Discussion:

Amongst mullerian anomalies, unicornuate uterus accounts for 2.4-13% [7][2]. Pregnancy in rudimentary horn of unicornuate uterus is rare, incidence being 1 in 76.000 - 1 in 150.000 [5]. Here we report pregnancy in ASRM classification type A1b of unicornuate uterus/ ESHRE-ESGE classification U4a [10]. The pregnancy in non-communicating horn which has no connection with cervix, or the main horn bears the growing fetus. It is due to transperitoneal migration of sperm to the contralateral rudimentary horn, fertilizing the ova on that side [1] or migration of fertilized ovum, which probably could have fertilized in the pouch of Douglas [5]. Diagnosis of such a case requires high suspicion index. Diagnosis can be made on 2D ultrasound with accuracy being only 26% [2], Other reported literature mentions ultrasound sensitivity to be around 29-33% [11]. It should be supplemented with 3D ultrasound, which improves accuracy rates. MRI also confirms the diagnosis, it is an excellent tool for diagnosing uterine anomalies and any other anomalies associated like urological anomalies, but it is expensive and not available globally under emergency circumstances. It can be done when expert ultrasound imaging is not present [2]. Tsafrir suggested a criteria to diagnose early pregnancy in the rudimentary horn via ultrasound: pseudopattern of assymetrical bicornuate uterus, absent visual continuity between cervical canal and lumen of pregnant horn and presence of myometrial tissue around the gestational sac, hypervascularisation typical of placenta accreta[12]. Similar criteria was proposed by Marvelos and it requires identification of empty uterus with single interstitial portion of fallopian tube, a gestational sac surrounded by myometrial tissue separate from uterus and a vascular pedicle connecting the unicornuate uterus to the G-sac [13]. Our patient, was first subjected to 2D USG, pregnancy was confirmed, and when we suspected that we were dealing with a uterine anomaly, 3D configurations were made to confirm the uterine anomaly. There was one cervix, which was communicating with the left uterine horn , the right horn had no communication with the cervix or the left horn. There was a live embryo, and G-sac was surrounded by myometrium. Differential diagnosis of ectopic in fallopian tube and pregnancy in an anomalous uterus should be ruled out, because treatment differs. 3D ultrasound configurations help in differentiating when in doubt. Transverse sections of the normal uterus and anomalous uterus with ectopic pregnancy may look the same, but with 3D configurations, they can be easily differentiated (Figure1 ). A table to help differentiate between them by ultrasound has been made (Table 1 ).
Management will depend upon the hemodynamic condition of the woman, her gestational age. Essentially, removal of uterine horn is the line of management. Earlier days, or in places where access to health care is difficult, when diagnosis is a problem, women often come with rupture of rudimentary horn with unstable hemodynamic condition. Emergency open surgery with multiple blood transfusions is the only option [14, 15]. But with advent of better diagnostics, and more women being diagnosed in first trimester scans, medical line of management with surgical removal being done on a later date has become possible [5].There are no fixed guidelines to manage such ectopics, but like management of other ectopic pregnancy, in early hemodynamically stable pregnancy, intrauterine or intramuscular methotrexate, or intrauterine KCL can be injected. She is followed up with Bhcg. Once pregnancy completely resolves, she is advised to get the rudimentary horn and ipsilateral fallopian tube removed to prevent further ectopic pregnancy [5] . This method improves operative morbidity and chances of intraoperative haemorrhage but delays definitive management.
There are case reports in literature wherein they have removed the rudimentary pregnant horn successfully without prior medical management [16] similar to ours. We did a primary surgical excision of the uterine horn with live fetus insitu. No complications arose. In our case, medical line of management did not seem appropriate, because we had a live fetus of 6weeks 4 days with high Bhcg values (47371 IU/ml), which could lead to intravenous methotrexate treatment failure. Most literature predicts successful methotrexate treatment with Bhcg values less than 5000IU/ml.[17]Hence, we recommend primary laparoscopic surgical management, because it removes the chances of methotrexate failure all together, does not depend upon Bhcg values and is a causal treatment and not just a treatment to remove the pregnancy. Complete management with removal of pregnancy and correction of anomaly is done at one shot with complications being almost nil. Our patient and her husband were satisfied with treatment option given and hope to get pregnant again soon.