Journal of Obstetrics and Gynaecology
ISSN: 0144-3615 (Print) 1364-6893 (Online) Journal homepage: http://www.tandfonline.com/loi/ijog20
Conjoined Twins: Experience in an Irish Tertiary Centre C. M. McCarthy & K. O’Donoghue To cite this article: C. M. McCarthy & K. O’Donoghue (2014) Conjoined Twins: Experience in an Irish Tertiary Centre, Journal of Obstetrics and Gynaecology, 34:3, 225-228 To link to this article: http://dx.doi.org/10.3109/01443615.2013.835305
Published online: 31 Jan 2014.
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Date: 14 November 2015, At: 14:52
Journal of Obstetrics and Gynaecology, 2014; 34: 225–228 © 2014 Informa UK, Ltd. ISSN 0144-3615 print/ISSN 1364-6893 online DOI: 10.3109/01443615.2013.835305
OBSTETRICS
Conjoined Twins: Experience in an Irish Tertiary Centre C. M. McCarthy & K. O’Donoghue
Downloaded by [University of Wisconsin Oshkosh] at 14:52 14 November 2015
Anu Research Centre, Department of Obstetrics and Gynaecology, Cork Universtity Maternity Hospital, University College Cork, Cork, Republic of Ireland
Conjoined twins are rare, with a reported incidence of 0.19 per 10,000 pregnancies in Europe. We discuss four spontaneous conjoined twin pregnancies presenting to a tertiary referral centre from 2005 to 2011, diagnosed on antenatal dating ultrasound. The cases were monitored closely throughout pregnancy by a multidisciplinary team, with serial surveillance, including ultrasound, fetal echocardiography, magnetic resonance imaging, amniocentesis and further referral to cardiology and paediatric surgery specialists, where indicated. Three female sets were determined antenatally to be not surgically separable; these infants were managed palliatively following a live birth. The male set of conjoined twins was accepted for surgical separation at Great Ormond Street Hospital, London, which was successfully performed electively at 4 months. Of interest, all four parents reside within 20 km of each other, representing a possible cluster of cases. The incidence of conjoined twins in our local population is approximately 0.63 per 10,000 over an 8-year period from 2005 to 2012. This case series highlights a cluster of conjoined twins, managed to viability and delivered in a tertiary referral centre. Keywords: Conjoined twins, investigation, management, prenatal diagnosis
Introduction Conjoined twins are a rare occurrence, occurring in 1% of monochorionic pregnancies (Fitzgerald et al. 1985). Conjoined twinning occurs due to an abnormality in the development of monozygotic twins. There are varied postulations regarding the pathogenesis of conjoined twinning. The two most widely held theories are the ‘fissure’ theory and the ‘fusion’ theory. The former involves the embryonic disc failing to completely separate between day 15 and 17 post-conception. The fusion theory hypothesises that secondary fusion occurs between two previously separate single ovum embryonic discs (Weber and Sebire 2010). Some animal studies have demonstrated that there is an increased incidence of monozygotic twinning following chemical exposure, such as in mice following vincristine sulphate exposure (Kaufman and O’Shea 1978). Monozygotic twins also have a greater incidence of congenital malformations and structural defects. Conjoined twins can be seen themselves as a congenital malformation, being a symmetrical monozygotic duplication. Conjoined twinning is also associated with secondary changes related to abnormal conjoined organs and superimposed effects of abnormal haemodynamics.
The incidence of conjoined twins is reported to be in the range of 1–2 in 50,000 pregnancies; however the true incidence is around 1 in 250,000 live births, with a 3:1 female preponderance (Spitz 2005). A recent European study (Boyle et al. 2013), has shown the incidence of conjoined twins to be 0.19 per 10,000 births, in-keeping with other published work. According to the European Surveillance of Congenital Anomalies Register (EUROCAT) for 2006–2010, Ireland has the second highest rate of live birth conjoined twins in Europe after Sweden, with a rate of 0.50 per 10,000 births. With regards to Ireland, in the period from 1980 to 2010, there were 20 cases of conjoined twins reported, with 18 live births. At a European scale, out of 14 conjoined twin live-birth cases reported between 2006 and 2010, three occurred in our region with another case in 2011. Conjoined twins are classified according to the most prominent site of interconnection, a classification system that was initially proposed by teratologist, Isidore Geoffroy Saint, using Greek etymology. There are many possible sites of fusion. The most common are the thoracopagus (40%); omphalopagus (33%); pygopagus (19%); ischiopagus (6%) and craniopagus (2%) (Spencer 1996; Spitz 1996). The presence of conjoined twinning has many implications, both for the parents and family of those affected, and for the ongoing pregnancy and the healthcare team. Conjoined twins should be managed at a fetal medicine unit, with expertise in multiple pregnancies. Multidisciplinary care is essential in the diagnosis and ongoing management of these pregnancies. Conjoined twinning is also associated with various maternal and fetal complications, and is thus associated with high perinatal mortality rates. Miscarriage and in-utero death occur in 60% of conjoined twins (Spitz 2005). Some 35% of live born conjoined twins do not survive beyond 24 hours of life (Inamdar et al. 2012). There are a number of treatment options available for conjoined twins. This is dependent on the site and extent of fusion between the twins, shared viscera, other congenital anomalies and the antenatal course. Termination of pregnancy, palliative management, surgical separation and conservative management are all viable options, depending on the resources available, clinical factors, parental decisions and expert advice. Termination of pregnancy is an option pursued by some parents. In a large Brazilian series of cases, 38% of pregnancies were terminated (Brizot et al. 2011). In this series, 16.6% were delivered live born, and the overall neonatal survival rate (excluding cases that opted for termination of pregnancy) was 13.6%. Generally, the degree of cardiovascular anomaly is the main limiting factor when considering surgical separation in conjoined
Correspondence: K. O’Donoghue, Anu Research Centre, Department of Obstetrics and Gynaecology, University College Cork, Cork University Maternity Hospital, Wilton, Cork, Republic of Ireland. E-mail: [email protected]
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twins. There are many reports of varied cardiovascular anomalies, showing that cardiac morphogenesis is complex in conjoined twins (Gilbert-Barness et al. 2003). In order to optimise management, conjoined twins must be detected early in the antenatal course to allow thorough investigation and optimal antenatal and postnatal preparation and management. In this series, we describe the evolving experience in the management of conjoined twins in an Irish tertiary-referral university teaching hospital. All pregnancies were spontaneous conceptions, and booked for antenatal care locally. All four women proceeded to delivery by caesarean section of live born infants.
