Mullerian Duct Abnormalities

As the female fetus develops, the uterus forms from the fusion of two identical structures called Mullerian ducts. Incomplete fusion or improper development of the endometrial cavity can result in an abnormally shaped uterus, which can lead to difficulty with reproduction. The various abnormalities have a wide-ranging spectrum; those that are clinically significant may contribute to menstrual disorders, endometriosis, infertility, miscarriages, and preterm labor. A classification system for the basic types of observed abnormalities exists, but the major types are:

• Uterine agenesis or uterine hypoplasia
  Complete or partial failure in formation of one or both Mullerian ducts
• Unicornuate uterus
  Complete or partial failure in formation of one Mullerian duct, leading to the formation of a “hemi” uterus with a small cavity, sometimes associated with an obstructed hemi-uterus that is not connected to the cervix.
• Bicornuate uterus
  Failure of the two ducts to fuse completely in the midline, leading to two separate, small uterine cavities with a single cervix.
• Septated uterus
  The cavity is subdivided by a band of tissue; the septum can be small or, at its extreme, can divide the cavity into two distinct halves.
• Other uterine anomaly associated with Diethylstilbestrol-induced (DES) exposure
  DES is a synthetic estrogen compound that was widely prescribed as a treatment for recurrent miscarriages from 1938-1971. Physicians ceased to prescribe DES when it was discovered that it damaged the reproductive systems of female fetuses, leading to Mullerian duct abnormalities. Mullerian duct abnormalities are typically characterized by a constricted or abnormally shaped uterine cavity.

Diagnosis

Diagnostic Imaging can help shed light on the configuration of the uterine cavity and help diagnose Mullerian duct abnormalities when they exist.

Pelvic Ultrasound with Transabdominal and Transvaginal Imaging – There are 2D and 3D sonographic techniques that can provide visualization of the uterine cavity and uterine contour.

Hysterosalpingogram (HSG) – an x-ray procedure in which a dye is injected through the cervix into uterus and fallopian tubes. The dye enables the radiologist and your physician to visualize the shape of the uterine cavity. However, limitations exist with an HSG in evaluating the external uterine contour and may not be sufficient to diagnose all types of Mullerian Duct abnormalities.

Magnetic Resonance Imaging (MRI) – If an ultrasound and HSG do not allow a confident diagnosis, an MRI can also be used to assess the uterine shape. MRI provides high-resolution images of the uterine body and endometrial cavity. An MRI is often used for patients who require surgical treatment.

Treatment

 Not all uterine abnormalities require surgical treatment, depending on the type and severity of abnormality. Although they can be associated with fertility problems, there are some interventions that can help improve the likelihood of a successful outcome.

Hysteroscopic Resection of a uterine septum – A reproductive endocrinologist who is skilled in reproductive surgery can quickly and effectively correct an abnormality such as a uterine septum. A hysteroscope, which is a fiberoptic scope attached to a small camera, enters the uterus through the cervix and visualizes the septum. The septum can then easily be divided. By the end of the procedure, the uterus can assume a normal contour and should have normal function. The majority of patients at RMA undergoing a hysteroscopic resection resume normal activity within a couple of days after the procedure; for those who wish to conceive, the reproductive endocrinologist can then quickly move on to the next step in formulating a treatment plan.