Hysterotomy level at Cesarean section and occurrence of large scar defects: a randomized single-blind trial

Evaluation of Cesarean section scar using saline contrast sonohysterography in women with previous Cesarean scar pregnancy

OBJECTIVE

To evaluate Cesarean scar defects using saline contrast sonohysterography (SCSH) in women with a history of Cesarean scar pregnancy (CSP).

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Prediction of spontaneous preterm birth in women with previous full dilatation cesarean delivery

BACKGROUND

A previous term (≥37 weeks' gestation), full-dilatation cesarean delivery is associated with an increased risk for a subsequent spontaneous preterm birth. The mechanism is unknown. We hypothesized that the cesarean delivery scar characteristics and scar position relative to the internal cervical os may compromise cervical function, thereby leading to shortening of the cervical length and spontaneous preterm birth.

OBJECTIVE

This study aimed to determine the relationship of cesarean delivery scar characteristics and position, assessed by transvaginal ultrasound, in pregnant women with previous full-dilatation cesarean delivery with the risk of shortening cervical length and spontaneous preterm birth.

STUDY DESIGN

This was a single-center, prospective cohort study of singleton pregnant women (14 to 24 weeks' gestation) with a previous term full-dilatation cesarean delivery who attended a high-risk preterm birth surveillance clinic (2017-2021). Women underwent transvaginal ultrasound assessment of cervical length, cesarean delivery scar distance relative to the internal cervical os, and scar niche parameters using a reproducible transvaginal ultrasound technique. Spontaneous preterm birth prophylactic interventions (vaginal cervical cerclage or vaginal progesterone) were offered for short cervical length (≤25 mm) and to women with a history of spontaneous preterm birth or late miscarriage after full-dilatation cesarean delivery. The primary outcome was spontaneous preterm birth; secondary outcomes included short cervical length and a need for prophylactic interventions. A multivariable logistic regression analysis was used to develop multiparameter models that combined cesarean delivery scar parameters, cervical length, history of full-dilatation cesarean delivery, and maternal characteristics. The predictive performance of models was examined using the area under the receiver operating characteristics curve and the detection rate at various fixed false positive rates. The optimal cutoff for cesarean delivery scar distance to best predict a short cervical length and spontaneous preterm birth was analyzed.

RESULTS

Cesarean delivery scars were visualized in 90.5% (220/243) of the included women. The spontaneous preterm birth rate was 4.1% (10/243), and 12.8% (31/243) of women developed a short cervical length. A history- (n=4) or ultrasound-indicated (n=19) cervical cerclage was performed in 23 of 243 (9.5%) women; among those, 2 (8.7%) spontaneously delivered prematurely. A multiparameter model based on absolute scar distance from the internal os best predicted spontaneous preterm birth (area under the receiver operating characteristics curve, 0.73; 95% confidence interval, 0.57-0.89; detection rate of 60% for a fixed 25% false positive rate). Models based on the relative anatomic position of the cesarean delivery scar to the internal os and the cesarean delivery scar position with niche parameters (length, depth, and width) best predicted the development of a short cervical length (area under the receiver operating characteristics curve, 0.79 [95% confidence interval, 0.71-0.87]; and 0.81 [95% confidence interval, 0.73-0.89], respectively; detection rate of 73% at a fixed 25% false positive rate). Spontaneous preterm birth was significantly more likely when the cesarean delivery scar was <5.0 mm above or below the internal os (adjusted odds ratio, 6.87; 95% confidence interval, 1.34-58; P =.035).

CONCLUSION

In pregnancies following a full-dilatation cesarean delivery, cesarean delivery scar characteristics and distance from the internal os identified women who were at risk for spontaneous preterm birth and developing short cervical length. Overall, the spontaneous preterm birth rate was low, but it was significantly increased among women with a scar located <5.0 mm above or below the internal cervical os. Shortening of cervical length was strongly associated with a low scar position. Our novel findings indicate that a low cesarean delivery scar can compromise the functional integrity of the internal cervical os, leading to cervical shortening and/or spontaneous preterm birth. Assessment of the cesarean delivery scar characteristics and position seem to have use in preterm birth clinical surveillance among women with a previous, full-dilatation cesarean delivery and could better identify women who would benefit from prophylactic interventions.

Effect of cervical changes on the cesarean scar area and niche formation after preterm and term cesarean sections

OBJECTIVE

The purpose of this study is to assess the scar area and niche formation after cesarean section in women who had preterm or term deliveries and underwent cesarean section at various stages of labor.

METHOD

This prospective cohort study consists of cases who underwent the first cesarean section for different obstetric reasons. The patients were divided into four groups regarding gestational age and cervical dilatation. After a cesarean section, all patients were called for vaginal ultrasonography control at 12 weeks. The location of the scar and the presence of a niche were evaluated. The residual (RMT), proximal, and distal myometrial thicknesses were evaluated where the scar and niche were located.

RESULTS

A total of 87 cases were included in the study. There was no difference in the prevalence of niche between the groups (p > 0.05). RMT and proximal and distal myometrial thickness were not different between the 37 ≥ week and 37 < week groups, while RMT and proximal and distal myometrial thickness were significantly lower in women with active labor (p =0.001, p= 0.006, p =0.016). The location of the scar was the isthmus at 37 weeks and above (p= 0.002), it was in the cervical canal in the group below 37 weeks (p= 0.017).

CONCLUSION

The gestational week and cervical changes did not affect the prevalence of the niche. In cases of active labor and preterm deliveries, the CS scar defect was located in the cervical canal; however, in cases of term deliveries, it was located in the isthmic area.

