Abstract
Congenital anomalies of the female genital tract are alterations in embryonic development due to an interruption or deviation in the ontogenesis of individual organs, or part, of the reproductive tract. The aetiology of these anomalies is unknown. Various hypotheses have been proposed, relating to genetic alterations, hereditary factors and exposure to exogenous noxious substances, including environmental pathogens.
The terminology commonly used for describing female genital tract anomalies is various and sometimes misleading: indeed, terms such as ‘uterine anomalies’, ‘congenital malformations of the female genital tract’ and ‘Müllerian anomalies’ are often used synonymously, although they actually refer to different concepts. The expression ‘congenital anomalies of the female genital tract’ includes those malformations that affect the development and morphology of the fallopian tubes, uterus, vagina and vulva, with or without associated ovarian, urinary, skeletal or other organ malformations.
14.1 Definition and Classification
Congenital anomalies of the female genital tract are alterations in embryonic development due to an interruption or deviation in the ontogenesis of individual organs, or part, of the reproductive tract. The aetiology of these anomalies is unknown. Various hypotheses have been proposed, relating to genetic alterations, hereditary factors and exposure to exogenous noxious substances, including environmental pathogens.
The terminology commonly used for describing female genital tract anomalies is various and sometimes misleading: indeed, terms such as ‘uterine anomalies’, ‘congenital malformations of the female genital tract’ and ‘Müllerian anomalies’ are often used synonymously, although they actually refer to different concepts. The expression ‘congenital anomalies of the female genital tract’ includes those malformations that affect the development and morphology of the fallopian tubes, uterus, vagina and vulva, with or without associated ovarian, urinary, skeletal or other organ malformations. In contrast, ‘Müllerian anomalies’ includes those malformations that affect the embryological development of paramesonephric ducts, also called Müllerian ducts, thus being only part of the female genital anomalies. Furthermore, only a subcategory of Müllerian anomalies is represented by ‘uterine anomalies’. However, as most of the ‘female genital tract malformations’ affect the uterus, they are often reported as ‘uterine’ or ‘Müllerian’ (paramesonephric) malformations, which explains the existing confusion in the terminology.
The true incidence of congenital anomalies of the female genital tract in the general population and among women with poor reproductive outcome is not known accurately. Incidences of 0.16–10% have been reported, but recent reviews of all published studies [1–3] suggest an incidence of about 5.5–6% in the general population, 8% in infertile women, 16% in women with recurrent pregnancy loss and poor reproductive outcomes and 24.5% in women with miscarriage and infertility. Overall, the prevalence of major congenital anomalies in women with poor reproductive outcome appears to be at least three times that in the general population.
Due to their prevalence and clinical importance, a reliable classification system seems to be extremely useful for their management; indeed, an effective categorisation enables more effective diagnosis and treatment. The international classification system revised in 1988 by the American Fertility Society (AFS) is today’s most widely noted system in the world for classifying congenital anomalies of the uterus [4] (Figure 14.1). This system distinguishes between seven classes that are based on the degree of uterine anomaly and grouped according to reproductive prognosis and therapeutic options.
Figure 14.1 Classification of congenital anomalies of the female genital tract according to the American Society for Reproductive Medicine (ASRM) / American Fertility Society (AFS) [4].
One of the limitations of the AFS system is that it does not specify diagnostic modalities or the criteria that should be applied to the classification. Moreover, the classification system does not include all female genital tract anomalies diagnosed to date. For this reason, the AFS classification serves merely as a first tool for describing the anomalies in question, rather than being considered an exhaustive list of all possible existing anomalies.
In the light of these considerations, the European Society of Human Reproduction and Embryology (ESHRE) and the European Society for Gynaecological Endoscopy (ESGE), recognising the clinical significance of female genital anomalies, recently established a common working group under the name CONUTA (CONgenital UTerine Anomalies), with the goal of developing an updated classification system [5]. It has been designed mainly from a clinical perspective and is primarily based on the anatomy of the female genital tract (Figure 14.2).
The ESHRE/ESGE classification system of female genital anomalies is used in this chapter and only uterine and vaginal anomalies will be examined.
Figure 14.2 Classification of uterine anomalies proposed by the Joint Task Force CONUTA (CONgenital UTerine Anomalies) group of the European Society of Human Reproduction and Embryology (ESHRE) and the European Society of Gynaecological Endoscopy (ESGE) [5].
