Bicornuate uterus (BU) is a congenital uterine abnormality or a Mullerian anomaly where the uterus (womb) is heart-shaped and has two horns. The uterus is normally pear-shaped, but the partial fusion of the Mullerian ducts (analogs of female reproductive organs) in the developmental phase can give rise to the heart shape. The bicornuate uterus may compromise nearly 10-39% of Mullerian duct anomalies. There are two types of anomalies depending on the partition of the cervix–bicornuate unicollis (partial bicornuate) and bicornuate bicollis (complete bicornuate). Women with a bicornuate uterus can have adverse pregnancy outcomes, including repeated pregnancy loss and preterm birth (1) (2). Read on to know the causes, symptoms, diagnosis, complications, and treatment of the bicornuate uterus.
Can You Get Pregnant With A Bicornuate Uterus?
Although the bicornuate uterus was previously thought to be associated with infertility, recent studies are not confirming these associations. Most women with a bicornuate uterus can conceive. However, there can be a high risk for certain adverse pregnancy outcomes and require additional monitoring. Infertility, intrauterine fetal death, or miscarriage can also be due to other reasons in women with bicornuate uterus. This can be an incidental finding while looking for causes of infertility or pregnancy loss in many women. Successful pregnancies without correction surgeries or cerclage indicate that the bicornuate uterus itself is not a cause of infertility (1).
What Causes Bicornuate Uterus?
The cause of malformation in Mullerian ducts is not well understood. Genetic and environmental factors might play a role. Several studies showed that uterine anomalies are due to abnormal gene expression. In addition, exposure to environmental factors such as certain chemicals and drugs can cause uterine anomalies (3).
What Are The Symptoms Of A Bicornuate Uterus?
Most women with bicornuate uterus may not have any symptoms and will not know they have the uterine anomaly until they undergo ultrasound or other imaging. The following symptoms can be present in some women (3):
Painful periods
Abdominal pain Dyspareunia (pain during sex) Repeated miscarriages or pregnancy loss Irregular bleeding (rare)
A bicornuate uterus is associated with a longitudinal vaginal septum in 25% of cases. This can cause obstructive symptoms or pain during sex. The vaginal septum can also cause the inability to control menstrual bleeding with tampons (3). Double cervix and uterus can be present in many women who bleed through tampons. Genital system and urinary track embryologic formation share common steps. For these reasons, we have to look for coexisting renal (kidney or ureter) abnormalities that may cause symptoms such as pelvic pain and urinary retention.
When To See A Doctor?
It is recommended to seek a gynecologic consultation for any menstrual irregularities. You may also seek medical care for repeated pregnancy loss and infertility problems. Seek care from infertility specialists skilled in reproductive surgeries if you fail to conceive within one year of trying (six months if youre older than 36 years). Surgical repairs can enhance fertility and pregnancy outcomes.
How Is The Bicornuate Uterus Diagnosed?
Imaging tests are standard for diagnosing bicornuate uterus. The external uterine borders can be concave or heart-shaped, and the uterine horns look prominent on the images. The fundal cleft is more than one centimeter deep, and the intracorneal distance is wider. The diagnostic tests for bicornuate uterus include (4) (5):
Pelvic examination in case of suspected symptoms. It will help identify the vaginal septum if present.
Classic ultrasound imaging (sonography) helps visualize the uterus shape suggesting the condition. New 3d vaginal probes give an exact image of the malformation.
Diagnosis hysteroscopy with the introduction of a camera inside the uterus will show the septa separating the two cavities
Hysterosalpingogram (HSG) can visualize the divided uterus. However, the accuracy is 55% since the septate and bicornuate anomalies may appear similar. The angle of more than 105° indicates a bicornuate uterus, and less than 75° is a septate uterus. It is and old way to visualize the malformation.
Magnetic resonance imaging (MRI) also helps visualize the uterus’s anatomy and the depth of fungal cleft and intercornual distances. The abnormality is indicated by the fundal cleft of more than 1cm and intercornual distance of more than 4cm.
How Is The Bicornuate Uterus Treated?
Surgical correction is recommended for women with bicornuate uterus and fertility problems. History of recurrent pregnancy loss and reproductive issues without any cause of infertility indicates a surgical correction of the bicornuate uterus. Cervical cerclage increases the fetal survival rate if the woman has coexisting cervical incompetence (cervical insufficiency). This procedure involves various sutures on the cervix to prevent pregnancy loss due to cervical insufficiency. In addition, doctors may suggest prophylactic cervical cerclage for some women since the association between cervical incompetence and the bicornuate uterus is high. Vaginal and uterine septums are also surgically resected by operative hysteroscopy. Strassman metroplasty, urethroplasty, or hysteroplasty is the corrective surgery for the bicornuate uterus. This procedure helps to fuse the bi-uterine cavity and the fundus. Pregnancy outcomes can be improved after the procedure (5).
What Are The Complications Of The Bicornuate Uterus?
Common adverse pregnancy outcomes in women with bicornuate uterus may include (3):
Fertility problems: Approximately 15-25% of women with uterine anomalies can have fertility and reproduction issues. There is an increased risk for abnormal placentation, poor fetal growth, and ectopic pregnancies with a bicornuate uterus.
Recurrent pregnancy loss or miscarriage can be due to reduced uterine capacity or irregular uterine contractions from the abnormal shape.
Fetal deformities: Congenital disabilities such as fetal limb deformity can be seen in some cases due to prolonged pressure on the limbs from space constraints in the uterine horn.
Malpresentations: Lack of space for rotation may cause fetal malpresentation in many women with bicornuate uterus. In some cases, the cephalic presentation occurs if the fetus turns at the beginning of the third trimester and maintains the position until term.
Preterm birth: Cervical incompetence may result in early delivery if the cervical cerclage is not placed. However, there are cases of successful singleton and twin pregnancies without cerclage, and the outcomes may vary for each woman. This is common if the cervical length is less than 25mm on transvaginal ultrasound.
Postpartum hemorrhage: Severe postpartum bleeding may occur if the bicornuate uterus does not contract after delivery. However, surgical and nonsurgical alternatives such as suturing or ligating the blood vessels or Bakri balloon may help reduce the bleeding.
Pregnancy-induced hypertension: Women with coexisting renal and uterine anomalies may have a higher risk of high blood pressure in pregnancy. During pregnancy, frequent monitoring of the blood pressure may help identify and control the pressure before developing complications.
Uterine rupture: The presence of fibrous bands or abnormal development of the lower part of the uterus (corpora) can increase the risk for rupture even in first-time pregnant women.
Urinary tract anomalies: Many women with uterine anomalies have coexisting urinary tract anomalies such as renal agenesis or pelvic kidney.
A bicornuate uterus is not an independent risk factor for developing endometrial cancer. However, cancer may go undetected if samples are collected from the healthy part of the uterus. Delay in detection and treatment can worsen the prognosis. Most doctors recommend MRI scans for women with uterine bleeding and bicornuate uterus to avoid false-negative results.
Can You Have Twins With A Bicornuate Uterus?
It is possible to have twin pregnancies with a bicornuate uterus. However, twin pregnancies have a higher risk of complications in women with uterine malformations. Preterm birth and low birth weight are common twin pregnancy complications in women with a bicornuate uterus and other uterine malformations. Cervical cerclage and vaginal progesterone may help prevent preterm delivery (6).