Hysteroscopic management of uterine diverticulum after myomectomy: a case report

BACKGROUND

A uterine diverticulum is defined as the presence of a niche within the inner contour of the uterine myometrial wall. Although secondary uterine diverticula can occur after hysterotomy such as cesarean section, reports of diverticula after myomectomy are extremely rare.

CASE PRESENTATION

A 45-year-old nulliparous woman undergoing infertility treatment was referred to our hospital because of abnormal postmenstrual bleeding after myomectomy. Transvaginal sonography and magnetic resonance imaging revealed a diverticulum in the isthmus. Fat-saturated T1 image showed a blood reservoir in the diverticulum. Hysteroscopic surgery was performed to remove the lowed edge of the defect and coagulate the hypervascularized area. Two months after surgery, the abnormal postmenstrual bleeding and chronic endometritis improved.

DISCUSSION AND CONCLUSIONS

This report highlights the similarities of the patient's diverticulum to cesarean scar defects in terms of symptoms and pathophysiology. First, this patient developed a diverticulum with hypervascularity after myomectomy and persistent abnormal bleeding. Second, after hysteroscopic surgery, the symptoms of irregular bleeding disappeared. Third, endometrial glands were identified within the resected scar tissue. Fourth, preoperatively identified CD138-positive cells in endometrial tissue spontaneously disappeared after hysteroscopic resection. To the best of our knowledge, this is the first report of symptomatic improvement following hysteroscopic surgery in a patient with an iatrogenic uterine diverticulum with persistent irregular bleeding after myomectomy.

Aetiology, risk factors and preventive strategies for niche development: A review

The increase in caesarean sections (CS) has resulted in an increase in women with a uterine niche. The exact aetiology of niche development has yet to be elucidated but is likely multifactorial. This study aimed to give a systematic overview of the available literature on histopathological features, risk factors and results of preventive strategies on niche development to gain more insight into the underlying mechanisms. Based on current published data histopathological findings associated with niche development were necrosis, fibrosis, inflammation, adenomyosis and insufficient approximation. Patient-related risk factors included multiple CS, BMI and smoking. Labour-related factors were CS before onset of labour, extended cervical dilatation, premature rupture of membranes and presenting part of the fetus at CS below the pelvic inlet. Preventive strategies should focus on the optimal level of incision, training of surgeons and full-thickness closure of the myometrium (single or double-layer) using non-locking sutures. Conflicting data exist concerning the effect of endometrial inclusion. Future studies without heterogeneity in population, using standardized performance of the CS after proper training and using standardized niche evaluation with a relevant core outcome set are required to allow meta-analyses and to develop evidence-based preventive strategies. These studies are needed to reduce the prevalence of niches and prevent complications in subsequent pregnancies such as caesarean scar pregnancies.

Cesarean scar disorder: Management and repair

Cesarean scar disorder (CSD) is an entity recently defined as uterine niche with at least one primary or 2 secondary symptoms. CSDs can be visualized by hysterosalpingography, transvaginal sonography, saline infusion sonohysterography, hysteroscopy, and magnetic resonance imaging, but diagnosis should be performed by exams able to measure the residual myometrial thickness (RMT). Although there is a limited number of studies evaluating fertility and reproductive outcomes after different types of surgery, the following consideration should be kept in mind. Asymptomatic women should not be operated with the hope of improving obstetrical outcomes. It is reasonable to consider hormone therapy for CSDs as a symptomatic treatment in women who no longer wish to conceive and have no contraindications. In case of failure of or contraindications to medical treatment, surgery should be offered according to the severity of symptoms, including infertility, the desire or otherwise to preserve the uterus, the size of the CSD, and RMT measurement. Hysteroscopy is considered to be more of a resection than a repair, so women who desire pregnancy should be excluded from this technique in case of RMT <3 mm. In this instance, repair is essential and can only be achieved by a laparoscopic or vaginal approach. The benefit of laparoscopic approach seems to persist after subsequent CS. Women with CSDs need to be given complete information, including available literature, before any treatment decision is made.

A Trimming Technique: A Case Report of a Novel Surgical Approach for Cesarean Scar Dehiscence During Cesarean Section

Cesarean section can lead to residual myometrial thickness thinning and cesarean scar syndrome. We report a novel trimming technique for residual myometrial thickness recovery in women with cesarean scar syndrome. Case 1: A 33-year-old woman who developed cesarean scar syndrome (CSS) and abnormal uterine bleeding post-cesarean scar became pregnant following hysteroscopic treatment. The myometrium at previous scar was dehiscent; therefore, a transverse incision was made above the scar. Post-operative uterine recovery failed owing to lochia retention, and developed cesarean scar syndrome again. Case 2: A 29-year-old woman who developed cesarean scar syndrome post-cesarean section became pregnant spontaneously. The myometrium at the previous scar was dehiscent like case 1. Scar repair was performed using a trimming technique during cesarean section; there were no subsequent complications and she conceived again spontaneously. Performing this novel surgical procedure during cesarean section may contribute to residual myometrial thickness recovery in women with cesarean scar syndrome.

Prognostic model on niche development after a first caesarean section: development and internal validation

OBJECTIVE

To develop and internally validate a prognostic prediction model for development of a niche in the uterine scar after a first caesarean section (CS).

STUDY DESIGN

Secondary analyses on data of a randomized controlled trial, performed in 32 hospitals in the Netherlands among women undergoing a first caesarean section. We used multivariable backward logistic regression. Missing data were handled using multiple imputation. Model performance was assessed by calibration and discrimination. Internal validation using bootstrapping techniques took place. The outcome was 'development of a niche in the uterus', defined as an indentation of ≥ 2 mm in the myometrium.

