Ultrasound showing didelphys
|Classification and external resources|
Uterus didelphys (sometimes also uterus didelphis) represents a uterine malformation where the uterus is present as a paired organ when the embryogenetic fusion of the Müllerian ducts fails to occur. As a result there is a double uterus with two separate cervices, and often a double vagina as well. Each uterus has a single horn linked to the ipsilateral fallopian tube that faces its ovary.
In non human species (e.g. nematodes), a didelphic genital tract may be normal rather than a malformation. Such species are described as didelphic, as opposed to monodelphic, with a single tract.
The uterus is formed during embryogenesis by the fusion of the two paramesonephric ducts (also called Müllerian ducts). This process usually fuses the two Müllerian ducts into a single uterine body but fails to take place in these affected women who maintain their double Müllerian systems. A didelphic uterus will have a double cervix and is usually associated with a double vagina. The cause of the fusion failure is not known. Associated defects may affect the vagina, the renal system and, less commonly, the skeleton.
Women with the condition may be asymptomatic and unaware of having a double uterus. However, a study by Heinonen showed that certain conditions are more common. In his study of 26 women with a double uterus gynecological complaints included dysmenorrhea and dyspareunia. All patients displayed a double vagina. The fetal survival rate in 18 patients who delivered was 67.5%. Breech presentation was present in 43% and premature delivery common (21%).
A pelvic examination will typically reveal a double vagina and a double cervix. Investigations are usually prompted on the basis of such findings as well as when reproductive problems are encountered. Not all cases of uterus didelphys involve duplication of the cervix and vagina.
Helpful techniques to investigate the uterine structure are transvaginal ultrasonography and sonohysterography, hysterosalpingography, MRI, and hysteroscopy. More recently 3-D ultrasonography has been advocated as an excellent non-invasive method to evaluate uterine malformations.
Uterus didelphys is often confused with a complete uterine septum. Often more than one method of investigation is necessary to accurately diagnose the condition. Correct diagnosis is crucial as treatment for these two conditions is very different. Whereas most doctors recommend removal of a uterine septum, they generally concur that it is better not to operate on a uterus didelphys. In either case, a highly qualified reproductive endocrinologist should be consulted.
In the United States, uterus didelphys is reported to occur in 0.1–0.5% of women. It is difficult to know the exact occurrence of this anomaly, as it may go undetected in the absence of medical and reproductive complications.
Uterus didelphys, in certain studies, has also been found associated with higher rate of infertility, spontaneous abortion, intrauterine growth retardation, and postpartum bleed.
A number of twin gestations have occurred where each uterus carried its pregnancy separately. A recent example occurred on February 26, 2009, when Sarah Reinfelder of Sault Ste. Marie, Michigan delivered two healthy, although seven weeks premature, infants by cesarean section at Marquette General Hospital. It is possible that the deliveries occur at different times, thus the delivery interval could be days or even weeks.
A UK woman with a double uterus gave birth to triplets in 2006. Hannah Kersey, of Northam in Devon, gave birth to a pair of identical twins from an egg that implanted into one womb and then divided, and to an 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. It is estimated that the possibility of such a birth is about 1 in 25 million. 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.
The film Dead Ringers depicts a woman with a trifurcate uterus.
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- Heinonen, P.K. (1984). "Uterus didelphys: a report of 26 cases". European Journal of Obstetrics & Gynecology and Reproductive Biology 17 (5): 345–50. doi:10.1016/0028-2243(84)90113-8. PMID 6479426.
- Woelfer, B; Salim, R; Banerjee, S; Elson, J; Regan, L; Jurkovic, D (2001). "Reproductive outcomes in women with congenital uterine anomalies detected by three-dimensional ultrasound screening". Obstetrics & Gynecology 98 (6): 1099–103. doi:10.1016/S0029-7844(01)01599-X. PMID 11755560.
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- Madureira, A. J.; Mariz, C. M.; Bernardes, J. C.; Ramos, I. M. (2006). "Case 94: Uterus Didelphys with Obstructing Hemivaginal Septum and Ipsilateral Renal Agenesis". Radiology 239 (2): 602–6. doi:10.1148/radiol.2392031187. PMID 16641359.
- "Associated Press "Mich. woman with 2 wombs delivers twin daughters"".
- "Triplets for woman with two wombs". BBC News. December 21, 2006. Retrieved 2007-06-27.
- "Howstuffworks "13 People with Extra Body Parts"".
- Mashiach, S; Ben-Rafael, Z; Dor, J; Serr, DM (1981). "Triplet pregnancy in uterus didelphys with delivery interval of 72 days". Obstetrics and gynecology 58 (4): 519–21. PMID 7279347.