Robert’s uterus unveiled: a comprehensive exploration of four cases and literature reviews

All procedures performed in this study were in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Institutional Review Board of West China Second University Hospital, Sichuan University (approval No. 2025008). Written informed consent was obtained from all participants for publication of this article, the anonymized use of their clinical data and images. A copy of the written consent is available for review by the editorial office of this journal. To establish our case series, we conducted a retrospective review of all female patients who presented to West China Second University Hospital, Sichuan University with primary infertility and/or dysmenorrhea between June 2020 and June 2023 and who subsequently received a postoperative diagnosis of Robert’s uterus. Clinical data were systematically extracted from electronic medical records, including patient demographics [age, body mass index (BMI)], obstetric history, presenting symptoms, detailed preoperative imaging findings (ultrasound, MRI), surgical reports, operative findings, complications, and postoperative outcomes. The definitive diagnosis of Robert’s uterus for each patient was established intraoperatively via combined hysteroscopic and laparoscopic examination, which serves as the diagnostic gold standard. While preoperative MRI was utilized in our diagnostic workflow for its superior ability to characterize the asymmetric septum and obstructed hemi-cavity, the final confirmation was achieved through direct surgical visualization. All identified patients underwent the same corrective procedure: combined hysteroscopic-laparoscopic metroplasty. Hysteroscopic surgery guided by transabdominal ultrasound was used in all cases. After inserting the hysteroscope, a needle electrode gently separated the weakened diaphragm area, allowing dark brown blood to overflow. A ribbon electrode then removed the septal tissue, exposing the affected side of the uterine cavity and uterine angle. Efforts are made to restore the uterine cavity to its normal shape. Postoperatively, both uterine horns and tubal openings are visible. Following surgery, a standardized postoperative protocol was implemented, which included temporary uterine stenting and cyclical hormonal therapy. A balloon supports the uterine cavity for 2 weeks to prevent adhesions. Patients are discharged 2 days after surgery and receive sequential estrogen and progestin treatment to prevent recurrence. Four weeks postoperatively, hysteroscopic examination shows generally normal uterine cavities and endometria. Follow-up data were collected systematically according to a scheduled protocol at 1, 3, 6, and 12 months postoperatively to monitor for resolution of symptoms (specifically dysmenorrhea) and to evaluate anatomical outcomes, assessing for any evidence of recurrence. All analyses were performed using SPSS 20.0 software (SPSS, Inc.; Chicago, IL, USA). Descriptive statistical methods were employed to summarize the cohort data. Continuous variables are presented as medians and ranges, while categorical variables are reported as frequencies and percentages. Owing to the descriptive nature of this case series design, no inferential statistical tests were applied. In this study, we report on four female patients who presented to West China Second University Hospital, Sichuan University for infertility treatment. The median age was 25 years (range, 22-30 years), and the median BMI was 21.10 kg/m 2 (range, 14.45–25.60 kg/m 2 ). A comprehensive overview of patient characteristics, clinical presentation, and outcomes is provided in Table 1 . Except for Patient 1, all patients experienced primary dysmenorrhea, which was particularly severe on the first and second days of menstruation and required regular painkillers for about a week. The pain eased after menstruation, and Patient 3’s dysmenorrhea had worsened over the past year. All patients had sought consultation for infertility. All patients had regular menstrual cycles. 2D, two-dimensional; 3D, three-dimensional; BMI, body mass index; HSC, hysteroscopic; HSG, hysterosalpingography; LSC, laparoscopic; MRI, magnetic resonance imaging; US, ultrasound. Preoperative imaging revealed uterine malformations in all cases. The preoperative imaging findings for each patient were as follows: transvaginal two-dimensional (2D)/3D ultrasound for evaluating the preoperative uterine status. The 3D ultrasound of Patient 1 showed that the shape of the uterine cavity was abnormal, with the right uterine horn showing that the right uterine horn was connected to the uterine cavity in the shape of a ‘1’; the left uterine cavity was shown near the left uterine horn, which was connected to the right uterine cavity in the middle of the uterine cavity with the right uterine cavity endothelium, and the width of the connected area was about 0.15 cm ( Figure 2A ). Figure 2B shows a patent uterine cavity and blood accumulation in Patient 2. The image from Patients 2 shows the right uterine cavity communicating with the cervix and the right uterine horn. A small amount of blood is seen in the left stump uterine cavity with adenomyosis changes and a possible left tubal effusion ( Figure 2C ). And MRI images from Patient 3 revealed the presence of