RESULTS

We developed two models to predict niche development: in the total population and after elective CS. Patient related risk factors were: gestational age, twin pregnancy and smoking, and surgery related risk factors were double-layer closure and less surgical experience. Multiparity and Vicryl suture material were protective factors. The prediction model in women undergoing elective CS revealed similar results. After internal validation, Nagelkerke R² ranged from 0.01 to 0.05 and was considered low; median area under the curve (AUC) ranged from 0.56 to 0.62, indicating failed to poor discriminative ability.

CONCLUSIONS

The model cannot be used to accurately predict the development of a niche after a first CS. However, several factors seem to influence scar healing which indicates possibilities for future prevention such as surgical experience and suture material. The search for additional risk factors that play a role in development of a niche should be continued to improve the discriminative ability.

Prevalence, definition, and etiology of cesarean scar defect and treatment of cesarean scar disorder: A narrative review

Background

Cesarean scar defects (CSD) are caused by cesarean sections and cause various symptoms. Although there has been no previous consensus on the name of this condition for a long time, it has been named cesarean scar disorder (CSDi).

Methods

This review summarizes the definition, prevalence, and etiology of CSD, as well as the pathophysiology and treatment of CSDi. We focused on surgical therapy and examined the effects and procedures of laparoscopy, hysteroscopy, and transvaginal surgery.

Main findings

The definition of CSD was proposed as an anechoic lesion with a depth of at least 2 mm because of the varied prevalence, owing to the lack of consensus. CSD incidence depends on the number of times, procedure, and situation of cesarean sections. Histopathological findings in CSD are fibrosis and adenomyosis, and chronic inflammation in the uterine and pelvic cavities decreases fertility in women with CSDi. Although the surgical procedures are not standardized, laparoscopic, hysteroscopic, and transvaginal surgeries are effective.

Conclusion

The cause and pathology of CSDi are becoming clear. However, there is variability in the prevalence and treatment strategies. Therefore, it is necessary to conduct further studies using the same definitions.

Prediction of Scar Myometrium Thickness and Previous Cesarean Scar Defect Using the Three-Dimensional Vaginal Ultrasound

This research aimed to explore the related factors of scar myometrial thickness and scar diverticulum formation and then predict the occurrence of uterine diverticula. 140 patients with cesarean section were selected as the research objects. According to the three-dimensional (3D) vaginal ultrasound echo and the diagnostic criteria of uterine diverticulum, the research objects were divided into a diverticulum group and a control group, with 70 cases in each group. Data such as age, number of cesarean sections, endometrial thickness, uterine position, and diverticulum size was collected, and their relationship with uterine diverticulum was compared and analyzed. The results showed that there were significant differences in menstrual days, cesarean section times, and uterine position between the two groups (P < 0.05). The height (9.02 ± 2.97), width (14.02 ± 3.08), and depth (5.14 ± 1.23) of the posterior uterine diverticula in the scar diverticulum group were all greater than the anterior uterine height (6.69 ± 1.36), the width (10.69 ± 2.15), and the depth (3.86 ± 0.69), respectively. The residual myometrium thickness in posterior position of the uterus (2.98 ± 0.75) was < anterior position of uterus (3.43 ± 0.47), and the difference was statistically significant (P < 0.05). Multivariate analysis showed that the frequency of cesarean section (1 time, 2 times), uterine position, and abnormal menstruation were independent risk factors in the scar diverticulum group (P < 0.05). In conclusion, menstrual abnormalities, the number of cesarean sections (1 time or twice), and the position of the uterus are independent risk factors for the formation of uterine scar diverticula. The deeper the diverticula, the more likely to have menstrual abnormalities, the more prone to diverticulum in patients with posterior uterus, and the deeper the diverticula in patients with 2 dissections.

The Impact of Uterine Incision Closure Techniques on Post-cesarean Delivery Niche Formation and Size: Sonohysterographic Examination of Nonpregnant Women

OBJECTIVE

To compare the prevalence and size of residual niche in the nongravid uterus following Cesarean delivery (CD) with different hysterotomy closure techniques (HCTs).

METHODS

Saline infusion sonohysterogram (SIS) was performed in women after one prior CD, documenting the presence or absence of a postoperative niche and measuring its depth, width, length, and residual myometrial thickness. Women were grouped by HCT: Technique A (endometrium-free) and Technique B (routine non-endometrium-free). The primary outcome was the prevalence of a clinically significant niche, defined as a depth of >2 mm. HCT groups were compared using χ² , T-test (ANOVA), and analyzed using logistic regression and two-sided test (P < .05).

RESULTS

Forty-five women had SIS performed, 25 and 20 via Technique A and B, respectively. Technique groups varied by average interval time from CD to SIS (13.6 versus 74.5 months, P = 0.006) but were otherwise similar. Twenty niches were diagnosed, 85% of which were clinically significant, including five following Technique A, nine following Technique B with double-layer closure, and three following Technique B with single-layer (P = .018). The average niche depth was 2.4 mm and 4.9 mm among the two-layer subgroups following Techniques A and B, respectively (P = .005). A clinically significant niche development was six times higher with Technique B when compared to Technique A (OR 6.0, 95% CI 1.6-22.6, P = .008); this significance persisted after controlling for SIS interval on multivariate analysis (OR 4.4, 95% CI 1.1-18.3, P = .04). The average niche depth was 5.7 ± 2.9 mm following Technique B with single-layer.

CONCLUSION

Hysterotomy closure techniques determine the prevalence of post-Cesarean delivery niche formation and size. Exclusion of the endometrium at uterine closure reduces the development of significant scar defects.