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Methods This was a retrospective descriptive cohort study. Ethical approval was granted from the Cork Research and Ethics Committee (CREC) of the Cork Teaching Hospitals in 2011, as part of a wider study of multiple pregnancies. All pregnancies with a diagnosis of conjoined twinning in hospitals operating in the Cork region during the period from 2005 to 2012, were included. These were the Erinville Hospital (closed 2007), St Finbarr’s maternity hospital (closed 2007), the maternity unit in the Bons Secours Hospital (closed 2007) and Cork University Maternity Hospital, which was formed from the amalgamation of all three maternity units and opened in April 2007. All women in the study were booked for consultant-led antenatal care at one of these units. Cases were first identified using birth registers, labour ward records, annual reports, medical records, ultrasound reports and reports from prenatal genetic testing. Identified cases were then verified using the EUROCAT (European surveillance of congenital anomalies) database, which has recorded data for the region studied, from 1995. Following verification, individual case reviews were performed on the maternity and baby charts. Information was collected on parental demographics, gestation at diagnosis, structural abnormalities, pregnancy complications (maternal and fetal), pregnancy outcome, timing of fetal or neonatal death, mode of delivery, delivery complications and neonatal survival time. Anonymised data were recorded.
Results Case 1 In 2005, a 30-year-old woman was booked at 27 weeks’ gestation. She had a previous pre-term delivery at 35 weeks, and on that occasion, had also booked for antenatal care in the late second trimester. A departmental ultrasound revealed craniothoracopagus conjoined twins, with polyhydramnios. She had no significant past medical history, was allergic to penicillin and smoked 10 cigarettes per day. She subsequently presented at 28 ⫹ 1 weeks’ gestation, with a history of painful uterine contractions. Tocolysis was administered, however, she was soon in established labour, and an emergency classical caesarean section was carried out under general anaesthesia. Live female infants were delivered, weighing 1,380 g, with Apgar scores of 2 at 1 minute and 2 at 5 minutes. They died at 90 minutes of age. The mother had no postpartum complications, and made an uneventful recovery.
Case 2 In 2006, a 32-year-old woman booked at 12 ⫹ 1 weeks’ gestation in her second pregnancy, and was diagnosed with conjoined twins. Serial transabdominal ultrasound and fetal magnetic resonance imaging revealed craniothoracopagus twins, conjoined cranially to the level of the umbilicus. There was a single
umbilical cord with four vessels. There were four lower limbs, and four kidneys, with a single shared liver and shared thoracic organs. A comprehensive prenatal review was carried out during the antenatal period, including a neonatal and radiological review. It was decided by a multidisciplinary team, in consultation with the parents, that palliative management was the most suitable option, given the extent of visceral sharing and poor prognosis. An emergency classical caesarean section was carried out at 33 weeks’ gestation due to pre-term labour, by two consultant obstetricians. Live female infants were delivered, weighing 3,350 g together, and received by a neonatal team, led by a consultant neonatologist. The twin girls were joined from the lower face to umbilicus, with three upper limbs. Apgar scores were 7 at 1 minute, and they died at 30 minutes of age. The mother had an uncomplicated postnatal course, and recovered well, physically. She was supported by the bereavement and loss team in the antenatal and postnatal period, and was reviewed by the Fetal Medicine team.
