Uterine shape abnormalities are structural differences in the uterus that develop before birth. They are also known as congenital uterine anomalies or Müllerian anomalies.
Some women have no symptoms and may only discover the condition during a fertility check, ultrasound, or pregnancy. In some cases, the abnormal shape can affect conception or increase the risk of pregnancy complications.
The impact depends on the type of uterine abnormality. Understanding the specific shape of the uterus helps doctors recommend the right treatment, fertility care, and pregnancy monitoring.
Uterine shape abnormalities are structural differences in the uterus that occur while the reproductive organs are developing before birth. They result from changes in the development, joining, or separation of the Müllerian ducts.
These abnormalities can affect the outer shape of the uterus, the inside of the uterine cavity, or both. The main types include septate uterus, bicornuate uterus, unicornuate uterus, uterus didelphys, and certain less common complex abnormalities.
Importantly, having an unusual uterine shape does not automatically mean that a woman is infertile. The clinical effect varies considerably from one person to another.
Uterine shape abnormalities vary in structure and may affect fertility or pregnancy in different ways.
The main types include septate, bicornuate, unicornuate, didelphys, and arcuate uterus.
A septate uterus has a band of tissue called a septum that divides part or most of the uterine cavity. It is one of the uterine anomalies most commonly associated with recurrent miscarriage and certain pregnancy complications.
A 3D transvaginal ultrasound, sometimes combined with saline infusion, can help doctors assess the shape of the uterus and identify a septum. Further testing may be recommended when the diagnosis is unclear.
A bicornuate uterus has a noticeable indentation on the outside of the upper uterus, giving it a heart-shaped appearance. The upper part of the uterine cavity is divided into two sections, while there is often one cervix.
Many women with a bicornuate uterus can become pregnant. However, some may have a higher risk of complications such as miscarriage, preterm birth, or abnormal fetal position.
A unicornuate uterus develops mainly from one Müllerian duct, so the uterus is usually smaller and more curved to one side. This can reduce the available space for a developing pregnancy.
Some women also have a rudimentary horn, which is a small additional uterine structure. Because its anatomy can vary, specialist assessment is important to understand potential fertility and pregnancy risks.
A uterus didelphys develops when the two Müllerian ducts do not fully join, resulting in two separate uterine cavities. In some cases, there are also two cervices and a divided vaginal canal.
Some women with uterus didelphys have few or no fertility problems. However, the condition can be linked with pregnancy complications, so individual assessment and appropriate pregnancy monitoring may be recommended.
An arcuate uterus has a small, smooth indentation at the top of the uterine cavity. It is generally considered a mild anatomical variation rather than a significant uterine malformation.
In most cases, an arcuate uterus does not require treatment. Its effect on fertility and pregnancy is generally limited, although doctors may consider the finding alongside other reproductive or pregnancy factors.
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A uterine shape abnormality does not automatically mean infertility.
Conception can also be affected by factors such as age, ovulation, egg quality, sperm health, fallopian tube function, and endometriosis.
Depending on the abnormality, the shape of the uterus may affect implantation or the available space for an embryo. Factors that should be considered during a fertility assessment include:
For example, current ASRM guidance does not conclude that a septate uterus itself causes infertility, although it is associated with miscarriage and some adverse pregnancy outcomes.
Fertility treatment should therefore be based on the complete clinical picture rather than uterine shape alone.
Some uterine anomalies are associated with a higher risk of pregnancy complications. Depending on the type and severity, these may include:
The Royal College of Obstetricians and Gynaecologists notes that most women with congenital uterine anomalies can become pregnant and that pregnancy outcomes are generally good, although some anomalies are linked with increased pregnancy risks.
The level of risk depends on the specific uterine anatomy and the person’s previous pregnancy history.
Many uterine shape abnormalities cause no obvious symptoms. They may be discovered during a routine pelvic ultrasound or investigation for infertility.
Possible signs can include:
Some complex uterine and vaginal anomalies can cause more significant symptoms, including severe period pain, pelvic pain, or menstrual obstruction.
Diagnosis usually starts with pelvic imaging.
A standard transvaginal ultrasound may identify an unusual uterine shape, but a 3D transvaginal ultrasound can provide a clearer view of both the uterine cavity and external uterine contour.
Depending on the suspected condition, a doctor may also recommend:
The appropriate test depends on the suspected abnormality.
For example, HSG can suggest a Müllerian anomaly but may not reliably distinguish a septate uterus from a bicornuate uterus because it does not show the outer uterine contour well.
A uterine abnormality may be considered during an evaluation for recurrent pregnancy loss, especially when imaging suggests a septate uterus.
A septum has been associated with spontaneous miscarriage and adverse obstetric outcomes.
Current ASRM guidance recommends discussing hysteroscopic septum incision with patients who have a septum and a history of recurrent miscarriage, using shared decision-making.
However, surgery is not automatically appropriate for every uterine abnormality. The decision depends on the diagnosis, symptoms, reproductive history, and other fertility factors.
Treatment depends on the type of uterine abnormality and whether it affects fertility or pregnancy.
Some women need no treatment and only require regular monitoring.
Common options include:
A gynaecologist or fertility specialist can explain the most suitable option based on your symptoms, fertility goals, and pregnancy history.
Pregnancy with a uterine abnormality may require closer monitoring, depending on the type of anomaly and individual risk factors.
Your obstetric team may monitor:
Varicocele treatment can improve semen parameters in some men, and some couples may have a better chance of achieving pregnancy afterward. However, improvement is not guaranteed.
The outcome can depend on factors such as the man’s age, varicocele grade, testicular function, sperm quality, and the fertility status of his partner.
A doctor should assess the complete fertility picture rather than assuming that treating the varicocele alone will resolve infertility.
A pregnancy plan should be personalised.
Having a uterine abnormality does not automatically mean that a caesarean birth or other intervention will be necessary.
Yes. Many women with congenital uterine anomalies conceive and have healthy pregnancies.
The RCOG notes that most cases do not cause difficulty becoming pregnant and that pregnancy outcomes are good in most cases.
The important point is that the diagnosis should not be viewed in isolation. Your age, fertility history, general health, previous pregnancies, and the exact uterine anatomy all matter.
Speak with a gynaecologist or a fertility specialist clinic if you have been diagnosed with a uterine shape abnormality and are planning a pregnancy, have difficulty conceiving, or have experienced repeated miscarriages.
Specialist advice can help confirm the diagnosis, explain the reproductive implications, identify other fertility factors, and determine whether treatment or additional monitoring is appropriate.
Uterine shape abnormalities can vary widely, and their effect on fertility and pregnancy is not the same for everyone.
Some have little or no impact, while others may be associated with miscarriage, preterm birth, or abnormal fetal position.
Accurate diagnosis is the first step. Modern imaging, particularly 3D ultrasound, can help identify the specific uterine anatomy and guide appropriate care.
With individualised fertility advice and pregnancy monitoring, many women with uterine abnormalities can achieve a healthy pregnancy.
