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StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.

StatPearls [Internet].

Show detailsTreasure Island (FL): StatPearls Publishing; 2025 Jan-.Search term Conjoined Twins

Abhinav Pal; Freddy J. Montero.

Author Information and Affiliations

Authors

Abhinav Pal1; Freddy J. Montero2.

Affiliations

1 Stormont Vail Hospital2 Medical College of Georgia at Augusta University

Last Update: December 13, 2025.

Continuing Education Activity

Conjoined twins are a rare and complex congenital condition resulting from the incomplete division of a single fertilized egg between days 13 and 17 of embryogenesis. This anomaly results in the physical fusion of the twins at birth, often involving shared organs or body structures. Management of conjoined twin pregnancies presents unique diagnostic, surgical, and ethical challenges, requiring early identification through prenatal imaging and detailed anatomical assessment.

This activity provides an in-depth review of the pathophysiology, classification, and imaging modalities essential for accurate diagnosis and treatment planning. The importance of a multidisciplinary, interprofessional approach in managing conjoined twins from prenatal counseling and surgical decision-making to postoperative care and long-term follow-up is emphasized. Learners explore surgical separation techniques, palliative care options, and the role of advanced technologies, including 3-dimensional modeling and simulation. By enhancing clinicians' understanding of evaluation and treatment pathways, this activity aims to improve patient outcomes and support informed, compassionate decision-making in a highly sensitive clinical context.

Objectives:

• Identify the embryologic factors contributing to the etiology of conjoined twinning.
• Differentiate between surgically separable conjoined twin types and those that are not based on shared anatomy and physiology.
• Implement coordinated perinatal management strategies that optimize survival and reduce complications for conjoined twins.
• Strategize approaches to collaboration and communication amongst the interprofessional team that enhance care coordination for conjoined twins and their families.

Access free multiple choice questions on this topic.

Introduction

Conjoined twins are twins who are physically fused in utero and remain joined at birth. This rare phenomenon occurs when a single fertilized egg (zygote) partially divides into 2 embryos, resulting in twins joined at 1 or more body regions. The anomaly is believed to result from an abnormal embryological event occurring approximately 13 to 17 days after fertilization, which is later than the usual time for complete twinning.

The first historical mention of conjoined twins dates back to the Neolithic period.[1] The condition is proposed to result from either fission or fusion.[2] Conjoined twins have been historically referred to as Siamese twins, a term originating from the famous case of Chang and Eng Bunker.[3] Conjoined twins are monochorionic (1 placenta) and monoamniotic (1 amniotic sac). Conjoined twins occur at a 3:1 female-to-male ratio. With advancements in prenatal imaging and neonatal surgery, conjoined twins can now be diagnosed early, and their management can be optimized through a multidisciplinary approach. Despite these advancements, conjoined twinning is associated with high morbidity and mortality.[2][4][5]

Etiology

Conjoined twinning is most commonly believed to result from either partial fission or secondary fusion. Both of these processes can be used to explain the embryological and anatomical findings observed in conjoined twins. However, the fission and fusion theories do not unequivocally account for every possible conjunction and cannot be applied to the full spectrum of findings in conjoined twins. Current models (the embryonic disk theory) propose that 2 embryonic axes arise in a single embryo (2 embryonic primordia) and develop so close that their organizers overlap, producing shared structures. The initial distance and angle between the embryonic axes determine the type of conjunction and organ sharing. Accordingly, conjoined twins can be broadly categorized into non-dorsally conjoined twins, which include ventral, lateral, and caudal conjunctions, and dorsally conjoined twins.

Non-dorsal conjunction may present in various ways but typically involves a single shared umbilical cord and the sharing of organs. For example, ventrally conjoined twins arise when the twin primordia are facing each other, leading to compound (shared) thoracoabdominal structures, whereas laterally conjoined (parapagus) twins arise when the primordia lie side-by-side, causing mirror-image anatomy. On the other hand, the dorsal conjunction presents with 2 umbilical cords and mostly separate internal organs. This outcome may result from secondary fusion of initially separate monozygotic twins.[6]

The precise molecular triggers for this anomalous cleavage remain unknown, and no specific genetic or environmental risk factors have been identified. There is some evidence that assisted reproductive technologies, which increase monozygotic twinning rates, may slightly raise the risk, but definitive data are lacking. In most cases, conjoined twinning appears to be a sporadic developmental accident.[6][7]