Case 3 In 2009, a 31-year-old woman presented at 11 weeks’ gestation. She had previous uncomplicated pregnancies, with two normal deliveries at term. Routine ultrasound at 11 weeks revealed monochorionic, monoamniotic parapagus conjoined twins. She was reviewed fortnightly with routine maternal antenatal checks and intensive fetal surveillance. Fetal magnetic resonance imaging in the second trimester confirmed the twins were joined from mid-chest to pelvis and perineum, with the anatomic arrangement confirmed closest to parapagus classification. Fetal echocardiography performed at 18 weeks, revealed two grossly normal and separate cardiac structures, with a shared pericardial sac. One twin appeared to have a small inlet ventricular septal defect. Suspected further anomalies that were detected on antenatal surveillance included moderate bowel dilatation and abnormal lower limbs, with bilateral talipes. It also appeared that the pelvis was joined, with a shared liver, intestine and bladder. At 24 weeks’ gestation, she was referred to Great Ormond Street Hospital for Children, London, an international centre specialising in the management of conjoined twins for further assessment and consideration for neonatal separation. Intramuscular corticosteroids to accelerate fetal lung maturity were administered at 29 weeks’ gestation. To facilitate immediate assessment at birth, detail the degree of separation and plan neonatal surgery, the infants were delivered in close proximity to the Paediatric Unit. The pregnancy was delivered by elective classical caesarean section at 35 weeks. There were no maternal postnatal complications. Live male infants were successfully separated at 4 months of age in Great Ormond Street Hospital, London.
Case 4 In 2011, a 33-year-old woman presented with thoracopagus conjoined twins at 13 ⫹ 1 gestation. She had a previous emergency caesarean section at term, in an otherwise uncomplicated pregnancy. Routine ultrasound revealed monochorionic monoamniotic conjoined twins, joined from upper thorax to upper pelvis with a central complex cardiac mass, consistent with the thoracopagus classification. Bilateral cystic hygromas were evident. Amniocentesis was performed at 16 weeks’ gestation, revealing a normal female karyotype. She was reviewed every 2 weeks with routine maternal antenatal checks and intensive fetal surveillance, reviewing growth, biophysical profiles and liquor volume. A detailed anomaly ultrasound scan at 20 weeks’ gestation revealed normal growth, with normal bladders and pelvis. Fetal echocardiography confirmed a single complex multi-chamber heart; there was a single atrium with one atrioventricular valve, with a single
An Irish Experience of Conjoined Twins 227
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outlet and two arterial vessels. Fetal magnetic resonance imaging confirmed the extra-cardiac ultrasound findings, describing a single six-vessel umbilical cord and a shared small intestine. It was determined the infants would not be successfully separated after birth. Polyhydramnios was identified at 27 weeks’ gestation. Intramuscular corticosteroids were administered at 29 weeks’ gestation. A multidisciplinary approach was utilised, with a detailed birth plan formulated at 30 weeks’ gestation. This pregnancy was delivered by elective classical caesarean section at 33 ⫹ 6 weeks’ gestation. Live-born female infants, weighing 3,730 g died at 91 minutes of age. The family received support from the pregnancy loss service and neonatal palliative care team. A postpartum appointment allowed a thorough review of events, and discussion about future pregnancy plans.
Discussion This case series describes four cases of conjoined twins, presenting to a tertiary referral centre in Southern Ireland, between 2005 and 2011. Unlike other series, termination of pregnancy was not pursued in any case, despite its availability to parents (albeit in other jurisdictions), which results in our institution having a live birth rate of 100% in conjoined twins. There were also no cases of intrauterine fetal death in our series, which has been reported elsewhere, in up to 50% of conjoined twin cases (Chen et al. 2011). Cases in these multigravida women were all spontaneously conceived to Irish nationals, with a mean maternal age of 31.5 years. Our series exactly demonstrates the 3:1 female-to-male preponderance in conjoined twins that has previously been reported (Spitz 2005). In addition, we demonstrate how thorough antenatal investigation, both invasive and non-invasive diagnosis, can aid and improve the management of conjoined twins, allowing appropriate intervention, which is noted to be integral in the management of conjoined twins (Spitz and Kiely 2003). We also highlight the importance of multidisciplinary care, and effective communication between involved parties. This small series is particularly interesting, as it demonstrates a cluster in a short period of time, within a small population. All families resided within a 20-km radius of each other. The rate of live birth conjoined twinning in our population in this 8-year period is 6.3/100,000 from 2005 to 2012, which is higher than the reported average of 1.47/100,000 (Mutchnik et al. 2011) or the reported European incidence of 0.19/10,000 births (Boyle et al. 2013). Prior to these reported cases, the last case of conjoined twins in our region occurred in 1996. EUROCAT estimated the prevalence of conjoined twins in the Cork and Kerry region to be at 0.36/10,000 births from 1995 to 2009. The body of information about conjoined twins is increasing, facilitated by published reports and the improving survival of conjoined twins, corresponding to a higher success rate of separation techniques. Medical advances have allowed fetal MRI, and more invasive investigations to become integral in the management of these complex cases. However, the literature is largely restricted to a number of complex case reports, and small case series, apart from a notable large case series from Great Ormond Street Hospital for Children, in London. Few reports display both prenatal diagnosis and postnatal outcome. One recent case series has demonstrated both aspects successfully (Brizot et al. 2011). However, our series provides an alternative European perspective to this congenital anomaly, in a setting where termination of pregnancy is often not pursued, and pregnancies are continued to their natural outcome.
