Version July 2025
INTRODUCTION —
Congenital uterine anomalies (CUAs) include septate, bicornuate, didelphys, and unicornuate uterus and result from the abnormal formation, fusion, or resorption of the müllerian ducts. Such anomalies may be associated with cervical and vaginal anomalies, as well as other (eg, renal, skeletal, cardiac, abdominal wall) abnormalities.
Some patients with CUAs present with symptoms of pelvic pain, abnormal bleeding at the time of menarche, recurrent pregnancy loss, or preterm birth. Other patients are diagnosed based on physical examination findings (eg, longitudinal vaginal septum) or imaging performed for another indication (eg, infertility, symptoms related to nonreproductive organ systems, trauma).
This topic provides an overview of major CUAs. Congenital anomalies of the hymen and vagina, surgical repair of CUAs, and other related issues are discussed separately.
●(See "Congenital anomalies of the hymen and vagina".)
●(See "Congenital uterine anomalies: Surgical repair".)
●(See "Outcome and follow-up of diethylstilbestrol (DES) exposed individuals".)
●(See "Benign cervical lesions and congenital anomalies of the cervix".)
CLASSIFICATION —
There is no universally accepted classification system for CUAs, which is problematic because such a system would allow physicians to codify the symptomatology, treatment, and outcome of affected patients and more accurately compare their research data with that of others [1].
●The American Society for Reproductive Medicine's (ASRM; formerly the American Fertility Society) classification system for müllerian defects has been the standard in the United States for decades (figure 1A and figure 1B) [2]. The 2021 system emphasizes CUAs and associated anomalies of the vagina, cervix, fallopian tubes, and renal system and utilizes descriptive terminology, including müllerian agenesis, cervical agenesis, unicornuate uterus, uterus didelphys, bicornuate uterus, septate uterus, longitudinal vaginal septum, transverse vaginal septum, and other complex anomalies.
●The European Society of Human Reproduction and Embryology (ESHRE) and the European Society for Gynaecological Endoscopy (ESGE) have published their own classification system (figure 2A-B) [3].
●Other classification systems have also been proposed to further clarify the vast array of complex anomalies and include Acien's classification (table 1) [4] and Congenital Uterine Malformation by Experts [5].
EPIDEMIOLOGY —
An accurate prevalence of CUAs is difficult to determine since many are never identified, especially if they are asymptomatic. Reported prevalence varies depending on the population studied.
●In a systematic review of 94 observational studies including almost 90,000 females, the prevalence of CUAs in an unselected population and in patients with infertility (primary or secondary) was similar at 5.5 and 8 percent, respectively [6]. The prevalence was increased in those with a history of pregnancy loss (12.3 percent) and a history of pregnancy loss and infertility (24.5 percent).
●In a series of 5590 females with renal anomalies, 29 percent were found to have müllerian anomalies [7].
It is important to note that the prevalence of CUAs in patients with primary infertility is similar to those of fertile patients with normal reproductive outcomes [8].
EMBRYOGENESIS —
The müllerian ducts are first identifiable at approximately six weeks of gestation when they begin to elongate caudally and cross the metanephric ducts medially to meet in the midline. By the seventh week, the urorectal septum has developed and separates the rectum from the urogenital sinus. Around 12 weeks, the caudal portion of the müllerian ducts fuse to form the uterovaginal canal, which inserts into the dorsal wall of the urogenital sinus at Müller's tubercle. The two müllerian ducts are initially composed of solid tissue and lie side by side. Subsequently, internal canalization of each duct produces two channels divided by a septum that is absorbed in a cephalad direction by 20 weeks. The cranial, unfused portions of the müllerian ducts develop into the fimbria and fallopian tubes, while the caudal, fused portions form the uterus and upper vagina (figure 3).
PATHOGENESIS —
The underlying etiology of abnormal uterine development is not well understood. Most defects are likely related to polygenic and multifactorial causes.
●The three main mechanisms for abnormal uterine development are agenesis/hypoplasia, defective lateral fusion, and defective vertical fusion.