Definition of large niche after Cesarean section based on prediction of postmenstrual spotting: Chinese cohort study in non-pregnant women

OBJECTIVE

A large niche after Cesarean section (CS) is associated with long-term complications, of which postmenstrual spotting is associated positively with the size of the niche. However, the diagnosis of a large niche in the literature is inconsistent and the definition is largely subjective. The aim of this study was to generate a definition for a large niche in non-pregnant women based on the presence of postmenstrual spotting.

METHODS

Women who had undergone CS in our hospital between January 2012 and June 2017 were selected randomly from our database, contacted by telephone and subsequently examined between January 2016 and June 2020. Eligible for inclusion were non-pregnant women who had their last CS more than 1 year earlier and agreed to undergo transvaginal sonography (TVS). All participants underwent examination of their CS scar by TVS (two-dimensional color Doppler) during the midfollicular phase. Niche depth, length, width, residual myometrial thickness (RMT), adjacent myometrial thickness (AMT) and ratio of niche depth/AMT were recorded. Women diagnosed with a niche, defined as an indentation at the site of the CS with a depth of at least 2 mm, were classified into two groups (symptomatic or asymptomatic) according to whether they experienced postmenstrual spotting. Logistic regression analysis was used to establish the best cut-off values for the niche parameters to predict postmenstrual spotting. A new definition was generated based on the niche parameters with the highest area under the receiver-operating-characteristics (ROC) curve (AUC) for the prediction of postmenstrual spotting.

RESULTS

A total of 727 women who had a CS > 1 year earlier underwent TVS examination, of whom 263 were diagnosed with a niche (prevalence of 36.2%). Of these, 160 women experienced postmenstrual spotting and 103 were asymptomatic. The three variables with the highest AUC for prediction of postmenstrual spotting were niche depth/AMT ratio (AUC, 0.798; 95% CI, 0.745-0.852), niche depth (AUC, 0.731; 95% CI, 0.668-0.795) and RMT (AUC, 0.683; 95% CI, 0.618-0.748). Based on the best cut-offs according to ROC-curve analysis, a large niche was defined as: niche depth ≥ 0.50 cm, RMT ≤ 0.21 cm or niche depth/AMT ratio ≥ 0.56. The prevalence of a large niche according to this definition was 22.4% (163/727). The new definition had a specificity of 61.17% (95% CI, 52.34-70.41%) and sensitivity of 76.87% (95% CI, 70.28-84.16%) for a large niche.

CONCLUSION

This study has provided a new definition for a large niche after CS. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Prospective Evaluation of the Ultrasound Signs Proposed for the Description of Uterine Niche in Nonpregnant Women

OBJECTIVES

To evaluate the new ultrasound-based signs for the diagnosis of post-cesarean section uterine niche in nonpregnant women.

METHODS

We investigated prospectively a cohort of 160 consecutive women with one previous term cesarean delivery (CD) between December 2019 and 2020. All women were separated into two subgroups according to different stages of labor at the time of their CD: subgroup A (n = 109; 68.1%) for elective CD and CD performed in latent labor at a cervical dilatation (≤4 cm) and subgroup B (n = 51; 31.9%); for CD performed during the active stage of labor (>4 cm).

RESULTS

Overall, the incidence of a uterine niche was significantly (P < .001) higher in women who had an elective (20/45; 44.4%) compared with those who had an emergent (21/115; 18.3%) CD. Compared with subgroup B, subgroup A presented with a significantly (P = .012) higher incidence of uterine niche located above the vesicovaginal fold and with a significantly (P = .0002) lower proportion of cesarean scar positioned below the vesicovaginal fold. There was a significantly (P < .001) higher proportion of women with a residual myometrial thickness (RMT) > 3 mm in subgroup A than in subgroup B and a significant negative relationship was found between the RMT and the cervical dilatation at CD (r = -0.22; P = .008).

CONCLUSIONS

Sonographic cesarean section scar assessment indicates that the type of CD and the stage of labor at which the hysterotomy is performed have an impact on the location of the scar and the scarification process including the niche formation and RMT.

Fantastic niches and where to find them: the current diagnosis and management of uterine niche

Background

Caesarean section (CS) scar niche is a well recognised complication of caesarean delivery and is defined as an indentation at the site of the CS scar with a depth of at least 2mm.

Objectives

To review systematically the medical literature regarding the current diagnosis and management of uterine niche

Materials and methods

We carried out a systematic review using MeSH terms ‘niche’ OR ‘sacculation’ OR ‘caesarean scar defect’ OR ‘caesarean section scar’ OR ‘uterine defect’ OR ‘isthmocele.’ Articles included were peer-reviewed and in English language.

Main outcome measures

Prevalence, symptoms, diagnosis, pathophysiology and management of uterine niche.

Results

CS scar niche is common and, in a subgroup, produces a range of symptoms including post-menstrual bleeding, dyspareunia and subfertility. It may be linked to use of locked sutures during CS closure. Niche repair can be achieved laparoscopically or hysteroscopically and appears to improve symptoms, although solid conclusions regarding fertility outcomes cannot be drawn.

Conclusions

CS scar niche is associated with a range of symptoms. Repair may aid subfertile patients and those with post-menstrual spotting. The presence of a niche is probably irrelevant in the absence of symptoms.

What is new?

LNG-IUS and surgical repair appear to improve symptoms in those with a niche.

Can uterine niche be prevented?

Uterine niche is a potential significant consequence of Caesarean section and is diagnosed by ultrasound. The timing of Caesarean section (during pre, early or advanced labour), location of the incision (distance from the internal os), techniques for opening and closing the uterine cavity, and bladder flap have been frequently mentioned in the literature, however, these factors continue to be a source of disagreement with respect to whether they increase the risk of uterine niche or protect against this complication. In this review, we outline and discuss the possible risk factors that may be responsible for this entity. The main factor upon which obstetricians can act is the rate of first Caesarean section, which can and should be reduced. Moreover, a rather high incision at a distance from the internal os, and a sparing use of bladder detachment should be always kept in mind as well.