This report describes the various anatomical classifications of conjoined twins, including two cases of the less common craniothoracopagus classification. We demonstrate a higher incidence of craniothoracopagus conjoined twins, than published rates (Kingston et al. 2001). In our cases, those who experienced early neonatal death, cardiac anatomy was a significant factor in their poor prognosis (Andrews et al. 2006). There are no reported surviving conjoined twin pairs of singletons following separation attempts in those with shared cardiac anatomy (Spitz 2005). We were unable to postnatally further investigate the three sets of conjoined twins who died after birth, as parental consent was not obtained for post-mortem examination. Facilities and expertise for the surgical separation of conjoined twins do not exist within this State, and surgical experience is limited with these pregnancies, to a small number of centres worldwide. Here, suitable candidates travel internationally for consultation, and we facilitate their delivery and care abroad. Our maternity hospital is co-located on the site of a large adult tertiary referral centre, with paediatric surgical and radiology specialities available. There is expertise in complex multiple pregnancies, with specialists in maternal and fetal medicine, as well as a Level 3 neonatal intensive care unit. Such modalities of investigation and levels of tertiary care are not available in all institutions within the State. In summary, we describe a case series of four conjoined twin sets occurring in our population, with varying levels of union and congenital anomaly, all resulting in live births, with a 75% rate of neonatal death. One set of conjoined twins were successfully separated. In the management of conjoined twins, we recommend early diagnostic dating and anomaly ultrasound, with serial ultrasonographic follow-up at appropriate intervals. We endorse amniocentesis for karyotyping to establish other congenital anomalies, and advise fetal echocardiography and fetal MRI to delineate visceral involvement and level of union. Multidisciplinary team management, expert opinion and inter-institution collaboration are integral in the successful management of pregnancies with conjoined twins. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References Andrews RE, McMahon CJ, Yates RW, Cullen S, de Leval MR, Kiely EM et al. 2006. Echocardiographic assessment of conjoined twins. Heart 92:382–387. Boyle B, McConkey R, Garne E, Loane M, Addor M, Bakker M et al. 2013. Trends in the prevalence, risk and pregnancy outcome of multiple births with congenital anomaly: a registry-based study in 14 European countries 1984–2007. British Journal of Obstetrics and Gynaecology 120:707–716. Brizot ML, Liao AW, Lopes LM, Okumura M, Marques MS, Krebs V et al. 2011. Conjoined twins pregnancies: experience with 36 cases from a single centre. Prenatal Diagnosis 31:1120–1125. Chen CP, Hsu CY, Su JW, Chen HE, Hwa-Ruey AH, Hwa-Jiun AH et al. 2011. Conjoined twins detected in the first trimester: a review. Taiwan Journal of Obstetrics and Gynecology 50:424–431. European Surveillance of Congenital Anomalies. Prevalence data tables for conjoined twins. Available at: www.eurocat-network.eu/prevdata/ resultsPdf.aspx?title ⫽ A5andallanom ⫽ falseandallregf ⫽ trueandallrega ⫽ trueandanomalies ⫽ 80andwinx ⫽ 1342andwiny ⫽ 628 (Accessed 3 March 2013). Fitzgerald EJ, Toi A, Cochlin DL. 1985. Conjoined twins. Antenatal ultrasound diagnosis and review of the literature. British Journal of Radiology 58:1053–1056. Gilbert-Barness E, Debich-Spicer D, Opitz JM. 2003. Conjoined twins: morphogenesis of the heart and a review. American Journal of Medical Genetics 120:568–582.
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Inamdar SA, Goel SS, Subhedar VS. 2012. A thoracophagus conjoined twins with myelomeningocele: an unusual case. International Journal of Reproduction, Contraception Obstetrics and Gynecology 1:61–63. Kaufman MH, O’Shea KS. 1978. Induction of monozygotic twinning in the mouse. Nature 276:707–708. Kingston CA, McHugh K, Kumaradevan J, Kiely EM, Spitz L. 2001. Imaging in the preoperative assessment of conjoined twins. Radiographics 21:1187–1208. Mutchnik OM, Luna-Muñoz L, Amar E, Bakker MK, Clementi M, Cocchi G et al. 2011. Conjoined twins: a worldwide collaborative epidemiological study of the International Clearinghouse for Birth
Defects Surveillance and Research. American Journal of Medical Genetics (Seminars in Medical Genetics) 157:274–287. Spencer R. 1996. Anatomic description of conjoined twins: a plea for standardized terminology. Journal of Pediatric Surgery 31:941–944. Spitz L. 1996. Conjoined twins. British Journal of Surgery 83:1028–1030. Spitz L. 2005. Conjoined twins. Prenatal Diagnosis 25:814–819. Spitz L, Kiely E. Conjoined twins. 2003. Journal of the American Medical Association 289:1307–1310. Weber M, Sebire N. 2010. Genetics and developmental pathology of twinning. Seminars in Fetal and Neonatal Medicine 15:313–318.
