Does Catch-Up Growth Come with a Cognitive Cost? Cognitive Outcome and Growth Patterns in Growth Discordant Identical Twins.

OBJECTIVE: To determine whether it is the magnitude of early postnatal catch-up growth (CUG) in response to fetal growth restriction (FGR) or the FGR itself that negatively impacts cognitive outcome in a model of monochorionic twins discordant for fetal growth. STUDY DESIGN: This analysis is part of the LEMON study, a cohort study including all monochorionic twins with selective FGR aged 3 through 17 years. Growth measurements as documented by our primary care system were collected retrospectively. An age-appropriate neurodevelopmental test was performed generating a full-scale IQ (FSIQ). CUG at 2 years was calculated as (weight [kg] at 2 years-birth weight [kg]). We used a multivariable regression model investigating the association between FSIQ (outcome) and birth weight zscore, gestational age at birth and CUG at 2 years (predictors). Generalized estimating equations accounted for the fact that observations between cotwins are not independent. RESULTS: Median age at follow-up of the 46 included twin pairs was 11 (IQR 8-13) years. Birth weight z score and gestational age at birth were significantly associated with FSIQ, with ß-coefficients of 5.897 (95% CI 3.382-8.411), and 2.589 (95% CI 1.227-3.951), respectively (P < .0001). Adjusted for birth weight z score and gestational age, CUG in the first 2 years after birth was not significantly associated with FSIQ (ß-coefficient 0.108 [95% CI -1.373 to 1.590], P = .886). CONCLUSIONS: Our results, combining detailed growth measurements and neurodevelopmental follow-up in a discordant identical twin model, demonstrate that FGR itself rather than early postnatal CUG has negative consequences for cognitive development.

Monochorionic triplet pregnancy complicated by conjoined twins and early twin-twin transfusion syndrome.

BACKGROUND: The condition of monozygotic, monochorionic triplet fetuses with a pair of conjoined twins is extremely rare (close to one in a million births), presents challenges in its management, and with poor prognosis. CASE REPORT: We report a case of monochorionic diamniotic triplet pregnancy, ultrasound at 14 weeks shows a pair of conjoined thoracopagus fetuses, sharing heart, liver, and umbilical cord, in addition to omphalocele. The third fetus, without malformations, presents signs of early heart failure compatible with twin-to-twin transfusion syndrome. It was decided to carry out expectant management where at 18 weeks, intrauterine death of the three fetuses occurs. An abortion is performed by hysterotomy. CONCLUSIONS: The treatment in these cases is discussed, three management options have been proposed: expectant management, selective reduction of the conjoined fetuses, or termination of the pregnancy. A review of the literature found only 12 cases with this combination of pathologies, in which only 3 normal fetuses (25%) survived and none of the conjoined twins survived. To our knowledge, this case is the first of a monochorionic triplet pregnancy with conjoined fetuses complicated with early twin-to-twin transfusion.

Biocellulose patch technique for fetoscopic repair of open spina bifida in twin pregnancy.

OBJECTIVES: Twin pregnancy is currently an exclusion criterion for prenatal repair of open spina bifida (OSB). The main objective of this study was to report on our experience of treating twin pregnancies with OSB using the skin-over-biocellulose for antenatal fetoscopic repair (SAFER) technique. We also discuss reconsideration of the current exclusion criteria for fetal OSB repair. METHODS: Eight fetuses with OSB from seven twin pregnancies underwent successful prenatal repair. Six pregnancies were dichorionic diamniotic with only one twin affected, and one was monochorionic diamniotic with both twins affected. Percutaneous fetoscopy was performed under CO2 insufflation of the sac of the affected twin. Neurosurgical repair was performed using a biocellulose patch to protect the placode, with the skin sutured to hold the patch in place, with or without a myofascial flap. Neurodevelopment was assessed using the pediatric evaluation of disability inventory scale in babies older than 6 months of adjusted age, whereas the Alberta scale was used for babies younger than 6 months of adjusted age. RESULTS: All 14 fetuses were liveborn and none required additional repair. Gestational age at surgery ranged from 27.3 to 31.1 weeks, and gestational age at birth ranged from 31.6 to 36.0 weeks. Four out of eight affected twins developed sepsis, but had a good recovery. No sequela of prematurity was found in any of the unaffected twins. Short-term neurodevelopment was normal in all evaluated unaffected twins (5/5) and in all but one affected twins (7/8). In the affected group, only one baby required ventriculoperitoneal shunt placement. CONCLUSIONS: Prematurity is frequent after fetal surgery, and the risk is increased in twin pregnancy. Nevertheless, prenatal surgery using the SAFER technique is feasible, with low risk to both twins and their mother when performed by a highly experienced team. Long-term cognitive assessment of the unaffected twin is needed. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Secuencia de perfusión arterial reversa en embarazo gemelar; coagulación de arteria nutricia. Reporte del primer caso en el país / Twin reversed arterial perfusion sequence; coagulation of the umbilical cord. A report on the first case in Uruguay / Seqüência reversa de perfusão arterial na gravidez gemelar; coagulação da artéria nutritiva. Relato do primeiro caso no país

