Uterus Didelphys

Uterus didelphys (from Ancient Greek di- 'two' and delphus 'womb'; sometimes also uterus didelphis) is a uterine malformation where the uterus appears as a paired organ due to the failure of the embryogenetic fusion of the Müllerian ducts. This results in a double uterus with two separate cervices, and possibly a double vagina. Each uterus has a single horn connected to the ipsilateral fallopian tube that faces its ovary.

Most non-human mammals have a non-single uterus with separated horns. Marsupials and rodents possess a double uterus (uterus duplex). In other animals (e.g. nematodes), 'didelphic' refers to a double genital tract, unlike monodelphic, which has a single tract.

Signs and symptoms

Women with this condition may be asymptomatic and unaware of having a double uterus. However, a study by Heinonen indicated that certain conditions are more prevalent. In his study of 26 women with a double uterus, gynecological complaints included dysmenorrhea and dyspareunia. All patients had a double vagina. The fetal survival rate in 18 patients who delivered was 67.5%. Premature delivery occurred in 21% of the pregnancies. Breech presentation was noted in 43% of women, and cesarean section was performed in 82% of the cases.

Cause

The uterus is formed during embryogenesis by the fusion of the two paramesonephric ducts (also known as Müllerian ducts). This process typically merges the two Müllerian ducts into a single uterine body but does not occur in affected women, who retain their double Müllerian systems. A didelphic uterus will have a double cervix and is often associated with a double vagina. The reason for the fusion failure is unknown. Associated defects may impact the vagina, the renal system, and less commonly, the skeleton.

The condition is less common than other uterine malformations such as arcuate uterus, septate uterus, and bicornuate uterus. It is estimated to occur in 1/3,000 women.[2]

Syndrome

A specific combination of uterus didelphys (double uterus), unilateral hematocolpos (inadequate drainage of menstrual blood), and ipsilateral renal agenesis (having only one kidney) has been noted.

Diagnosis

A pelvic examination will typically reveal a double vagina and a double cervix. Investigations are usually initiated based on such findings and when reproductive issues arise. Not all cases of uterus didelphys involve duplication of the cervix and vagina.

Useful techniques to examine the uterine structure include transvaginal ultrasonography, sonohysterography, hysterosalpingography, MRI, and hysteroscopy. Recently, 3-D ultrasonography has been recommended as an excellent non-invasive method to assess uterine malformations.

Uterus didelphys is often mistaken for a complete uterine septum. Multiple investigation methods are often needed to accurately diagnose the condition. Accurate diagnosis is vital as treatments for these conditions differ significantly. While most doctors suggest removing a uterine septum, they generally agree that surgery on a uterus didelphys is not advisable. In either case, consulting a highly qualified reproductive endocrinologist is recommended.

Management

Patients with a double uterus may require special care during pregnancy as premature birth and malpresentation are common. Cesarean section was performed in 82% of patients reported by Heinonen.

Uterus didelphys has also been associated with higher rates of infertility, miscarriage, intrauterine growth retardation, and postpartum bleeding in certain studies.

Epidemiology

In the United States, uterus didelphys is reported to occur in 0.1–0.5% of women. The exact prevalence of this anomaly is difficult to determine, as it may go undetected in the absence of medical and reproductive complications.

Multiple pregnancy

There have been cases where twin gestations occurred with each uterus carrying its own pregnancy. Approximately 100 cases worldwide have been reported of a woman with a double uterus being pregnant in both wombs simultaneously. Before 2005, only 11 such cases had been documented globally. It is possible for deliveries to occur at different times, with intervals ranging from days to weeks.

Maricia Tescu of Iași, Romania, gave birth to a premature son on December 11, 2004. Her second son was born via C-section at full term 59 days later, in early February 2005.

On February 26, 2009, Sarah Reinfelder of Sault Ste. Marie, Michigan, delivered two healthy, although seven weeks premature, infants by cesarean section at Marquette General Hospital.

On September 15, 2011, Andreea Barbosa of St. Petersburg, Florida, gave birth to fraternal twins, a boy and a girl, via C-section.

On October 23, 2020, Kelly Fairhurst of Essex, England, delivered twins, a boy and a girl, at 35 weeks via a planned C-section.

On December 19 and 20, 2023, Kelsey Hatcher delivered fraternal twin girls at 39 weeks, with one girl delivered vaginally and the other by C-section the next day, at the University of Alabama at Birmingham Hospital.

Triplets

A UK woman with a double uterus gave birth to triplets in 2006. Hannah Kersey, of Northam, Devon, gave birth to a pair of identical twin girls from an egg that implanted into one womb and then divided, and to a female infant from a single egg that implanted into the other womb. This was the first known birth of viable triplets in a woman with a double uterus.

A triplet pregnancy in a woman with uterus didelphys was reported from Israel in 1981; one baby died in utero, and of the remaining babies, one was delivered at 27 weeks gestation and the other 72 days later. In 2019, Arifa Sultana of Bangladesh gave premature birth in February and then via emergency Caesarean section to twins, 26 days later.