ISSN: 0144-3615 (Print) 1364-6893 (Online) Journal homepage: http://www.tandfonline.com/loi/ijog20
Conjoined Twins: Experience in an Irish Tertiary Centre C. M. McCarthy & K. O’Donoghue To cite this article: C. M. McCarthy & K. O’Donoghue (2014) Conjoined Twins: Experience in an Irish Tertiary Centre, Journal of Obstetrics and Gynaecology, 34:3, 225-228 To link to this article: http://dx.doi.org/10.3109/01443615.2013.835305
Published online: 31 Jan 2014.
Submit your article to this journal
Article views: 62
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ijog20 Download by: [University of Wisconsin Oshkosh]
Date: 14 November 2015, At: 14:52
Journal of Obstetrics and Gynaecology, 2014; 34: 225–228 © 2014 Informa UK, Ltd. ISSN 0144-3615 print/ISSN 1364-6893 online DOI: 10.3109/01443615.2013.835305
OBSTETRICS
Conjoined Twins: Experience in an Irish Tertiary Centre C. M. McCarthy & K. O’Donoghue
Downloaded by [University of Wisconsin Oshkosh] at 14:52 14 November 2015
Anu Research Centre, Department of Obstetrics and Gynaecology, Cork Universtity Maternity Hospital, University College Cork, Cork, Republic of Ireland
Conjoined twins are rare, with a reported incidence of 0.19 per 10,000 pregnancies in Europe. We discuss four spontaneous conjoined twin pregnancies presenting to a tertiary referral centre from 2005 to 2011, diagnosed on antenatal dating ultrasound. The cases were monitored closely throughout pregnancy by a multidisciplinary team, with serial surveillance, including ultrasound, fetal echocardiography, magnetic resonance imaging, amniocentesis and further referral to cardiology and paediatric surgery specialists, where indicated. Three female sets were determined antenatally to be not surgically separable; these infants were managed palliatively following a live birth. The male set of conjoined twins was accepted for surgical separation at Great Ormond Street Hospital, London, which was successfully performed electively at 4 months. Of interest, all four parents reside within 20 km of each other, representing a possible cluster of cases. The incidence of conjoined twins in our local population is approximately 0.63 per 10,000 over an 8-year period from 2005 to 2012. This case series highlights a cluster of conjoined twins, managed to viability and delivered in a tertiary referral centre. Keywords: Conjoined twins, investigation, management, prenatal diagnosis
Introduction Conjoined twins are a rare occurrence, occurring in 1% of monochorionic pregnancies (Fitzgerald et al. 1985). Conjoined twinning occurs due to an abnormality in the development of monozygotic twins. There are varied postulations regarding the pathogenesis of conjoined twinning. The two most widely held theories are the ‘fissure’ theory and the ‘fusion’ theory. The former involves the embryonic disc failing to completely separate between day 15 and 17 post-conception. The fusion theory hypothesises that secondary fusion occurs between two previously separate single ovum embryonic discs (Weber and Sebire 2010). Some animal studies have demonstrated that there is an increased incidence of monozygotic twinning following chemical exposure, such as in mice following vincristine sulphate exposure (Kaufman and O’Shea 1978). Monozygotic twins also have a greater incidence of congenital malformations and structural defects. Conjoined twins can be seen themselves as a congenital malformation, being a symmetrical monozygotic duplication. Conjoined twinning is also associated with secondary changes related to abnormal conjoined organs and superimposed effects of abnormal haemodynamics.
The incidence of conjoined twins is reported to be in the range of 1–2 in 50,000 pregnancies; however the true incidence is around 1 in 250,000 live births, with a 3:1 female preponderance (Spitz 2005). A recent European study (Boyle et al. 2013), has shown the incidence of conjoined twins to be 0.19 per 10,000 births, in-keeping with other published work. According to the European Surveillance of Congenital Anomalies Register (EUROCAT) for 2006–2010, Ireland has the second highest rate of live birth conjoined twins in Europe after Sweden, with a rate of 0.50 per 10,000 births. With regards to Ireland, in the period from 1980 to 2010, there were 20 cases of conjoined twins reported, with 18 live births. At a European scale, out of 14 conjoined twin live-birth cases reported between 2006 and 2010, three occurred in our region with another case in 2011. Conjoined twins are classified according to the most prominent site of interconnection, a classification system that was initially proposed by teratologist, Isidore Geoffroy Saint, using Greek etymology. There are many possible sites of fusion. The most common are the thoracopagus (40%); omphalopagus (33%); pygopagus (19%); ischiopagus (6%) and craniopagus (2%) (Spencer 1996; Spitz 1996). The presence of conjoined twinning has many implications, both for the parents and family of those affected, and for the ongoing pregnancy and the healthcare team. Conjoined twins should be managed at a fetal medicine unit, with expertise in multiple pregnancies. Multidisciplinary care is essential in the diagnosis and ongoing management of these pregnancies. Conjoined twinning is also associated with various maternal and fetal complications, and is thus associated with high perinatal mortality rates. Miscarriage and in-utero death occur in 60% of conjoined twins (Spitz 2005). Some 35% of live born conjoined twins do not survive beyond 24 hours of life (Inamdar et al. 2012). There are a number of treatment options available for conjoined twins. This is dependent on the site and extent of fusion between the twins, shared viscera, other congenital anomalies and the antenatal course. Termination of pregnancy, palliative management, surgical separation and conservative management are all viable options, depending on the resources available, clinical factors, parental decisions and expert advice. Termination of pregnancy is an option pursued by some parents. In a large Brazilian series of cases, 38% of pregnancies were terminated (Brizot et al. 2011). In this series, 16.6% were delivered live born, and the overall neonatal survival rate (excluding cases that opted for termination of pregnancy) was 13.6%. Generally, the degree of cardiovascular anomaly is the main limiting factor when considering surgical separation in conjoined
Correspondence: K. O’Donoghue, Anu Research Centre, Department of Obstetrics and Gynaecology, University College Cork, Cork University Maternity Hospital, Wilton, Cork, Republic of Ireland. E-mail: [email protected]
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twins. There are many reports of varied cardiovascular anomalies, showing that cardiac morphogenesis is complex in conjoined twins (Gilbert-Barness et al. 2003). In order to optimise management, conjoined twins must be detected early in the antenatal course to allow thorough investigation and optimal antenatal and postnatal preparation and management. In this series, we describe the evolving experience in the management of conjoined twins in an Irish tertiary-referral university teaching hospital. All pregnancies were spontaneous conceptions, and booked for antenatal care locally. All four women proceeded to delivery by caesarean section of live born infants.