Epidemiology

The incidence of conjoined twins is 1 per 50,000 to 200,000 births, often quoted as roughly 1.5 per 100,000 births.[8] The rate of stillbirth is high and is estimated to be approximately 60%.[2] Conjoined twinning appears to be largely sporadic, with no clear genetic inheritance pattern. There is no increased risk in future pregnancies. Accurate epidemiology across multiple countries and ethnicities cannot be calculated because the condition is underreported. Conjoined twins are associated with a higher prevalence of females, with a female-to-male ratio of 3:1.[2][9]

Pathophysiology

Conjoined twinning is the result of cleavage or axis duplication that occurs after day 13 of fertilization. The condition is described according to the site of fusion.[4]

Types of conjoined twins, along with their frequency, are as follows: 

• Thoraco-omphalopagus (joined at thorax and abdomen) 28%
• Thoracopagus (joined at the thorax) 18.5%
• Omphalopagus (joined at the abdomen) 10%
• Heteropagus (parasitic twins) 10%  
• Craniopagus (joined at the level of the cranium) 6%

Less commonly observed conjoined twins include:

• Pyopagus (joined at the sacrum and perineum)
• Rachipagus (joined at the vertebral column)
• Ischiopagus (joined at the lower abdomen and pelvis)
• Cephalopagus (joined from head to umbilicus) [10]

Ventral conjunctions (eg, thoracopagus and omphalopagus) involve fusion of the anterior bodies and often result in shared thoracoabdominal organs. For example, thoracopagus twins are joined at the chest and commonly share a single heart. Omphalopagus twins are joined at the abdomen around the umbilicus and typically share liver and gastrointestinal structures. Dorsal conjunctions (eg, craniopagus and pygopagus) involve fusion at the back; craniopagus twins share a skull (with separate brains), and pygopagus twins are joined at the sacrum. Lateral conjunctions (eg, parapagus dicephalus) involve side-by-side fusion and often 2 heads on 1 torso, sometimes with a shared pelvis or limbs (see Image. Major Types of Conjoined Twins).[11][12]

The site of fusion and the organs involved are primary considerations for separation surgery. Cardiac anatomy is the most important factor influencing viability. Twins that share a heart, especially a single complex heart, are generally not surgically separable and have uniformly fatal outcomes, whereas twins with separate hearts (even if joined at the chest) may survive surgery. Typically, 25% of live births live long enough to be candidates for surgery.[4][13]

History and Physical

A conjoined twin pregnancy presents similarly to other twin pregnancies but with some characteristic ultrasound findings. Due to advances in imaging techniques, most cases are recognized early on prenatal ultrasound.[14]

A key prenatal clue could be a larger-than-expected uterine size for gestational age, accompanied by the absence of a separating membrane, as conjoined twins are invariably monoamniotic. Doppler and color flow imaging may reveal a single shared umbilical cord. Fetal physical examination is necessarily limited to what is visible by imaging. After birth, examination reveals the type of fusion (eg, fused chest in thoracopagus and joined skulls in craniopagus).[15][16]

Evaluation

First-trimester ultrasonography remains the best modality for early diagnosis. Prenatal magnetic resonance imaging (MRI) can also help with identifying the type of conjunction, embryological malformations, and tissue characterization. Prenatal imaging should inform postnatal MRI.[17] Modern methods, such as 3D printing, may aid in surgical pre-planning and, if applicable, subsequent separation.[5][18]

Essential details to ascertain include cardiac anatomy (critical), hepatic and intestinal sharing, renal anatomy, and vascular connections. If an MRI is performed, it can clarify cerebral malformations or spinal fusion. Echocardiography details cardiac structures. Color Doppler should be used to map any cross-circulation. All imaging findings should be discussed in a multidisciplinary conference.