Resumen: La secuencia de perfusión arterial reversa (TRAP) es una complicación muy poco frecuente y grave de los embarazos gemelares monocoriónicos. Generalmente ocurre cuando el corazón de un gemelo de apariencia normal sirve como bomba para uno o más gemelos dismórficos cuya cabeza, órganos torácicos y extremidades superiores no se desarrollan completamente o no se desarrollan en absoluto y, por lo tanto, carecen de actividad cardíaca. La arquitectura placentaria vascular anómala provoca un cambio en el flujo arterial hacia el gemelo acardíaco. Los mecanismos fisiopatológicos exactos que conducen a este fenómeno devastador no se conocen bien. Compartiremos el caso clínico de una paciente de 19 años, cursando un embarazo gemelar monocorial monoamniótico, en que realizamos diagnóstico de TRAPS, y realizamos la coagulación laser de la arteria nutricia del feto acárdico.

Abstract: Twin reversed arterial perfusion sequence (TRAPS) is rather an unusual and severe complication of monochorionic twin pregnancies. It usually occurs when the normal-appearance heart of a twin acts as a pump for one or more dysmorphic twins whose head, thoracic organs and upper limbs fail to totally develop or do not develop at all and thus, have no cardiac activity. The abnormal vascular architecture at the placenta changes the arterial flow towards the acardiac twin. The exact pathophysiological mechanisms that result in this devastating phenomenon are still unknown. The study presents the clinical case of a 19-year- old patient pregnant with monoamniotic, monochorionic twins and a diagnosis of TRAPS, treated by laser coagulation of the acardiac twin's umbilical cord.

Resumo: A seqüência reversa de perfusão arterial (TRAPS) é uma complicação muito rara e grave de gestações gemelares monocoriônicas. Geralmente ocorre quando o coração de um gêmeo de aparência normal serve como uma bomba para um ou mais gêmeos dismórficos cuja cabeça, órgãos torácicos e membros superiores não se desenvolvem totalmente ou não se desenvolvem e, portanto, não têm atividade cardíaca. A arquitetura vascular placentária anormal causa uma mudança no fluxo arterial para o gêmeo acardíaco. Os mecanismos fisiopatológicos exatos que levam a esse fenômeno devastador não são bem compreendidos. Descrevemos o caso clínico de uma paciente de 19 anos, portadora de gestação gemelar monocoriônica monoamniótica, na qual fizemos o diagnóstico de TRAPS e realizamos coagulação a laser da artéria nutritiva do feto acardíaco.

Perinatal Outcome of Selective Intrauterine Growth Restriction in Monochorionic Twins: Evaluation of a Retrospective Cohort in a Developing Country.

Selective intrauterine growth restriction (sIUGR) in monochorionic twin pregnancies is associated with greater morbidity and mortality for both fetuses when compared to singleton and dichorionic pregnancies. This retrospective cohort study aimed to assess the perinatal outcomes of monochorionic twin pregnancies affected by this disorder and conducted expectantly, by analyzing the results according to the end-diastolic flow in the umbilical artery Doppler of the smaller twin (type I: persistently forward/type II: persistently absent or reversed/type III: intermittently absent or reversed). Seventy-five monochorionic diamniotic twin pregnancies with sIUGR were included in this study. sIUGR was defined by estimated fetal weight below the 3rd centile for gestational age, or below the 10th centile, when associated with at least one of the following three criteria: abdominal circumference below the 10th percentile, umbilical artery pulsatility index of the smaller twin above the 95th percentile, or estimated fetal weight discordance of 25% or more. Perinatal outcomes were analyzed from the prenatal period to hospital discharge and included perinatal death, neurological injury, retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), and sepsis. The mortality rate was 1.33% in this cohort. The overall morbidity rate was lower in type I twin pregnancies. In conclusion, this study shows that sIUGR type I has lower morbidity than types II and III in expectant management.

