Uterine anomalies, affecting 3% of fertile women, arise from three key mechanisms: failure of mullerian duct formation, fusion, or septum dissolution. Conditions include unicornuate, didelphys, bicornuate, and septate uteri, each presenting unique structural implications and associated risks during pregnancy. The arcuate uterus, while having a minor indentation, is considered normal and does not negatively impact pregnancy outcomes.

1. L A YA N S I N N A W I
Disorders of the uterus

3. Mullerian anomalies
Uterine anomalies are found in 3% of fertile women
with normal reproductive
outcomes. Uterine anomalies may result from 3
mechanisms:
- Stage 1: failure of one or both of the 2 Mullerian
ducts to form.
- Stage 2: failure of the 2 ducts to fuse completely.
- Stage 3: failure of the 2 fused Mullerian ducts to
dissolve the septum that results from
fusion.

4. Failure to Form:
 1. Hypoplasia/agenesis:
 ▪ Patients with Mullerian agenesis have primary
amenorrhea due to an absent uterus, cervix,
 and upper 1/3 of the vagina (blind vaginal pouch).
 ▪ Urogenital development is from a common embryologic
source: therefore, renal
 malformations are common and patients require
evaluation with a renal ultrasound.
 May present as 1° amenorrhea (due to a lack of uterine
development) in females with fully
 developed 2° sexual characteristics (functional ovaries).

5. Unicornuate Uterus
 When one of the Müllerian ducts fails to form, a
single-horn (banana-shaped)
 uterus develops from the healthy Müllerian duct.
This single-horn uterus may stand alone. However,
in 65% of women with a unicornuate uterus, the
remaining Müllerian duct may form an incomplete
(rudimentary) horn.

7. Failure to Fuse:
 1. Didelphys uterus:
 ▪ A double uterus results from the complete failure of the
2 Mullerian ducts to fuse together.
 So each duct develops into a separate uterus, each of
which is narrower than a normal uterus and has only a
single horn.
 ▪ These 2 uteri may each have a cervix or they may share
a cervix. In 67% of cases, a didelphys uterus is associated
with 2 vaginas separated by a thin wall.
 ▪ Preterm delivery is common if pregnancy occurs in
these patients.

8. Bicornuate Uterus
 Bicornuate uterus (most common congenital uterine
anomaly [45%]) results
 from failure of fusion between the Müllerian ducts at
the “top.” This failure maybe “complete,” resulting in 2
separate single-horn uterine bodies sharing one cervix.
 Alternatively, in a “partial” bicornuate uterus, fusion
between the Müllerianducts occurs at the “bottom” but
not the “top.”
 Preterm delivery and malpresentation are common
with pregnancy.

10. FAILURE TO DISSOLVE SEPTUM
 Septate Uterus
 A septate uterus results from a problem in stage 2 or 3 of uterine
development.
 The two Müllerian ducts fuse normally; however, there is a failure
in degeneration of the median septum.
 Because this uterine anomaly occurs later in uterine development
after completeduct fusion, the external shape of the uterus is a
normal-appearing single unit.
 This is distinct from the bicornuate uterus, which can be seen
branching into 2 distinct horns when viewed from the outside.
 Preterm delivery and malpresentation are common with
pregnancy.
 ▪ Treat with septoplasty.

11. Arcuate Uterus
 This type of uterus is essentially
normal in shape with a small
midline indentation in the uterine
fundus, which results from failure to
dissolve the median septum
completely.
 It is given a distinct classification
because it seems to have no negative
effects on pregnancy with regard to
preterm labor or malpresentation.

12. Enlarged uterus