El embarazo gemelar monocorial desde la perspectiva de la teoría de la complejidad / Monochorionic twin pregnancy from the perspective of the theory of complexity

En la práctica, es muy frecuente asociar las gestaciones gemelares monocoriales (MC) con embarazos complejos o complicados, utilizando ambos términos en forma intercambiable. Sin embargo, no lo son; el dinamismo es protagonista en los sistemas complejos, pero no en los complicados. Para entender a la embarazada con una gestación MC como un sistema complejo, primero se desarrollarán las características principales de los embarazos MC; su placenta es una de las principales responsables de los problemas. Luego se analizará el embarazo MC desde la complejidad, identificando las características del sistema y sus complicaciones como propiedades emergentes.

In practice, it is very common to associate monochorionic (MC) twin pregnancies with complex or complicated pregnancies, using both terms interchangeably. However, these are not synonyms; dynamism is the protagonist in complex systems, but not in complicated ones. In order to understand a MC pregnancy as a complex system, it is necessary to first look into its main characteristics. The placenta is one of the main sources of problems. Then, the MC pregnancy has to be analyzed from the perspective of complexity, identifying the system characteristics and its complications as emergent properties.

Actualización del diagnóstico prenatal y cirugía fetal del mielomeningocele / Update on prenatal diagnosis and fetal surgery for myelomeningocele

A partir del estudio seminal Management of Myelomeningocele Study en el año 2011, el cual demostró que la reparación prenatal del defecto del mielomeningocele antes de la semana 26 mejoraba los resultados neurológicos, la cirugía fetal fue incorporada dentro de las opciones de estándar de cuidado. Así, el diagnóstico prenatal del mielomeningocele dentro de la ventana terapéutica se convirtió en un objetivo obligatorio y, por ello, se intensificó la investigación de estrategias de tamizaje, sobre todo, en el primer trimestre. Además, se desarrollaron distintas técnicas de cirugía fetal para mejorar los resultados neurológicos y disminuir los riesgos maternos. El objetivo de la siguiente revisión es actualizar los avances en tamizaje y diagnóstico prenatal en el primer y segundo trimestre, y en cirugía fetal abierta y fetoscópica del mielomeningocel

A seminal study titled Management of Myelomeningocele Study, from 2011, demonstrated that prenatal myelomeningocele defect repaired before 26 weeks of gestation improved neurological outcomes; based on this study, fetal surgery was introduced as a standard of care alternative. Thus, prenatal myelomeningocele diagnosis within the therapeutic window became a mandatory goal; therefore, research efforts on screening strategies were intensified, especially in the first trimester. In addition, different fetal surgery techniques were developed to improve neurological outcomes and reduce maternal risks. The objective of this review is to provide an update on the advances in prenatal screening and diagnosis during the first and second trimesters, and in open and fetoscopic fetal surgery for myelomeningocele

Update on prenatal diagnosis and fetal surgery for myelomeningocele. / Actualización del diagnóstico prenatal y cirugía fetal del mielomeningocele.

A seminal study titled Management of Myelomeningocele Study, from 2011, demonstrated that prenatal myelomeningocele defect repaired before 26 weeks of gestation improved neurological outcomes; based on this study, fetal surgery was introduced as a standard of care alternative. Thus, prenatal myelomeningocele diagnosis within the therapeutic window became a mandatory goal; therefore, research efforts on screening strategies were intensified, especially in the first trimester. In addition, different fetal surgery techniques were developed to improve neurological outcomes and reduce maternal risks. The objective of this review is to provide an update on the advances in prenatal screening and diagnosis during the first and second trimesters, and in open and fetoscopic fetal surgery for myelomeningocele.