Secuencia de perfusión arterial reversa gemelar (TRAP): reporte de caso clínico de manejo expectante / Twin Reverse Arterial Perfusion Sequence (TRAP): clinical case report of expectant management

TRAP describe la perfusión crónica de un gemelo acardíaco por un gemelo de bomba a través de canales vasculares entrelazados permeables. La secuencia TRAP ocurre en 1 de cada 35.000 nacimientos o en 1 de cada 100 pares de gemelos monocigóticos. Se diagnostica mediante los hallazgos ecográficos de un feto de desarrollo normal y una masa amorfa con frecuencia con partes fetales perceptibles. El Doppler color revela el flujo sanguíneo reverso hacia el gemelo acardíaco dentro de la arteria umbilical lo que lleva a las complicaciones típicas del cuadro. El manejo expectante es razonable en ausencia de características pronósticas deficientes. El propósito de este artículo es revisar los aspectos básicos y el estado actual de esta condición, haciendo énfasis en el diagnóstico y el manejo expectante.

TRAP describes the chronic perfusion of an acardiac twin by a pump twin through permeable interlocking vascular channels. TRAP occurs in 1 in 35,000 births or 1 in 100 pairs of monozygotic twins. It is diagnosed by ultrasound findings of a normally developing fetus and an amorphous mass often with noticeable fetal parts. Color Doppler reveals the reverse blood flow to the acardiac twin within the umbilical artery, leading to typical complications of the condition. Expectant management is reasonable in the absence of poor prognostic characteristics. The purpose of this article is to review the basic aspects and current status of this condition, emphasizing the diagnosis and expectant management.

Restricción de crecimiento intrauterina selectiva tipo III, en gemelos monocoriales: serie de casos y revisión de la literatura / Monochorionic twins with type III selective intrauterine growth restriction: case series and review of the literature

We present four cases of monochorionic twin pregnancies with diagnosis of type III selective intrauterine growth restriction, highlighting the ultrasonographic characteristics (evaluation of the umbilical artery intermittent reverse diastole and the superficial arterio-arterial anastomosis), its evolution during pregnancy and its follow-up during the first month of life.

Se presenta cuatro casos de gestaciones dobles monocoriales afectadas con restricción selectiva de crecimiento de tipo III, con énfasis en las características ecográficas (evaluación de la diástole intermitente reversa de la arteria umbilical y la anastomosis superficial arterio-arterial), evolución durante la gestación y seguimiento hasta el mes de vida.

Secuencia perfusión arterial reversa: Reporte de caso / Twin reversed arterial perfusion sequence: A case report

Twin reversed arterial perfusion sequence is a complication of monochorionic twin pregnancies in which one twin that exhibits lethal anomalies, including acardia, is perfused by the other 'pump' twin via anastomoses between placental arteries. This results in growth and characteristic anomalies of the acardiac twin, and possible heart failure of the pump twin. The exact pathophysiological mechanisms that lead to this devastating phenomenon are not well known. It occurs in about 1% of monochorionic pregnancies and in one out of 35 000 pregnancies. Mortality is usually due to anemia and cardiac complications which can lead to cardiac failure, appear early during pregnancy and cause the death of the pump twin. We report a case of twin reversed arterial perfusion in a 28-year-old patient with 12 weeks monochorionic-diamniotic pregnancy that was referred for absent cardiac activity in one twin. Ultrasound showed an acardiac twin with flow reversal seen in the umbilical artery and umbilical vein and a normal second twin. At 28 weeks an emergency cesarean section was done due preterm labor and transverse situation of the second twin. The first twin was malformed and the second twin died two days later due to complications of prematurity. Accurate prenatal diagnosis of twin reversed arterial perfusion sequence is essential to improve the prognosis of this rare entity.

