimed to determine isthmocele prevalence, associated symptoms, and risk factors among women with a history of cesarean delivery.
METHODS: This cross-sectional study evaluated 297 women with prior cesarean delivery using transvaginal ultrasound to screen for isthmocele. Data on demographics, pregnancy details, comorbidities, and indications for cesarean delivery were collected. Isthmocele was defined sonographically as any niche or defect at the hysterotomy site. Descriptive and comparative analyses identified factors associated with isthmocele.
RESULTS: Isthmocele prevalence was 65.3% (n=194). Abnormal vaginal bleeding was reported in 21.1% of participants, pelvic pain by 4.1% of participants, and both by 4.1% of participants. Compared to women without isthmocele, those with isthmocele were older (35.9 vs 31.6 years), had higher body mass index (26.8 vs 25.5 kg/m2), gravidity (1.8 vs 1.3), and parity (1.7 vs 1.2). Repeat cesarean delivery was more common (30.4% vs 12.6%) and elective cesarean delivery less common (33.5% vs 67.9%) among those with isthmocele.
CONCLUSIONS: Over half of the women with history of cesarean delivery had an isthmocele. Abnormal bleeding was common. Advanced maternal age, obesity, repeat procedures, and certain comorbidities appear to increase risk. Further research on prevention and treatment is warranted given the high prevalence.

OBJECTIVE: Is there a correlation between various morphological parameters of the uterine niche and post-menstrual spotting using three-dimensional models from thin-slice (1 mm) magnetic resonance imaging (MRI)?
METHODS: This study retrospectively identified women diagnosed with a symptomatic niche by thin-slice MRI between December 2019 and December 2021. Univariable and multivariable linear regression models assessed the correlations between morphological parameters and the duration post-menstrual spotting. Morphological differences of the niche formed by one versus two Caesarean sections were analysed by univariable and multivariable logistic analysis.
RESULTS: A total of 205 women diagnosed with symptomatic niche were included in the study. The niche among most women with post-menstrual spotting was ellipsoidal, with width greater than length greater than depth, from which niche volume was estimated based on manual measurements (volume = 0.520 × length × width × depth). Manually calculated niche length (β = 0.257, 95% confidence interval [CI] 0.040-0.473, P = 0.020) and radiomically assessed minor axis length (β = 0.329, 95% CI 0.009-0.795, P = 0.045) both positively correlated with the duration of post-menstrual spotting, whereas the distance between the niche and external os (β = -0.120, 95% CI -0.202 to -0.038, P = 0.004) was inversely correlated. Women with two Cesarean sections reported more days of post-menstrual spotting (8.76 ± 3.54 versus 6.68 ± 3.90 days, P < 0.001) and had increased niche length diameter (adjusted odds ratio [aOR] 1.304, 95% CI 1.190-1.429) and a smaller surface-area-to-volume ratio (aOR 0.296, 95% CI 0.129-0.680).
CONCLUSIONS: Niche-associated post-menstrual spotting correlates with the length diameter of the niche and the distance between the niche and external os. Niches in women after two Caesarean sections tend to be longer in length diameter and more spherical.

To evaluate Cesarean scar defects using saline contrast sonohysterography (SCSH) in women with a history of Cesarean scar pregnancy (CSP).
A cohort of 38 non-pregnant women with a history of CSP treated with combined local and systemic methotrexate was investigated prospectively by SCSH. For the purpose of analysis, they were classified, according to the modified Delphi consensus criteria for CSP in early gestation, into three subgroups based on the depth of the gestational sac herniation in the midsagittal plane. Subgroup A included eight (21.1%) cases, in which the largest part of the gestational sac protruded towards the uterine cavity; Subgroup B included 20 (52.6%) cases, in which the largest part of the gestational sac was embedded in the myometrium; and Subgroup C included 10 (26.3%) cases, in which the gestational sac was located partially outside the outer contour of the cervix or uterus.
SCSH revealed that all women in Subgroup C had a uterine niche. The median niche length (P = 0.006) and depth (P = 0.015) were significantly greater in Subgroup C than in Subgroups A or B. The median residual myometrial thickness (RMT) was significantly lower in Subgroup C than in Subgroups A or B (P = 0.006).
Women with prior CSP who had a gestational sac protruding beyond the serosal line had a significantly greater niche length and depth, and lower RMT. This knowledge may guide individualized risk counseling. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