14.2 Diagnosis
The diagnostic workup for female genital tract anomalies continues to represent a great challenge for the gynaecologist because the various techniques available for the diagnosis differ in their invasiveness, availability, need for training and, more importantly, diagnostic accuracy. It seems that despite advances in ultrasound and new pelvic imaging techniques, late diagnosis of female genital tract anomalies remains frequent, accounting for 10% of the causes of primary infertility [6].
14.2.1 Gynaecological Examination
A physical examination should raise suspicion of a congenital uterine, cervical or vaginal anomaly. However, it does not allow the doctor to establish a differential diagnosis for the precise nature of the anomaly. During the diagnostic workup, it is necessary to keep in mind that the congenital anomalies of the uterine cervix may be associated with normally developed secondary sexual characteristics and a regular vaginal introitus and canal. In these circumstances, the cervix may be absent on inspection through the speculum, or may not exhibit a typical appearance owing to absence of the external cervical os. Finally, in the case of a transverse vaginal septum, a speculum may suggest a blind-ended vagina.
14.2.2 Investigations
Hysterosalpingography
According to guidelines issued by the World Health Organization, the American Society for Reproductive Medicine (ASRM) and ESHRE, hysterosalpingography (HSG) is an integral part of the diagnostic workup of infertile women and is specified as the diagnostic modality of choice for the primary examination and evaluation of uterine and tubal factors [7]. It is very useful in the diagnosis of the unicornuate uterus, allowing confirmation of the presence of a single tube and, if there is a rudimentary horn, whether it has a cavity. However, HSG does not allow evaluation of the outer contours of the uterus. In such cases, the HSG examination only permits a tentative diagnosis of a double uterine cavity, showing two half-cavities divided medially and presenting with the typical Y shape.
Transvaginal Sonography
According to several authors, transvaginal sonography (TVS) is the first-line diagnostic modality in the assessment of uterine morphology and function, and is also useful for intraoperative monitoring during surgical treatment [8, 9]. In addition, it offers the benefit of being suitable for use during pregnancy when other diagnostic measures are contraindicated. Similar to HSG, transvaginal sonography is capable of diagnosing first- and second-class uterine anomalies. Moreover, in the case of a ‘double’ uterus it provides more information, allowing examination of the morphology of the fundus and adnexa. TVS may also demonstrate two hyperechoic endometrial lines in cross-section separated by a uterine fundus that may appear normal, flat, partly concave or even split, thereby giving the operator a clue as to a specific ESHRE/ESGE class. Sonography techniques also enable the identification of a vaginal septum, as well as diagnosing a hematocolpos.
Recently, the use of three-dimensional ultrasound (3D-US) has been shown to enhance the diagnosis of uterine anomalies on account of its high sensitivity and reproducibility. It allows a detailed examination of the outer uterine contour and the relationships between the uterine cavity and fundus, with accuracy comparable to that of laparoscopy. In addition, it enables the identification of anomalies that are not distinguishable with two-dimensional ultrasound, as it allows measurement of the length and thickness of a uterine septum (Figure 14.3) and the volume of the uterine cavity (Figure 14.4).
Doppler images are also capable of confirming and supporting findings obtained via ultrasound imaging. The use of Doppler techniques as a screening method provides a reliable prognosis for the anticipated reproductive outcome of patients with confirmed uterine anomalies [10, 11].
Sonohysterography
Sonohysterography (SHG) provides a good view of the uterine cavity and is associated with moderate costs [12]. This diagnostic modality has recently become even more widely accepted owing to excellent results relating to the use of 3D-US [13].
Magnetic Resonance Imaging
Among all third-level examinations, magnetic resonance imaging (MRI) allows not only the correct classification of the anomaly, but also the identification of any possible concomitant gynaecological and extragenital pathology. MRI is particularly useful for the diagnosis of complex anomalies, especially as part of the pre-operative evaluation, providing a complete examination of the pelvis and an assessment of the size, morphology and thickness of any vaginal septa. However, MRI is still not used on a routine basis as the primary diagnostic modality because of its high cost and the fact that it is not readily available in daily clinical practice.
Hysteroscopy
Hysteroscopic examination is confined to the analysis of intracavity morphology and structure, and therefore a complementary diagnostic investigation is required to evaluate the external shape of the organs. Laparoscopy has long been the gold-standard procedure used as an adjunct to diagnostic hysteroscopy. However, 3D-US is gaining acceptance as an alternative option that is both highly accurate and minimally invasive.
In the presence of suspected anomalies, hysteroscopy must always be performed in the first phase of the menstrual cycle, as a thickened endometrium can make it difficult to visualise the entire uterine cavity.
