What is Septate Uterus?
In 2021, The American Society of Reproductive Medicine (ASRM) revised its rules for classifying anomalies, or abnormalities, of the Müllerian duct system. This is the scientific term for the system in females that develops into the reproductive tract, including the uterus, fallopian tubes, cervix, and the upper part of the vagina. The aim of this revision, known as the MAC2021, was to make it applicable to all types of healthcare providers and to encourage patients to be more aware and involved in their own healthcare. The MAC2021 system identifies 9 types of Müllerian duct anomalies.
The most frequently seen anomaly is called a septate uterus, which is a condition where the uterus has an additional wall or septum. The ASRM describes a septate uterus as having an indentation, or dip, deeper than 15 mm and an angle of less than 90°. However, there are different definitions used by other societies. The European Society of Human Reproduction and Embryology (ESHRE) evaulates a septate uterus based on a ratio of indentation to overall wall thickness greater than 50%. Meanwhile, the Congenital Uterine Malformation by Experts (CUME) group advises considering a septate uterus if the indentation is 1 cm deep or more.
Determining if surgery is needed for a septate uterus can be a tough decision for clinicians. This is mainly because the different societies have different yet widely accepted definitions of what a septate uterus is.
What Causes Septate Uterus?
A septate uterus is a physical irregularity that comes from defects when the Müllerian or paramesonephric ducts, crucial parts involved in female organ development, don’t form correctly as an embryo develops. We don’t know the exact cause of this irregularity. There have been efforts to locate a genetic cause of Müllerian anomalies, which are abnormalities in the female reproductive system, but we still haven’t found a clear genetic link. It’s generally believed that a mix of several factors cause Müllerian anomalies.
Risk Factors and Frequency for Septate Uterus
A septate uterus is a type of birth defect that’s found in the female reproductive system, and it’s the most common one of its kind, making up about 55% of these cases. It’s estimated that up to 1.5% of women of childbearing age have this condition. However, getting an accurate count of how many women have a septate uterus is tough because there’s more than one accepted definition of what a septate uterus is, and many women who have this condition don’t show any symptoms.
Signs and Symptoms of Septate Uterus
A septate uterus is a condition that often doesn’t cause any symptoms and is usually discovered during a pelvic examination or imaging. It is most commonly identified following a miscarriage in the first three months of pregnancy, after a pregnancy complication, or during a cesarean section. A thorough medical history of pregnancy is important in diagnosing this condition.
It’s noteworthy that physical exams don’t reveal any specific signs associated with a septate uterus.
Testing for Septate Uterus
A septate uterus, which is a malformation of the uterus, can be detected using various methods. These include looking directly inside the uterus through a process known as hysteroscopy or laparoscopy, or through imaging studies like ultrasound, hysterosalpingography (which is a special type of X-ray), or magnetic resonance imaging (MRI).
Hysteroscopy is a procedure where a tiny telescope is passed through the cervix into the womb. This allows for a full view of the inside of the uterus. However, it does not allow for the view of the outside surface of the uterus, meaning another imaging method is needed to rule out a more complex abnormality of the uterus.
Laparoscopy is a surgical procedure done under general anesthesia, where a small telescope is inserted, permitting direct vision of structures within the abdomen and pelvis. This method can be used along with hysteroscopy and hysterosalpingography to get a more thorough view of the uterus. However, these procedures can be as effective as a 3D ultrasound, which is less invasive.
For an ultrasound, a technique called saline-infusion sonohystogram is used. Here, sterile saline is injected into the uterus to better visualize its shape. The measurement of the uterine septum is done by drawing two lines, one from one corner of the uterus to another and a second line from this to the tip of the septum. One study found this method to be more accurate than both hysterosalpingography and hysteroscopy.
Hysterosalpingography uses X-rays to study the structure of the uterus and fallopian tubes. While this method can show a uterine septum, it’s difficult to determine if the septum is a result of a septate uterus or a bicornuate uterus. Therefore, if a septum is revealed, further examination with ultrasound, sonogram, MRI, or laparoscopy is needed to confirm.
MRI scans are also used and can provide clear imagery of the uterus shape. This method is similarly done by drawing two lines for the uterine septum. Comparatively, a 3D ultrasound can diagnose a uterine septum as effectively as an MRI but is generally more cost-effective.
Treatment Options for Septate Uterus
If a woman has been diagnosed with a uterine septum, which is a wall of tissue that divides the uterus, and she’s struggling to get pregnant or has had complications with previous pregnancies, the generally recommended treatment is to remove the tissue via a procedure called a hysteroscopic resection. Numerous studies have backed up this treatment approach.
However, one study, known as the Randomized Uterine Septum Transection (TRUST) trial, compared hysteroscopic resection with simply waiting and seeing how things progress (expectant management) in women who had a uterine septum, wanted to become pregnant, and had a history of subfertility, pregnancy loss, or preterm birth. The study found no difference in the time it took to become pregnant or the live birth rate between the two groups. But this study was relatively small and only included seven women with a complete uterine septum. Also, the study didn’t separate out women with septate and arcuate uteruses (two different types of divided uterus), which might have skewed the results.