A partir del estudio seminal Management of Myelomeningocele Study en el año 2011, el cual demostró que la reparación prenatal del defecto del mielomeningocele antes de la semana 26 mejoraba los resultados neurológicos, la cirugía fetal fue incorporada dentro de las opciones de estándar de cuidado. Así, el diagnóstico prenatal del mielomeningocele dentro de la ventana terapéutica se convirtió en un objetivo obligatorio y, por ello, se intensificó la investigación de estrategias de tamizaje, sobre todo, en el primer trimestre. Además, se desarrollaron distintas técnicas de cirugía fetal para mejorar los resultados neurológicos y disminuir los riesgos maternos. El objetivo de la siguiente revisión es actualizar los avances en tamizaje y diagnóstico prenatal en el primer y segundo trimestre, y en cirugía fetal abierta y fetoscópica del mielomeningocele.

Cardiopatías congénitas, diagnóstico y manejo prenatal / Congenital heart disease, prenatal diagnosis and management

Dentro de las malformaciones congénitas, las cardiopatías son las anomalías más frecuentes y se asocian a una elevada morbimortalidad perinatal y a largo plazo. El objetivo de esta actualización es revisar la tasa de detección prenatal, las características del tamizaje a lo largo del embarazo, tanto en el primero como en el segundo trimestre, las indicaciones de ecocardiografía avanzada, y establecer un algoritmo de manejo ante el diagnóstico prenatal de una cardiopatía congénita. Se discutirán los estudios invasivos y no invasivos que pueden realizarse y el seguimiento obstétrico. Finalmente, se revisarán las características principales de la terapia fetal en anomalías cardíacas, tanto intervencionismo cardíaco como el tratamiento intrauterino de las arritmias.

Among congenital malformations, heart defects are the most common type of anomaly, and these are associated with a high perinatal, long-term morbidity and mortality. The objective of this update was to review the rate of prenatal detection, screening characteristics throughout the pregnancy, in both the first and second trimesters, indications for advanced echocardiography, and to establish a management algorithm in case of prenatal diagnosis of a congenital heart disease. Potential invasive and non-invasive tests and obstetric follow-up will be discussed here. Finally, the main characteristics of fetal therapy in heart anomalies will be reviewed, both cardiac interventions and intrauterine treatment of arrhythmias.

[Advances in fetal therapy]. / Avances en terapia fetal.

Fetal therapy may be needed in certain clinical settings with the primary indication to improve perinatal or long-term outcomes for the fetus or the newborn. It can be classified in pharmacotherapy or non-invasive, and invasive therapy. The first one involves the administration of drugs to the mother that cross the placenta and get to the fetus, a non-invasive approach. On the other hand, invasive therapy involves the use of needles, fetoscopic treatments or open fetal surgery. This review provides an update of non-invasive and invasive fetal therapy.

Avances en terapia fetal / [Advances in fetal therapy].

Fetal therapy may be needed in certain clinical settings with the primary indication to improve perinatal or long-term outcomes for the fetus or the newborn. It can be classified in pharmacotherapy or non-invasive, and invasive therapy. The first one involves the administration of drugs to the mother that cross the placenta and get to the fetus, a non-invasive approach. On the other hand, invasive therapy involves the use of needles, fetoscopic treatments or open fetal surgery. This review provides an update of non-invasive and invasive fetal therapy.

Foetal aortic valvuloplasty: experience of five cases.

OBJECTIVES: Foetal aortic valvuloplasty has been proposed as a strategy to improve left heart growth and function in foetuses with severe aortic stenosis at risk of progression to hypoplastic left heart syndrome. We report our experience with this intervention. METHODS AND RESULTS: Between 2005 and 2010, five foetuses with aortic stenosis and at risk of progression to hypoplastic left heart syndrome underwent ultrasound-guided percutaneous foetal aortic valvuloplasty. There were no associated maternal complications or foetal demise. In one case, the pregnancy was terminated a couple of weeks after the intervention, one foetus evolved to hypoplastic left heart syndrome, and three did not. CONCLUSIONS: Foetal aortic valvuloplasty seems to be a safe and feasible procedure. It has been reported that it has the potential to prevent progression to hypoplastic left heart syndrome in selected foetuses with severe aortic stenosis. Further investigation regarding physiological and clinical aspects of this disease both prenatally and postnatally will probably allow to improve therapeutic strategies and clinical outcome.

