We continue our effort to keep you up to date on advances in reproductive medicine and the availability of the newest technologies at FCI. This letter addresses the diagnosis, clinical implications, and management of congenital anomalies of the uterus.
The incidence of uterine anomalies is approximately 1:200 to 1:600 in childbearing women. Most studies report that these women usually have problems with maintenance of pregnancy rather than Infertility. Patients with abnormalities of the uterus are at risk for preterm delivery, abnormal fetal presentation, and a higher frequency of Spontaneous Abortion in the first and second trimester of pregnancy.
Most uterine anomalies are due to a defect in the lateral fusion or a disturbance in the migration of the mullerian ducts that occur in embryologic development at about the eighth to twentieth week of Gestation. The urinary tract develops closely with the reproductive system so it is important to assess for urologic abnormalities that can be found in 20-30% of women with uterine anomalies.
Recent advances in imaging techniques have improved the diagnosis of uterine anomalies. Available radiological tests include transvaginal ultrasonography, both two and three dimensional, Hysterosalpingogram (HSG), magnetic resonance imaging (MRI), and sonohysterography. We have found that sonohysterography is particularly helpful in differentiating bicornuate from septate uterus due to the ability to assess the fundus of the uterus with Ultrasound.
The most common uterine malformation is the bicornuate uterus, which is due to an incomplete fusion of the mullerian ducts resulting in a single heart shaped uterine cavity with a single Cervix. The bicornuate uterus is more commonly associated with preterm loss and not necessarily with miscarriages. The need for surgical correction for a bicornuate uterus is controversial due to the extensive nature of the Strassman metroplasy that unifies the two endometrial cavities.
The septate uterus is characterized by a midline structure within the uterine cavity that can be short in length or extend to the cervix to cause a complete division. The recommended surgical management of the septate uterus is hysteroscopic septum resection. While concomitant Laparoscopy is often employed, we have found intraoperative transabdominal ultrasound guidance to be an alternative helpful modality for optimum hysteroscopic resection of the septum. A review of several studies has demonstrated an approximate decrease in the rate of recurrent miscarriage from 85 to 15% with an increase in the number of term deliveries to 80% in women who have undergone hysteroscopic resection of the uterine septum. This surgery is done on an outpatient basis with excellent results and quick recovery. A partial septate uterus can often be mistaken for a bicornuate uterus. The arcuate uterus is a very mild uterine septum that has no impact on reproductive outcome.
Less common anomalies of the uterus are the unicornuate uterus and the didelphys uterus.
The unicornuate uterus may be associated with obstetric complications such as miscarriage, preterm delivery and intrauterine growth retardation. Patients with a unicornuate uterus are not candidates for surgical reconstruction. The uterus didelphys or double uterus is due to complete lack of fusion of the two mullerian ducts, and this malformation results in two uteri, two cervices and a longitudinal vaginal septum. This type of anomaly is usually associated with successful pregnancy outcome thus surgery is generally not necessary.
Suggested further reading:
Rackow BW, Arici A. Reproductive performance of women with mullerian anomalies. Current Opinion in Obstetrics & Gynecology 2007: 19; 229-237.
Lin PC et al. Female genital anomalies affecting reproduction. Fertility and Sterility 2002: 78; 899-915.
Homer HA, et al. The septate uterus: a review of management and reproductive outcome. Fertility and Sterility 2000; 1-14.