a muscular structure in the uterus of the patient with Robert’s uterus, which was visible as a cavity-like structure in the center of the muscular structure, and within which fluid and layering, i.e., blinding of the cavity and accumulation of blood, were visible ( Figure 2D ). All of these confirmed the diagnosis, and hysterosalpingography showed that the uterine cavity was willowy and identical to the left uterine horn and left fallopian tube, while the right uterine horn and fallopian tube were not shown ( Figure 2E ); and 2D ultrasound for Patient 4 suggested a septate or unicornuate uterus. Preoperative imaging findings in patients with Robert’s uterus. (A) 3D transvaginal ultrasound from Patient 1 demonstrating the asymmetric muscular septum (arrow). (B) 2D transvaginal ultrasound from Patient 2 revealing hematometra (upper arrow) in the obstructed right hemi-cavity and the patent left hemi-cavity communicating with the cervix (lower arrow). (C) Axial T2-weighted MRI from Patient 2 illustrating the thick muscular septum (arrow) separating the patent and obstructed hemi-cavities. (D) Coronal T2-weighted MRI from Patient 3 showing the blind obstructed hemi-cavity containing hematometra (arrow). (E) Hysterosalpingogram from Patient 3 showing unilateral contrast filling and spill (arrow) from the patent left hemi-cavity, with non-visualization of the right hemi-cavity and fallopian tube. 2D, two-dimensional; 3D, three-dimensional; MRI, magnetic resonance imaging. Hysteroscopic examination was diagnostic. Representative images from one case ( Figure 3 ) show the preoperative view with a septum obscuring the blind hemi-cavity ( Figure 3A ) and the postoperative view after resection, revealing a unified cavity and the second tubal ostium ( Figure 3B ). The final diagnosis of Robert’s uterus was confirmed intraoperatively for all patients. Representative hysteroscopic findings. (A) Preoperative view showing the uterine septum (arrow) obscuring the entrance to the blind hemi-cavity. (B) Postoperative view after septum resection, revealing the unified uterine cavity and the tubal ostium (arrow) of the previously obstructed side. All patients underwent combined hysterolaparoscopy with abdominal ultrasound-guided hysteroplasty. Laparoscopy revealed a normal external contour in Patients 1 and 2, and a saddle-shaped contour in Patients 3 and 4. Hysteroscopic septum resection successfully restored a single uterine cavity. A balloon was placed postoperatively for 2 weeks to prevent adhesions, and patients received a standard sequential hormonal regimen (estradiol valerate 2 mg daily for 21 days, with dydrogesterone 10 mg added daily for the final 10 days) to promote endometrial regeneration and prevent adhesion recurrence. Patients were then followed clinically at 3, 6, and 12 months to evaluate symptom resolution, menstrual flow, and any recurrence. During this follow-up period (6–12 months), no recurrence of obstructive symptoms or septal reformation was observed. Furthermore, one patient (Patient 4) achieved a spontaneous pregnancy postoperatively. After 6 months to 1 year, patients showed significant relief in dysmenorrhea, even becoming pain-free. Menstrual flow increased to about 1.5–2 times the original amount, with a median of 40 mL (range, 20–60 mL) ( Table 2 ).

Robert’s uterus is an extremely rare obstructive septate uterus anomaly, first reported in 1970 ( 1 ), representing a very small subset of Müllerian anomalies (2–3% prevalence) ( 2 ). Robert’s uterus is anatomically characterized by an asymmetric, thick muscular septum completely dividing the uterine cavity into a non-communicating blind hemi-cavity and a contralateral normal-sized cavity communicating with the cervix ( 3 , 4 )( Figure 1 ). This obstructive asymmetric septum distinguishes it from typical symmetrical septate uteri ( 3 ). Diagnosis is confirmed through magnetic resonance imaging (MRI) and three-dimensional (3D) ultrasound imaging, which visualize the unique septal anatomy ( 3 , 4 ), or via combined hysteroscopic-laparoscopic surgery ( 3 ). Schematic of Robert’s uterus anatomy. The diagram illustrates the asymmetric muscular septum dividing the uterine cavity into a blind, obstructed hemi-cavity with hematometra (left) and a patent hemi-cavity communicating with the cervix (right). In the updated classification of Müllerian duct anomalies by the American Society for Reproductive Medicine (ASRM) in 2021, Robert’s uterus is classified as a special type of septate uterus ( 5 ). Due to its extremely low incidence, patients with Robert’s uterus often do not exhibit clinical symptoms during childhood when there is no menstrual flow. Symptoms typically appear during adolescence due to a blocked posterior uterine cavity, which can lead to conditions like adenomyosis and endometriosis. Unlike many other Müllerian anomalies, Robert’s uterus is distinguished by an oblique septum creating a non-communicating asymmetrical uterine hemi-cavity, leading to unilateral menstrual fluid retention (hematometra). This obstruction causes characteristic symptoms including severe dysmenorrhea (reported in 90.91% of cases) and repetitive pain attacks at four-weekly intervals around menarche ( 3 , 6 ). Common symptoms include severe dysmenorrhea, recurrent abdominal pain, and abnormal menstrual flow ( 4 , 