Congenital structural abnormalities of genital tract

Question 1

Embryological development of the female genital ducts and glands:

Answer 1

• 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.

Question 2

Embryological development of the vagina:

Answer 2

• 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.

Question 3

MRKH syndrome:

What anomaly results in MRKH syndrome?

Describe the anatomical abnormalities associated with MKRH syndrome.

Answer 3

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

Question 4

What anomalies result from lateral fusion defects?

Answer 4

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

Question 5

What anomalies result from vertical fusion defects?

Answer 5

• 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

Question 6

What synthetic oestrogen medication used to prevent pregnancy loss from 1949 to 1971 is associated with a variety of female genital tract anomalies?

Answer 6

In utero exposure to diethylstilbestrol (DES)

Question 7

List some non-pregnant complications associated with congenital structural abnormalities of the genital tract:

Answer 7

• 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

Question 8

Regarding pregnancy complications and congenital structural abnormalities:

List proposed mechanisms of complication and associated complications.

Answer 8

• 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

Question 9

Evaluate the role of hysterosalpingogram (HSG) for congenital structural abnormalities of the genital tract:

Answer 9

• 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.

Question 10

Evaluate the role of MRI for congenital structural abnormalities of the genital tract:

Answer 10

• 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

Question 11

Arcuate uterus:

Outline the:

• Diagnosis
• Clinical significance
• Management of

Answer 11

• 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

Question 12

Septate or subseptate uterus:

Outline the:

• Aetiology
• Diagnosis
• Clinical significance
• Management

Answer 12

• 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.

Question 13

Bicornuate uterus is associated with what pregnancy complications?

Answer 13

• Cervical insufficiency
• Spontaneous miscarriage
• Fetal demise
• IUGR
• Malpresentation

Question 14

What surgery could you perform for a bicornuate uterus?

What is the indication for this procedure?

What are the risks of this procedure?

Answer 14

• 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

Question 15

Unicornuate uterus:

What diagnostic imaging findings are associated?

What complications are associated?

What surgical management may be offered?

Answer 15

• 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.

Question 16

What is the incidence of MRKH syndrome?

Answer 16

1 in 4000 - 6000

Question 17

What other anomalies are associated with MRKH syndrome?

Answer 17

• Renal (25-50%)
• Vertebral dysplasia (up to 15%)
• Facial (cleft lip/palate, unilateral facial deformity)
• conductive hearing loss
• distal limb deformities
• cardiac defects

Question 18

What are the causes of upper vaginal agenesis or hypoplasia?

Answer 18

• MRKH syndrome (46XX)
• Androgen insensitivity i.e. CAIS (46XY)

Question 19

Outline briefly the management options for vaginal agenesis or hypoplasia:

Answer 19

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.

Question 20

What is the AFS (American fertility Society) Classification of uterine anomalies

Answer 20

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

Question 21

What is the definition of MRKH?

Answer 21

Mayer-Rokitansky-Koster-Hauser syndrome Absent or rudimentary uterus or bilateral rudimentary horns on either side of the pelvic wall

Question 22

What is the incidence of MRKH?

Answer 22

1:4000-6000

Question 23

How does MRKH present?

Answer 23

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

Question 24

What is the treatment of cervical agenesis?

Answer 24

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.

Question 25

Women with uterine anomaly, particularly type ______ should undergo imaging of the _____

Answer 25

2
Renal tract

Question 26

For women with Type 2 ASRM uterine anomalies, what % have associated renal malformations?

Answer 26

50%

Question 27

What is the prevalence of mullerian anomalies?

Answer 27

7%

~15% in women with recurrent pregnancy loss

Question 28

When and how do mullerian abnormalities present?

Answer 28

• 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

Question 29

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)

Answer 29

• 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

Question 30

What are the effects for women exposed to DES in utero?

Answer 30

• 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

Question 31

What is the risk of preterm delivery with a mullerian anomaly?

Answer 31

34% on average

Differs depending on anomaly.

Question 32

What surgery should be considered for type II AFS mullerian anomalies?

Answer 32

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.

Question 33

Aetiology of mullerian abnormalities:

Answer 33

• Failure of fusion of both mullerian ducts
• Failure of development of one or both mullerian ducts
• Failure of resolution of septum after fusion