Conjoined twins pregnancies: experience with 36 cases from a single center

Phenotypically Discordant Anomalies in Conjoined Twins: Quirks of Nature Governed by Molecular Pathways?

A multitude of additional anomalies can be observed in virtually all types of symmetrical conjoined twins. These concomitant defects can be divided into different dysmorphological patterns. Some of these patterns reveal their etiological origin through their topographical location. The so-called shared anomalies are traceable to embryological adjustments and directly linked to the conjoined-twinning mechanism itself, inherently located within the boundaries of the coalescence area. In contrast, discordant patterns are anomalies present in only one of the twin members, intrinsically distant from the area of union. These dysmorphological entities are much more difficult to place in a developmental perspective, as it is presumed that conjoined twins share identical intra-uterine environments and intra-embryonic molecular and genetic footprints. However, their existence testifies that certain developmental fields and their respective developmental pathways take different routes in members of conjoined twins. This observation remains a poorly understood phenomenon. This article describes 69 cases of external discordant patterns within different types of otherwise symmetrical mono-umbilical conjoined twins and places them in a developmental perspective and a molecular framework. Gaining insights into the phenotypes and underlying (biochemical) mechanisms could potentially pave the way and generate novel etiological visions in the formation of conjoined twins itself.

Conjoined twins: an obstetrician's guide to prenatal care and delivery management

OBJECTIVE

Obstetricians infrequently encounter conjoined twins. Much of the clinical care literature focuses on postnatal management from a neonatology and pediatric surgery perspective; guidance on obstetrical management is limited. We outline steps for prenatal evaluation, obstetrical care, and delivery planning.

STUDY DESIGN

Experiences with two cases of conjoined twins.

RESULTS

We identified several points throughout the planning, delivery, and postnatal process that are important to highlight for optimizing clinical outcome, patient safety, and parental satisfaction.

CONCLUSION

After diagnosis, patients should be referred to a center experienced in the management of conjoined twins. Specialists in fields including maternal fetal medicine, pediatric surgery, neonatology, and radiology play a vital role in the management of these patients. Early referral allows for timely family counseling and decision-making. Prenatal evaluation beyond the first trimester should include a detailed ultrasound, fetal echocardiogram, and fetal MRI. 3D printed life-sized models can improve delivery planning and patient understanding.

Successful dilation and evacuation for second trimester conjoined twin: a case report and review of the literature

Background

Conjoined twins are a rare clinical event occurring in about 1 per 250,000 live births. Though the prognosis of conjoined twins is generally low, there is limited evidence as to the optimal method of pregnancy termination, particularly in cases of advanced gestational age. We report a successful dilation and evacuation (D&E) done for conjoined twins at 22 weeks of gestation.

Case presentation

A 20-year-old primigravid woman was diagnosed with a conjoined, thoraco-omphalopagus twin pregnancy after undergoing a detailed two-dimensional (2D) fetal ultrasound anatomic scanning. Assessment and counseling were done by a multidisciplinary team. The team discussed the prognosis and options of management with the patient. The patient opted for termination of pregnancy. Different options of termination were discussed and the patient consented for D&E, with the possibility of reverting to hysterotomy in case intraoperative difficulty was encountered. A 2-day cervical preparation followed by D&E was done under spinal anesthesia and ultrasound guidance.

Conclusion

In this patient, D&E was done successfully without complications. Adequate cervical preparation, pain control, and ultrasound guidance during the procedure are critical for optimal outcomes. A literature review of methods of pregnancy termination for conjoined twins in the second trimester revealed 75% delivered vaginally through medical induction while 18% underwent cesarean section. Only one other report described successful D&E for conjoined twins after 20 weeks. D&E can be safely performed for carefully selected cases of conjoined twins beyond 20 weeks’ gestations avoiding the need for induction or hysterotomy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13256-021-02815-4.

