Congenital structural abnormalities of genital tract Flashcards
Embryological development of the female genital ducts and glands:
- Absence of SRY gene leads to differentiation of indifferent gonads into ovaries.
- Absence of AMH (produced by testis) leads to persistance of paramesonephric (Müllerian) ducts.
- Absence of testosterone leads to regression of mesonephric (Wolffian) ducts.
- Fallopian tubes: arise from unfused cranial portion of the paramesonephric ducts.
- Uterus and upper 1/3rds of vagina: arise from the uterovaginal primordium, the fused caudal portion of the paramesonephric ducts.
- Fusion occurs around 6 weeks.
- Canalisation then occurs to form the uterine cavity.
- Hox gene is responsbiel for regulating developement of female genital ducts.
- Fusion of the paramesonephric ducts also forms a peritoneal fold that becomes the broad ligament.
Embryological development of the vagina:
- Vaginal epithelium derived from the endoderm of the urogenital sinus.
- Vaginal fibromusclar wall develops from the surrounding mesenchyme.
- Lower 1/3rd of vagina:
- The paired sinovaginal bulbs (endoderm outgrowths) extends from the urogenital sinus to the caudal end of the urogenital primordium.
- The sinovaginal bulbs fuse to form a vaginal plate.
- Central portion of the vaginal plate breaks down to form the vaginal lumen by third trimester.
- Vagina is is separated from the cavity of the urogenital sinus by the hymen membrane (an invagination of the posterior wall of the urogenital sinus.
- In the first 28 days of life the hymen membrane ruptures and remains as a thin mucous membrane just within the vaginal orifice.
MRKH syndrome:
What anomaly results in MRKH syndrome?
Describe the anatomical abnormalities associated with MKRH syndrome.
Müllerian agenesis or hypolasia resulting in:
- Absent uterus and vaginal agenesis
- OR rudimentary uterus +/- atresia of the upper vagina
- In some cases abscence of the fallopain tubes
Type I MRKH = isolated mullerian anomalies
Type 2 MRKH = associated anomalies
- Renal anomalies (most commonly) - agenesis, hypoplasia, dysplasia or ectopic kidney
- Vertebral - cervical and thoracic dysplasia, scoliosis
- Facial - cleft lip/palate, micrognathia, unilateral underdevelopment of the face
- conductive deafness
- Cardiac defects
- Distal limb defects
What anomalies result from lateral fusion defects?
Failure of formation of one of the two Müllerian ducts
Failure of duct migration
Failure of Müllerian ducts fusion: resulting in didelphus or bicornuate uterus.
Failure of resorption resulting in a uterine or longitudinal vaginal septum
What anomalies result from vertical fusion defects?
- Defective fusion of the caudal end of the Müllerian ducts: cervical agenesis or dysgenesis
- Defective fusion of the caudal end urogenital sinus: transverse vaginal septum.
- Defective vaginal canalisation: segmental vaginal agenesis
What synthetic oestrogen medication used to prevent pregnancy loss from 1949 to 1971 is associated with a variety of female genital tract anomalies?
In utero exposure to diethylstilbestrol (DES)
List some non-pregnant complications associated with congenital structural abnormalities of the genital tract:
- Pelvic pain, cyclic or non-cyclic.
- Amenorrhoea:
- Hematometra (blood-filled uterine cavity)
- Hematocolpos (blood-filled vagina)
- Retrograde-menstruation and development of endometriosis.
- Abnormal uterine bleeding or discharge
- Genital tract infection
- Dyspareunia
Regarding pregnancy complications and congenital structural abnormalities:
List proposed mechanisms of complication and associated complications.