Hysteroscopic Technique
Stage I: Vaginoscopy
Vaginoscopic inspection is essential in cases of suspected congenital anomalies of the genital tract, as a traditional hysteroscopic approach with speculum and cervical forceps may preclude the identification of certain types of vaginal anomalies [14]. The vaginoscopic approach allows the morphology and size of the vaginal canal to be established and any septa identified (Figure 14.5).
In the case of a blind-ended vaginal pouch with failed visualisation of the cervix, the differential diagnosis is between a complete transverse vaginal septum with a normal uterus, a blind-ended vagina with concomitant uterine agenesis and segmental vaginal atresia. Where there is doubt, ultrasound imaging and the patient’s history provide important clues. For the diagnosis of segmental vaginal atresia, MRI can be of particular assistance: if the distance between the superior and inferior vaginal segments is at least 1 cm, this is evidence to suggest a diagnosis of segmental vaginal atresia; if the measured distance is smaller, the presence of a transverse septum should be assumed.
Stage II: Examination of the Uterine Cervix
This includes a detailed assessment of the position, morphology and size of the cervix. Proceeding in a stepwise fashion, the four vaginal fornices are identified using a panoramic view of the cervix. When presented with two clearly distinguishable cervical canals, the differential diagnosis is between a single cervix with a cervical septum, and a double cervix. In the case of cervical duplication, the two cervices are typically seen to be set apart from each other, and a view of the complete outline of each cervix can be obtained. In this case, hysteroscopic examination should be complemented by a precise ultrasound examination. In order to differentiate between the two anatomic variations, the following anatomic criteria should be considered:
Double cervix: both cervices are normally developed and generally divergent
Single cervix: the hemicervices are ipsilaterally deflected and their whole outline may not be identified.
In the presence of a transverse vaginal septum, either atresia or aplasia of the uterine cervix may be found. In such cases, the cervix is not visible with vaginoscopy. Hysteroscopy, of course, may only provide a tentative diagnosis in these cases and should give rise to referring the patient for MRI investigation.
The presence of a cervical septum is generally easily differentiated from an overt double cervix; indeed, a single cervix is generally regular in volume and morphology, with well-defined edges and a more or less broad central septation.
The finding of a co-existing longitudinal vaginal septum can make it even more difficult to differentiate between a single or double cervix. A useful strategy is to ‘mark’ the cervical surface with a small incision made with scissors or a 5 Fr bipolar electrode. Subsequently, the marked site is checked from either side of the vaginal septum: if the mark is not visible from both sides of the vaginal septum, it is diagnostic of a double cervix. In the opposite case, a diagnosis of two hemicervices may be made.
Stage III: Examination of the Uterine Cavity
In the uterine cavity, hysteroscopic evaluation is focused on assessing the morphology, size and shape of the fundus, as well as on the number and characteristics of the tubal ostia. A reduced intertubal distance is suggestive of a uterine cavity with tubular or hypoplastic morphology; conversely, an extended intertubal distance in the longitudinal uterine axis may be a clue to a T-shaped uterus, while a more or less pronounced fundus should raise the suspicion of either a subseptate or arcuate uterus.
Failure to visualise a tubal ostium should prompt the tentative diagnosis of a unicornuate uterus: in such cases, the operator should search for a rudimentary horn at the level of the uterine isthmus that is communicating with the main cavity. Moreover, a detailed ultrasound examination of the uterine cavity is indicated to complement the hysteroscopic findings.
In the presence of extensive septation of the uterine cavity, the endoscopic image encountered is that of bilateral finger-shaped cavities with a tubal ostium revealed at each apex. In the case of incomplete septation with a single cervical canal, the hysteroscopic aspect is that of a bifid cavity presenting with an interposed central projection of variable thickness, which is lined with normal endometrium. At the level of both hemicavities, the tubal ostia come into view. In such cases, a hysteroscopic panoramic view should assess the dimensions of the septum by comparing its length with the longitudinal diameter of the uterus, e.g. estimated as less than 0.5 cm, or equal to about a third, two-thirds or all of the cavity (Figure 14.6).
Figure 14.6 Double uterine cavities, under hysteroscopic examination using a liquid distension medium, extending (a) <0.5 cm, (b) 1/3 , (c) 2/3 and (d) 3/3 of its length. The endocervical mucosa in (d) indicates that a tract of the endocervical canal is involved in the septation. In these cases, 3D ultrasound provided evidence of a subseptate uterus (a–c) and complete septate uterus with involvement of the cervix (d). (Source of images: Attilio Di Spiezio Sardo.)