La secuencia de perfusión arterial reversa en gemelos es una complicación del embarazo gemelar monocoriónico, en la que un gemelo muestra anomalías mortales, incluyendo acardia, y es perfundido por el otro gemelo 'bomba' a través de anastomosis arteriales placentarias, produciendo el crecimiento y las anomalías características del gemelo acárdico, con posible insuficiencia cardíaca en el gemelo bomba. Los mecanismos fisiopatológicos exactos que conducen a este fenómeno devastador no son bien conocidos. Ocurre en aproximadamente 1% de los embarazos monocoriónicos y en 1 de cada 35 000 embarazos. La mortalidad se debe generalmente a anemia y complicaciones cardíacas que pueden conducir a insuficiencia cardíaca, que aparecen temprano durante el embarazo y causan la muerte del gemelo bomba. Se presenta un caso de perfusión arterial reversa en gemelos en paciente de 28 años de edad con un embarazo monocoriónicodiamniótico de 12 semanas quien fue referida por ausencia de actividad cardíaca de uno de los gemelos. La ecografía mostró un gemelo acárdico con reversión de flujo visto en arteria-vena umbilical y un segundo gemelo normal. A las 28 semanas se realizó una cesárea de emergencia debido a parto pretérmino y situación transversa del segundo gemelo, obteniendo el primer gemelo marcadamente malformado y un segundo gemelo vivo que murió dos días después de las complicaciones de la prematuridad. El diagnóstico prenatal exacto secuencia de perfusión arterial reversa en gemelos es esencial para mejorar el pronóstico de esta rara entidad.

Resultados périnatales en embarazos múltiples monocoriales relacionados con las características placentarias / Perinatal outcomes in monochorionic multiple pregnancies regarding the placental characteristics

Resumen OBJETIVO: evaluar las características placentarias de pacientes con embarazos múltiples monocoriales relacionados con el resultado obstétrico en nuestro medio. MATERIAL Y MÉTODO: estudio observacional, descriptivo, prospectivo efectuado en dos instituciones de tercer nivel de atención de Bogotá, Colombia, entre el 31 julio de 2009 y el 31 de agosto de 2011. Evaluación de pacientes con embarazos monocoriales, complicaciones, tratamientos y resultados perinatales; análisis placentarios relacionados con el número y tipo de anastomosis, forma y distancia entre las inserciones de los cordones umbilicales y distribución placentaria. RESULTADOS: se incluyeron 72 embarazos monocoriales: 93.1% correspondieron a embarazos dobles y 86.1% a biamnióticos. De las placentas analizadas, 91.6% tuvieron al menos una anastomosis, específicamente arterioarterial (70.8% de los casos). Se encontraron complicaciones propias de los embarazos monocoriales (41.6%), principalmente: restricción de crecimiento intrauterino selectivo (16 casos) y trasfusión feto-fetal (11 pares de gemelos). Se registró un caso de trasfusión arterial reversa y una muerte fetal (10.7%) provocada por síndrome de transfusión feto-fetal. Entre las causas de morbilidad neonatal se encontraron: taquipnea transitoria del recién nacido y enfermedad de membrana hialina. La mortalidad neonatal fue de 5.4%. No hubo casos de mortalidad materna. CONCLUSIÓN: las características placentarias determinan las complicaciones propias del embarazo monocorial, principalmente: síndrome de trasfusión feto-fetal, restricción de crecimiento intrauterino selectivo. La detección ecográfica prenatal de estas alteraciones es importante para ofrecer consejería y vigilancia gestacional programada.

Abstract OBJECTIVE: To evaluate placental characteristics in monochorionic multiple pregnancies in relation to obstetric outcome in our environment. MATERIAL AND METHOD: Prospective and observational study was made; carried to 31 July 2009 and 31 August 2011 in two high complexity institutions in Bogota, Colombia. We included monochorionic pregnancies for diagnosis of complications, management and perinatal outcome, placental analyzes were evaluated with respect to the number and type of anastomosis, type and distance between umbilical cord insertions and placental sharing. RESULTS: We registrered 72 monochorionic pregnancies, twin pregnancies were 93.1% and 86.1% diamniotic. Placentas analyzed 91.6% had at least one placental anastomosis, arterio-arterial mainly in 70.8% of patients. Complications of monochorionic pregnancies in 41.6% of cases mainly selective growth restriction in 16 cases, followed by twin to twin transfusion in 11 pairs of twins were found. A case of blood transfusion reverse was presented; and a fetal mortality of 10.7% remains the leading cause twin to twin transfusion syndrome. Among the causes of neonatal morbidity transient tachypnea of the newborn, followed by hyaline membrane disease were found. The neonatal mortality rate was 5.4%. There were no maternal deaths. CONCLUSION: Placental characteristics determine the complications of monochorionic pregnancy, as the presence of twin to twin transfusion syndrome selective growth restriction and perinatal outcome. Prenatal sonographic identification of these features is important for prenatal counseling and the frequency of gestational surveillance.