•Agenesis or hypoplasia – Müllerian agenesis or hypoplasia leads to variable uterine development and congenital absence of the vagina, termed Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome. The resulting uterus may consist of lateral hemi-uteri or uterine horns (eg, unicornuate uterus), a midline uterus without a cervix, or, most commonly, it may not develop at all. (See "Congenital anomalies of the hymen and vagina", section on 'Vaginal agenesis (Mayer-Rokitansky-Kuster-Hauser syndrome)'.)
•Lateral fusion defect – Defective lateral fusion leads to development of organs that are either symmetric or asymmetric and nonobstructed or obstructed (eg, bicornuate uterus, uterus didelphys). One or more of the following can lead to a lateral fusion defect:
-Failure of resorption resulting in a uterine or longitudinal vaginal septum
-Failure of formation of one of the two müllerian ducts
-Failure of duct migration
-Failure of müllerian ducts fusion
•Vertical fusion defect – Defective vertical fusion leads to the development of a transverse vaginal septum, segmental vaginal agenesis, and/or cervical agenesis or dysgenesis. The vagina and/or cervix may be nonobstructed or obstructed. It results from either defective fusion of the caudal end of the müllerian duct and urogenital sinus or from defective vaginal canalization. (See "Congenital anomalies of the hymen and vagina" and "Benign cervical lesions and congenital anomalies of the cervix".)
●In utero exposure to diethylstilbestrol (DES), a synthetic estrogen used to prevent pregnancy loss from 1949 to 1971, is also associated with abnormalities of the uterus (eg, T-shaped uterine cavity (figure 4A-C), hypoplastic uterus, midfundal constrictions, filling defects, endometrial cavity adhesions), vagina (eg, adenosis, vaginal ridges, transverse septa), and cervix (eg, hypoplasia, hoods, collars, pseudopolyps). This is discussed in detail separately. (See "Outcome and follow-up of diethylstilbestrol (DES) exposed individuals", section on 'Reproductive tract abnormalities'.)
●The karyotype of patients with uterine anomalies is usually normal (46,XX) [9].
GENERAL FEATURES
Clinical presentation — Many patients with CUAs are asymptomatic.
Patients who are symptomatic may present with pain, abnormal vaginal bleeding, and/or infection; the presenting symptom varies depending on the defects involved:
●Pain – Cyclic or chronic pelvic pain may occur in patients with an obstructive anomaly of the müllerian duct. Pain typically occurs beginning at menarche but can also occur earlier, for example, if there is an ectopic ureter communicating with an obstructive uterine or vaginal anomaly. (See 'Uterus didelphys' below and 'Unicornuate uterus' below.)
●Abnormal uterine bleeding
•Amenorrhea occurs in patients with complete obstruction of the müllerian duct, while hypomenorrhea may occur in patients with partial obstruction. (See 'Uterus didelphys' below and 'Unicornuate uterus' below.)
•Prolonged menstrual bleeding may occur in patients with a transverse vaginal septum with a small fenestration as normal menstrual flow is unable to be expelled from the partially obstructed upper vagina. (See "Congenital anomalies of the hymen and vagina", section on 'Transverse vaginal septum'.)
•Vaginal bleeding despite use of a tampon may occur in patients with a longitudinal vaginal septum; such patients may need two tampons, one in each vagina. They may also report dyspareunia. (See 'Septate or subseptate uterus' below and 'Uterus didelphys' below and "Congenital anomalies of the hymen and vagina", section on 'Longitudinal vaginal septum'.)
●Vaginal discharge/infection – Microperforations in a transverse vaginal septum or obstructed hemivagina allow organisms to infect the hematocolpos. These patients may present with profuse, foul-smelling vaginal discharge. Rarely the upper genital tract becomes infected, resulting in "cyclic pelvic inflammatory disease." (See "Congenital anomalies of the hymen and vagina", section on 'Transverse vaginal septum' and "Congenital anomalies of the hymen and vagina", section on 'Obstructed hemivagina'.)