Treatment / Management

The management of conjoined twins requires an individualized, multidisciplinary approach from the outset. The conjoined twins that survive until birth can be broadly categorized into 2 categories—those who can be surgically separated and those who cannot (conservative/palliative management). Determining which set of conjoined twins can be separated is an interprofessional effort that employs imaging modalities and multiple reviews. The conjoined twins that extensively share vital organs generally cannot be separated, as separation may lead to the death of 1 or both twins. This scenario presents some ethical dilemmas in the surgical management of conjoined twins, but the overall decision still lies with the parents. Some cases may require involvement of the hospital ethics committee.[19]

Prenatally, management may include expectant follow-up or elective termination. After birth, the mainstay of treatment (if feasible) is surgical separation of the twins. Surgical management requires identification of the anatomic relationship of the conjunction between the twins. After detailed imaging, the pediatric surgical team, often accompanied by specialists in plastic surgery, neurosurgery, or orthopedic surgery as needed, plans the separation. Three-dimensional modeling and simulation enable the team to make informed surgical decisions. The use of preoperative tissue expansion is highly advantageous due to issues with abdominal wall closure. At least 1 simulation of the separation event is recommended preoperatively, as it helps improve the outcome for conjoined twins.[20] Anesthesia planning is critical, often necessitating separate anesthesiology teams for each twin during the procedure. Preoperative simulations to anticipate and manage potential complications—such as significant hemorrhage—are strongly recommended.[5]

If separation is attempted, it is typically performed as a single, carefully coordinated surgery by dual teams (1 for each twin). Essential technical points include establishing separate cardiac support (if needed), careful division of shared organs with microsurgical reconstruction, and thorough hemostasis. Postoperatively, the twins require intensive care for multiorgan support. During medical management, certain pharmacokinetic considerations must be taken into account, as the shared circulation of conjoined twins may lead to variable volumes of distribution and clearance.[21]

If separation is not feasible, for example, if the twins share a heart or major brain structures, then management may be purely supportive or palliative. Parents should receive clear counseling on the likely outcome in such cases.

Differential Diagnosis

Conjoined twins are a rare condition that is uniquely identifiable on prenatal ultrasonography. However, the differential diagnosis may include conditions with aberrant ultrasonographic findings such as cystic hygroma, teratoma, and lymphangioma.

Prognosis

Conjoined twins generally have a poor prognosis. Historically, only 5% to 25% of conjoined twins survive long-term, and approximately 60% of the surgically separated cases survive.[22] In a systematic review of thoracopagus twins—the most common type—approximately 50% of those who underwent surgical separation survived.[23] Twins who share critical organs, especially the heart, have a low chance of survival. In contrast, twins with separable hearts can achieve higher survival if separated. Outcomes are also highly dependent on case selection and center experience. Antenatal imaging, postnatal surgery if applicable, the use of tissue expansion in surgery, and cadaveric transplant for vital organs shared between the twins may result in a better prognosis.

Complications

Numerous complications can occur both before and after any attempted separation. The intrauterine demise of the twins is likely, given the complicated nature of the pregnancy. Postnatally, complications related to the complex anatomy of the twins may lead to death. Twins may experience respiratory failure (if the twins compete for space in the thorax or have compressed lungs), cardiac failure, and disseminated coagulopathy.

If surgery is an option, complications related to separation include organ failure, skin defects, surgical infection, bleeding, injury to internal organs and/or vasculature, and inability to complete the procedure. Even with successful separation, infants often require lengthy intensive care stays for total parenteral nutrition, ventilatory support, and rehabilitation.

Deterrence and Patient Education

Conjoined twins present a complex psychosocial challenge. As the condition is not preventable, early prenatal screening and counseling are essential. All pregnant patients with multiple gestations should have early ultrasounds to determine chorionicity and amnionicity. In suspected conjoined twins, patients should receive non-directive counseling regarding the high risks of death or severe disability. If the diagnosis is made early, counseling includes discussion of options: continuing the pregnancy with preparation for specialized care or elective termination.

Surgical separation raises ethical dilemmas, especially in cases of unequal separation. Furthermore, the conjoined twins often struggle to establish their individuality and may experience a twinning reaction.[24] Parental education is essential—they should learn what to expect during pregnancy (frequent monitoring and possibility of obstetric complications) and after birth (the need for neonatal intensive care unit care, uncertain outcomes). Multidisciplinary fetal care teams typically include social workers and ethics consultants who can assist parents with decision-making and help them cope with grief or stress.[25] The use of visual aids (videos or 3-dimensional models) and the involvement of parent support groups (if available) can be very beneficial.