Resultados perinatales en el síndrome de transfusión feto fetal manejados con la técnica de Solomon: revisión de la literatura / Perinatal outcomes in fetal-fetal transfusion syndrome managed with the Solomon technique: literature review

INTRODUCCIÓN: Entre 15-20% de los embarazos gemelares monocoriales biamnióticos se complican con el síndrome de transfusión feto/fetal el cual se asocia con mortalidad superior a 90% y morbilidad significativa en el 50% del gemelo sobreviviente. La técnica láser que coagula la superficie de la placa coriónica entre los principales canales a lo largo del ecuador (técnica de Solomon), se ha sugerido para disminuir la recurrencia, prevenir complicaciones secundarias sin incrementar resultados adversos. Métodos: REVISIÓN de la literatura existente en las bases de datos MEDLINE, EBSCO, OVID, PROQUEST, COCHRANE, Lilacs, SciELO, desde el año 2000 al 2015. Se incluyeron los artículos de revisión e investigaciones originales que compararon la técnica estándar de fotocoagulación secuencial con láser y la técnica de Solomon, el resultado primario fue la reducción de la incidencia Secuencia Anemia Policitemia, recurrencia del síndrome de transfusión feto/fetal, mortalidad perinatal y morbilidad neonatal severa. RESULTADOS: Se encontraron 200 artículos, se seleccionaron seis: 1 ensayo clínico y su análisis secundario, 2 estudios de cohorte retrospectivos, 1 revisión sistemática y un estudio que compara los resultados del neurodesarrollo. Los estudios sugieren una mejoría en la sobrevida de algunos de los fetos con la técnica Solomon, menor recurrencia del síndrome de transfusión feto/fetal y Secuencia Anemia Policitemia, sin la presencia de eventos adversos. CONCLUSIÓN: La técnica de Solomon mejora la sobrevida de algunos gemelos, sin embargo no puede concluirse que haya mejoría en la mortalidad pues los estudios no tienen el suficiente poder para determinarlo.

INTRODUCTION: Between 15 to 20% of monochorionic diamniotic twin pregnancies are complicated by the twin-twin transfusion syndrome. It has a mortality greater than 90% and a significant morbidity, 50% in the surviving twin. The Solomon technique (laser photocoagulation of the main vascular channels of the chorio-nic plate surface along the entire vascular equator) has been suggested to reduce the recurrence, and pre-vent secondary complications without increasing adverse results. METHODS: Systematic review of electronic searches of the literature from 2000 to 2015 (MEDLINE, EBSCO, OVID, PROQUEST, COCHRANE, Lilacs, and SciELO). We included review articles and original investigations comparing the standard photocoagulation technique with laser ablation against the Solomon technique. The primary results were reduction of Anemia Polycythemia Sequence incidence, twin-twin transfusion syndrome recurrence, perinatal mortality and severe neonatal morbidity. RESULTS: Of 200 articles, we selected six: one clinical essay and its secondary analysis, two retrospective cohort studies, one systematic review and a study comparing neurodeve-lopmental outcomes. The studies suggested a survival improvement in some fetuses using the Solomon technique, less twin-twin transfusion syndrome recurrence and Anemia Polycythemia Sequence without the presence of adverse effects. CONCLUSION: Solomon technique improves the survival of some twins, although we cannot conclude there is mortality improvement, because the studies do not have enough power to determine that.

Rapid Resolution of Polyhydramnios Foretells Circulatory Collapse for the Donor Twin in Feto-Fetal Transfusion Syndrome.

Feto-fetal transfusion syndrome is a pathological process unique to diamniotic monochorionic pregnancies. It is the consequence of an unbalanced fetal blood flow through communicating vessels within a shared placenta. When it occurs, a polyuric, hypervolemic recipient twin co-exists with a hypovolemic oliguric donor. The presence of polyhydramnios or oligohydramnios is considered a poor prognostic indicator, whereas normal amniotic fluid volumes indicate a lack of clinically significant twintwin transfusion. In addition, the spontaneous normalization of amniotic fluid volume is usually seen as a favorable prognostic sign. Here, however, we present a case of feto-fetal transfusion in a 31 year-old primigravida at 19 week, in which the spontaneous normalization of amniotic fluid volume in the recipient twin preceded the death of the donor.