The Outcomes of Surgical Separation in Thoracopagus Twins with Conjoined Hearts: An Analysis of the Literature

We sought to perform a comprehensive review of reported cases of conjoined thoracopagus twins with cardiovascular conjunction to determine the overall survival after separation and factors that might be associated with survival. We performed a systematic review of cases of thoracopagus twins with conjoined cardiovascular systems reported in the English medical literature using Embase, PubMed, Web of Science, and Scopus. We employed standard statistical methods to analyze differences among groups. We identified 102 unique cases of thoracopagus twins (69% female) with some degree of cardiovascular conjunction who had undergone surgical separation. We identified 6 distinct types of cardiovascular union. Median age was 47 days (IQR 12, 120). Survival to at least hospital discharge occurred in 51% (105/204). Median age at separation was lower in emergent (9 days, IQR 1, 25) versus elective cases (93 days, IQR 49, 180) (p < 0.0001). Survival to hospital discharge was higher in those who underwent elective separation (70%, 93/132 total children versus 17%, 12/72) (p < 0.0001). Survival was associated with the type of cardiovascular union (p < 0.0001). The separation of thoracopagus twins with cardiovascular conjunction is higher than expected. Increased survival is associated with elective separation, older age, and shared pericardium only. These findings suggest survival could be improved with better delineation of degree of union and delayed separation.

Fetal Diagnosis in a Unique Case of Vascular and Cardiac Interdependence in Omphaloischiopagus Conjoined Twins

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Cardiac interdependence in conjoined twins is a rare phenomenon.

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Presence of congenital heart disease may be an important prognostic factor.

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There is high risk of high-output heart failure and pulmonary hypertension in the donor twin.

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If reconstruction is feasible, early separation may improve the chance of survival.

Investigating the use of ultrasonography for the antenatal diagnosis of structural congenital anomalies in low-income and middle-income countries: a systematic review

BACKGROUND

Congenital anomalies are the fifth leading cause of under-5 mortality globally. The greatest burden is faced by those in low/middle-income countries (LMICs), where over 95% of deaths occur. Many of these deaths may be preventable through antenatal diagnosis and early intervention. This systematic literature review investigates the use of antenatal ultrasound to diagnose congenital anomalies and improve the health outcomes of infants in LMICs.

METHODS

A systematic literature review was conducted using three search strings: (1) structural congenital anomalies; (2) LMICs; and (3) antenatal diagnosis. The search was conducted on the following databases: Medline, Embase, PubMed and the Cochrane Library. Title, abstract and full-text screening was undertaken in duplicate by two reviewers independently. Consensus among the wider authorship was sought for discrepancies. The primary analysis focused on the availability and effectiveness of antenatal ultrasound for diagnosing structural congenital anomalies. Secondary outcomes included neonatal morbidity and mortality, termination rates, referral rates for further antenatal care and training level of the ultrasonographer. Relevant policy data were sought.

RESULTS

The search produced 4062 articles; 97 were included in the review. The median percentage of women receiving an antenatal ultrasound examination was 50.0% in African studies and 90.7% in Asian studies (range 6.8%-98.8%). Median detection rates were: 16.7% Africa, 34.3% South America, 34.7% Asia and 47.3% Europe (range 0%-100%). The training level of the ultrasound provider may affect detection rates. Four articles compared morbidity and mortality outcomes, with inconclusive results. Significant variations in termination rates were found (0%-98.3%). No articles addressed referral rates.

CONCLUSION

Antenatal detection of congenital anomalies remains highly variable across LMICs and is particularly low in sub-Saharan Africa. Further research is required to investigate the role of antenatal diagnosis for improving survival from congenital anomalies in LMICs.

PROSPERO REGISTRATION NUMBER

CRD42019105620.

An ethically-justifiable, practical approach to decision-making surrounding conjoined-twin separation

Conjoined twins present unique ethical and palliative care challenges. We present an ethically-justifiable, practical approach to decision-making with regards to surgical separation. These decisions must account for the short- and long-term prognoses for each infant prior to, and after, separation. Other considerations include the benefits and burdens of separation and the family's values and goals. Caregivers should recognize that decisions surrounding separation may be unduly influenced by social biases. The palliative care team aids in developing goals of care to guide decision-making by promoting communication between the medical team and family. They play an important role in supporting families regardless of the planned course of treatment. This support may be social or spiritual in nature, and is promoted by the interdisciplinary structure of the team. Early involvement of palliative care services facilitates complex decision making and can aid in the transition from cure-oriented therapies to support if needed during and after the dying process.