Pearls and Other Issues

The topic of conjoined twins provides unique clinical insights that extend beyond the management of rare anomalies. Understanding key pearls helps clinicians recognize critical diagnostic features, anticipate complications, and apply coordinated, compassionate care strategies. Clinical pearls include the following:

• Conjoined twins only occur in cases of monozygotic, monochorionic–monoamniotic twinning, which happens when the embryo divides after day 13.
• The estimated incidence of conjoined twins is approximately 1.5 per 100,000 births. Females are much more common (approximately 3:1 ratio), and the majority of conjoined fetuses do not survive to term.
• Fusion is classified based on the site of attachment—thoracopagus (joined at the chest; often share heart), omphalopagus (joined at the abdomen, share liver or gastrointestinall tract), parapagus (joined side-by-side; often 2 heads), craniopagus (joined at the skull; separate brains), pygopagus (joined at the sacrum), ischiopagus (joined at the pelvis), and cephalopagus (joined at the face or upper body).
• The extent of shared organs, especially cardiac sharing, is the most critical prognostic factor. Twins sharing a single heart typically cannot be separated and have a fatal prognosis.
• Prenatal ultrasound, typically by 12 to 14 weeks of gestation, can diagnose conjoined twins. Fetal MRI and 3D modeling improve visualization of internal anatomy.
• Definitive treatment is surgical separation in experienced centers. Survival rates post-separation hover around 50% to 60% in reported series, depending on the type. Without surgery, long-term survival is very unlikely.
• Interdisciplinary planning involving obstetrics, neonatology, pediatric surgery, anesthesia, ethics, and other specialties is essential. If separation is attempted, techniques such as staged tissue expansion and intraoperative simulations are routinely used.

Enhancing Healthcare Team Outcomes

Conjoined twins are a rare and complex congenital condition resulting from the incomplete division of a single fertilized egg between days 13 and 17 of embryogenesis. This anomaly results in the physical fusion of the twins at birth, often involving shared organs or body structures. 

The management of conjoined twins is a complex process. Conjoined twins can be classified into the following groups based on prognosis:

• Those who do not survive in utero
• Those who survive pregnancy but do not survive past infancy 
• Those who survive infancy but cannot be separated
• Those who survive infancy and can be surgically separated

This classification system may be preferred over anatomic classification because it provides more specific guidance for management. Furthermore, surgical separation, if necessary, should be performed during infancy..[26] There is also an ethical dilemma associated with the management of conjoined twins. Ethical considerations should be taken into account when assessing prognosis. Clinical or ethical scenarios that may be observed include the following:

• Survival time is 6 months or less
• Both twins survive after separation
• Both twins survive without separation
• One twin dies after separation
• Both twins die the following separation
• Both twins die without separation

Keeping these considerations in mind, the interprofessional healthcare team can make decisions regarding surgical treatment and palliative care.[27] Some consider sacrificial separation—performed when it is known preoperatively that surgery will be lethal for 1 of the twins—unethical.[19] The sharing of organs, particularly the heart, is a crucial consideration because it determines whether surgical treatment is possible and the patient's prognosis.[2] Prenatal counseling for the family plays a vital role, given the complex nature of management and prognosis.[28]

Obstetric Considerations

The timing and mode of delivery should be individualized, taking into consideration any antenatal complications and the altered anatomy based on prenatal imaging. Cesarean delivery is often necessary, as vaginal delivery may not be feasible depending on where the twins are joined. An interprofessional team is essential for addressing the challenges of a complicated pregnancy and childbirth process.[28] The pregnancy should be managed in conjunction with a maternal-fetal medicine specialist and should be delivered at a tertiary care center equipped to manage the twins postnatally. Pregnancy termination is an option and should be offered in accordance with state laws.

Medical Considerations

Nutritional support is crucial in the management of conjoined twins during the neonatal period.[29] Medications should be administered with caution and with increased monitoring due to variability in pharmacokinetic parameters.[21]

Surgical Considerations

The identification of anatomical structures is accomplished using postnatal imaging, preferably MRI, while also considering prenatal imaging.[17] Three-dimensional modeling and simulation-based clinical rehearsal are important in preoperative preparation.[20][30] The surgical survival rate is estimated at 66.7%.[31]

Conjoined twins should be cared for at specialized centers with a maternal-fetal medicine, neonatal intensive care unit, and pediatric subspecialties available.[32] Maternal nursing care considerations include ensuring patient privacy, offering grief counseling when needed, and providing emotional support to both the patient and their family.