Downloaded by [University of Wisconsin Oshkosh] at 14:52 14 November 2015
Methods This was a retrospective descriptive cohort study. Ethical approval was granted from the Cork Research and Ethics Committee (CREC) of the Cork Teaching Hospitals in 2011, as part of a wider study of multiple pregnancies. All pregnancies with a diagnosis of conjoined twinning in hospitals operating in the Cork region during the period from 2005 to 2012, were included. These were the Erinville Hospital (closed 2007), St Finbarr’s maternity hospital (closed 2007), the maternity unit in the Bons Secours Hospital (closed 2007) and Cork University Maternity Hospital, which was formed from the amalgamation of all three maternity units and opened in April 2007. All women in the study were booked for consultant-led antenatal care at one of these units. Cases were first identified using birth registers, labour ward records, annual reports, medical records, ultrasound reports and reports from prenatal genetic testing. Identified cases were then verified using the EUROCAT (European surveillance of congenital anomalies) database, which has recorded data for the region studied, from 1995. Following verification, individual case reviews were performed on the maternity and baby charts. Information was collected on parental demographics, gestation at diagnosis, structural abnormalities, pregnancy complications (maternal and fetal), pregnancy outcome, timing of fetal or neonatal death, mode of delivery, delivery complications and neonatal survival time. Anonymised data were recorded.
Results Case 1 In 2005, a 30-year-old woman was booked at 27 weeks’ gestation. She had a previous pre-term delivery at 35 weeks, and on that occasion, had also booked for antenatal care in the late second trimester. A departmental ultrasound revealed craniothoracopagus conjoined twins, with polyhydramnios. She had no significant past medical history, was allergic to penicillin and smoked 10 cigarettes per day. She subsequently presented at 28 ⫹ 1 weeks’ gestation, with a history of painful uterine contractions. Tocolysis was administered, however, she was soon in established labour, and an emergency classical caesarean section was carried out under general anaesthesia. Live female infants were delivered, weighing 1,380 g, with Apgar scores of 2 at 1 minute and 2 at 5 minutes. They died at 90 minutes of age. The mother had no postpartum complications, and made an uneventful recovery.
Case 2 In 2006, a 32-year-old woman booked at 12 ⫹ 1 weeks’ gestation in her second pregnancy, and was diagnosed with conjoined twins. Serial transabdominal ultrasound and fetal magnetic resonance imaging revealed craniothoracopagus twins, conjoined cranially to the level of the umbilicus. There was a single
umbilical cord with four vessels. There were four lower limbs, and four kidneys, with a single shared liver and shared thoracic organs. A comprehensive prenatal review was carried out during the antenatal period, including a neonatal and radiological review. It was decided by a multidisciplinary team, in consultation with the parents, that palliative management was the most suitable option, given the extent of visceral sharing and poor prognosis. An emergency classical caesarean section was carried out at 33 weeks’ gestation due to pre-term labour, by two consultant obstetricians. Live female infants were delivered, weighing 3,350 g together, and received by a neonatal team, led by a consultant neonatologist. The twin girls were joined from the lower face to umbilicus, with three upper limbs. Apgar scores were 7 at 1 minute, and they died at 30 minutes of age. The mother had an uncomplicated postnatal course, and recovered well, physically. She was supported by the bereavement and loss team in the antenatal and postnatal period, and was reviewed by the Fetal Medicine team.
