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Abstract
Müllerian anomalies are congenital malformations of the female reproductive organs that occur when the müllerian ducts develop abnormally. Different types of müllerian anomalies have different pregnancy outcomes. Breech presentation is a common occurrence in pregnant women with uterus didelphys, and caesarean section is the traditional mode of delivery under such circumstances. Here, we present the case of a 29-year-old woman (gravida 2, para 1) with her fetus in a frank breech presentation. The patient had a known history of uterus didelphys and previous vaginal delivery. She elected to undergo external cephalic version (ECV) at 37 weeks with a trial of labour at 39 weeks as opposed to planned cesarean delivery. The version was successful, and the fetus was subsequently delivered vaginally without complications. This case demonstrates ECV as a possible option in women with uterus didelphys, provided the risks of the procedure are carefully weighed and individualised to each patient.
- obstetrics and gynaecology
- pregnancy
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Background
The female genital tract develops from fusion of the paired embryological structures, the müllerian ducts, which form the fallopian tubes, uterus and upper two-thirds of the vagina. Incomplete fusion of these ducts results in various congenital anomalies of the reproductive organs.1 In the most extreme and rare form, the müllerian ducts do not reach each other and develop side by side, giving rise to two entirely separate, functional genital tracts. This müllerian anomaly is called uterus didelphys (or uterus duplex separatus), which affects 0.3% to 11% of women.2
Different types of müllerian anomalies have different pregnancy outcomes. Recurrent pregnancy loss is a common complication in müllerian anomalies, possibly due to the abnormal shape of the uterine cavities and altered blood supply.3 Other complications include miscarriage, fetal growth restriction, preterm delivery and fetal malpresentation.2
Although rarer, uterus didelphys has better pregnancy outcomes than septate or unicornuate uterus with 60%–70% of pregnancies being viable. This is possibly due to increased blood supply through collateral circulation between the two uterine horns.4 Regardless, the risk of preterm labour and fetal malpresentation is 3.58 and 3.7 times higher, respectively, in women with uterus didelphys compared with the normal population, thus increasing the likelihood of caesarean delivery 20-fold.2 Here, we report a case of frank breech presentation in a patient with uterus didelphys who underwent external cephalic version (ECV) at 37 weeks with subsequent vaginal delivery at 39 weeks.
Case presentation
A 29-year-old woman (gravida 2, para 1) with no significant medical history, who was known to have uterus didelphys, presented for prenatal care at 8 weeks and 6 days with a singleton intrauterine pregnancy in the left uterus (figure 1). She had undergone vaginal septum excision as a teenager. Her obstetric history was significant for one similar prior pregnancy in the left uterus with normal spontaneous cephalic vaginal delivery at term.
First trimester ultrasound of both uteri with singleton intrauterine pregnancy in the left uterus.
At 19 weeks, she underwent a normal targeted fetal ultrasound (fetal anomaly scan). Serial ultrasounds demonstrated normal fetal growth in the left horn through 35 weeks with the fetus in a frank breech presentation. The amniotic fluid index was within normal limits throughout the pregnancy. At 35 weeks, the options were discussed with the patient and an ECV attempt was scheduled at 37 weeks. The patient understood the risks associated with the procedure and was counselled on the uncertainty associated with her uterine anomaly. Informed consent was obtained.
At 37 weeks, ultrasound demonstrated a fundal grade 2 placenta with normal amniotic fluid volume. ECV was successfully performed in the hospital setting with no anaesthesia or analgesia. A single dose of terbutaline 0.25 mg was subcutaneously administered. Under ultrasound guidance, the fetal breech was manually lifted from the pelvis, and the head was guided clockwise in a forward roll. Post procedure, fetal heart and uterine activity were monitored and she was discharged home with postoperative and follow-up instructions. Elective induction of labour (IOL) was subsequently scheduled at 39 weeks.
Outcome and follow-up
On admission for scheduled IOL at week 39, her cervix was noted to be 1 cm dilated and 50% effaced on digital examination, with the vertex presentation at −2 station. She underwent oxytocin IOL with standard low-dose protocol and delivered a male fetus with Apgar scores of 9 and 9 at 1 and 5 min, respectively, and weight of 3 kg. The delivery was without complications.
The patient was discharged home 48 hours following the delivery. She was satisfied with the outcome of the delivery with an unremarkable postpartum course. She reported doing well at the regular 6 week postpartum visit with no complications (figure 2). The baby had no developmental delays and has achieved all milestones at 2 years of age.
3D ultrasonography of the uterus 2 years post pregnancy demonstrating uterus didelphys.
Discussion
Müllerian anomalies are associated with an increased risk of adverse pregnancy outcomes. Although uterus didelphys has better fetal survival among the uterine anomalies, such pregnancies can still cause various complications. A case series by Heinonen followed 26 patients with uterus didelphys over 21 years. Of them, 18 became pregnant with a total of 40 pregnancies. The fetus survival rate was 67.5% with the frequency of breech presentation at 43%, which was significantly higher than the overall annual incidence of 3.0%–4.1% in the same hospital. The rate of caesarean section (CS) was high at 82%, breech presentation being the indication in slightly less than half of the cases.3
Another study that followed 68 pregnancies in women with uterine anomalies, 10% of whom had uterus didelphys, reported that 32.4% of the fetuses exhibited malpresentation and the rate of caesarean deliveries in this population was 64.7%.5 Yet another study on uterine anomalies by Green and Harris reported breech presentation in 43% of pregnancies in their population.6 These studies highlight the higher rate of breech presentation seen in patients with uterus didelphys when compared with those without such anomalies.
