If diagnosed in a nonpregnant woman, mOSt recommend prophylactic excision of a horn thac has a cavity (Fedele, 2005; Rackow, 2007). Data regarding subsequent pregnancy after excision are scarce. In one series of eight women, all had a preterm cesarean delivery (pados, 2014).
This mullerian anomaly arises from a complere lack of fusion rhat results in twO enrirely separate hemiureri, cervices, and usually (yo vaginas (see Fig. 3-5). It is common among marsupials, for example, the American possum-Didelphys virginiana. Most women have a double vagina or a longitudinal vaginal septum. Urerine didelphys may be isolated. Or, it may compose a triad with an Qbstructed hemiyagina and with ipsilateral renal Igenesis (OHVlRA), also known as HerlynWerner-Wunderlich syndrome (Tong, 2013).
These anomalies are suspected on pelvic examinarion by identificarion of a longitudinal vaginal septum and two cervices. During HSG for fertility evaluation, contrast shows twO separate endocervical canals. These open into separare noncommunicating fusiform endometrial cavities char each ends wirh a solitary fallopian tube. In women without fertility issues, 2-or 3-D TVS is a logical initial imaging tool, and separate diver gent uterine horns with a large intervening fundal cleft are seen.
Endometrial cavities are uniformly separate. MR imaging may be valuable in cases without classic indings.
Adverse obstetrical outcomes associated with uterine didel phys are similar but less frequent than those seen with unicornu ate uterus. Increased risks include miscarriage, pre term birth, and malpresentation (Chan, 2011a; Grimbizis, 2001; Hua, 2011).
Metroplasty for either uterine didelphys or bicornuate uterus involves resection of intervening myometrium and fundal recombination (Alborzi, 2015). hese rarely performed surgeries are chosen for highly selected patients with otherwise unexplained miscarriages. Moreover, no evidence-based data conirm the eicacy of such surgical repair.
his fusion anomaly results in two hemiuteri. As shown in Figure 3-5, the central myometrium runs either partially or completely to the cervix. A complete bicornuate uterus may extend to the internal cervical os and have a single cervix (bicornuate unicollis) or reach the external os (bicornuate bicollis). As with uterine didelphys, a coexistent longitudinal vaginal septum is not uncommon.
Radiological discrimination of a bicornuate uterus from a septate uterus can be challenging. This distinction, however, is important because septate uterus can be treated with hysteroscopic septal resection. HSG or 2-D TVS may initially suggest an anomaly, but further distinction is provided by 3-D TVS or MR imaging (see Fig. 3-6). With these, an intercornual angle greater than 105 degrees typiies a bicornuate uterus, whereas one less than 75 degrees indicates a septate uterus. Fundal contour also assists, and a straight line drawn between the imaged tubal ostia serves as the defining threshold. Referent to this, an intrafundal downward cleft measuring �1 em or more is indicative of bicornuate uterus. A septate uterus shows a cleft depth < 1 em, or it may have a normal fundal contour.
Bicornuate uterus carries increased risks for adverse obstetrical outcomes that include miscarriage, preterm birth, and malpresentation. As discussed in the prior section, rare surgical correction by metroplasty is reserved for highly selected patients.