In other cases, CUAs are discovered incidentally during evaluation for another indication (eg, pelvic examination for cervical cancer screening in which a longitudinal vaginal septum or double cervixes are noted [10,11]; bimanual examination with a palpable mass from hematocolpos or hematometra due to obstruction; work-up of infertility, pelvic mass, pelvic pain, or recurrent pregnancy loss [12]; evaluation of a female patient with renal, skeletal, or abdominal wall abnormalities [13]). (See 'Common anomalies' below and 'Associated anomalies in other organ systems' below.)
Frequency of specific CUAs in affected patients — Septate uterus is the most common CUA [8,14].
In a literature review of nine studies including almost 1400 patients with CUAs with and without infertility, the frequencies of specific anomalies were [8]:
●Septate (35 percent)
●Bicornuate (26 percent)
●Arcuate (18 percent)
●Unicornuate (10 percent)
●Didelphys (8 percent)
●Agenesis (3 percent)
However, these frequencies can vary substantially depending on the specific population studied and the methodology used to identify the abnormalities.
Associated anomalies in other organ systems — Patients with CUAs are at increased risk of associated anomalies in other organ symptoms (eg, renal, skeletal, cardiac, abdominal wall abnormalities, inguinal hernia) and vice versa.
Renal anomalies are found in 20 to 30 percent of patients with müllerian defects [7,15,16]. Duplex collecting system, horseshoe kidney, pelvic kidney, and unilateral renal agenesis have been associated with an obstructed hemiuterus, obstructed hemivagina, and transverse vaginal septa. When a renal anomaly is present, it is typically ipsilateral to the CUA. For example, a patient with an obstructed hemiuterus on the left and a normal right hemiuterus will have an abnormal left and a normal right kidney.
Inguinal hernias are also commonly seen in individuals with congenital anomalies of the reproductive tract.
Potential consequences
●Nonpregnant patients – In nonpregnant patients, CUAs that obstruct or partially obstruct the flow of menses (eg, noncommunicating functioning uterine horn, uterine duplication with an obstructed hemivagina, uterine septum with an obstructed hemivagina (figure 5)) can lead to:
•Abnormal uterine bleeding or discharge
•Genital tract infection (which can result in pelvic inflammatory disease and/or tubo-ovarian abscesses)
•Hematocolpos (blood-filled vagina)
•Hematometra (blood-filled uterine cavity)
•Pelvic pain, cyclic or noncyclic
•Retromenstruation and development of endometriosis
CUAs typically do not prevent conception and implantation, either spontaneous or after in vitro fertilization [17-20].
●Pregnant patients – In pregnant patients, CUAs have been associated with [8,20-29]:
•Antepartum and postpartum bleeding
•Cervical insufficiency
•Cesarean birth
•Fetal malpresentation
•Intrauterine growth restriction
•Placental attachment abnormalities
•Pregnancy-associated hypertension
•Pregnancy loss, including recurrent pregnancy loss
•Prelabor rupture of membranes
•Preterm birth
•Rupture of a rudimentary horn
Various hypotheses have been proposed to explain these associations. For example, fetal malpresentation and, in turn, cesarean birth may be related to the small uterine cavity of the anomalous uterus, which may inhibit fetal movement to cephalic presentation. Vaginal septa may also be a reason for cesarean birth [30]. Intrauterine growth restriction may be related to abnormal uterine vasculature. Postpartum hemorrhage may result from the placenta becoming partially trapped in an accessory horn or a placental attachment abnormality. Pregnancy-associated hypertension has been attributed to coexistent congenital renal abnormalities [25]. Pregnancy loss may be related to implantation at an unfavorable site, such as a septum [8].
The frequencies of obstetric complications according to CUA type vary among reports and are presented in the table (table 2) [20,29].
DIAGNOSTIC TOOLS —
When a CUA is suspected, evaluation and diagnosis are based on imaging.
First-line imaging — Either transvaginal ultrasound (if possible, or transabdominal for prepubertal individuals and/or those who decline transvaginal imaging) or magnetic resonance imaging (MRI) may be used as the initial imaging modality.