Monoamniotic twin pregnancy discordant for lethal open cranial defect: management dilemmas.

OBJECTIVE: To report the sonographic findings, prenatal courses, and management options in four cases of monoamniotic twin pregnancy complicated by a discordant, lethal open cranial vault defect. METHODS: Cases were collected from two Latin American fetal medicine referral centers after the sonographic detection of a monoamniotic twin pregnancy in which one fetus was structurally normal and the other had a lethal open cranial vault defect. Three abnormal fetuses had acrania-anencephaly sequence and one had a large occipital encephalocele. The diagnosis was confirmed at referral, at which time umbilical cord entanglement was also diagnosed with color Doppler ultrasound in all cases. RESULTS: Two cases were managed with selective termination, one of which required referral to a fetal surgery center abroad because this option was illegal in Chile. The other case underwent radiofrequency ablation of the fetal intra-abdominal umbilical vessels after the corresponding ethics and legal committees approved the procedure. In both cases, the non-anomalous twin was born after 35 weeks and had no perinatal complications. Expectant management was performed in the other two cases, resulting in the death of the normal twin at 25 weeks. CONCLUSIONS: Monoamniotic twin pregnancy discordant for severe cranial vault defect is a serious condition with a high risk of fetal demise of the structurally normal fetus. Our experience, although limited, suggests that aggressive management with selective termination of the abnormal twin and transection of its umbilical cord in these cases may prevent the demise of the structurally normal co-twin.

Prenatal diagnosis of skeletal dysplasias: contribution of three-dimensional computed tomography.

OBJECTIVE: To describe the contribution of 3-dimensional computed tomography (3D-CT) in the prenatal diagnosis of skeletal dysplasias (SD) in a cohort of patients with inconclusive diagnosis by ultrasound (US). METHODS: Between May 2007 and February 2010, six pregnant women with suspected fetal SD on US examination but with no specific diagnosis were studied with 3D-CT. The images were evaluated by a multidisciplinary team who proposed a likely diagnosis. Further postnatal workup included clinical and radiological evaluation in all cases. Prenatal and postnatal diagnoses were compared. RESULTS: The use of 3D-CT provided a precise diagnosis confirmed postnatally in 5/6 patients. These included osteogenesis imperfecta type II (n = 2), osteogenesis imperfecta type III (n = 1), chondrodysplasia punctata (n = 1) and thanatophoric dysplasia type I (n = 1). A precise diagnosis could not be made in 1 case - either pre- or postnatally. CONCLUSION: Prenatal 3D-CT contributed to the diagnosis of the specific fetal SD in the majority of these cases. 3D-CT may have a complementary role to US where fetal SD is suspected, but no specific diagnosis can be made using US alone. Further studies on clinical performance and risk-benefit analysis are needed.

Tratamiento extrauterino intraparto: manejo del recién nacido con síndrome de obstrucción congénita de la vía aérea superior: informe de un caso / Ex utero intrapartum treatment: management of neonatal congenital high airway obstruction syndrome: case report

En años recientes, el tratamiento extrauterino intraparto, que consiste en la intubación fetal extrauterina previa al nacimiento, ha adquirido relevancia en la reducción de la morbimortalidad de neonatos afectados por el síndrome de obstrucción congénita de la vía aérea superior. Caso clínico. Presentamos una madre con un feto de 22 semanas de gestación y diagnóstico de estenosis de la vía aérea, que anticipaba déficit ventilatorio fetal extraparto y derivó en la aplicación del tratamiento extrauterino intraparto para garantizar el intercambio gaseoso fetal en el momento del nacimiento. Conclusiones. La práctica oportuna del procedimiento extrauterino intraparto logró en este caso, mediante el control de los factores maternos y fetales que pudieran afectar la circulación feto-placentaria, el nacimiento de un niño cuya evolución inmediata y a largo plazo fue exitosa con desarrollo deuna vida normal.