The management of conjoined twins requires the intimate cooperation of an interprofessional team.[33] The management of conjoined twins requires the intimate cooperation of an interprofessional team. Ongoing collaboration, compassionate communication, and shared decision-making among all members of the care team are crucial to optimizing outcomes and supporting the family throughout the continuum of care.

Review Questions

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• Comment on this article.

Figure

Major Types of Conjoined Twins Contributed by Abhinav Pal, MD

References

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Zygotic-splitting rates after single-embryo transfers in in vitro fertilization. N Engl J Med. 2003 Jun 05;348(23):2366-7. [PubMed: 12789011]8.De Ugarte DA, Boechat MI, Shaw WW, Laks H, Williams H, Atkinson JB. Parasitic omphalopagus complicated by omphalocele and congenital heart disease. J Pediatr Surg. 2002 Sep;37(9):1357-8. [PubMed: 12194133]9.Mutchinick OM, Luna-Muñoz L, Amar E, Bakker MK, Clementi M, Cocchi G, da Graça Dutra M, Feldkamp ML, Landau D, Leoncini E, Li Z, Lowry B, Marengo LK, Martínez-Frías ML, Mastroiacovo P, Métneki J, Morgan M, Pierini A, Rissman A, Ritvanen A, Scarano G, Siffel C, Szabova E, Arteaga-Vázquez J. Conjoined twins: a worldwide collaborative epidemiological study of the International Clearinghouse for Birth Defects Surveillance and Research. Am J Med Genet C Semin Med Genet. 2011 Nov 15;157C(4):274-87. [PMC free article: PMC4457318] [PubMed: 22002822]10.Baken L, Rousian M, Kompanje EJ, Koning AH, van der Spek PJ, Steegers EA, Exalto N. Diagnostic techniques and criteria for first-trimester conjoined twin documentation: a review of the literature illustrated by three recent cases. Obstet Gynecol Surv. 2013 Nov;68(11):743-52. [PubMed: 24193193]11.Kobets A, Fullerton J, Lober RM, Gordon C, Machado HR, Lee SK, Cohen A, Walker ML. Characterizing the Venous Anatomy of Craniopagus Twins. Neurosurgery. 2025 Jul 07; [PubMed: 40622169]12.Özgen Z, Çataloğlu B, Altun D, Sahillioğlu E, Şeker M, Karaman S, Kosdak Y, Gezgin S, Kahraman D, Öztürk Y, Saçan F, Yildiz E, Dinçer A, Saraç M, Akbal C, Annayev A, Çıtak A, Büyüktaş D, Değerli İ, Kocak M, Tanrıkulu B, Tander B, Ağır H, Özek M, Dirilen E, Kurt K, Seluck M. Anesthetic planning and management for successful separation surgery of pygopagus conjoined twins: a multidisciplinary approach. J Surg Case Rep. 2025 Jun;2025(6):rjaf320. [PMC free article: PMC12165828] [PubMed: 40521041]13.Langert KA, Goshu B, Stubbs EB. Attenuation of experimental autoimmune neuritis with locally administered lovastatin-encapsulating poly(lactic-co-glycolic) acid nanoparticles. J Neurochem. 2017 Jan;140(2):334-346. [PMC free article: PMC5225029] [PubMed: 27861905]14.Melo Â, Dinis R, Portugal A, Sousa AI, Cerveira I. Early prenatal diagnosis of parapagus conjoined twins. Clin Pract. 2018 Mar 28;8(2):1039. [PMC free article: PMC5890089] [PubMed: 29657701]15.Firriolo JM, Chen SA, Wong GB. A Contemporary Approach to Craniopagus Separation. J Craniofac Surg. 2025 Apr 10; [PubMed: 40208958]16.Gašparová P, Ballová Z, Sitáš M, Dosedla E. Prenatal diagnosis of parasitic conjoined twins. Ceska Gynekol. 2025;90(1):44-47. [PubMed: 40117257]17.Mehollin-Ray AR. Prenatal and postnatal radiologic evaluation of conjoined twins. Semin Perinatol. 2018 Oct;42(6):369-380. [PubMed: 30170825]18.Mathew RP, Francis S, Basti RS, Suresh HB, Rajarathnam A, Cunha PD, Rao SV. Conjoined twins - role of imaging and recent advances. J Ultrason. 2017 Dec;17(71):259-266. [PMC free article: PMC5769666] [PubMed: 29375901]19.Kallberg L. The ethics of separating conjoined twins: two arguments against. Theor Med Bioeth. 