Bicornuate uterus is a rare congenital malformation of the uterus. It belongs to the group of mulerian malformations and occurs in approx. 0.1-0.6% of women. It is characterised by an internal division of the uterus which may extend as far as the cervix. A distinction can be made between a unicollis bicornuate uterus (two horns, one cervix) and a bicollis bicornuate uterus (two horns and two cervices).
2D and 3D ultrasound, hysterosalpingography, hysteroscopy and other imaging techniques such as MRI are commonly used for diagnosis. Differences in development may be seen between the two horns, for example, a less developed or almost atrophic horn, although it is also possible for both horns to have normal appearing endometrium and myometrium. In general, a bicornuate uterus does not require specific treatment.
Women with a bicornuate uterus can usually become pregnant naturally or after assisted reproductive techniques. In both cases, closer than usual monitoring during pregnancy is recommended, as the risk of miscarriage, preterm delivery, premature rupture of the membranes or other obstetric complications may be increased. An increase in abnormal fetal presentations, e.g. breech or transverse presentation, may also be observed, which may increase the rate of caesarean delivery.
When IVF is performed on a patient with a bicornuate uterus, several factors must be taken into account to increase the chances of pregnancy. During ultrasound scans we need to monitor the endometrial thickness and appearance of both horns very closely. There may be differences between the endometrial development of the two horns and it is important to identify the side that may offer the best chance of harbouring a pregnancy. There is also the possibility of performing a hysteroscopy before starting stimulation, to verify which side of the uterine horn is better suited to receive the embryo.
The embryo transfer should be performed under ultrasound control via vaginal or abdominal route and the embryo should be left on the good side, with the best conditions for pregnancy, in an endometrium of good thickness. We recommend the transfer of a single embryo to avoid obstetric complications that could be related to a multiple pregnancy.
