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pregnancies occurring in a malformed uterus are relatively rare . even more rare are those occurring in a rudimentary uterine horn .
the frequency of a pregnancy in a rudimentary uterine horn is about one in 150,000 pregnancies .
this leads to an urgent foetal extraction and it is then recommended to carry out a rudimentary horn excision . if the latter is not realized , it exposes the patient to the risk of a repeated uterine rupture in the event of a new pregnancy in the rudimentary horn .
a 20 year old female , g2p0 , presented to the emergency department at the end of her 17th week of amenorrhea with violent abdominal pain .
her first pregnancy was marked by the appearance of an intense pelvic pain occurring at 18 weeks in the context of hemorrhagic shock . during laparotomy
, the amniotic membranes were discovered bulging into the abdominal cavity from a breach in the ruptured left rudimentary uterine horn in what was discovered to be a pseudo - unicornuate uterus .
treatment consisted of ablation of the left rudimentary horn , with excision extending to its junction with the right hemi - uterus .
there was no bleeding but the patient was noted to have malaise and fatigue . on clinical examination ,
the blood pressure was 90/50 mm / hg , pulse was 100 bpm , and there was mucocutaneous pallor .
ultrasound scan showed a uterus of normal structure with an empty cavity , placenta , and a non - viable pregnancy of 17 week 's gestation outside the myometrium .
they also noted a large intra - peritoneal effusion , suggesting an abdominal pregnancy ( figure 1 ) .
ultrasound scan showing a uterus of normal structure with an empty cavity , a placenta , and a non - viable foetus of 17 week 's gestation outside the myometrial structure .
an urgent lower midline laparotomy was carried out together with simultaneous resuscitation of the patient .
the surgical findings included a hemoperitoneum of two liters , a full thickness rupture of the uterine wall measuring 6 cm involving the remaining hemi - uterus , and a dead foetus with a placenta showing no sign of placental insertion in the abdomino - pelvic cavity ( figure 2 ) .
after extraction of the foetus and placenta , repair of the hemi - uterus was carried out by way of interrupted stitches in two layers .
the post operative course was uncomplicated and the patient was discharged on the 7th post - operative day .
full thickness uterine rupture of 6 cm involving the remaining hemi - uterus , and a dead foetus with a placenta presenting no sign of placental insertion in the abdomino - pelvic cavity
the embryological origin of pseudo - unicornuate uteri is a lack of development of one of the two mllerian tubes .
this entity accounts for only 10% of uterine malformations [ 2 , 3 ] and only a proportion of these have a patent rudimentary horn lined with functional endometrium .
co - existing urinary tract abnormalities are frequent in these patients and are dominated by unilateral renal agenesies , homolateral to the side of the rudimentary horn .
the incidence of the unicornuate uterus , although difficult to specify , is estimated at 1/1000 women .
the occurrence of a hematometrium is infrequent , and this lack of menstrual retention in the rudimentary horn could be explained by isthmic aplasia , or by the paucity of bleeding from the often hypoplastic endometrium . the diagnosis should be considered in cases of severe dysmenorrhea , unexplained infertility , or miscarriages with repeated premature births , intra - uterine growth restriction , and hypertension in pregnancy , which all merit radiological assessment .
the only constant clinical sign is an intense , brutal abdominal pain which may or may not be associated with a hemoperitoneum .
sometimes , there is hemorrhagic shock imposing an urgent laparotomy for maternal and possibly foetal rescue depending on the gestation .
pelvic examination during the first trimester can raise the alert , with the finding of a latero - uterine mass corresponding to the small gravid horn beside the normal horn .
ultrasound confirms the diagnosis by showing a pregnancy surrounded by a variable thickness of myometrium which is usually absent in the event of tubal pregnancy .
laparoscopy allows formal confirmation of this type of uterine malformation if there is doubt about the localization of the pregnancy , or the nature of uterine malformation .
indeed , the muscle of the rudimentary horn is particularly delicate because it is so thin .
thus , the pregnancy generally evolves towards rupture in the beginning of the second trimester bringing about a hemorrhagic acute abdominal syndrome similar to a cataclysmic ruptured ectopic pregnancy [ 7 , 8 ] . the treatment of the rudimentary horn pregnancy , whether complicated or not , classically involves foetal extraction , followed by resection of the rudimentary horn and of its homolateral tube .
certain authors even propose to carry out this procedure on diagnosis of a pseudo - unicorn uterus with rudimentary horn in the non - gravid state , to avoid an obstetrical accident .
obstetricians caring for these patients should be aware of the serious risk of uterine rupture during pregnancy . a caesarean section prior to labour is strongly recommended .
the rudimentary horn pregnancy is a very serious condition which may put the maternal life in danger . improving the outcome
the treatment will consist of an urgent laparotomy with foetal extraction and ablation of the ruptured horn in order to avoid a repeated , potentially more severe incident .
pregnancy in a rudimentary horn is a very rare condition . 
 it is responsible for several complications . 
 prognosis is reserved because the natural evolution generally leads to a cataclysmic uterine rupture at the beginning of the second trimester . 
 classically , the treatment after foetal extraction consists of ablation of the rudimentary horn and associated fallopian tube . 
 we report the obstetric outcome of a patient with history of rudimentary uterine horn rupture , the treatment of which was ablation of the rudimentary horn .