2018 Feb;39(1):27-56. [PubMed: 29446009]20.Fallon SC, Olutoye OO. The surgical principles of conjoined twin separation. Semin Perinatol. 2018 Oct;42(6):386-392. [PubMed: 30477661]21.Rodman E, Placencia JL. Pharmaceutical considerations with conjoined twins. Semin Perinatol. 2018 Oct;42(6):350-354. [PubMed: 30122608]22.Brizot Mde L, Liao AW, Lopes LM, Silva MM, Krebs V, Schultz R, Zugaib M. [Conjoined twins: prenatal diagnosis, delivery and postnatal outcome]. Rev Bras Ginecol Obstet. 2011 May;33(5):211-8. [PubMed: 21860927]23.Saxena R, Sinha A, Pathak M, Rathod KJ. Conjoined thoracopagus twins: A systematic review of the anomalies and outcome of surgical separation. Afr J Paediatr Surg. 2023 Jul-Sep;20(3):157-165. [PMC free article: PMC10450114] [PubMed: 37470549]24.Lipsky K. Conjoined twins: psychosocial aspects. AORN J. 1982 Jan;35(1):58-61. [PubMed: 6915747]25.Carreker C, De Jong H, Javor V, Fox L, Jacome J, Johns C, Springmeyer K, Davies J. Family support and media considerations with conjoined twins. Semin Perinatol. 2018 Oct;42(6):393-401. [PubMed: 30201416]26.Harper RG, Kenigsberg K, Sia CG, Horn D, Stern D, Bongiovi V. Xiphopagus conjoined twins: a 300-year review of the obstetric, morphopathologic, neonatal, and surgical parameters. Am J Obstet Gynecol. 1980 Jul 01;137(5):617-29. [PubMed: 6992583]27.Thomas A, Johnson K, Placencia FX. An ethically-justifiable, practical approach to decision-making surrounding conjoined-twin separation. Semin Perinatol. 2018 Oct;42(6):381-385. [PMC free article: PMC6786881] [PubMed: 30217664]28.C Sager E, Thomas A, C Sundgren N. Conjoined twins: Pre-birth management, changes to NRP, and transport. Semin Perinatol. 2018 Oct;42(6):321-328. [PubMed: 30150080]29.Bergner EM, Gollins L, Massieu LA, Hurst N, Hair AB. Nutritional considerations in the care of conjoined twins. Semin Perinatol. 2018 Oct;42(6):355-360. [PubMed: 30197028]30.Parmekar S, McMullen L, Washington C, Arnold JL. Role of simulation in preparation for the care of conjoined twins-prenatal preparation to separation. Semin Perinatol. 2018 Oct;42(6):329-339. [PubMed: 30144953]31.Tannuri AC, Batatinha JA, Velhote MC, Tannuri U. Conjoined twins: twenty years' experience at a reference center in Brazil. Clinics (Sao Paulo). 2013;68(3):371-7. [PMC free article: PMC3611880] [PubMed: 23644858]32.Willobee BA, Mulder M, Perez EA, Hogan AR, Brady AC, Sola JE, Thorson CM. Predictors of in-hospital mortality in newborn conjoined twins. Surgery. 2019 Nov;166(5):854-860. [PMC free article: PMC10353765] [PubMed: 31402130]33.Luton A, Estrada N, Barrientez K, McGinnis J, Pitlik J, Carter A, Davenport L, Davies J. Nursing considerations and interdisciplinary coordination in the care of conjoined twins. Semin Perinatol. 2018 Oct;42(6):340-349. [PubMed: 30185382]

Disclosure: Abhinav Pal declares no relevant financial relationships with ineligible companies.

Disclosure: Freddy Montero declares no relevant financial relationships with ineligible companies.

Copyright © 2025, StatPearls Publishing LLC.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

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• Cite this PagePal A, Montero FJ. Conjoined Twins. [Updated 2025 Dec 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.

In this Page

• Continuing Education Activity
• Introduction
• Etiology
• Epidemiology
• Pathophysiology
• History and Physical
• Evaluation
• Treatment / Management
• Differential Diagnosis
• Prognosis
• Complications
• Deterrence and Patient Education
• Pearls and Other Issues
• Enhancing Healthcare Team Outcomes
• Review Questions
• References

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