The arcuate uterus is a form of a

uterine The uterus (from Latin ''uterus'', : uteri or uteruses) or womb () is the organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic and fetal development of one or more fertilized eggs until bir ...

anomaly or variation where the

uterine cavity The uterine cavity is the inside of the uterus The uterus (from Latin ''uterus'', : uteri or uteruses) or womb () is the hollow organ, organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic d ...

displays a concave contour towards the fundus. Normally the uterine cavity is straight or convex towards the fundus on anterior-posterior imaging, but in the arcuate uterus the

myometrium The myometrium is the middle layer of the uterine wall, consisting mainly of uterine smooth muscle cells (also called uterine myocytes) but also of supporting stromal and vascular tissue. Its main function is to induce uterine contractions. Stru ...

of the fundus dips into the cavity and may form a small septation. The distinction between an arcuate uterus and a septate uterus is not standardized.

Signs and symptoms

The condition may not be known to the affected individual and not result in any reproductive problems; thus normal pregnancies occur. Indeed, there is no consensus on the relationship of the arcuate uterus and

recurrent pregnancy loss Recurrent miscarriage or recurrent pregnancy loss (RPL) is the spontaneous loss of 2-3 pregnancies that is estimated to affect up to 5% of women. The exact number of pregnancy losses and gestational weeks used to define RPL differs among medic ...

. Accordingly, the condition may be a variation or a pathology. One view maintains that the condition is associated with a higher risk for

miscarriage Miscarriage, also known in medical terms as a spontaneous abortion, is an end to pregnancy resulting in the loss and expulsion of an embryo or fetus from the womb before it can fetal viability, survive independently. Miscarriage before 6 weeks ...

premature birth Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is betwee ...

, and malpresentation. Thus a study that evaluated women with uterine bleeding by hysteroscopy found that 6.5% of subjects displayed the arcuate uterus and had evidence of reproductive impairments. A study based on hysterosalpingraphic detected arcuate lesions documented increased fetal loss and

obstetrical complications Complications of pregnancy are health problems that are related to or arise during pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are term ...

as a risk for affected women. Woelfer found that the miscarriage risk is more pronounced in the second trimester. In contrast, a study utilizing 3-D ultrasonography to document the prevalence of the arcuate uterus in a gynecological population found no evidence of increased risk of reproductive loss; in this study 3.1% of women had an arcuate uterus making it the most common uterine anomaly; this prevalence was similar than in women undergoing sterilization and lower than in women with recurrent pregnancy loss.

Cause

The uterus is formed during

embryogenesis An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male ...

by the fusion of the two

Müllerian duct The paramesonephric ducts (or Müllerian ducts) are paired ducts of the embryo in the reproductive system of humans and other mammals that run down the lateral sides of the genital ridge and terminate at the sinus tubercle in the primitive uroge ...

s. During this fusion a resorption process eliminates the partition between the two ducts to create a single cavity. This process begins caudally and advances cranially, thus an arcuate uterus represents an incomplete absorption process in the final stage.

Diagnosis

A transvaginal ultrasound can reveal the condition. Helpful techniques to investigate the uterine structure are

transvaginal ultrasonography Vaginal ultrasonography is a medical ultrasonography that applies an ultrasound transducer (or "probe") in the vagina to visualize organs within the pelvic cavity. It is also called transvaginal ultrasonography because the ultrasound waves go ''a ...

and sonohysterography,

hysterosalpingography Hysterosalpingography (HSG), also known as uterosalpingography, is a radiology, radiologic procedure to investigate the shape of the uterine cavity and the shape and patency of the fallopian tubes. It is a special x-ray procedure using Contrast ...

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

, and

hysteroscopy Hysteroscopy is the inspection of the uterine cavity by endoscopy with access through the cervix. It allows for the diagnosis of intrauterine pathology and serves as a method for surgical intervention (operative hysteroscopy). Hysteroscope A hyst ...

. More recently 3-D ultrasonography has been advocated as an excellent non-invasive method to delineate the condition.

Differential diagnosis

The major differential diagnosis is the uterine septum. The lack of agreement to separate these two entities makes it difficult to assess the results in the literature.

Management

Many patients with an arcuate uterus will not experience any reproductive problems and do not require any surgery. In patients with recurrent pregnancy loss thought to be caused by an arcuate uterus hysteroscopic resection can be performed.

Epidemiology

Most studies of

uterine malformation A uterine malformation is a type of female genital malformation resulting from an abnormal development of the Müllerian duct(s) during embryogenesis. Symptoms range from amenorrhea, infertility, recurrent pregnancy loss, and pain, to normal f ...

s are based on populations of women who have experienced a

and thus do not address the issue of the prevalence in the general population. A screening study by Woelfer et al. of women without a history of reproductive problems found that about 5% of women had an arcuate uterus when they defined an arcuate uterus any fundal protrusion into the cavity that had an apical angle of more than 90 degrees. Accordingly, it was the most common uterine anomaly, followed by septate uterus (3%) and

bicornuate uterus A bicornuate uterus or bicornate uterus (from the Latin ''cornū'', meaning "horn"), is a type of müllerian anomalies, Müllerian anomaly in the human uterus, where there is a deep indentation at the Uterus#Structure, fundus (top) of the uterus. ...

(0.5%).

References

External links

{{DEFAULTSORT:Arcuate Uterus Anatomical pathology Congenital disorders of female genital organs