Restricción selectiva del crecimiento intrauterino en la gestación gemelar monocorial: diagnóstico y manejo / Selective intrauterine growth restriction in monochorionic-diamniotic twins: diagnosis and management

La Restricción Selectiva del Crecimiento Intrauterino se produce en 10 a 19% de los gemelos monocoriónicos, y se asocia con un aumento importante de la mortalidad y la morbilidad perinatal. La evolución clínica está dada en gran parte por la presencia de anastomosis vaculares y la distribución placentaria asimétrica. Se propuso una clasificación en tres tipos según el Doppler de la arteria umbilical del gemelo más pequeño, la que sé que se correlaciona con distintos comportamientos clínicos y características de la placenta, lo que ayuda en el asesoramiento y conducta obstétrica. Los del tipo I tienen un pronóstico favorable por el resultado perinatal satisfactorio por lo que se recomienda un seguimiento cercano por ecografía y Doppler. Los de tipo II tienen un mal pronóstico y el tipo III un pronóstico intermedio e impredecible. En estos dos últimos se puede realizar un manejo expectante hasta que se observe deterioro del feto pequeño, considerando la posibilidad de la coagulación con láser o la oclusión del cordón (feticidio selectivo). Ambas conductas aparentemente aumentan las posibilidades de supervivencia del feto de peso normal.

Selective intrauterine growth restriction occurs in 10-19% of monochorionic twins, and is associated with increased mortality important and perinatal morbidity. The clinical course is given largely by the presence of placental vascular anastomosis and asymmetric distribution. It classified into three types according to the proposed Doppler umbilical artery smaller twin, the one that correlates with different clinical behaviors and characteristics of the placenta, which helps in counseling and obstetric conduct. The type I have a favorable prognosis for satisfactory perinatal outcome so closely monitored by ultrasound and Doppler is recommended. The type II has a poor prognosis and type III intermediate and unpredictable prognosis. In these last two you can make an expectant management until deterioration of the small fetus is observed, considering laser coagulation or cord occlusion (selective feticide). Both behaviors appear to increase the chances of survival of the fetus of normal weight.

Restricción selectiva del crecimiento intrauterino (RCIUs)

La restricción de crecimiento intrauterino selectivo es una complicación de la gestación monocorial poco frecuente, caracterizada por el déficit de crecimiento de uno de los fetos, fenómeno que se explica principalmente por la distribución asimétrica del territorio placentario. La influencia de las anastomosis vasculares determina el tipo de evolución de cada caso. El estudio Doppler de la arteria umbilical del feto con restricción es la mejor maneja de valorar el comportamiento clínico y la posible evolución, con la finalidad de minimizar el riesgo de muerte intraútero y el daño cerebral que podrían sufrir ambos fetos.

Selective intrauterine growth restriction is arare complication of monochorionic gestation characterized by growth deficiency of one fetus, phenomenon due to asymmetric distribution of the placental territory; the influence of the vascular anastomosis determines the type of evolution in each case. Umbilical artery Doppler study ofthe restricted fetus determines the clinical status and possible outcome in order to minimize risk of intrauterine death and brain da mage in both fetuses.

Selective fetoscopic laser photocoagulation of superficial placental anastomoses for the treatment of severe twin-twin transfusion syndrome

OBJECTIVE: To report our initial institutional experience with fetoscopic laser photocoagulation of placental anastomoses in severe twin-twin transfusion syndrome using a 1.0 mm endoscope. METHODS: Between July 2006 and June 2008, 19 monochorionic diamniotic twin pregnancies complicated by severe TTTS (Quintero stages III and IV) underwent fetoscopic laser therapy. Perinatal data were prospectively collected and compared according to the Quintero stages. RESULTS: Nine patients were classified as stage III and ten as stage IV. The Mean gestational ages at diagnosis and procedure were 20 (range: 17-25) and 22.0 (range: 19.0-26.0) weeks, respectively, with no statistical difference between the two groups. Preterm premature rupture of the membranes occurred in two cases (10.5 percent), and spontaneous preterm delivery in eight (42.1 percent). Overall mean gestational age at delivery was 32.1 (range: 26.0-38.0) weeks. Prematurity was more severe in stage IV patients (p<0.01). Among all cases, the overall survival rate was 52.6 percent, and the percentages of pregnancies with survival of both babies and at least one twin were 26.3 percent and 78.9 percent, respectively. In the case of stage III patients, the overall survival rate was 61.1 percent. Of the stage III pregnancies, 33.3 percent resulted in both babies surviving, and 88.9 percent of these pregnancies resulted in at least one surviving twin. For stage IV, as the corresponding statistics were 45.0 percent, 20.0 percent and 70.0 percent respectively. CONCLUSIONS: Our initial institutional experience with 1.0 mm fetoscopic laser therapy for severe TTTS showed results similar to those reported in the literature for larger endoscopes.