In recent years, the ex utero intrapartum treatment (EXIT), that involves extrauterine fetal intubation prior to delivery, has become relevant for the reduction in morbidity and mortality of neonates affected by congenital high airway obstructionsyndrome (CHAOS). Clinical case. We report the case of the mother of an unborn child at pregnancy week 22, who was diagnosed a congenitalpulmonary malformation that precluded intrapartum fetal circulatory deficit and resulted in the conduction of an EXITtechnique, with the aim of ensuring fetal blood gas exchange at the time of delivery. Conclusions. A timely practice of the EXIT technique resulted, by monitoring both maternal and fetal factors that might affect fetoplacental circulation, in the birth of a child whoseimmediate and long-term outcomes were successful allowing the child live a normal life.

Diagnóstico genético prenatal no invasivo de factor Rh y sexo fetal a través del análisis de ADN fetal libre en plasma materno / Non invasive prenatal genetic diagnosis of fetal RhD and sex through the analysis of free fetal DNA in maternal plasma

Introducción. El análisis de ADN fetal libre en plasma materno permite estudiar material genético del feto sin realizar procedimientos invasivos sobre el embarazo. Objetivo. Evaluar la factibilidad y desempeño diagnóstico de la determinación del genotipo RhD y del sexo fetal a través del análisis molecularde ADN fetal libre en plasma de embarazadas mediante reactivos de uso general en biología molecular. Material y métodos. Se extrajeron 109 muestras de sangre de embarazadas. Se amplificó por PCR en tiempo real una porción del gen RhD para el diagnóstico de Rh fetal en mujeres Rh-negativas y una región del cromosoma Y para la determinación del sexo fetal. Ambos datos se compararon con los resultados neonatales. Resultados. Respecto de las 109 muestras, 26 embarazos están en curso, 4 tuvieron abortos espontáneos y en 3 se perdió el seguimiento. De las 76 restantes con resultado neonatal, en 65 mujeres Rh-negativas se efectuó el análisis del gen RhD para la determinación del Rh fetal y en 66 muestras se realizó la determinación del sexo fetal. Quince muestras fueron no concluyentes y se excluyeron del análisis. El valor predictivo para RhD-positivo y RhD-negativo fue 85 por ciento y 90%, respectivamente, mientras que la predicción de sexo masculino fue 94,3 por ciento y la del femenino 95 por ciento. Conclusiones. La determinación no invasiva del RhD y sexo fetal en plasma materno mediante reactivos de uso general en biología molecular fue factible en la mayoría de los casos, con un desempeño diagnóstico similar al descripto en la bibliografía.

Introduction. The analysis of free fetal DNA in maternal plasma allows the assessment of fetal genetic material avoiding the necessity of invasive procedures during pregnancy. Objective. To evaluate the feasibility and the diagnostic performance of fetal sex and fetal RhD detection through the analysis of free fetal DNA in maternal plasma using standard reagents in molecular biology. Material and methods. A hundred and nine blood samples of pregnant women were obtained obtained. Amplification by real time PCR a sequence from the RhD gene in Rh negative patients and a Y-chromosome sequence, for the diagnosis of fetal Rh and sex respectively, were performed. Results were compared with neonatal outcomes. Results. From the 109 samples, 26 are still ongoing, 4 ended in spontaneous abortions and in 3 were lost to follow up. From the remaining 76 samples with neonatal result, the determination of fetal Rh from the RhD gene was performed in 65 Rh negative women, whereas in 66 samples the fetal sex analysis was evaluated. Overall, 15 samples had not conclusive results and were excluded from the study. The predictive values for RhD positive and negative were 85 percent and 90 percent, respectively, while the prediction for male sex was 94.3 percent and for female sex 95 percent. Conclusion. The non invasive determination of fetal RhD and sex in maternal plasma using standard reagents in molecular biology was feasible in the majority of the samples, with a diagnostic performance similar to the reported in the literature.

