Uterine Anomalies

Uterine abnormalities are anatomical problems of the uterus that women are born with (congenital anomalies), including a septate, unicorneous, or bicorneous uterus.

Uterine Anomalies

Abnormalities of the uterus, or müllerian anomalies, include a spectrum of uterine abnormalities caused by abnormal embryologic fusion. These malformations of the female reproductive tract are congenital in nature, developed during the embryonic life of a female. They may also affect the fallopian tubes, cervix, and upper vagina. Uterine anomalies may cause infertility or problems with pregnancy. Congenital uterine anomalies occur in less than 5% of all women, but have been noted in up to 25% of women who have had miscarriages or deliveries of premature babies.

Uterine anomalies develop when a female is growing in her mother's womb. The uterus and part of the vagina normally develop from tissue on the left and right side of the body. Two tube-shaped structures known as the Müllerian ducts migrate down separately and fuse together to create the triangular, hollow uterine cavity. Anomalies occur when this structure does not fuse correctly or does not hollow out completely.

The types of congenital uterine anomalies include:

  • Septate - a normal external uterine surface but two endometrial cavities with a partition in the middle
  • Bicornuate - an abnormal, indented external uterine surface and two endometrial cavities (heart-shaped uterus)
  • Arcuate - a normal external uterine surface with a 1 cm or less indentation into the endometrial cavity
  • Unicornuate - only one half of the uterus has developed
  • Didelphys - the two halves of the uterus remain separate

The septate uterus and bicornuate uterus are the most common congenital uterine anomalies. In some cases, the uterus is absent.

Symptoms and Diagnosis

In the majority of cases, the cause of a congenital uterine anomaly is unknown. Although congenital uterine anomalies are present at birth, they are often asymptomatic and unrecognised. Moreover, congenital uterine anomalies also do not typically cause a woman to have difficulty in getting pregnant nor cause medical or reproductive problems. Some women may have pain with their menstrual periods though. Uterine anomalies may also increase the likelihood that a woman will have a miscarriage or a premature delivery.

Uterine abnormalities are often diagnosed during an evaluation for infertility issues or pregnancy loss. A complete medical history and physical examination may also cause an obstetrician or gynaecologist to suspect a congenital uterine anomaly. However, imaging studies such as a hysterosalpingogram and ultrasound, or an MRI is required to visualise the uterus and confirm that a congenital uterine anomaly is indeed present.

Treatment of Uterine Anomalies

Most women with congenital uterine abnormalities do not require treatment. But in a few cases, the presence of a uterine anomaly appears to increase the risk of adverse pregnancy outcomes such as preterm birth, foetal growth restriction, malpresentation, caesarean delivery, and preeclampsia. Women with a septate uterus may have an increased risk of early miscarriage if the pregnancy implants onto the septum itself, instead of the uterine wall. Such complications could include premature birth or diminished foetal growth during pregnancy.

In such cases, a gynaecologist may recommend surgical correction. This may be done using minimally invasive techniques, such as laparoscopy or hysteroscopy, in order to correct the uterine anomalies. The type of surgery recommended depends upon the type of abnormality and the woman's reproductive history and health. In almost all cases of pregnant women with uterine abnormalities, the delivery of the baby is done through caesarean section.