Case 3 In 2009, a 31-year-old woman presented at 11 weeks’ gestation. She had previous uncomplicated pregnancies, with two normal deliveries at term. Routine ultrasound at 11 weeks revealed monochorionic, monoamniotic parapagus conjoined twins. She was reviewed fortnightly with routine maternal antenatal checks and intensive fetal surveillance. Fetal magnetic resonance imaging in the second trimester confirmed the twins were joined from mid-chest to pelvis and perineum, with the anatomic arrangement confirmed closest to parapagus classification. Fetal echocardiography performed at 18 weeks, revealed two grossly normal and separate cardiac structures, with a shared pericardial sac. One twin appeared to have a small inlet ventricular septal defect. Suspected further anomalies that were detected on antenatal surveillance included moderate bowel dilatation and abnormal lower limbs, with bilateral talipes. It also appeared that the pelvis was joined, with a shared liver, intestine and bladder. At 24 weeks’ gestation, she was referred to Great Ormond Street Hospital for Children, London, an international centre specialising in the management of conjoined twins for further assessment and consideration for neonatal separation. Intramuscular corticosteroids to accelerate fetal lung maturity were administered at 29 weeks’ gestation. To facilitate immediate assessment at birth, detail the degree of separation and plan neonatal surgery, the infants were delivered in close proximity to the Paediatric Unit. The pregnancy was delivered by elective classical caesarean section at 35 weeks. There were no maternal postnatal complications. Live male infants were successfully separated at 4 months of age in Great Ormond Street Hospital, London.
Case 4 In 2011, a 33-year-old woman presented with thoracopagus conjoined twins at 13 ⫹ 1 gestation. She had a previous emergency caesarean section at term, in an otherwise uncomplicated pregnancy. Routine ultrasound revealed monochorionic monoamniotic conjoined twins, joined from upper thorax to upper pelvis with a central complex cardiac mass, consistent with the thoracopagus classification. Bilateral cystic hygromas were evident. Amniocentesis was performed at 16 weeks’ gestation, revealing a normal female karyotype. She was reviewed every 2 weeks with routine maternal antenatal checks and intensive fetal surveillance, reviewing growth, biophysical profiles and liquor volume. A detailed anomaly ultrasound scan at 20 weeks’ gestation revealed normal growth, with normal bladders and pelvis. Fetal echocardiography confirmed a single complex multi-chamber heart; there was a single atrium with one atrioventricular valve, with a single
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outlet and two arterial vessels. Fetal magnetic resonance imaging confirmed the extra-cardiac ultrasound findings, describing a single six-vessel umbilical cord and a shared small intestine. It was determined the infants would not be successfully separated after birth. Polyhydramnios was identified at 27 weeks’ gestation. Intramuscular corticosteroids were administered at 29 weeks’ gestation. A multidisciplinary approach was utilised, with a detailed birth plan formulated at 30 weeks’ gestation. This pregnancy was delivered by elective classical caesarean section at 33 ⫹ 6 weeks’ gestation. Live-born female infants, weighing 3,730 g died at 91 minutes of age. The family received support from the pregnancy loss service and neonatal palliative care team. A postpartum appointment allowed a thorough review of events, and discussion about future pregnancy plans.
Discussion This case series describes four cases of conjoined twins, presenting to a tertiary referral centre in Southern Ireland, between 2005 and 2011. Unlike other series, termination of pregnancy was not pursued in any case, despite its availability to parents (albeit in other jurisdictions), which results in our institution having a live birth rate of 100% in conjoined twins. There were also no cases of intrauterine fetal death in our series, which has been reported elsewhere, in up to 50% of conjoined twin cases (Chen et al. 2011). Cases in these multigravida women were all spontaneously conceived to Irish nationals, with a mean maternal age of 31.5 years. Our series exactly demonstrates the 3:1 female-to-male preponderance in conjoined twins that has previously been reported (Spitz 2005). In addition, we demonstrate how thorough antenatal investigation, both invasive and non-invasive diagnosis, can aid and improve the management of conjoined twins, allowing appropriate intervention, which is noted to be integral in the management of conjoined twins (Spitz and Kiely 2003). We also highlight the importance of multidisciplinary care, and effective communication between involved parties. This small series is particularly interesting, as it demonstrates a cluster in a short period of time, within a small population. All families resided within a 20-km radius of each other. The rate of live birth conjoined twinning in our population in this 8-year period is 6.3/100,000 from 2005 to 2012, which is higher than the reported average of 1.47/100,000 (Mutchnik et al. 2011) or the reported European incidence of 0.19/10,000 births (Boyle et al. 2013). Prior to these reported cases, the last case of conjoined twins in our region occurred in 1996. EUROCAT estimated the prevalence of conjoined twins in the Cork and Kerry region to be at 0.36/10,000 births from 1995 to 2009. The body of information about conjoined twins is increasing, facilitated by published reports and the improving survival of conjoined twins, corresponding to a higher success rate of separation techniques. Medical advances have allowed fetal MRI, and more invasive investigations to become integral in the management of these complex cases. However, the literature is largely restricted to a number of complex case reports, and small case series, apart from a notable large case series from Great Ormond Street Hospital for Children, in London. Few reports display both prenatal diagnosis and postnatal outcome. One recent case series has demonstrated both aspects successfully (Brizot et al. 2011). However, our series provides an alternative European perspective to this congenital anomaly, in a setting where termination of pregnancy is often not pursued, and pregnancies are continued to their natural outcome.
