Structural Causes of Recurrent Miscarriages include Uterine Septum and Fibroids.
How the Female Reproductive System Forms.
The embryological development of the vagina and uterus is quite complex. It involves the fusion of two hollow tube like structures in the midline. These “tubes” come together and then there is a recession of the segment in the midline that connects the structures. Any defect in this process can result in a variety of midline fusion defects.
Examples of this include a uterine septum or a complete double system (uterine didelphys). The central piece invariably has a very poor blood supply. If an embryo implants upon this area, or immediately adjacent to it, it is likely to miscarry relatively early on.
Fibroid tumors are another example of a structural lesion which can distort the uterine cavity and architecture. Here again, the blood flow dynamics can be significantly impeded and implantation of the embryo upon or immediately adjacent to these lesions, can be sub optimal and result in an early miscarriage.
Other examples of structural abnormalities within the uterine cavity include polyps, adhesions (Asherman’s syndrome – due to prior surgeries or infection).
In all cases of suspected structural anomalies, the defects are identified by one of several uterine imaging techniques. Each has advantages and disadvantages.
- fluid ultrasound
- MRI with contrast
The best uterine imaging techniques is arguably a hysteroscopy because it allows direct visualization, as well as the ability to treat any lesions then and there. Surgical correction of the uterine cavity should not be undertaken lightly because the surgery itself can cause scar tissue formation. Therefore, the benefits of the procedure should outweigh the risks of the procedure. Hysteroscopic procedures can be quite effective at restoring normal or near normal anatomy of the uterine cavity. In cases of extremely severe structural abnormalities, not amenable to surgical correction, the option of gestational surrogacy can be discussed with the patient.