Comparative effectiveness of laparoscopic versus hysteroscopic approach in patients with previous cesarean scar defect: a retrospective cohort study

Background

The aim of this study was to evaluate the clinical effectiveness and obstetric outcomes of laparoscopic and hysteroscopic surgery in patients with previous cesarean scar defect (PCSD).

Methods

A retrospective cohort analysis was performed on women who underwent laparoscopic or hysteroscopic surgery for PCSD from 2016 to 2019 at the Third Xiangya Hospital of Central South University. Among these participants, 13 underwent laparoscopic surgery and 33 received hysteroscopic surgery.

Results

Significant differences were displayed in the operative times (156.9±42.3 vs. 40.7±38.9 min, P<0.05), intra-operative blood loss (80.0±61.0 vs. 17.9±51.2 mL, P<0.05), hospital stay (7.1±1.6 vs. 4.1±2.1 days, P<0.05), postoperative hospital stay (4.3±0.8 vs. 1.5±1.1 days, P<0.05), and hospitalization expenses (22,240.3±249.9 vs. 9,547.1±4,747.2 yuan, P<0.05) between the laparoscopic surgery and hysteroscopic group. No significant difference was observed in the incidence of clinical efficacy between the laparoscopic and hysteroscopic surgery group. A total of 2 of the 4 patients in the laparoscopic surgery group, and 9 of 11 patients in the hysteroscopic surgery group delivered successfully. All 2 participants in the laparoscopic surgery group and 2 participants in the hysteroscopic surgery group were diagnosed with placenta previa. No uterine rupture was reported in our study.

Conclusions

Both laparoscopic and hysteroscopic surgery are safe and effective treatments for PCSD patients, and hysteroscopic surgery is more efficient for PCSD patients.

Number and quality of randomized controlled trials in obstetrics published in the top general medical and obstetrics and gynecology journals

BACKGROUND

There has been an increasing number of randomized controlled trials published in obstetrics and maternal-fetal medicine to reduce biases of treatment effect and to provide insights on the cause-effect of the relationship between treatment and outcomes.

OBJECTIVE

This study aimed to identify obstetrical randomized controlled trials published in top weekly general medical journals and monthly obstetrics and gynecology journals, to assess their quality in reporting and identify factors associated with publication in different journals.

STUDY DESIGN

The 4 weekly medical journals with the highest 2019 impact factor (New England Journal of Medicine, The Lancet, The Journal of the American Medical Association, and British Medical Journal), the top 4 monthly obstetrics and gynecology journals with obstetrics-related research (American Journal of Obstetrics & Gynecology, Ultrasound in Obstetrics & Gynecology, Obstetrics & Gynecology, and the British Journal of Obstetrics and Gynaecology), and the American Journal of Obstetrics & Gynecology Maternal-Fetal Medicine were searched for obstetrical randomized controlled trials in the years 2018 to 2020. The primary outcome was the number of obstetrical randomized controlled trials published in the obstetrics and gynecology journals vs the weekly medical journals and the percentage of trials published, overall and per journal. The secondary outcomes included the proportion of positive vs negative trials overall and per journal and the assessment of the study characteristics of published trials, including quality assessment criteria.

RESULTS

Of the 4024 original research articles published in the 9 journals during the 3-year study period, 1221 (30.3%) were randomized controlled trials, with 137 (11.2%) randomized controlled trials being in obstetrics (46 in 2018, 47 in 2019, and 44 studies in 2020). Furthermore, 33 (24.1%) were published in weekly medical journals, and 104 (75.9%) were published in obstetrics and gynecology journals. The percentage of obstetrical randomized controlled trials published ranged from 1.5% to 9.6% per journal. Overall, 34.3% of obstetrical trials were statistically significant or "positive" for the primary outcome. Notably, 24.8% of the trials were retrospectively registered after the enrollment of the first study patient. Trials published in the 4 weekly medical journals enrolled significantly more patients (1801 vs 180; P<.001), received more often funding from the federal government (78.8% vs 35.6%; P<.001), and were more likely to be multicenter (90.9% vs 42.3%; P<.001), non-United States based (69.7% vs 49.0%; P=.03), and double blinded (45.5% vs 18.3%; P=.003) than trials published in the obstetrics and gynecology journals. There was no difference in study type (noninferiority vs superiority) and trial quality characteristics, including pretrial registration, ethics approval statement, informed consent statement, and adherence to the Consolidated Standards of Reporting Trials guidelines statement between studies published in weekly medical journals and studies published in obstetrics and gynecology journals.

CONCLUSION

Approximately 45 trials in obstetrics are being published every year in the highest impact journals, with one-fourth being in the weekly medical journals and the remainder in the obstetrics and gynecology journals. Only about a third of published obstetrical trials are positive. Trials published in weekly medical journals are larger, more likely to be funded by the government, multicenter, international, and double blinded. Quality metrics are similar between weekly medical journals and obstetrics and gynecology journals.

Comparative Study of USG and MRI in Evaluation of Isthmocele

Objective

To study the presence of isthmocele in post-cesarean women using USG and MRI and its correlation with risk factors.

Method

This was a prospective observational study. A total of 90 patients were enrolled at the time of discharge of cesarean delivery and were advised to come for follow-up at 3-4 months for detection of isthmocele. A total of 82 patients reported for follow-up, and TVS and MRI Pelvis were done for visualization of isthmocele. If isthmocele was diagnosed, its correlation with risk factors was studied.