Ultrasonography — Transvaginal ultrasound is often the initial imaging modality as it is widely available, usually well tolerated, does not involve ionizing radiation or iodinated contrast, and reliably demonstrates the number and contour of the endometrial cavity(ies). It is also useful for detecting hematometra or hematocolpos. Translabial ultrasound may be used when a vaginal obstructive anomaly is also suspected so that the distance from the vaginal orifice to the obstruction can be accurately measured. Transrectal ultrasound is another option for individuals with vaginal anomalies.
●Three-dimensional (3D) reconstructed images of the cine clips, if available, can be used to evaluate the external uterine contour to differentiate between septate and bicornuate uteri [31-35].
●3D reconstructed imaging can also be helpful in identifying the relationship of an early pregnancy to the uterine anatomy [36].
●Performing the ultrasound in the secretory phase of the menstrual cycle improves visualization of the endometrium. A longitudinal division that separates the endometrial echo from the fundus towards the cervix into two separate cavities suggests duplication.
●Concurrent kidney ultrasound can be obtained to evaluate for renal anomalies that often coexist [32,37-41]. The American College of Radiology (ACR), American College of Obstetricians and Gynecologists (ACOG), and American Institute of Ultrasound in Medicine (AIUM) standard for pelvic ultrasound does not include routine renal imaging [42], so, if desired, a separate exam of the kidneys should be ordered.
●Saline infusion sonohysterography provides more detailed information about the interior contour of the uterine cavity and can be helpful for assessment of the length/width of a uterine septum when planning surgical resection [43,44]. (See "Saline infusion sonohysterography".)
Endovaginal probes may not be tolerated by a nonsexually active adult, younger adolescent, or child.
Magnetic resonance imaging — Pelvic MRI without contrast is the historic "gold standard" for diagnosing CUAs and surgical planning [45-48]. MRI provides reliable delineation of both internal and external uterine contours, detects rudimentary or separate horns (eg, unsuspected didelphys, complete septate), determines the presence or absence of a cervix, and delineates the septum from the fundus through the endocervical canal. Associated pathologies such as renal anomalies, hematometra/hematocolpos, or retrograde menses are also routinely visualized.
MRI may be used in patients who cannot tolerate or decline transvaginal ultrasound, or as an alternative to translabial or transrectal ultrasound.
Role of hysterosalpingography — Hysterosalpingography (HSG) is not routinely obtained to diagnose CUAs as the examination involves ionizing radiation and iodinated contrast. However, CUA may be diagnosed incidentally with HSG during an evaluation for infertility. In patients with a known CUA, HSG can also be helpful in evaluating possible complex communications involving the uterus and vagina and between uterine horns [47]. (See "Hysterosalpingography".)
HSG provides information about the internal (image 1 and image 2), but not the external uterine contour, and demonstrates the relationship of the fallopian tubes to the cavity and evaluates for their patency. It cannot detect a separate rudimentary horn or a separate cavity and cervix. When two cervixes are known to be present, the procedure can be performed with catheters in each hemiuterus (image 3).
Other — In patients with complicated müllerian anomalies, additional information may be obtained (if clinically indicated) by examination under anesthesia, vaginoscopy, laparoscopy, and/or hysteroscopy [47,49].
COMMON ANOMALIES
Arcuate uterus: Normal variant
●Definition – An arcuate uterus has a minimal (≤1 cm) and often broad fundal cavity indentation; the angle of indentation is >90 degrees (figure 1B and figure 6) [2].
●Diagnostic features – The diagnosis is typically based on imaging findings of two closely separated endometrial cavities (image 1) and a smooth fundal contour (by contrast, the bicornuate uterus has an indented fundus) (figure 1B) [2]. 3D ultrasound can be helpful in confirming the diagnosis.
●Clinical significance – Although previously believed to have clinical significance and some studies have described adverse pregnancy outcomes [20,50], an arcuate uterus is now considered to be a normal variant [8,15,19,21,31,51-53]. Patients are typically asymptomatic, have no compromise of fertility, and have similar pregnancy outcomes as those in the general obstetric population.