- Absence or rudimentary uterus (e.g. MRKH)
- infertility - need for surrogate
- Small uterine cavity:
- Preterm delivery
- Malpresentation
- Caesarean section delivery
- Obstructed birth canal / vaginal septum:
- Caesarean section delivery
- Abnormal uterine vascularture:
- IUGR
- Unfavourable implantation sites - e.g. septum:
- Spontaneous miscarriage
- Recurrent miscarriage
- Cervical insufficiency:
- Preterm delivery
- Unicornuate uterus with non-communicating canalised rudimentary
- ectopic pregnancy
Evaluate the role of hysterosalpingogram (HSG) for congenital structural abnormalities of the genital tract:
- Gives more information than an ultrasound about the interior contour of the uterine cavity.
- Helpful for planning surgical resection of uterine septums: length and width of septum.
- Cannot assess external uterine contour so cannot differentiate between septate and biconurate uterui.
Evaluate the role of MRI for congenital structural abnormalities of the genital tract:
- Not fully validated
- Indicated for:
- Inconclusive ultrasound
- Complex anomalies
- Intolerate of internal exam/probe
- May not identify small rudimentary structures
- Not as sensitive for cervical and vaginal abnormalities as examination
Arcuate uterus:
Outline the:
- Diagnosis
- Clinical significance
- Management of
- Diagnosis:
- Deviation of the endometrial cavities at the fundus.
- <1 cm fundal indentation
- Angle of indentation >90 degrees
- Clinical significance:
- Normal variant, no clinical consequences
- Management:
- None
Septate or subseptate uterus:
Outline the:
- Aetiology
- Diagnosis
- Clinical significance
- Management
- Aetiology:
- Failure of canalisation of two fused Müllerian ducts OR
- Failure of resorption of midline septum
- Diagnosis:
- Two closely separated endometrial cacities
- Smooth fundal contour
- Clinical significance:
- Can have complete septum with TWO cervixes.
- Increased risk of spontaneous miscarriage, recurrent miscarriage, preterm birth, IUD, malpresentation, placental abruption.
- Management:
- conservative Rx
- Hysteroscopic resection of septum - some evidence for improved conception rate, lower miscarriage rate, reduced preterm birth and increased live pregnancy rate. But no good RCTs yet.
Bicornuate uterus is associated with what pregnancy complications?
- Cervical insufficiency
- Spontaneous miscarriage
- Fetal demise
- IUGR
- Malpresentation
What surgery could you perform for a bicornuate uterus?
What is the indication for this procedure?
What are the risks of this procedure?
- Strassman procedure: open uterine reunification.
- Indication: indentation >1 cm and history of poor pregnancy outcomes.
- Risks:
- Uterine rupture (scarred uterus)
- Intra-uterine adhesions
- Laparotomy associated risks
Unicornuate uterus:
What diagnostic imaging findings are associated?
What complications are associated?
What surgical management may be offered?
- Diagnostic imaging:
- Unilateral development of the uterus and fallopian tube, single cervix
- +/-presence of rudimentary horn
- Complications:
- Cornual ectopic pregnancy
- Cyclical pain, obstructed menstrual bleeding in rudimentry horn
- Recurrent miscarriage
- Preterm delivery
- Malpresentation
- Fetal demise
- Uterine rupture
- Abnormal placentation
- Surgical management: laparoscopic resection of rudimentary horn containing endometrium.
What is the incidence of MRKH syndrome?
1 in 4000 - 6000
What other anomalies are associated with MRKH syndrome?
- Renal (25-50%)
- Vertebral dysplasia (up to 15%)
- Facial (cleft lip/palate, unilateral facial deformity)
- conductive hearing loss
- distal limb deformities
- cardiac defects
What are the causes of upper vaginal agenesis or hypoplasia?
