Uterus Didelphys: Pathophysiology, MRI Imaging Features, Diagnosis, and Clinical Management of a Rare Müllerian Duct Anomaly

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Introduction


Uterus didelphys is a rare congenital Müllerian duct anomaly characterized by complete duplication of the uterus and cervix, frequently accompanied by partial or complete duplication of the vagina. Although uncommon, this condition holds significant clinical importance due to its association with pelvic pain, reproductive complications, renal anomalies, and obstetric challenges.

With the widespread use of high-resolution pelvic MRI, uterus didelphys is now more accurately diagnosed and distinguished from other uterine anomalies such as bicornuate uterus and septate uterus. This article provides a comprehensive, expert-level review of uterus didelphys based on the attached imaging case, integrating pathophysiology, epidemiology, clinical presentation, imaging features, differential diagnosis, diagnostic strategy, treatment, and prognosis, supported by authoritative contemporary literature.

Pathophysiology of Uterus Didelphys

The female reproductive tract originates from the paired Müllerian (paramesonephric) ducts, which normally undergo three critical embryologic processes between gestational weeks 6 and 11:

  1. Formation

  2. Fusion

  3. Septal resorption

Uterus didelphys results from complete failure of Müllerian duct fusion, leading to the development of:

  • Two separate uterine bodies

  • Two distinct endometrial cavities

  • Two cervices

  • Often, partial or complete vaginal duplication

Unlike septate uterus or bicornuate uterus, there is no shared myometrial fundus and no midline septum requiring resorption.

Importantly, because Müllerian duct development is embryologically linked to the Wolffian (mesonephric) system, uterus didelphys is frequently associated with ipsilateral renal agenesis, a relationship known as the Müllerian–renal association.

Epidemiology

  • Estimated prevalence: 1 in 3,000 women

  • Represents 8–11% of Müllerian duct anomalies

  • Overall Müllerian anomalies occur in 1–3% of women

  • Vaginal duplication or septum occurs in up to 75% of uterus didelphys cases

  • Renal anomalies are present in approximately 20–30%

Despite its rarity, uterus didelphys is likely underdiagnosed, particularly in asymptomatic individuals.

Clinical Presentation

Symptoms

Many patients with uterus didelphys are asymptomatic. When symptoms occur, they typically include:

  • Pelvic pain

  • Dysmenorrhea

  • Dyspareunia

  • Pain with tampon use

  • Infertility or recurrent pregnancy loss

Obstructive Phenomena

In cases involving vaginal septum or hemivaginal obstruction, patients may present with:

  • Hematocolpos

  • Hematometra

  • Endometriosis secondary to retrograde menstruation

Reproductive Outcomes

  • Estimated term pregnancy rate: ~40%

  • Increased risk of:

    • Miscarriage

    • Preterm delivery

    • Malpresentation

    • Cesarean delivery

Imaging Features

Figure 1. Pelvic MRI Findings; Axial and sagittal pelvic MRI demonstrate two completely separate uterine bodies with independent endometrial cavities and two cervices, consistent with uterus didelphys.

Pelvic MRI is the gold standard for diagnosing uterus didelphys due to its superior soft-tissue contrast and multiplanar capability.

Key MRI features include:

  • Two symmetric uterine horns

  • Normal zonal anatomy of each uterus

  • Absence of a shared fundus

  • Two cervices

  • Reduced uterine volume per horn

Figure 2. Coronal T2-Weighted MRI; Coronal T2-weighted MRI from upper abdomen to pelvis reveals complete uterine duplication with associated vaginal duplication and evaluation for associated renal anomalies.

This imaging plane is particularly valuable for:

  • Differentiating uterus didelphys from bicornuate uterus

  • Identifying fundal cleft >1 cm

  • Detecting associated renal anomalies such as ipsilateral renal agenesis

Differential Diagnosis

Accurate distinction between Müllerian anomalies is critical due to differing management strategies.

ConditionKey Features
Uterus DidelphysComplete duplication of uterus & cervix, wide fundal separation
Bicornuate UterusPartial fusion, single cervix, deep fundal cleft
Septate UterusSingle uterus, internal septum, normal external fundus
Unicornuate UterusSingle uterine horn, contralateral agenesis
Arcuate UterusMild fundal indentation, normal fertility

MRI (especially T2-weighted coronal images) is essential for reliable differentiation.

Diagnosis

The most accurate diagnostic approach includes:

  • Pelvic MRI without contrast (preferred)

  • Adjunctive renal imaging

  • Hysterosalpingography (HSG) for cavity assessment

Correct diagnostic answer from the case:
👉 Non-contrast pelvic MRI

Treatment

Conservative Management

  • Asymptomatic patients require no intervention

  • Regular gynecologic follow-up recommended

Surgical Intervention

  • Metroplasty may be considered in recurrent pregnancy loss, though benefits remain controversial

  • Resection of obstructing vaginal septum is indicated when symptomatic

Obstetric Management

  • High-risk pregnancy monitoring

  • Planned cesarean delivery in select cases

Prognosis

  • Generally favorable with appropriate management

  • Many women achieve successful pregnancy outcomes

  • Prognosis worsens with associated renal anomalies or obstructive vaginal septum

Quiz

Question 1. A 21-year-old woman presents with pelvic pain and dyspareunia. MRI reveals two uterine bodies and two cervices. What is the most likely diagnosis?

A. Septate uterus
B. Bicornuate uterus
C. Uterus didelphys
D. Unicornuate uterus

Answer & Explanation

Answer: C
Explanation: Complete duplication of uterus and cervix is diagnostic of uterus didelphys.

Question 2. Which embryologic process fails in uterus didelphys?

A. Septal resorption
B. Partial fusion
C. Complete Müllerian duct fusion
D. Vaginal canalization

Answer & Explanation

Answer: C
Explanation: Uterus didelphys results from complete failure of Müllerian duct fusion.

Question 3. Which anomaly is most commonly associated with uterus didelphys?

A. Hepatosplenomegaly
B. Adrenal hypoplasia
C. Ipsilateral renal agenesis
D. Intestinal malrotation

Answer & Explanation

Answer: C
Explanation: Renal agenesis is frequently associated due to shared embryologic origin.

Conclusion

Uterus didelphys is a rare but clinically significant Müllerian duct anomaly best diagnosed with pelvic MRI. Understanding its embryology, imaging features, and associated anomalies is essential for accurate diagnosis, appropriate counseling, and optimal reproductive outcomes. With modern imaging and tailored management, most patients can expect a favorable prognosis.

References

[1] S. C. Behr, J. L. Courtier, and A. Qayyum, “Imaging of Müllerian duct anomalies,” Radiographics, vol. 32, no. 6, pp. E233–E250, 2012.
[2] J. A. Steinkeler et al., “Female infertility: Radiologic imaging approach,” Radiographics, vol. 29, no. 5, pp. 1353–1370, 2009.
[3] M. Midiri et al., “Congenital genitourinary anomalies,” EURORAD, 2002.
[4] A. Troiano and S. McCarthy, “Müllerian duct anomalies,” Radiology, vol. 233, pp. 19–34, 2004.
[5] R. Grimbizis et al., “ESHRE classification of uterine anomalies,” Hum Reprod, 2013.
[6] A. Acien and M. Acien, “Renal anomalies and Müllerian defects,” Fertil Steril, 2011.
[7] J. Bermejo et al., “Three-dimensional ultrasound and MRI in uterine anomalies,” Ultrasound Obstet Gynecol, 2010.

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