Septate or subseptate uterus
●Definition – A septate uterus has a depth from the interstitial line to the apex of the indentation of >1 cm, and an angle of indentation <90 degrees (figure 1B) [2]. The degree of septation is defined by the proximity of the septum to the internal os [54], which varies widely from a partial midline septum (referred to as a subseptate uterus) (figure 7) to a complete midline septum extending into the cervix (figure 8) or vagina (longitudinal vaginal septum) (figure 9). However, definitions vary [55]. The etiology of a uterine septum is not clearly understood but is hypothesized to occur either from a defect in canalization of the two fused müllerian ducts or a defect in resorption of the midline septum between the two müllerian ducts.
The septum is usually thin and consists of myometrium covered by endometrium and is usually vascularized [56]. In some studies, the endometrium covering the septum showed differences in histologic composition and gene expression compared with the normal uterine wall. The thickness and composition of the septum, the relative amounts of fibrous and muscular tissue, and the degree of vascularization from the adjacent uterine wall may also vary; no classification system standardizes all of these variations.
●Diagnostic features – The diagnosis is typically based on imaging findings of two closely separated endometrial cavities and a smooth fundal contour (by contrast, the bicornuate uterus has an indented fundus) (image 4 and image 5).
The sensitivity and specificity of MRI for diagnosis of septate uterus has been reported to be as high as 100 percent [47] as MRI reliably shows whether the contour of the fundus is smooth (septate uterus) or indented (bicornuate uterus). In cases of a large, wide, and deep septum, the appearance of the septum on MRI may help with surgical planning since it is the fibrous portion of the septum that is typically removed hysteroscopically.
●Clinical significance –Septate uterus is more likely to be associated with adverse pregnancy outcomes than other uterine anomalies (see 'Potential consequences' above). However, no clear biological basis for impaired reproductive outcomes in affected patients has been found [56]. Specifically, patients with septate uterus are at increased risk of pregnancy loss (21 to 44 percent) and preterm birth (12 to 33 percent); the live birth rate ranges from 50 to 72 percent [8,24,54]. There appears to be a higher risk of recurrent pregnancy loss associated with longer septa, but this is controversial, and many patients with a septate uterus have good pregnancy outcomes. Pregnancy loss, when present, often occurs in the second trimester and may be distinguished from cervical insufficiency because of signs of labor [57]. The septate uterus is also associated with an increased risk of breech presentation [57] and abruption [20].
A septum that extends into the vagina and causes an obstructed hemivagina can lead to cyclic pain, a lateral vaginal mass, and, if the obstructed hemivagina is perforated, spotting or purulent vaginal discharge if the contents become infected. Sepsis has been reported [58].
●Role of surgery – Resection of the septum hysteroscopically (hysteroscopic metroplasty) can improve pregnancy outcomes [59]. (See "Congenital uterine anomalies: Surgical repair", section on 'Septate uterus'.)
Bicornuate uterus
●Definition – A bicornuate uterus has a fundus that is indented >1 cm (figure 1A) [2]. It results from partial rather than complete fusion of the müllerian ducts. Depending on the extent of fusion, separation of the uterine horns will be complete (figure 10), partial (figure 11), or minimal [60]. The vagina and cervix are generally normal (typically one cervix is present) [31].
●Diagnostic features – The diagnosis is typically based on imaging findings of two usually moderately separated (ie, divergent) endometrial cavities and an indented fundal contour (image 6 and image 7).
●Potential consequences – Literature reviews have reported pregnancy loss in 36 percent, preterm birth in 21 to 23 percent, and fetal survival in 50 to 60 percent of patients with a bicornuate uterus [8,24,61]. Fetal growth restriction and malpresentation in labor are also increased [20].
●Role of surgery – In patients with poor pregnancy outcomes that are thought to be related to the anomaly, uterine reunification can be performed surgically. Due to an association between bicornuate uterus and cervical insufficiency, the cervical length should be assessed during pregnancy. (See "Congenital uterine anomalies: Surgical repair" and "Short cervix before 24 weeks: Screening and management in singleton pregnancies".)