Breech presentation places the fetus and the mother at increased risk of complicated vaginal delivery or CS.7 Additionally, breech delivery, whether vaginal or by CS, has a higher incidence of poor perinatal outcomes when compared with cephalic birth.8 The majority of women with a breech presenting baby would prefer vaginal birth; however, they would choose CS if there is a medical indication.7 Although fetal risks associated with CS are low, it is still a major abdominal surgery not without maternal morbidity.
In developed countries, CS remains the largest contributing factor to the incidence of maternal morbidity and mortality following childbirth.9 A 2015 Cochrane review of ECV for breech presentation at term showed that, in addition to increased immediate morbidity following CS compared with vaginal birth, there is also a risk of subsequent infertility secondary to intra-abdominal adhesions which may occur.7 Furthermore, the presence of the uterine scar increases the risk of complications in future pregnancies, including ectopic pregnancy, placenta previa, accrete and abruption, and uterine rupture.7 Avoiding the need for surgery is additionally important in countries that have limited access to healthcare.7 Therefore, achieving cephalic vaginal delivery by successfully rotating the baby via ECV offers the potential of decreasing CS rates and improving perinatal and maternal outcomes.
A review of strategies for reduction of CS rates has identified ECV as the only clinical intervention with level 1 evidence for reducing primary CS rates overall.10 Using this technique, pressure is applied to the external gravid abdomen of the mother, manipulating the baby into a cephalic (head down) position.7 This is the same technique we performed in our patient with uterus didelphys. Classically, ECV was performed prior to term (usually before 34 weeks); however, with the advent of tocolytic use to relax the uterus before performing the procedure, more evidence shows advantages of performing the intervention at or near term (36 weeks or after).7 Several advantages to ECV around this time are the fetus being mature and capable of being delivered more readily in the event of complications, and additionally, there is less chance of spontaneous reversion of the fetus after a successful version.7
There is no general consensus regarding contraindications to ECV aside from cases where labour and vaginal birth are contraindicated regardless of the fetal presentation.11 Based primarily on expert opinion, ECV is generally contraindicated in multiple gestations, severe oligohydramnios, abnormal cardiotocography, hyperextended fetal head, severe fetal or uterine anomaly, placental abruption, ruptured membranes, or active labour with fetal descent.11 Although uterine anomaly is included in the above list of potential contraindications, it should be noted that uterus didelphys has been shown to have better pregnancy outcomes than most other uterine anomalies, making it less severe than septate or unicornuate uteri for example. However, due to uterine anomalies increasing the risk of pregnancy complications overall, each case should be reviewed closely to ensure no other contraindications exist.
Majority of women have been shown to prefer vaginal birth over CS.12 With ECV being the primary intervention available to achieve a vaginal delivery when the baby is in breech presentation,10 it should be offered to patients with uterus didelphys and no other contraindications. However, the procedure should be discussed at length to ensure the patient’s understanding of risks and benefits. Complication rates of ECV at term in the general population are low,7 but can include fetal-maternal haemorrhage,13 vaginal bleeding, placental abruption, emergency CS, perinatal mortality and those affecting the baby such as femur fracture,14 prolonged tachycardia15 and sinusoidal heart rate pattern.16
Our case is a unique presentation of successful ECV followed by vaginal delivery, performed on a patient with uterus didelphys who had a fetus in breech presentation. According to our review of the literature, there has been one other report of ECV in a uterus didelphys patient which was ultimately unsuccessful, requiring subsequent CS.2 A factor which may have been in favour of a successful ECV in our patient was her history of a previous vaginal delivery with cephalic presentation which was suggestive of the left horn of the didelphys uterus being wide enough to accommodate ECV and a fetus in cephalic presentation with sufficient amniotic fluid.
While our presentation is limited in its generalisability to all uterus didelphys patients with fetal malpresentation, it serves to draw attention to the paucity in the literature of this topic and the need for further investigation. Here we demonstrated that ECV is a possible option in patients with uterus didelphys to facilitate cephalic vaginal delivery, provided the risks of the procedure are carefully weighed and individualised to each patient. It is important to note that this case does not provide guidance or reassurance regarding the use of ECV in patients with septate or subseptate uteri due to worse pregnancy outcomes associated with these uterine anomalies when compared with patients with uterus didelphys. Our patient with uterus didelphys wished to attempt an ECV to avoid potential risks of elective CS due to her desire for future pregnancies, and she was very satisfied with the outcome.
Learning points
Although rarer, uterus didelphys has better pregnancy outcomes than septate or unicornuate uterus, possibly due to increased blood supply through collateral circulation between the two uterine horns.
Breech presentation is common in pregnant women with uterus didelphys, and caesarean section (CS) is the traditional mode of delivery under such circumstances.
External cephalic version (ECV) is a possible option in women with uterus didelphys to facilitate cephalic vaginal delivery, provided the risks of the procedure are carefully weighed and individualised to each patient.
There is no general consensus regarding contraindications to ECV, and although uterine anomalies tend to be considered a potential contraindication, better pregnancy outcomes seen with uterus didelphys specifically may allow for use of the technique in this population.
Considering the current paucity in the literature regarding ECV in uterus didelphys patients, further investigation is required into its risks and benefits to reduce the rate of CS in this population and improve perinatal and maternal outcomes.
Footnotes
Contributors The authors have equally contributed to the planning, revision and submission of this case report. The patient was under the care of SBW. SMirz performed the primary literature review and gathering of data. SMirz prepared the original draft and performed major revisions. SBW, SMili and AOR aided with manuscript revisions. SBW and AOR approved of the final version.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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