Arcuate Uterus: What It Means for Fertility and Pregnancy

By Your Health Magazine Health Information Team

An arcuate uterus has a shallow, smooth indentation at the top of the uterine cavity. It is congenital, meaning it develops before birth, and is generally considered a normal variation rather than a condition that needs treatment. Most people with an arcuate uterus can become pregnant and have a healthy pregnancy, although research on possible pregnancy risks has produced mixed results.

What Does an Arcuate Uterus Look Like?

A typical uterine cavity is roughly triangular. With an arcuate uterus, a small amount of muscle at the top of the uterus creates a broad dip into the cavity. The uterus usually has a normal outer shape.

An arcuate uterus does not typically cause pain, unusual menstrual bleeding, or other noticeable symptoms. It is often discovered incidentally during imaging performed for infertility, pregnancy loss, pelvic symptoms, or another reason.

The terminology can be confusing because classification systems and imaging criteria have changed over time. The American Society for Reproductive Medicine’s classification of Müllerian anomalies groups the arcuate configuration with the normal uterus because of its generally limited clinical significance.

Arcuate, Septate, and Bicornuate Uterus: Key Differences

Correctly identifying the uterine shape is important because an arcuate uterus is managed differently from a septate or bicornuate uterus.

Uterine shape	Inside the uterus	Outer uterine contour	General significance
Arcuate	A shallow, broad indentation	Usually smooth and normal	Usually considered a normal variation
Septate	A deeper wall of tissue divides part or all of the cavity	Usually smooth or nearly normal	May be associated with miscarriage and certain pregnancy complications
Bicornuate	The cavity forms two upper sections or “horns”	A noticeable external indentation is present	May affect fetal position and the risk of preterm birth

An arcuate uterus describes the shape of the uterine cavity. It is different from a report describing a heterogeneous uterus or uneven uterine appearance, which concerns the texture seen on imaging and may have different causes.

How Is an Arcuate Uterus Diagnosed?

A routine two-dimensional pelvic ultrasound may suggest an unusual uterine shape, but it may not show enough detail to distinguish an arcuate uterus from a small septum. Accurate assessment requires a view of both the internal cavity and the outside of the uterus.

Possible tests include:

Three-dimensional transvaginal ultrasound: Produces a detailed view of the uterine cavity and external contour.
Saline-infusion sonography: Uses sterile fluid to outline the cavity during ultrasound.
Magnetic resonance imaging: May help clarify complex or uncertain findings.
Hysterosalpingography: Uses contrast and X-rays to evaluate the uterine cavity and fallopian tubes, but cannot reliably show the uterus’s external contour by itself.
Hysteroscopy: Allows a clinician to look inside the uterine cavity, although additional imaging may be needed to determine the external shape.

The ASRM guideline on uterine septum evaluation recommends three-dimensional transvaginal ultrasound, with or without saline infusion, as the first-line noninvasive method for assessing uterine shape. If a report uses terms such as “arcuate versus subseptate,” review by a gynecologist, reproductive endocrinologist, or radiologist experienced in congenital uterine differences may help clarify the diagnosis.

Does an Arcuate Uterus Affect Fertility?

Current evidence does not establish an arcuate uterus as a common direct cause of infertility. Many people with this uterine shape conceive without treatment, and finding it during a fertility evaluation does not prove that it is preventing pregnancy.

Infertility can involve ovulation, egg quantity or quality, fallopian tube problems, endometriosis, sperm-related factors, age, or multiple factors at once. A complete evaluation should therefore avoid focusing solely on a mild uterine indentation. MedlinePlus provides an overview of infertility, its possible causes, and evaluation.

Evidence also does not support routinely reshaping an otherwise confirmed arcuate uterus to improve natural conception, in vitro fertilization outcomes, or live birth rates. Before considering a procedure, it is especially important to confirm that the finding is not actually a clinically significant uterine septum.

What Does It Mean for Pregnancy?

Most professional guidance treats an arcuate uterus as a normal variation that is not expected to cause major pregnancy problems. However, studies have not been completely consistent. Some older and newer observational research has reported associations with outcomes such as miscarriage, preterm birth, abnormal fetal position, impaired fetal growth, or cesarean delivery.

For example, a recent population-based study of arcuate uterus and pregnancy outcomes found higher rates of several complications among pregnancies coded as involving an arcuate uterus. Observational findings cannot prove that uterine shape caused those outcomes, however. Results may also be influenced by differences in diagnostic definitions, referral patterns, fertility treatment, multiple pregnancy, previous cesarean delivery, or other health factors.

An arcuate uterus alone does not automatically make a pregnancy high risk. An obstetrician may consider additional monitoring when there is a history of recurrent pregnancy loss, preterm birth, fetal growth concerns, cervical shortening, or another medical or obstetric risk factor.

Is Treatment Necessary?

Treatment is usually not recommended for a confirmed arcuate uterus. Hysteroscopic surgery may be discussed for selected patients with a true uterine septum, particularly when recurrent miscarriage is involved, but that evidence should not be automatically applied to an arcuate uterus.

If surgery has been proposed, useful questions include:

Which diagnostic criteria were used?
Was the outside of the uterus evaluated as well as the cavity?
Could the finding represent a septate or bicornuate uterus instead?
What specific problem is the procedure intended to address?
What are the expected benefits and possible risks of observation versus intervention?

When to Seek Care

Discuss the finding with an obstetrician-gynecologist or reproductive endocrinologist if you are having difficulty becoming pregnant, have experienced repeated pregnancy losses, previously delivered preterm, or received an unclear imaging report. Evaluation is also appropriate if pelvic pain or abnormal bleeding is present, since an arcuate uterus generally does not explain those symptoms and another cause may need attention.

During pregnancy, seek prompt medical care for bleeding, fluid leakage, regular contractions before term, severe pelvic or abdominal pain, dizziness, fainting, or a noticeable decrease in fetal movement. These symptoms have many possible causes and should not be attributed to uterine shape without medical evaluation.

For most people, an arcuate uterus is a mild anatomical variation rather than a barrier to fertility or a reason to expect pregnancy complications. The most important step is making sure the imaging diagnosis is accurate and interpreting it alongside the person’s complete fertility and pregnancy history.