7 - 9 ). The obstructive hemi-cavity creates a significant risk for developing secondary complications. In severe cases, the accumulated blood can lead to hematosalpinx and retrograde menstruation, resulting in pelvic endometriosis ( 10 ). Endometriosis affects approximately 5–10% of reproductive-aged women globally ( 10 ), and in this context, findings like ovarian endometriomas often indicate broader pelvic disease ( 11 ). These complications, including adhesions and tubal damage, significantly impact fertility ( 12 ). Diagnosis is frequently delayed because the initial severe dysmenorrhea is often mistaken for primary dysmenorrhea, leading many patients to present in adulthood for infertility evaluation rather than during adolescence ( 6 , 10 ). Approximately 11.4% of women with Robert’s uterus experience miscarriage, and 5.7% face primary infertility. Dysmenorrhea affects 54.3% of these individuals, and 14.3% have coexisting endometriosis. Diagnosis is often delayed, with many patients seeking medical help after age 20 years ( 8 ). Imaging is crucial for accurate diagnosis. While ultrasound may show abnormal morphology or suggest a pelvic hematoma, it can miss abnormalities if the blind cavity is narrow, potentially leading to misdiagnosis as a unicornuate uterus ( 13 , 14 ). MRI is the preferred non-invasive modality for definitive preoperative characterization, as it clearly delineates the septum and obstructed hemi-cavity ( 3 , 4 , 15 ). Early and accurate diagnosis is vital to prevent long-term sequelae. Surgical intervention via hysteroscopic septum resection, often combined with laparoscopy, is the standard treatment to restore normal uterine anatomy, relieve symptoms, and improve reproductive potential ( 4 , 15 , 16 ). Despite its rarity, understanding Robert’s uterus is essential for optimizing care. Several case reports exist, yet key clinical challenges remain. This study aims to address these gaps by presenting a detailed analysis of four new cases from West China Second University Hospital, Sichuan University, supplemented by a comprehensive review of contemporary literature. We specifically highlight two novel clinical insights: (I) the phenotypic diversity in the external uterine contour (normal vs. saddle-shaped) observed in our series, which poses a significant diagnostic challenge during laparoscopy, and (II) the proposal of a streamlined diagnostic-therapeutic pathway to guide clinicians in the effective management of this complex condition. Through this work, we emphasize the critical importance of early and accurate diagnosis to prevent long-term complications and improve reproductive outcomes for patients with Robert’s uterus. We present this article in accordance with the AME Case Series reporting checklist (available at https://gpm.amegroups.com/article/view/10.21037/gpm-2025-1-55/rc ).

Müllerian anomalies have been observed in approximately 2% to 3% of females ( 9 ). Robert’s uterus is a rare congenital Müllerian anomaly initially identified by Robert in 1970, and there have been only a limited number of reported cases ( 10 ). The Robert’s uterus is an asymmetrical longitudinal uterus characterized by a uterine septum that divides the uterine cavity into a blind half-cavity and a contralateral non-obstructed half-cavity that is normally connected to the cervix ( 11 ). The blind cavity obstructs menstruation and permits some of the retained menstruation to flow back into the peritoneal cavity, resulting in uterine hematometra, dysmenorrhea, tubal hematochezia, and even endometriosis. Endometriosis, including ovarian and deep infiltrative endometriosis, could be accurately detected by transvaginal ultrasound, but superficial endometriosis requires laparoscopy ( 12 ). These phenomena are linked to the intensity of abdominal pain and dysmenorrhea ( 13 ). In our cases, we observed that the location of the patients’ dysmenorrhea is closely associated with the blind cavity. The primary mechanism of dysmenorrhea involves prostaglandin-mediated uterine contractions causing tissue hypoxia and ischemia ( 17 ). As Tables 1,3 show, in Robert’s uterus, this is compounded by mechanical obstruction from the spectated blind cavity, leading to hematometra—the accumulation of menstrual fluid which causes direct pelvic pain and pressure ( 18 ). Importantly, dysmenorrhea can occur in Robert’s uterus independently of surgically-confirmed endometriosis, with hematometra being a sufficient cause. When endometriosis is present (affecting up to 29% of dysmenorrhea cases generally ( 17 ), it represents a secondary complication from retrograde menstruation, further exacerbating pain. The accumulation of menstrual blood in the blind cavity manifests as progressive menstrual pain. Worse, retrograde flow through the fallopian tubes can lead to secondary pelvic endometriosis and adhesions, contributing to infertility ( 19 ). Most patients with Robert’s uterus present with associated conditions such as hematosalpinx, adenomyosis, or ovarian endometriomas ( 19 ). Early diagnosis and hysteroscopic surgery may reduce these complications ( 6 ). Regrettably, three of our four patients presented around age 20 years for infertility rather than adolescent dysmenorrhea. While literature on early surgical impact on fertility is limited, timely detection and treatment remain clinically valuable. 