Shetty A*, Thosar MA**, Gupta AS***
(* First year Resident, ** Assistant Professor, *** Professor; Department of Obstetrics and Gynecology, Seth GS Medical College and KEM Hospital, Mumbai.)
A bicornuate uterus is a unification defect of the Müllerian ducts. The incidence of müllerian anomalies in women with recurrent pregnancy loss is more than double than that in the general population. Pregnancies in the bicornuate uterus are high-risk because of association with poor reproductive outcomes. We present to you a case of pregnancy in a bicornuate uterus with its antenatal course and perinatal outcome.
Mullerian duct anomalies are commonly associated with recurrent pregnancy loss, poor perinatal outcomes due to abruptions or preterm labor. The incidence of müllerian anomalies in women with recurrent pregnancy loss is up to 10.4% whereas the mean incidence in general population is about 4.2%. One of the easily recognized and described müllerian duct anomalies is the bicornuate uterus. A bicornuate uterus is generally associated with recurrent pregnancy loss. We present a case of live pregnancy in one horn of a bicornuate uterus which was initially diagnosed as an ectopic pregnancy and its tragic perinatal outcome in a 23 year old P0L0A4 woman with 4 years history of unevaluated first trimester recurrent abortions.
A 23 year old G5A4; married for 4 years; with no major medical or surgical illness presented to out patient department for evaluation of recurrent first-trimester abortion. At presentation, the patient had missed her periods by 5 days and was unaware of her pregnancy. Urine pregnancy test was weakly positive. A ultrasonography (USG) was done. USG findings were suspicious for a right cornual ectopic pregnancy or a pregnancy in a bicornuate uterus. Due to confusing USG picture a MRI pelvis was performed. MRI report diagnosed a bicornuate uterus with right cornual endometrium showing a small sac-like structure that in a clinical setting would represent an early gestational sac. Live intrauterine pregnancy was confirmed by serial β HCG estimations and serial USG assessment. Pregnancy was found to be localized in right horn of the bicornuate uterus. Her kidneys were normal. Other workup for recurrent abortion was negative. However, parental karyotyping could not be done due to financial restrictions.
She was started on 17 hydroxyprogesterone depot weekly injections. Early and late malformation USG scan were normal and cervical length was maintained on serial monitoring. OGTT with 75-gram glucose load was normal. At 34 weeks she presented with threatened preterm labor that was managed with tocolysis. She desired to remain admitted in view of her previous pregnancy losses. Biweekly NST was done. They were reactive. At 35 weeks of gestation, she had acute onset of uterine contraction 3-4 in each 10 minutes lasting for 45-50 seconds each with no relaxation in between associated with preterm premature rupture of membranes (PPROM). Fetal heart could not be heard and fetal demise was confirmed with USG. Coagulation profile was normal. Labor progressed spontaneously. She delivered a male fresh stillborn baby of 2.1 kg. The placenta was expelled immediately after the delivery of the baby. A large retro placental clot of about 240 gm was noted. On examination, the placenta was tubular, weighed 410 grams had a very small implantation surface under which a large clot of 240 gm was noted. Post-delivery hemoglobin was 7 gm%. One unit blood transfusion was given. Lactation suppression was given. Histopathology of placenta was suggestive of infarct occupying greater than 50% surface area with a placental size of about 17x12x3 cm.
Uterine anomalies commonly present with second-trimester fetal losses however, it can also present with first-trimester pregnancy loss. The reported incidence of ectopic pregnancy is as high as 20% as compared to 1% in the normal population. Rupture of the gravid horn of the bicornuate uterus has also been reported. Both these conditions may mimic live pregnancy at early gestation in cases of mullerian anomalies as in the present case.
A bicornuate uterus is also an independent risk factor for cervical insufficiency. Women with müllerian anomalies are at increased risk of 25-47% for preterm labor and PPROM. Regular cervical length screening helps in early diagnosis and progesterone supplementation may prevent preterm labor. High incidences of fetal intrauterine growth restriction also has been reported. Prenatal steroids are advocated to achieve lung maturity to optimize fetal outcome.
Takami et al in a study reported a higher incidence of abruptions (up to 14 %) in the bicornuate uterus as compared to 0.6 to 1% in the general population. The increased risk of abruptions may be due to premature detachment of a placenta that is implanted on an abnormal site or due to decreased surface area of placentation. Strict fetal heart monitoring with uterine contractions at the onset of active labor may prevent the poor fetal outcome. There is no reported incidence of decrease in abruption rate with continuous progesterone supplementation.
Metroplasty for bicornuate or septate uteri results in a successful pregnancy outcome in about 65 to 85% of these cases but the risk of uterine rupture increases with the progression of pregnancy. There is no case-control study to compare live birth rates in women who had surgery compared with non-operated cases. Further study is needed to confirm the benefits of metroplasty vs progesterone only. Since our patient had sustained pregnancy till 35 weeks with progesterone supplementation we emphasize the importance of progesterone support. We believe surgical option should be offered to cases of failure of progesterone therapy only. Our patient unfortunately developed an abruption at 35 weeks of gestation and lost her child. Had tocolysis not been given when she went in preterm labor one week prior would probably have prevented this tragedy as she would then have delivered a 34 week mature neonate. She also had a tubular placenta, probably as it implanted in the cornua and so managed to grow in that shape. This was a suspected case of cornual ectopic pregnancy due to this implantaion image in early pregnancy. Unfortunately there are no clear guidelines regarding gestational age for termination of pregnancy in these patients. Our patient has been advised elective termination of pregnancy at 34 weeks in her subsequent pregnancies.
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Shetty A, Thosar MA, Gupta AS. Pregnancy In Müllerian Anomaly: A Diagnostic Dilemma To Fetal Outcome. JPGO 2017. Volume 4 No.4. Available from: http://www.jpgo.org/2017/04/pregnancy-in-mullerian-anomaly.html