A uterine septum is a congenital uterine anomaly, a condition present from birth, where a fibrous band of tissue divides the uterine cavity. This structural variation can affect reproductive outcomes.
Understanding a Uterine Septum
The uterus normally forms during fetal development from two Müllerian ducts. These ducts fuse, and the wall between them reabsorbs, creating a single, hollow uterine cavity. A uterine septum occurs when this reabsorption is incomplete, leaving a membrane or wall of tissue that partially or completely divides the uterus. This septum is a structural abnormality, composed of fibrous tissue and sometimes muscle, rather than a growth or tumor.
A uterine septum can vary in length and thickness. A partial septum extends only partway into the uterine cavity, while a complete septum divides the uterus entirely, potentially reaching the cervix or, in rare cases, extending into the vagina. Unlike a bicornuate uterus, which has a heart-shaped exterior due to incomplete fusion, a septate uterus typically maintains a normal external uterine shape. This distinction is important for diagnosis and treatment planning.
Identifying and Diagnosing a Uterine Septum
A uterine septum often remains undetected until reproductive issues arise. Many individuals with a septate uterus are asymptomatic. Common signs leading to suspicion include recurrent pregnancy loss, particularly miscarriages in the first or second trimester. Some may also experience painful menstruation or pelvic pain, though these symptoms are less specific.
Diagnosis involves various imaging methods to visualize uterine anatomy. A transvaginal ultrasound is often the initial step, though a 2D ultrasound may miss a septum or not clearly show its extent. Three-dimensional (3D) ultrasound offers a more comprehensive view, providing detailed images of the uterine cavity and external contour, making it a highly accurate diagnostic tool.
Saline infusion sonography (SIS), which involves injecting saline into the uterus to distend the cavity, can further enhance visualization. Magnetic resonance imaging (MRI) is another reliable method, particularly useful for distinguishing a septate uterus from other uterine anomalies like a bicornuate uterus. Hysteroscopy, where a thin, lighted scope is inserted directly into the uterus, allows for direct visual confirmation and assessment.
Impact on Reproductive Health
A uterine septum is medically significant due to its effects on fertility and pregnancy outcomes. It is the most common uterine anomaly associated with reproductive failure. While it generally does not affect the ability to conceive, it significantly increases the risk of complications once pregnancy occurs.
The primary concern is its association with recurrent miscarriage, with estimates suggesting 20-40% of pregnancies in a septate uterus may result in miscarriage. This is believed to be due to the septum’s poor blood supply; if an embryo implants on the septum, it may not receive adequate nourishment, leading to implantation failure or early pregnancy loss. Beyond miscarriage, a septate uterus also increases the risk of preterm birth and abnormal fetal presentation, such as breech position. The reduced functional space within the uterine cavity may restrict fetal growth and movement, contributing to these complications.
Treatment and Prognosis
For individuals experiencing recurrent pregnancy loss or other reproductive complications linked to a uterine septum, surgical intervention is often recommended. The primary treatment is hysteroscopic metroplasty, also known as septum resection. This minimally invasive outpatient procedure involves inserting a hysteroscope, a thin camera, through the cervix into the uterus. The septum is then cut or resected, typically using small surgical instruments or an electric scalpel, to create a single, unified uterine cavity. The procedure usually takes 15 to 20 minutes.
Hysteroscopic metroplasty aims to restore the uterus to a more typical shape, improving the environment for implantation and fetal development. Recovery is quick, with many patients returning home the same day. Studies indicate that the rate of successful pregnancies and live births increases considerably, with some research showing pregnancy rates around 65% and live birth rates ranging from 45% to 54.7% following the procedure. The risk of miscarriage also decreases substantially after septum resection.