Uterus didelphys
●Definition – Uterus didelphys, or double uterus, is a duplication of the reproductive structures (figure 1A) [2]. It results when the two müllerian ducts fail to fuse. Generally, the duplication is limited to the uterus and cervix (uterine didelphys and bicollis [two cervixes]) (picture 1A-C), although duplication of the vulva, bladder, urethra, vagina, and anus may also occur.
●Diagnostic features – The diagnosis is typically based on imaging findings of two widely separated uterine horns with a deep fundal indentation (image 8 and image 9) and two cervixes. On speculum examination, two cervixes are present.
●Potential consequences – Patients with uterine didelphys are at an increased risk of pregnancy loss (32 percent) and preterm birth (28 percent) [8,24]. Fetal growth restriction also appears to be increased [20]. A septated vagina is present in 75 percent of cases and may cause difficulty with vaginal birth.
Patients with an obstructed hemivagina and ipsilateral renal agenesis/anomaly (figure 12) will have regular menses because menstrual blood from one uterus can egress through its nonobstructed cervix and hemivagina [62]. Such patients will sometimes develop cyclic pain due to buildup of blood in the obstructed hemivagina [63]. Alternatively, there may be a microcommunication between the patent vagina and the obstructed vagina, resulting in an infected obstructed hemivagina. Bilateral complete obstruction is also possible and presents with primary amenorrhea and cyclical pain (figure 13). When associated with a septated vagina, a patient may report difficulty with sexual intercourse.
●Associated anomalies – Many (15 to 20 percent) patients with didelphic uterus also have unilateral anomalies, such as an obstructed hemivagina and ipsilateral renal agenesis; the anomalies are on the right in the majority (65 percent) of cases [64].
●Role of surgery – Metroplasty can be considered for patients with poor pregnancy outcomes. (See "Congenital uterine anomalies: Surgical repair".)
We and others [15,63] do not believe that existing data sufficiently support abdominal repair of the didelphic uterus to improve pregnancy outcomes.
Unicornuate uterus
●Definition – In the unicornuate uterus, one cavity is usually smaller than a normal uterus and has a fallopian tube, ovary, and cervix (figure 14), while the failed müllerian duct has various configurations (figure 1A and figure 15A-E). The affected müllerian duct may not develop at all, or it may develop only partially as either a rudimentary horn on the uterus or an anlage (a cluster of embryonic cells). This horn (or anlage) may or may not communicate with the uterus.
●Diagnostic features – The diagnosis is typically based on imaging findings of a uterus deviated to one side of the pelvis with an inner contour demonstrating a tubular rather than triangular configuration; 3D-reconstructed images are particularly helpful (image 10). MRI can be useful to more reliably assess for the presence of a rudimentary horn with or without functional endometrium and an ectopic ovary.
●Clinical significance – Most rudimentary horns are asymptomatic. Some contain functional, but not necessarily normal [65], endometrium that is shed cyclically. If a rudimentary horn is obstructed (without communication to the other uterus or cervix), the patient may develop cyclic or chronic abdominopelvic pain. Patients with a unicornuate uterus are also at higher risk for endometriosis.
A literature review of pregnancy outcomes in patients with unicornuate uteri reported the following adverse pregnancy outcomes: first-trimester pregnancy loss (24.3 percent), preterm birth (20.1 percent), second-trimester pregnancy loss (9.7 percent), fetal demise (3.8 percent), ectopic pregnancy (2.7 percent); over half (51.5 percent) of patients experienced a live birth [21]. An obstructed or rudimentary uterine horn is also associated with uterine rupture and/or placental attachment abnormalities (eg, accreta, increta, percreta) [65-72]. A study of 328 pregnancies in obstructed horns found that only 1 percent of such pregnancies were alive at term, and 89 percent of the horns ruptured [67]. Both spontaneous rupture and rupture during labor or induction have been reported. Thus, pregnancies in an obstructed horn should be terminated.