Manejo interdisciplinario de un quilotórax congénito complicado con hidropesía fetal / Interdisciplinary management of a congenital chylotorax complicated with hydrops fetalis

La evolución natural del quilotórax congénito complicadocon hidropesía fetal se asocia con alta mortalidadperinatal. El objetivo de la presente comunicaciónes describir una potencial alternativa terapéuticaintrauterina en el manejo perinatal de estapatología fetal grave. Se describe el caso de unembarazo de 27 semanas con una hidropesía fetalpor quilotórax congénito diagnosticado a travésdel análisis del líquido pleural fetal. Ante la progresióndel cuadro se insertó a las 29 semanas deembarazo un catéter de derivación pleuroamnióticacon guía ecográfica, con reversión de la hidropesíafetal y del hidrotórax. A las 32 semanas se constatóla expulsión del catéter a la cavidad amniótica y,ante la recurrencia del hidrotórax, se finalizó elembarazo. Se realizó una toracocentesis fetal inmediatamenteantes de la cesárea. Se extrajo un reciénnacido de sexo femenino de 2.160 gramos, se efectuóintubación endotraqueal electiva en sala departos. Se colocaron tubos de drenaje pleural. Elcuadro era compatible con hipoplasia pulmonar,recibió surfactante, asistencia respiratoria mecánicapor 3 semanas y alimentación parenteral y luegoenteral con leche adecuada por su enfermedad debase. La evolución fue favorable, con alta al mes devida y control normal al año. El manejo interdisciplinariode una patología fetal y neonatal grave apartir del diagnóstico prenatal, como el hidrotóraxfetal primario complicado con hidropesía fetal, permitiríaoptimizar los resultados perinatales a travésde estrategias terapéuticas prenatales, perinatales,y neonatales.Palabras clave: quilotórax; hidrotórax fetal, derivaciónpleuroamniótica, hidropesía fetal.

Intrafetal alcohol chemosclerosis of acardiac twins: a multicenter experience.

OBJECTIVE: To report a multicenter experience with intrafetal alcohol chemosclerosis in the treatment of pregnancies complicated with the twin reversed arterial perfusion sequence. METHODS: Percutaneous injection of 1- 2 ml of absolute alcohol into the intra-abdominal segment of the single umbilical artery was performed in 8 acardiac twins. Cases were collected from 5 centers following a standardized protocol. The procedure was performed under continuous ultrasound control, using color Doppler ultrasound to identify the main arterial vessel entering the abdomen of the acardiac twin and passing a 20-gauge spinal needle into the targeted vessel. Intraoperative and short-term complications were noted. Information on pregnancy outcome was obtained by reviewing the medical records or contacting the referring obstetrician. RESULT: At the time of the procedure, the acardiac twin was severely hydropic and the size exceeded 70% of the size of the pump twin in all cases. In addition, there were associated complications in all the pump twins including polyhydramnios in 8 cases (100%), cardiac insufficiency in 5 (63%), and fetal growth restriction in 1 (13%). The procedure was performed at a mean gestational age of 24.7 weeks (range 20-32), and it was technically successful in all cases. However, it was complicated with thrombosis of the umbilical vessels of the pump twin in 1 case, and transient bradycardia in 2 others. These 3 pump twins died in utero as a result of the procedure. The other 5 procedures were technically and clinically successful, resulting in an overall survival rate of 63%. In 4 pregnancies, the pump twin was delivered after 35 weeks and had no neonatal complications. CONCLUSIONS: Intrafetal alcohol chemosclerosis is a simple procedure that can be performed in any fetal medicine center around the world to stop the vascular supply to acardiac twins. However, the main concern with this technique is intravascular transfer of the ablative material to the circulation of the pump twin. The use of this technique should therefore be restricted to those pregnancies with poor prognostic factors and in countries where more sophisticated methods for the treatment of this condition are not available.