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Formation of a uterine niche following a C-section can predispose the patient to future obstetric complications such as dehiscence, uterine rupture, ectopic pregnancy, and placenta accreta. The significant morbidity and mortality of these complications along with increasing C-section rates emphasizes the importance of prevention. However, there are no clear guidelines on intra-operative protocol to prevent postpartum niche formation. Besides surgical technique, the novel use of platelet-rich plasma (PRP) and mesenchymal stem cell (MSC) injections has demonstrated promising potential and may have applications in hysterotomy closures. The objective is to examine current research on optimal C-section procedures to prevent uterine niche formation and subsequent obstetric complications. A systematic review was conducted using PubMed and Google Scholar. Initial searches yielded 827 results. Inclusion criteria were human, animal, and in-vitro studies, peer-reviewed sources, and outcomes pertinent to the uterine niche. Exclusion criteria applied to articles with outcomes unrelated to myometrium and interventions outside of the intra-operative and immediate pre-/post-operative period. Based on the criteria, 41 articles were cited. Pathophysiology of uterine niche formation was associated with incisions through cervical tissue, adhesion formation, and poor approximation. Significant risk factors were low uterine incisions, advanced cervical dilatation, low station, non-closure of the peritoneum, and creation of a bladder flap. There was no consensus on uterine closure as it likely depends on surgical proficiency with the given technique, but a double-layered non-locking suture appears reliable to reduce niche severity. Recent trials indicate that intra-operative PRP/MSC injections may decrease niche incidence and severity, but more research is needed. If prevention or minimization of uterine niche is desired, the optimal C-section protocol should avoid low uterine incisions, choose uterine closure technique based on the surgeon\'s proficiency (double-layered non-locking is reliable), and close the peritoneum, and myometrial injection of PRP/MSC may be a useful adjunct intervention pending further clinical evidence.

Of all neonates, 21% are delivered by cesarean section (CS). A long-term maternal complication of an SC is a uterine niche. The aim of this review is to provide an overview of the current literature on imaging techniques and niche-related symptomatology. We performed systematic searches on imaging and niche symptoms. For both searches, 87 new studies were included. Niche evaluation by transvaginal sonography (TVS) or contrast sonohysterography (SHG) proved superior over hysteroscopy or magnetic resonance imaging. Studies that used SHG in a random population identified a niche prevalence of 42%-84%. Niche prevalence differed based on niche definition, symptomatology, and imaging technique. Most studies reported an association with gynecological symptoms, poor reproductive outcomes, obstetrical complications, and reduced quality of life. In conclusion, non-invasive TVS and SHG are the superior imaging modalities to diagnose a niche. Niches are prevalent and strongly associated with gynecological symptoms and poor reproductive outcomes.

This study aimed to compare the effectiveness of oral contraceptives and a levonorgestrel intrauterine system in treating intermenstrual bleeding due to uterine niche. We retrospectively analyzed 72 patients with intermenstrual bleeding due to uterine niche from January 2017 to December 2021, of whom 41 were treated with oral contraceptives and 31 with a levonorgestrel intrauterine system. Post-treatment follow-ups at 1, 3, and 6 months were conducted to compare the efficiency and adverse effects between the two groups. In the oral contraceptive group, the effectiveness rate was higher than 80% at 1- and 3-months post-treatment and higher than 90% at 6 months. In the levonorgestrel intrauterine system group, the effectiveness rates were 58.06%, 54.84%, and 61.29% at 1, 3, and 6 months of treatment, respectively. Oral contraceptives were more effective than the levonorgestrel intrauterine system in treating intermenstrual bleeding caused by uterine niche (p < 0.05).