●Associated anomalies – Unicornuate uterus can also be associated with an ectopic ovary (which is of clinical importance in patients undergoing ovulation induction or who develop ovarian neoplasms) [73,74] and a particularly high incidence (40 percent) of renal abnormalities [75].
●Role of surgery – Patients with unicornuate uteri are generally not candidates for reconstructive procedures to improve pregnancy outcomes [4]. However, as a rudimentary horn with functioning endometrium can result in cyclic or chronic abdominopelvic pain or harbor an ectopic pregnancy, noncommunicating rudimentary horns with endometrium are sometimes surgically removed. (See "Congenital uterine anomalies: Surgical repair", section on 'Obstructed rudimentary horn'.)
SOCIETY GUIDELINE LINKS —
Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Congenital female reproductive tract anomalies".)
SUMMARY AND RECOMMENDATIONS
●Classification – Congenital uterine anomalies (CUAs) include septate, bicornuate, unicornuate, and didelphys uterus; arcuate uterus is a normal variant. There is no universally accepted classification system for CUAs. The American Society for Reproductive Medicine (ASRM) 2021 classification system for müllerian defects is the revised standard in the United States (figure 1A-B). Other classification systems are presented in the figures (figure 2A-B). (See 'Classification' above.)
●Pathogenesis – The underlying etiology of congenital müllerian defects is not well understood. The three main mechanisms for abnormal uterine development are agenesis/hypoplasia, defective lateral fusion, and defective vertical fusion. The karyotype of patients with these anomalies is usually normal and whole gene sequencing has identified some potential genetic associations (eg, HNF1B, WNT4, WNTZA, HOXA13) [76]. (See 'Pathogenesis' above.)
●General features
•Many patients are asymptomatic. Patients who are symptomatic may present with pain, abnormal vaginal bleeding, and/or infection; the presenting symptom varies depending on the defects involved. In other cases, the anomaly is discovered incidentally during evaluation for another indication (eg, pelvic examination for cervical cancer screening, work-up of infertility) or as part of the evaluation of a female patient with renal, skeletal, or abdominal wall abnormalities. (See 'Clinical presentation' above.)
•Septate uterus is the most common CUA. (See 'Frequency of specific CUAs in affected patients' above.)
•Patients with CUAs are at increased risk of having renal, skeletal, cardiac, abdominal wall abnormalities, or inguinal hernia and vice versa. (See 'Associated anomalies in other organ systems' above.)
•In nonpregnant patients, CUAs can lead to hematometra, hematocolpos, retromenstruation, pelvic pain, abnormal uterine bleeding, or genital tract infection. The ability to conceive a pregnancy is not typically impaired. (See 'Potential consequences' above.)
●Diagnostic tools – When a CUA is suspected, evaluation and diagnosis are based on imaging. Transvaginal ultrasound or magnetic resonance imaging may be used as the initial imaging modality; hysterosalpingography may be performed in some patients. In patients with complicated müllerian anomalies, additional information may be obtained (if clinically indicated) by examination under anesthesia, vaginoscopy, laparoscopy, and/or hysteroscopy.
●Common CUAs – Definitions, diagnostic features, and associated anomalies for the most common CUAs are described in the pertinent sections above. (See 'Common anomalies' above.)
•Arcuate uterus (normal variant) (figure 6) (see 'Arcuate uterus: Normal variant' above)
•Septate of subseptate uterus (partial (figure 7) or complete (figure 8)) (see 'Septate or subseptate uterus' above)
•Bicornuate uterus (partial (figure 11) or complete (figure 10)) (see 'Bicornuate uterus' above)
•Uterus didelphys (figure 12) (see 'Uterus didelphys' above)
•Unicornuate uterus (figure 14) (see 'Unicornuate uterus' above)
The role of surgery for these conditions is discussed separately. (See "Congenital uterine anomalies: Surgical repair".)
ACKNOWLEDGMENT —
The UpToDate editorial staff acknowledges Ronald E Iverson, Jr, MD, who contributed to an earlier version of this topic review.
