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.