Uterine anomalies Congenital anomalies of uterine development are the most common type of genital anomalies. The paramedian ducts on both sides are affected and disturbed by certain factors during the evolutionary process and can stop developing at different stages of evolution to form various anomalies of uterus development.
Prevalence of congenital uterine developmental anomalies Oppelt statistics
How does ultrasound diagnose uterine anomalies?
Transvaginal two-dimensional ultrasound scan
Transvaginal 3-D ultrasound scan
Three-segment analysis
Plasma surface at the base of the uterus → endometrium at the base of the uterus → cervix and vagina
1, Plasma surface of the uterine fundus covered by peritoneum, rounded or smooth without or with slight depression, but <5mm note the effect of intestinal gas acoustic shadow
2, the endometrium at the base of the uterus is located at the top of the uterine cavity, the border is adjacent to the myometrium at the bottom, flanked by the internal horn of the uterus, without or with slight depression, but <5mm note the effect of enhancement artifacts
3, cervical and vaginal single cervical, single cervical canal single cervical, double cervical canal double cervical, double cervical canal cervical judgment, to be combined with clinical vaginal judgment, mainly by clinical
Classification of congenital anomalies of genital duct development (miller’s duct development anomaly)
1.Symmetrical uterine developmental anomalies
2.Asymmetric uterine malformation
I. Symmetrical uterine malformation
1.Double uterus
Two independent uterine bodies and cervix. Each has a single fallopian tube and ovary. The two cervixes may be separate or connected and may be accompanied by a longitudinal vaginal septum.
Among the uterine malformations, the reproductive prognosis is best in the bicornuate uterus. The growth capacity and tolerance of both uteruses are the same, and the blood supply to the bicornuate uterus is increased, and the spontaneous abortion rate is similar to the normal one.
2. Complete bicornuate uterus
The outer edge of the uterine base is depressed and bicornuate, with the separated endometrium on both sides connected to one cervix (normal cervix)
3.Partial bicornuate uterus
Bilateral separation of the uterine horns above the endocervix (separation reaching above the endocervix) and a single cervix (normal cervix).
Bicornuate uterus accounts for 14% of adverse outcomes, 28% of miscarriages, 20% of preterm births, 66% of preterm births in complete bicornuate uterus, and reduced fetal survival rate. Unicornuate uterus and bicornuate uterus have 20%-30% chance to full term.
4.Complete longitudinal uterus
The longitudinal septum reaches from the bottom of the uterus to the endocervix, which is a single cervical canal; or the longitudinal septum reaches the cervical canal to the ectocervix, which is a double cervical canal.
5.Incomplete longitudinal uterus
The two endometrium fuse with each other in the lower part of the uterus, and the longitudinal septum reaches from the bottom of the uterus to above the level of the endocervical opening, with a Y shape, the depth of the angle of entrapment >10mm, the angle of entrapment between the two sides <90, and a normal cervix.
About 1/3 of patients with habitual abortion have a combined longitudinal uterus. Longitudinal uterus does not increase the rate of preterm delivery and cesarean section, but the rate of spontaneous abortion in early pregnancy is 42%, significantly higher than in bicornuate uterus, and pregnancy loss occurs in about 2/3 of bicornuate uteruses within 20 weeks of gestation. For complete longitudinal uterus, removal of the longitudinal cervical septum may lead to cervical insufficiency, which may cause secondary infertility.
6. Arch-shaped uterus
The external outline is normal, with a curved depression of the endometrium at the base of the uterus. It protrudes slightly into the uterine cavity and has deep bilateral corners. The angle is deep.
Patients with bowed uterus are mostly asymptomatic, because the thickened muscle layer at the bottom of the uterus in the central zone protrudes toward the uterine cavity, which is especially obvious during contractions. After pregnancy, the uterus is mostly transverse, which easily leads to late abortion and preterm delivery, and the bowed uterus has deeper bilateral uterine horns, so the tissue often remains in the deeper uterine horns after abortion, resulting in residual after abortion.
The main points of differentiation between normal, bowed and longitudinal uterus are 1. the distance between the external fundal contour and the line connecting the uterine horns on both sides is <10mm 2. the distance between the internal fundal contour and the line connecting the endometrial horns on both sides is <5mm, normal 5-10mm, bowed uterus >10mm, longitudinal uterus
Differentiation points of longitudinal septum and bicornuate uterus
The distance between the external fundal contour of the uterus and the line connecting the two uterine horns.
<10mm, longitudinal uterus; >10mm, bicornuate uterus
Asymmetric uterine malformation
1.Unicornuate uterus
Narrow shape, small transverse diameter, coronal endometrium is tubular, semilunar or Lancet-like, with fallopian tube, ovary and round ligament on one side, and the other side is completely undeveloped
2.Residual horned uterus
The residual uterus on the opposite side of the unicornuate uterus is called the residual horned uterus, which in most cases does not communicate with the uterine cavity on the opposite side of the uterus and is connected only by fibrous bands
Features: complex, sonographically diverse
1, mostly located in the middle or lower side of the developing side of the uterus, a few are located at the bottom of the uterus
2. The residual horned uterus has normal ovaries and ligaments, sometimes with normal fallopian tubes
3. endometrium type residual horned uterus and non-endometrium type residual horned uterus
4. The residual horned uterus is connected with the developing uterus and the residual horned uterus is not connected with the developing uterus
5.A normally developed uterus can be seen in the pelvic cavity, and a mass can be seen on one side of it, and in mild cases, the echogenicity is the same as that of the uterus; in the case of blood accumulation in the stump, no or low echogenicity can be seen in the uterine cavity. 74-90% of unicornuate uteruses are combined with stump uterus.
The possibility of rupture is higher in pregnancies with a stumped uterus that does not communicate with the developing side of the uterus (pregnancy by sperm swimming from the developing side of the uterus to the abdominal cavity). There is no risk of rupture in a non-functioning stump uterus.
Example: unicornuate combined stumpy uterus.
Conclusion: Transvaginal 3D ultrasound can visualize the uterine shape and cavity morphology with accuracy and speed, and is superior to 2D ultrasound for congenital uterine malformations and typing, providing more information for clinical purposes.