This report describes the various anatomical classifications of conjoined twins, including two cases of the less common craniothoracopagus classification. We demonstrate a higher incidence of craniothoracopagus conjoined twins, than published rates (Kingston et al. 2001). In our cases, those who experienced early neonatal death, cardiac anatomy was a significant factor in their poor prognosis (Andrews et al. 2006). There are no reported surviving conjoined twin pairs of singletons following separation attempts in those with shared cardiac anatomy (Spitz 2005). We were unable to postnatally further investigate the three sets of conjoined twins who died after birth, as parental consent was not obtained for post-mortem examination. Facilities and expertise for the surgical separation of conjoined twins do not exist within this State, and surgical experience is limited with these pregnancies, to a small number of centres worldwide. Here, suitable candidates travel internationally for consultation, and we facilitate their delivery and care abroad. Our maternity hospital is co-located on the site of a large adult tertiary referral centre, with paediatric surgical and radiology specialities available. There is expertise in complex multiple pregnancies, with specialists in maternal and fetal medicine, as well as a Level 3 neonatal intensive care unit. Such modalities of investigation and levels of tertiary care are not available in all institutions within the State. In summary, we describe a case series of four conjoined twin sets occurring in our population, with varying levels of union and congenital anomaly, all resulting in live births, with a 75% rate of neonatal death. One set of conjoined twins were successfully separated. In the management of conjoined twins, we recommend early diagnostic dating and anomaly ultrasound, with serial ultrasonographic follow-up at appropriate intervals. We endorse amniocentesis for karyotyping to establish other congenital anomalies, and advise fetal echocardiography and fetal MRI to delineate visceral involvement and level of union. Multidisciplinary team management, expert opinion and inter-institution collaboration are integral in the successful management of pregnancies with conjoined twins. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References Andrews RE, McMahon CJ, Yates RW, Cullen S, de Leval MR, Kiely EM et al. 2006. Echocardiographic assessment of conjoined twins. Heart 92:382–387. Boyle B, McConkey R, Garne E, Loane M, Addor M, Bakker M et al. 2013. Trends in the prevalence, risk and pregnancy outcome of multiple births with congenital anomaly: a registry-based study in 14 European countries 1984–2007. British Journal of Obstetrics and Gynaecology 120:707–716. Brizot ML, Liao AW, Lopes LM, Okumura M, Marques MS, Krebs V et al. 2011. Conjoined twins pregnancies: experience with 36 cases from a single centre. Prenatal Diagnosis 31:1120–1125. Chen CP, Hsu CY, Su JW, Chen HE, Hwa-Ruey AH, Hwa-Jiun AH et al. 2011. Conjoined twins detected in the first trimester: a review. Taiwan Journal of Obstetrics and Gynecology 50:424–431. European Surveillance of Congenital Anomalies. Prevalence data tables for conjoined twins. Available at: www.eurocat-network.eu/prevdata/ resultsPdf.aspx?title ⫽ A5andallanom ⫽ falseandallregf ⫽ trueandallrega ⫽ trueandanomalies ⫽ 80andwinx ⫽ 1342andwiny ⫽ 628 (Accessed 3 March 2013). Fitzgerald EJ, Toi A, Cochlin DL. 1985. Conjoined twins. Antenatal ultrasound diagnosis and review of the literature. British Journal of Radiology 58:1053–1056. Gilbert-Barness E, Debich-Spicer D, Opitz JM. 2003. Conjoined twins: morphogenesis of the heart and a review. American Journal of Medical Genetics 120:568–582.
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Downloaded by [University of Wisconsin Oshkosh] at 14:52 14 November 2015
Inamdar SA, Goel SS, Subhedar VS. 2012. A thoracophagus conjoined twins with myelomeningocele: an unusual case. International Journal of Reproduction, Contraception Obstetrics and Gynecology 1:61–63. Kaufman MH, O’Shea KS. 1978. Induction of monozygotic twinning in the mouse. Nature 276:707–708. Kingston CA, McHugh K, Kumaradevan J, Kiely EM, Spitz L. 2001. Imaging in the preoperative assessment of conjoined twins. Radiographics 21:1187–1208. Mutchnik OM, Luna-Muñoz L, Amar E, Bakker MK, Clementi M, Cocchi G et al. 2011. Conjoined twins: a worldwide collaborative epidemiological study of the International Clearinghouse for Birth
Defects Surveillance and Research. American Journal of Medical Genetics (Seminars in Medical Genetics) 157:274–287. Spencer R. 1996. Anatomic description of conjoined twins: a plea for standardized terminology. Journal of Pediatric Surgery 31:941–944. Spitz L. 1996. Conjoined twins. British Journal of Surgery 83:1028–1030. Spitz L. 2005. Conjoined twins. Prenatal Diagnosis 25:814–819. Spitz L, Kiely E. Conjoined twins. 2003. Journal of the American Medical Association 289:1307–1310. Weber M, Sebire N. 2010. Genetics and developmental pathology of twinning. Seminars in Fetal and Neonatal Medicine 15:313–318.