Results

On TVS isthmocele was present in 11 patients and on MRI in 16 patients. Detection rate was 77.07% in comparison with previous studies. Compared to MRI, sensitivity of USG was 68.75%; however, the specificity and positive predictive value for both were 100%. The negative predictive value for USG compared to MRI was 92.96%. Shape of the isthmocele was triangular in most women. Obesity, prior history of cesarean delivery, elective cesarean, gestational diabetes, preeclampsia and prolonged active labor were associated with development of isthmocele.

Conclusion

The study concluded that yield of diagnosis of isthmocele by MRI was better than TVS but not statistically significant. Further study with large sample size is needed to identify the best tool for diagnosis of isthmocele. Obesity, gestational diabetes, preeclampsia, prior history of cesarean, elective cesarean and prolonged active labor were associated with development of isthmocele.

Cost-effectiveness of single-layer versus double-layer uterine closure during caesarean section on postmenstrual spotting: economic evaluation alongside a randomised controlled trial

OBJECTIVE

To evaluate the cost-effectiveness of double-layer compared with single-layer uterine closure after a first caesarean section (CS) from a societal and healthcare perspective.

DESIGN

Economic evaluation alongside a multicentre, double-blind, randomised controlled trial.

SETTING

32 hospitals in the Netherlands, 2016-2018.

PARTICIPANTS

2292 women ≥18 years undergoing a first CS were randomly assigned (1:1). Exclusion criteria were: inability for counselling, previous uterine surgery, known menstrual disorder, placenta increta or percreta, pregnant with three or more fetuses. 1144 women were assigned to single-layer and 1148 to double-layer closure. We included 1620 women with a menstrual cycle in the main analysis.

INTERVENTIONS

Single-layer unlocked uterine closure and double-layer unlocked uterine closure with the second layer imbricating the first.

MAIN OUTCOME MEASURES

Spotting days, quality-adjusted life-years (QALYs), and societal costs at 9 months of follow-up. Missing data were imputed using multiple imputation.

RESULTS

No significant differences were found between single-layer versus double-layer closure in mean spotting days (1.44 and 1.39 days; mean difference (md) -0.056, 95% CI -0.374 to 0.263), QALYs (0.663 and 0.658; md -0.005, 95% CI -0.015 to 0.005), total healthcare costs (€744 and €727; md €-17, 95% CI -273 to 143), and total societal costs (€5689 and €5927; md €238, 95% CI -624 to 1108). The probability of the intervention being cost-effective at willingness-to-pay of €0, €10 000 and €20 000/QALY gained was 0.30, 0.27 and 0.25, respectively, (societal perspective), and 0.55, 0.41 and 0.32, respectively, (healthcare perspective).

CONCLUSION

Double-layer uterine closure is not cost-effective compared with single-layer uterine closure from both perspectives. If this is confirmed by our long-term reproductive follow-up, we suggest to adjust uterine closure technique guidelines.

TRIAL REGISTRATION NUMBER

NTR5480/NL5380.

[Cesarean scare niche: Definition, diagnosis, risk factors, prevention, symptoms, adverse effects, and treatments]

OBJECTIVES

To review the definitions, diagnostic methods, risk factors, symptoms, and treatments for caesarean scar niche.

METHODS

Review of the literature, critical reflection, and pragmatic advice.

RESULTS

There is no consensus on the definition of caesarean scar niche. Some suggest an indentation≥2mm of the myometrium of the caesarean scar, but this is present in more than half of women with caesarean history and takes no account of woman's symptoms. The most popular diagnostic method is ultrasound±hysterosonography. Risks factors for niche are multiple Caesareans, Cesarean during labor with too low incision, and retroverted uterus. Symptoms include abnormal gynaecologic bleeding and pelvic pain, and their presence establish the "Caesarean scar syndrome". The risks of pregnancy with niche is poorly studied, but pregnancy is not contraindicated, even if the niche is untreated. The treatment of caesarean scar niche is mainly surgery and conservative. The former should be reserved for symptomatic patients, and those with secondary infertility and fertility treatment failure. Patients with residual myometrium thickness≥2.5mm may benefit from first-line hysteroscopic treatment, whereas a laparoscopic or vaginal approach could be offered in other cases.

CONCLUSIONS

A pragmatic definition of caesarean scar niche as a disease including symptoms is the necessary prerequisite for the management of women. The treatment is mainly surgical, or conservative depending on the desire for subsequent pregnancy.

The effect of the onset of labor on the characteristics of the cesarean scar

OBJECTIVE

To assess the effect of cesarean section (CS) timing, elective versus unplanned, on the residual myometrial thickness (RMT) and CS scars.

METHODS

This is a prospective single-blinded observational cohort study with 186 observations. Patients indicated to undergo first singleton CS were preoperatively recruited. Exclusion criteria were history of repeated CS, vertical hysterotomy, diabetes, and additional uterine surgeries. Sonographic examination was performed for assessing the RMT ratio, the presence of a niche, fibrosis, and the distance from the scar to the internal os (SO) 1 year after CS. Power analysis was performed with 0.05 α, 0.1 β, and all statistical analyses were conducted with Stata^® .

RESULTS

Wilcoxon rank-sum test for the association between CS timing, RMT ratio and SO showed Z values of -0.59 and -4.94 (P = 0.553 and P < 0.001), respectively. There was no association between CS timing and niches and fibrosis (P > 0.99 and P = 0.268, respectively). Linear regression between SO and the extent of cervical dilatation showed a -0.45 β (95% confidence interval -0.68 to -0.21) and a 10.22-mm intercept (P < 0.001).

CONCLUSION

RMT is independent of the timing of CS, but the SO distance shows a negative linear relationship with the cervical dilatation.