Conjoined twins: Pre-birth management, changes to NRP, and transport

The management of conjoined twins is complex and requires careful preparation. Pre-birth management includes prenatal counseling, which is important due to the overall poor prognosis. In instances of trial of life, the delivery must be tailored to address the anticipated anatomy based on prenatal imaging and anticipated physiology. A multidisciplinary team is essential to anticipate and address the ergonomic challenges and medical issues related to organ fusion, cross-circulation and associated anomalies. There are several suggested modifications to the current Neonatal Resuscitation Program algorithm including modifications to initial assessment, airway management, administration of chest compressions, obtaining emergency access, and medication dosing. Simulation is essential to address challenges, practice Neonatal Resuscitation Program modifications, delineate clear roles during delivery and practice communication. This paper offers a discussion of unique issues associated with delivery of conjoined twins and recommendations on how to approach these challenges based on our experience and available literature.

Dicephalus dipus dibrachius twins: report of an autopsy case

Dicephalus dipus dibrachius twins are a rare form of conjoined twins. An autopsy of conjoined dicephalus twins is reported. The diagnosis was performed during the pregnancy and the family received a judicial authorization for termination of pregnancy. The preterm newborn progressed to cardiac arrest and died following a court order to terminate the pregnancy. The conceptus presented two arms, two legs, a trunk, two heads, and a single umbilical cord. The two spinal columns presented vertebral fusion in the sacral region. The heart exhibited complex malformations. The external genitalia were female; and cytogenetic analysis confirmed female sex (46, XX). This analysis also corroborated the etiopathogenic hypotheses described for this abnormality, which proposes failures in embryonic formation rather than specific chromosomal alterations. Current identification of cases by ultrasound permits medical management and multidisciplinary action with the family, enabling the legal termination of pregnancy.

Imperfect twinning: a clinical and ethical dilemma

OBJECTIVE To review the history, epidemiology, etiology, gestational aspects, diagnosis and prognosis of imperfect twinning. DATA SOURCES Scientific articles were searched in PubMed, SciELO and Lilacs databases, using the descriptors "conjoined twins", "multiple pregnancy", "ultrasound", "magnetic resonance imaging" and "prognosis". The research was not delimited to a specific period of time and was supplemented with bibliographic data from books.

DATA SYNTHESIS

The description of conjoined twins is legendary. The estimated frequency is 1/45,000-200,000 births. These twins are monozygotic, monochorionic and usually monoamniotic. They can be classified by the most prominent fusion site, by the symmetry between the conjoined twins or by the sharing structure. The diagnosis can be performed in the prenatal period or after birth by different techniques, such as ultrasound, magnetic resonance imaging and echocardiography. These tests are of paramount importance for understanding the anatomy of both fetuses/children, as well as for prognosis and surgical plan determination. CONCLUSIONS Although imperfect twinning is a rare condition, the prenatal diagnosis is very important in order to evaluate the fusion site and its complexity. Hence, the evaluation of these children should be multidisciplinary, involving mainly obstetricians, pediatricians and pediatric surgeons. However, some decisions may constitute real ethical dilemmas, in which different points should be discussed and analyzed with the health team and the family.

Undiagnosed xiphopagus twins: a perinatal malady

Conjoined twins are a very rare entity. It is associated with poor survival rate in the presence of vital organ sharing. The entity can be diagnosed as early as the first trimester. A conjoined twin diagnosed late in labor is a malady with high perinatal mortality and maternal morbidity. We present one such case of xiphopagus twins. The management of a case diagnosed late in labor can be very challenging. Such obstetric challenges can be avoided by a meticulous early scan with a high index of suspicion, especially in the absence of separating membrane while scanning multiple pregnancies.