2D, two-dimensional; 3D, three-dimensional; HSC, hysteroscopic; HSG, hysterosalpingography; LESS, laparo-endoscopic single site; LSC, laparoscopic; MRI, magnetic resonance imaging. A clear preoperative diagnosis optimizes surgical planning, with imaging playing a central role. Analysis of contemporary literature and our institutional experience indicates that MRI is the definitive non-invasive modality for preoperative diagnosis ( 14 ). MRI provides multiplanar views that accurately delineate the asymmetric muscular septum and the obstructed hemi-cavity containing hematometra, findings that can be ambiguous on standard ultrasound. While 2D ultrasound has limited sensitivity, 3D ultrasound offers valuable adjunctive information for perioperative guidance ( 20 ). Although combined laparoscopy-hysteroscopy remains the diagnostic gold standard, its invasive nature necessitates judicious use of advanced preoperative imaging ( 21 ). In the literature, MRI demonstrates high accuracy in diagnosing uterine anomalies, with studies showing 95% accuracy in correctly identifying Müllerian duct anomalies ( 22 ). MRI excels at differentiating between septate and bicornuate uteri by evaluating fundal contour morphology and septum characteristics, which is crucial for treatment planning since septate uteri require hysteroscopic septectomy while bicornuate uteri typically do not require surgical intervention ( 22 ). The imaging modality effectively delineates uterine anatomy and can identify complications such as hematometra in non-communicating horns ( 23 ). A critical observation from our series was the inconsistent external uterine morphology at laparoscopy. While half of our patients (2/4) presented a normal fundal contour, the other half exhibited a saddle-shaped fundus ( 24 ). This phenotypic divergence creates a major intraoperative diagnostic dilemma: a normal contour can be mistaken for a unicornuate uterus with a non-communicating rudimentary horn, and a saddle shape may be incorrectly interpreted as a bicornuate uterus. This finding decisively demonstrates that external laparoscopic appearance is an unreliable sole criterion for diagnosing Robert’s uterus and underscores the indispensable role of preoperative MRI to define the internal septal anatomy and diagnostic hysteroscopy for definitive confirmation ( 22 ). The standard treatment is combined hysterolaparoscopic metroplasty with intraoperative ultrasound guidance. Laparoscopy assesses external uterine morphology, excludes diagnoses like unicornuate uterus, and allows treatment of concurrent pelvic pathology. Hysteroscopy, guided by ultrasound, evaluates the cavity, identifies the septum and blind pouch, and enables precise resection to restore normal anatomy and improve fertility potential ( 25 ). Successful pregnancies following such surgery have been reported, with live-birth rates of 53.5% during postoperative follow-up ( 26 ). Synthesizing insights from our cohort’s diagnostic journey, which featured a common delay from symptom onset to diagnosis, we propose a structured clinical pathway to prevent such delays. This pathway is designed to translate suspicion into timely action: (I) clinical suspicion in adolescents or young adults presenting with severe, progressive dysmenorrhea, particularly when accompanied by infertility; (II) initial imaging with 2D/3D transvaginal ultrasound as a first-line screening tool; (III) definitive diagnosis via pelvic MRI for detailed anatomical characterization if ultrasound findings suggest an obstructive anomaly; (IV) treatment with combined hysteroscopic-laparoscopic metroplasty under intraoperative ultrasound guidance for definitive surgical correction; and (V) postoperative care including hormonal therapy to prevent adhesions and follow-up hysteroscopy to assess healing and cavity integrity. This study provides new insights into the phenotypic diversity of Robert’s uterus, documenting the variability in external uterine contour from normal to saddle-shaped, which poses a significant diagnostic challenge. A key contribution is the proposal of a streamlined diagnostic and management pathway to guide clinicians. Furthermore,this work adds to the literature with data from a Chinese cohort. However, its limitations include the retrospective design, the small sample size inherent to the study of a rare condition, and a moderate follow-up duration. Larger, prospective studies with long-term follow-up are needed to validate the proposed pathway and to better assess long-term reproductive outcomes.

Robert’s uterus is a complex obstructive Müllerian anomaly requiring a high index of suspicion for timely diagnosis. MRI is the key modality for accurate preoperative characterization and differentiation from other anomalies. Combined hysteroscopic-laparoscopic metroplasty is an effective treatment that reliably relieves symptoms and creates the anatomical conditions for improved reproductive potential. The clinical pathway proposed here, which emphasizes early imaging evaluation for severe dysmenorrhea, aims to standardize care, reduce diagnostic delays, and optimize management for this rare condition. Future collaborative, multi-center studies are warranted to further refine best practices.

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