Potential risk factors for caesarean scar pregnancy: a retrospective case-control study

STUDY QUESTION

What are the important risk factors for having a caesarean scar pregnancy (CSP)?

SUMMARY ANSWER

Independent risk factors were smoking in the first trimester, higher parity, and previous caesarean section (CS) before the index caesarean delivery.

WHAT IS KNOWN ALREADY

A spectrum of risk factors for CSP has been suggested but not proven: parity, number of previous caesarean section, elective as opposed to emergency CS, IVF-pregnancy, breech presentation, previous gynaecological surgery as well as suture technique.

STUDY DESIGN SIZE DURATION

This retrospective case-control study included 31 women with a CSP during the period 2003-2018 treated at a tertiary care centre for gynaecology and reproduction. A control cohort of 8300 women with a history of a CS and a subsequent delivery during the same time period was formed.

PARTICIPANTS/MATERIALS SETTING METHODS

Variables describing demography, lifestyle factors, and reproductive and obstetric history were retrieved from medical records and the obstetric hospital database. Logistic regression analyses were applied to identify potential risk factors.

MAIN RESULTS AND THE ROLE OF CHANCE

In a multivariable analysis, smoking in first trimester (adjusted odds ratio (OR) 3.03, 95% CI 1.01-9.07), higher parity (adjusted OR 1.30, 95% CI 1.03-1.64) and previous CS in addition to the preceding CS (adjusted OR 3.43, 95% CI 1.35-8.66) were independently predictive of a CSP. An elective CS at the index pregnancy was associated with an increased risk of CSP but did not remain significant in the multivariable analysis.

LIMITATIONS REASONS FOR CAUTION

CSP is a very rare phenomenon and several of the risk factor estimates are imprecise. Nevertheless, significant risk factors could be identified. Another limitation is the lack of electronically recorded details on suture techniques.

WIDER IMPLICATIONS OF THE FINDINGS

The identified factors, namely higher parity and previous CS before the index caesarean section, are in accordance with previously suggested risk factors. Whether there is a true risk association between elective CS and future CSP needs to be investigated further. Smoking in the first trimester is a new finding, which has a plausible rationale. These factors should be recognised when counselling women after a caesarean delivery, particularly in a subsequent pregnancy with early complications.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by a grant from the Swedish state under the agreement between the Swedish government and the county councils the ALF-agreement (ALFGBG-720291). None of the authors has any conflict of interest to declare.

Position and integrity of uterine scar are determined by degree of cervical dilatation at time of Cesarean section

OBJECTIVE

Abnormal placental invasion is more common after an elective Cesarean delivery, suggesting that prelabor Cesarean section (CS) increases the likelihood of the CS scar being above the internal cervical os and predisposing to a scar pregnancy in the future. The aim of this study was to assess the location and integrity of the CS scar in postpartum women delivered by CS at different stages of labor.

METHODS

This was a prospective cohort study of women at term who underwent a CS for the first time. In all women, cervical dilatation was determined by digital examination at the time of the CS. All patients had a transvaginal ultrasound examination to assess the location of the CS scar in relation to the internal cervical os, as well as the presence of a scar niche.

RESULTS

A total of 407 pregnant women were recruited into the study: 103 with cervical dilatation ≤ 2 cm, 261 with cervical dilatation 3-7 cm and 43 with cervical dilatation ≥ 8 cm at the time of the CS. A statistically significant correlation was observed between cervical dilatation at the time of the CS and the position of the CS scar. The scar was positioned in the uterus above the internal cervical os in 97.1% (100/103) of women delivered at a cervical dilatation of 0-2 cm, whereas the scar was located at or below the internal cervical os in 97.7% (42/43) of cases delivered at a cervical dilatation of 8-10 cm (P < 0.001). A uterine-scar defect (niche) was observed in 38.1% (64/168) of women with the scar located above, compared with 18.0% (43/239) of those with the scar situated at or below, the internal cervical os (P < 0.001).

CONCLUSIONS

Prelabor and early-labor Cesarean delivery are associated with an increased prevalence of a scar in the uterine cavity as well as a scar niche. CS in late labor is associated with the uterine scar being situated in the endocervical canal and with a lower incidence of a niche. The position and integrity of the CS scar after prelabor and early-labor Cesarean delivery explain the predisposition to abnormal placental invasion in subsequent pregnancy. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Risk for complications in the subsequent pregnancy following first versus second-stage cesarean delivery: 25 years follow-up in a large cohort

BACKGROUND

Cesarean delivery is a prevalent procedure worldwide, and an established risk factor for subsequent pregnancies.

AIMS

To examine if a prior cesarean delivery due to first vs. second stage non-progressive labor carries different risk profiles for adverse outcomes in the subsequent pregnancy.

MATERIALS AND METHODS

A retrospective cohort study, based on data accumulated over the years 1988-2013 at the Soroka University Medical Center. We compared pregnancy complications and adverse perinatal outcomes in subsequent delivery following a cesarean delivery due to first vs. second stage non-progressive labor. Multiple logistic regression models were constructed.

RESULTS

There were 3828 subsequent deliveries of patients who underwent prior cesarean delivery due to first vs. second stage non-progressive labor, 2791 (72.91%) and 1037 (27.09%), respectively. Patients with a prior cesarean delivery due to first stage non-progressive labor were more likely to have hypertensive disorders of pregnancy (7.4% vs 3.8% in first vs. second stage non-progressive labor, respectively, p = .002), and repeated cesarean delivery at the subsequent pregnancy (70% vs 62% in first vs. second stage non-progressive labor, respectively, p < .001). Patients with prior cesarean delivery due to second stage non-progressive labor were more likely to have preterm birth (10% vs 6.8% in second vs. first stage non-progressive labor, respectively, p = .001). Prior cesarean delivery due to first stage non-progressive labor was independently associated with a recurrent cesarean delivery in the subsequent pregnancy. In addition, prior cesarean delivery due to second stage non-progressive labor was independently associated with preterm birth.