14.3 Treatment of Uterine Anomalies
Operative hysteroscopy is the gold standard for the treatment of uterine and vaginal anomalies amenable to surgical correction. It offers numerous advantages over laparoscopic surgery with regard to intra- and post-operative aspects and reproductive outcomes.
14.3.1 Septate Uterus
Surgical Treatment
To date, the range of indications for surgical treatment of the septate uterus are the subject of ongoing lively debate in the literature. Most authors agree that a repeated or recurrent pregnancy loss constitutes the main indication for a metroplasty. However, it is still unclear which approach to take, given the diagnosis of a septate uterus when faced with a patient who has a history of just one pregnancy loss, with primary infertility or with a woman who has not even experienced a successful pregnancy. From our point of view, given the simplicity of the operation and the significant improvement in reproductive outcomes it may provide, it would be best to evaluate the opportunity to perform a metroplasty even in these women [15−17].
Over time, various hysteroscopic procedures have been developed. Currently, there are two hysteroscopic treatment options available for the septate uterus, namely resectoscopic surgery and operative mini-hysteroscopy. The rationale underlying these options is the hysteroscopic visualisation of the septum and its subsequent removal. This aims at correcting and restoring the physiological morphology and functionality of the uterine cavity, while at the same time maintaining an adequate fundal thickness [15, 18].
The majority of authors choose to perform this operation in the early proliferative phase, without pharmacological preparation of the endometrium [19]. However, in the case of a very extensive septum, some authors perform pre-operative therapy with gonadotrophin-releasing hormone analogues (GnRHa) or oestrogen–progestin, or simply by administration of a mini-pill, resulting in a significant decrease in both endometrial thickness and intraoperative blood loss [19, 20]. The surgical technique applied is based on incision of the septum along the median plane, starting from the apex and proceeding gradually towards the fundus. Given a thick septum with a wide base, the technique involves cutting alternately on both sides while keeping to the same transverse plane. The septum is gradually reduced until there is just a thin amount left, which is then resected in a latero-lateral direction, proceeding from one utero-tubal horn towards the other.
The most delicate part of the procedure is deciding when to stop the incision of the septum in order to avoid any immediate problem (perforation) or late complication, such as post-operative synechiae or uterine rupture in subsequent pregnancies. Generally, metroplasty is stopped once both tubal ostia are clearly and simultaneously visible with a panoramic hysteroscopic view and the scope can be moved freely from one cornual recess to the other one. Another suggestion is to end the procedure when the incision reaches the myometrium, as determined by bleeding from small fundal myometrial veins.
Resectoscopic Treatment
This involves the use of straight cutting loops or a Collins electrode (Figure 14.7). The technique is represented by the piecemeal removal of the septum, beginning at the medial portion of the septation and continuing with well-directed, smooth movements of the cutting loop oriented in an anterograde direction (i.e. from the apex towards the base of the septum).
Figure 14.7 Hysteroscopic metroplasty using a 26 Fr bipolar resectoscope (KARL STORZ, Germany) and a Collins electrode. The technique of resectoscopic removal of the septum generally involves anterograde movements of the electrode performed in the median plane of the septum, with the hook oriented transversely (i.e. perpendicular to the septum). (Source of image: Attilio Di Spiezio Sardo.).
In the case of a complete uterocervical septum, with the traditional approach the cervical canal is excluded from any resection, in order to reduce the risk of secondary cervical incompetence. Resection starts from the isthmic portion of the septum. According to this approach, the cervix of the larger uterine hemicavity is gradually dilated in order to introduce a resectoscope with a classical straight loop. Meanwhile, in the contralateral hemicavity, a curved dilator (Hegar) is inserted, serving as a guide to properly align the first blind incision. Cutting starts above the internal uterine ostium using an angular cutting loop. The next step involves incising the septum to produce a window through which the Hegar in the opposite hemicavity can be seen. Gradual resection then follows towards the fundus using the classical technique [21].
In the past, resectoscopic metroplasty was often performed under laparoscopic control, but with the use of modern 3D-US, the role of laparoscopy in the diagnostic and therapeutic management of the uterine septum is likely to diminish in importance. However, it remains the first choice in cases where it is necessary to examine associated pelvic pathologies or assess the fallopian tubes [22, 23].
Related posts:
Chapter 2 – Anatomy and Physiology of the Uterus
Chapter 3 – Infrastructure and Instrumentation for Hysteroscopy
Chapter 9 – Complications of Hysteroscopic Surgery
Chapter 8 – Hysteroscopic Electrosurgery
Chapter 17 – Audit, Data Collection and Clinical Governance in Hysteroscopy
Chapter 18 – Training in Hysteroscopic Skills
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