- MRKH syndrome (46XX)
- Androgen insensitivity i.e. CAIS (46XY)
Outline briefly the management options for vaginal agenesis or hypoplasia:
Non-surgical
- Vaginal dilation - up to 80% success rate
- will also be required to maintain vaginal patency and cpacity post-operatively
Surgical
- Creation of a neonvagina in the rectovesical space and lined with different tissues:
- skin graft mounted on mould (McIndoe-Reed procedure)
- sigmoid segment of bowel
- pelvic peritoneum (Davydov procedure)
- Laparoscopic Vecchietti procedure: acrylic olive with suture placed in vaginal dimple and connected to a spring-loaded tensioning device on the patient’s abdomen via laparoscopically placed sub-peritoneal sutures. Following placement of the system in the operating room, the sutures are tensioned by 1 to 2 cm each day and a 10 cm neovagina is created over the course of 7 to 10 days.
What is the AFS (American fertility Society) Classification of uterine anomalies
I. Hypoplasia or agenesis involving the vagina, cervix, uterus or tubes (MRKH)
II. Unicornuate (communicating, non-communciating, no horn)
III. Didelphys
IV. Bicornuate
V. septate
VI. Arcuate
VII. DES expsoure related anomalies
What is the definition of MRKH?
Mayer-Rokitansky-Koster-Hauser syndrome Absent or rudimentary uterus or bilateral rudimentary horns on either side of the pelvic wall
What is the incidence of MRKH?
1:4000-6000
How does MRKH present?
Normal development of secondary sexual characteristics (indicating normal ovarian function)
Primary amenorrhoea due to absent/rudimentary uterus
Short vagina or just a vaginal dimple
Associated with renal and skeletal anomalies
Also: Facial abnormalities, Conductive hearing loss, Distal limb deformities
What is the treatment of cervical agenesis?
Traditional treatment: Hysterectomy to relieve haematocolpos
Current treatment: laparoscopic creation of cervix by passing probe through uterus into vagina, guided by vaginal assistant. Placement of 24F catheter for 1 month to maintain patency.
Women with uterine anomaly, particularly type ______ should undergo imaging of the _____
2
Renal tract
For women with Type 2 ASRM uterine anomalies, what % have associated renal malformations?
50%
What is the prevalence of mullerian anomalies?
7%
~15% in women with recurrent pregnancy loss
When and how do mullerian abnormalities present?
- Obstruction of menstrual flow - i.e. primary amennorhea or pain (non-communicating uterine horn)
- Inability to establish sexual intercourse
- Recurrent miscarriage
- Infertility
- Incidental finding - often during antenatal scans
According to Saravelos and colleagues (2008) what are the type 1a investigations for mullerian anomalies?
What is their accuracy for diagnosing and categorising a mullerian anomaly?
(From O&G Magazine 2010)
- 1a tests are the most accurate
- >90% sensitivity for detection and accuracy for classifiying into the correct AFS subgroup
- Includes:
- Hysteroscopy with laparoscopy
- Sonohysterogram
- 3D USS
Class 1b (>90% sensitivity for detection, but inaccurate for classification)
- hysteroscopy alone
Class 2 (<90% snesitivity at detection)
- 2D USS
- Hysterosalpingogram
Class 3 (unvalidated)
- MRI - though anecdotal evidence is that MRI highly helpful and accurate
What are the effects for women exposed to DES in utero?
- uterine abnormalities (T-shape cavity, hypoplasia, intracavity synechiae)
- Cervical abnormalities (hypoplasia, cervical hood, collar or polyps)
- Consequently subfertility, miscarriage and preterm birth
- increased vaginal and cervical clear cell cancer (40x increase risk)
- increased risk of high grade CIN/VAIN
- increased risk of breast cancer
- increased risk of premature menopause
What is the risk of preterm delivery with a mullerian anomaly?
34% on average
Differs depending on anomaly.
What surgery should be considered for type II AFS mullerian anomalies?
Unicornuate uterus.
If there is a cannulated non-communicating rudimentary horn, laparoscopic removal of the rudimentary horn and fallopian tube should occur to reduce the risk of cornual ectopic pregnancy on that side.
Aetiology of mullerian abnormalities:
- Failure of fusion of both mullerian ducts
- Failure of development of one or both mullerian ducts
- Failure of resolution of septum after fusion