CONCLUSIONS

Cesarean delivery due to first stage non-progressive labor carries higher rates of hypertensive disorders of pregnancy and recurrent cesarean delivery in the subsequent pregnancy. Prior cesarean delivery due to second stage non-progressive labor carries higher rates of subsequent preterm birth.

Effect of single- versus double-layer uterine closure during caesarean section on postmenstrual spotting (2Close): multicentre, double-blind, randomised controlled superiority trial

OBJECTIVE

To evaluate whether double-layer uterine closure after a first caesarean section (CS) is superior compared with single-layer uterine closure in terms of postmenstrual spotting and niche development in the uterine caesarean scar.

DESIGN

Multicentre, double-blind, randomised controlled superiority trial.

SETTING

Thirty-two hospitals in the Netherlands.

POPULATION

A total of 2292 women aged ≥18 years undergoing a first CS were randomly assigned to each procedure (1:1): 1144 women were assigned to single-layer uterine closure and 1148 women were assigned to double-layer uterine closure.

METHODS

Single-layer unlocked closure and double-layer unlocked closure, with the second layer imbricating the first.

MAIN OUTCOME MEASURES

Number of days with postmenstrual spotting during one menstrual cycle 9 months after CS.

SECONDARY OUTCOMES

perioperative and menstrual characteristics; transvaginal ultrasound measurements.

RESULTS

A total of 774 (67.7%) women from the single-layer group and 770 (67.1%) women from the double-layer group were evaluable for the primary outcome, as a result of drop-out and amenorrhoea. The mean number of postmenstrual spotting days was 1.33 (bootstrapped 95% CI 1.12-1.54) after single-layer closure and 1.26 (bootstrapped 95% CI 1.07-1.45) after double-layer closure (adjusted mean difference -0.07, 95% CI -0.37 to 0.22, P = 0.810). The operative time was 3.9 minutes longer (95% CI 3.0-4.9 minutes, P < 0.001) and niche prevalence was 4.7% higher (95% CI 0.7-8.7%, P = 0.022) after double-layer closure.

CONCLUSIONS

The superiority of double-layer closure compared with single-layer closure in terms of postmenstrual spotting after a first CS was not shown. Long-term obstetric follow-up of our trial is needed to assess whether uterine caesarean closure guidelines should be adapted.

TWEETABLE ABSTRACT

Double-layer uterine closure is not superior for postmenstrual spotting after a first caesarean; single-layer closure performs slightly better on other outcomes.

Cesarean scar defects: management of an iatrogenic pathology whose prevalence has dramatically increased

Around 20% of pregnant women undergo cesarean section (CS), and in most regions of the world CS rates continue to grow. There is still no clear definition of what is considered a normal physiologic aspect of a CS scar and what is abnormal. Cesarean scar defects (CSDs) should be suspected in women presenting with spotting, dysmenorrhea, pelvic pain, or infertility and a history of CS. CSDs can be visualized with the use of hysterosalpingography, transvaginal sonography, saline infusion sonohysterography, hysteroscopy, and magnetic resonance imaging. It is reasonable to consider hormone therapy for CSDs as a symptomatic treatment in women who no longer wish to conceive and have no contraindications. In case of failure of or contraindications to medical treatment, surgery should be contemplated according to the severity of symptoms, including infertility, the desire or otherwise to preserve the uterus, the size of the CSD, and residual myometrium thickness (RMT) measurement. Hysteroscopy is considered to be more of a resection than a repair, so women who desire pregnancy should be excluded from this technique if the RMT is <3 mm, in which case repair is essential and can be achieved by only laparoscopic or vaginal approach. Women with CSDs need to be given complete information, including available literature, before any treatment decision is made. Because prevention is better than cure, risk factors should be identified early to ensure appropriate management.

Evaluation of the uterine scar stiffness in women with previous Cesarean section by ultrasound elastography: A cohort study

PURPOSE

To evaluate by means of elastography if the quantitative assessment of the cesarean scar elasticity is feasible using as reference the surrounding intact myometrium and to investigate if the cesarean scar stiffness is influenced by the clinical characteristics of the previous cesarean delivery.

METHODS

Prospective study including women with a previous Cesarean Section (CS) ≥ 37 weeks' gestation performed 12-15 months before. By transvaginal ultrasound two regions of interest (ROI) were selected: uterine scar (Region 1) and surrounding myometrium (Region 2). Strain index (SI) for each ROI was calculated and the Strain Ratio (SR) was defined as Region 1 SI/Region 2 SI. The primary outcome was to compare SR among women who were grouped in accordance to presence of previous vaginal delivery, CS during labor, type of suture or pyrexia during post-partum. The secondary outcome of this study was to evaluate the correlation between SR and maternal, neonatal and labor characteristics.

RESULTS

68 women were included. The mean SR was 1.8 ± 0.7 thus indicating an increased stiffness of the uterine scar compared to the surrounding myometrium. No significant differences were found in terms of SR according to presence of previous VD, CS during labor, type of suture or pyrexia during post-partum period. Strain Ratio was not correlated to maternal characteristics nor to labor and neonatal outcome.

CONCLUSIONS

Evaluation of uterine scar stiffness is feasible by using elastography. The stiffness of the uterine scar is higher than that of the surrounding myometrium and is not correlated to maternal and labor characteristics.