If a woman has a uterine septum but hasn’t had trouble getting pregnant or with previous pregnancies, it may still be an option to consider hysteroscopic resection of the septum. This decision should be made together with the doctor and after careful discussion. The best time to have this procedure is in the early part of the menstrual cycle, when the lining of the uterus is at its thinnest. Certain medications, like progestins, danazol, or gonadotropin-releasing hormone (GnRH) agonists, can help to reduce the thickening of the uterine lining and make it easier to see the uterine septum during the procedure.
The aim of hysteroscopic septal resection is to cut away the uterine septum. This can be done using various techniques, like using specialized scissors, electrical or heat energy (bipolar or unipolar cautery), or even argon lasers. All these methods have similar success rates. Complications from the procedure are rare. In some cases, where a woman has a particularly thick or complete uterine septum, the procedure may need to be done in stages, or in conjunction with treatment for a vaginal septum. Using ultrasound or fluoroscopy (a type of x-ray) can help guide the surgery and avoid cutting into the uterine muscle (myometrium).
There are a variety of techniques used to stop a uterine septum from reforming after it’s been removed, including the use of a balloon stent or intrauterine foley catheter (a type of tube), injecting a special gel into the uterus, placing a copper or hormonal intrauterine device, or taking certain oral medications. All of these methods have been tried, but there’s no clear evidence yet to show that any one of them is definitively better than the others.
Two types of older procedures that involved a larger surgical incision and removal of the uterine septum (Jones and Tompkins metroplasty) are now rarely used. These procedures involve significant surgical and obstetrical risks.
What else can Septate Uterus be?
When a woman has a septate uterus, it means the inside of her uterus is divided by a wall or “septum.” Other conditions that might seem similar when examining the uterus can include:
- An arcuate uterus, which is a mild form of a septate uterus where the divide is shallow and curved
- A bicornuate uterus, a uterus with two distinct chambers
- Uterus didelphys, a condition where a woman has two separate uterine cavities each connected to a separate cervix
It’s crucial for doctors to distinguish between these conditions to provide the most effective treatment.
What to expect with Septate Uterus
A uterine septum is a potential cause of difficulties in pregnancy, such as recurrent pregnancy loss and preterm delivery. There are conflicting views about whether a uterine septum can cause infertility. However, studies have shown that a medical operation to remove the septum can increase the chance of pregnancy in couples who have been struggling to conceive. This procedure can also improve the chances of a successful pregnancy in those who have experienced previous miscarriages or early deliveries.
Possible Complications When Diagnosed with Septate Uterus
Most people with a septate uterus – a congenital abnormality where the uterus has a wall of tissue – have regular reproductive experiences. However, some may face fertility issues or have a higher chance of delivering a baby prematurely. For every pregnancy that happens in a septate uterus, there’s a 26% to 94% risk of miscarriage and a 6% to 16% possibility of preterm birth.
Studies show that women with a septate uterus, as compared to those with a normal uterine cavity, have a higher chance of miscarriage during the first trimester (42% vs 12%). However, having a septate uterus does not increase the risk of miscarriage in the second trimester or of preterm labor.
Some evidence suggests that a septate uterus might increase the risk for issues like incorrect fetal positioning, slow growth of the fetus in the womb, detachment of the placenta, and the death of the fetus. But no large, randomized controlled clinical trials have been done to fully confirm or understand these risks.
Removing the uterine septum with a hysteroscope – a specialized instrument – has its own associated risks. These include injuring the uterus or nearby structures in the pelvis or developing scar tissue inside the uterus. Surgeons can reduce the risk of accidentally puncturing the uterus by using ultrasound during the procedure. After the surgery, they can lower the chance of an adhesion – an internal scar tissue – by prescribing hormone replacement therapy or placing a balloon inside the uterus. However, the data on these preventative measures is inconclusive.
There have been some reports of the uterus tearing during labor in women who had undergone hysteroscopic septum resection. It’s believed that these could have been caused by unintentional cuts to the uterine muscle during the surgery. In a 20-year analysis in Slovenia, there were four instances of uterine rupture in women who had term pregnancies after the removal of the uterine septum with hysteroscopy. Careful surgical methods that prevent cuts to the uterine muscle could help avoid this potentially life-threatening complication.
Potential Risks in Septate Uterus and its Surgical Treatment:
- Increased miscarriage rates in the first trimester
- Uterus or pelvic area injury during surgery
- Development of intrauterine scar tissue post-surgery
- Potential fetal malpositioning, slow growth, or placenta detachment
- Risk of uterine rupture during labor post-surgery
- Possible perinatal death
- Premature birth
Preventing Septate Uterus
A septate uterus, which is a condition where a wall or ‘septum’ divides the uterus, can make it difficult for a woman to carry a pregnancy to term and may cause fertility issues. If a woman has faced repeated miscarriages or if she is being assessed for fertility problems, it’s very important to check for a septate uterus. This is because, if a septate uterus is found, it can often be treated with a procedure called ‘hysteroscopic resection’. This treatment can greatly improve a woman’s chances of a successful pregnancy in the future.
