A septate uterus is a congenital condition where a wall of tissue partially or completely divides the inner cavity of the uterus, making it the most common type of congenital uterine anomaly. The condition is often asymptomatic, and many women are unaware they have it until they encounter difficulties with pregnancy or undergo unrelated pelvic imaging. While a septate uterus does not affect a woman’s ability to conceive, it can significantly impact the ability to carry a pregnancy to term.
The Anatomy and Embryological Origin
A septate uterus forms due to a variation in embryological development involving the Müllerian ducts, which typically fuse to create the uterus, fallopian tubes, and upper vagina. After these two ducts fuse, the central wall that forms between them normally dissolves through a process called resorption. When this process is incomplete, the remaining tissue forms a septum, a dividing wall within the uterine cavity.
The septum is primarily composed of fibrous and muscular tissue, contrasting with the well-vascularized tissue of the normal uterine lining. The length of this dividing wall leads to two classifications: a partial septate uterus, which is more common, extends only partway into the cavity, while a complete septate uterus reaches all the way to the cervix.
Clinical Discovery and Diagnostic Methods
Because a septate uterus rarely causes symptoms like pain or abnormal bleeding, it is frequently discovered incidentally during routine pelvic imaging. The condition is most often identified when a woman seeks medical evaluation following recurrent pregnancy loss or infertility. Distinguishing a septate uterus from other uterine shapes, such as a bicornuate uterus, is important for determining the correct course of action.
Three-dimensional (3D) transvaginal ultrasound is the initial diagnostic tool used for uterine shape assessment, providing a detailed view of the internal cavity and the external contour. Magnetic Resonance Imaging (MRI) is often used for definitive confirmation, as it offers high-resolution images that clearly differentiate the fibrous septum from normal uterine muscle. Hysteroscopy, which involves inserting a small camera through the cervix to view the cavity directly, can also be utilized for both diagnosis and simultaneous treatment.
How a Septate Uterus Affects Pregnancy
The presence of a uterine septum poses a challenge to a developing pregnancy and is associated with adverse reproductive outcomes. The primary reason for this difficulty is the poor blood supply within the septum itself. When an embryo attempts to implant onto the avascular tissue of the septum, it cannot establish a strong, healthy placenta. This poor placental growth leads directly to an increased risk of miscarriage. Women with an untreated septate uterus face a miscarriage rate as high as 20 to 40 percent, with losses occurring particularly in the first or second trimesters.
The constrained space of the divided cavity can also physically restrict the growth and movement of the fetus later in pregnancy. The restricted uterine space is associated with a higher incidence of premature delivery, as the uterus may contract earlier than expected. Furthermore, the condition increases the likelihood of fetal malpresentation, such as a breech position. This malpresentation, along with fetal growth restriction, can necessitate a cesarean section delivery.
Surgical Treatment and Prognosis
The standard method for correcting a symptomatic septate uterus is hysteroscopic metroplasty, or septum resection. This minimally invasive surgery is performed by inserting a hysteroscope through the cervix, avoiding the need for external incisions. Using specialized instruments guided by the camera, the surgeon cuts the fibrous septum, restoring the uterine cavity to a single, unified space.
This procedure improves reproductive outcomes for women who have experienced recurrent pregnancy loss. Studies show that following hysteroscopic metroplasty, the live birth rate can increase significantly, often rising to between 70 and 80 percent. The improved odds of carrying a pregnancy to term offer a favorable prognosis for women seeking treatment for this congenital anomaly.