A systematic review of early intrauterine intervention at 12 + 0 to 16 + 6 weeks in twin reversed arterial perfusion sequence

There is some evidence that in twin reversed arterial perfusion sequence, intervention at early gestational age could prevent a spontaneous death of the pump twin, achieving a better global survival.

OBJECTIVE

To review the perinatal outcomes of early intervention in pregnancies complicated by twin reversed arterial perfusion (TRAP) sequence.

STUDY DESIGN

A comprehensive search from inception to December 2022 was conducted on databases including MEDLINE, EMBASE, Cochrane Library and LILACS. All studies that reported intervention in twin or triplet pregnancy complicated with TRAP sequence at 12 + 0 to 16 + 6 weeks of gestation were eligible. A descriptive and bivariate analysis was performed.

RESULTS

Out of the 222 full-text articles, 44 studies reporting 108 cases of early intervention in TRAP sequence were included. A successful procedure was achieved in 105 (95.5 %) interventions: 89 (94.7 %) among twin pregnancies and 16(100 %) among triplet pregnancies. An overall livebirth rate was achieved in 75 patients (70.8 %): intrafetal laser group 55 (73.3 %), radiofrequency 10 (76.9 %) and endoscopic laser 3 (75.0 %). The median gestational age at delivery was 38 + 0 (37 + 4 - 39 + 4) weeks. The median treatment-delivery interval was 23 + 2 (IQR, 21 + 0-25 + 6) weeks. The most frequent adverse outcomes reported were preterm labor in 7 (13.7 %) patients. There were no severe adverse maternal outcomes.

CONCLUSION

Early intervention with intrafetal laser and radiofrequency in TRAP sequence achieves a livebirth rate of the pump twin of about 75 %.

Outcome of Monochorionic Diamniotic Twins with Twin Reversed Arterial Perfusion Sequence: Interstitial Laser versus Endoscopic Cord Occlusion

Twin reversed arterial perfusion sequence (TRAP) is a rare complication of monochorionic twins (MC). This study aimed to describe and compare the short- and long-term outcomes of MC pregnancies with the TRAP sequence treated with two different techniques: interstitial fetal laser (IFL) (n = 22) versus endoscopic cord occlusion (CO) (n = 24). The study population included 46 MC pregnancies with TRAP. Pregnancy loss within 2 weeks after the procedure occurred in 27% of cases (6/22) in the group treated with IFL and in 8% of cases (2/24) in the group treated with CO. The survival rate of the pump twin was 73% (16/22) in the IFL group and 83% (20/24) in the group treated with CO. The median gestational age at birth was 38 weeks in the group treated with IFL and 35 weeks in the group treated with CO. The rate of preterm birth before 34 weeks was 12.5% (2/16) in the group treated with IFL and 32% (7/22) in the group treated with CO. In the group treated with IFL, there were no cases of neurological disabilities reported by the parents compared to three cases in the CO group. IFL is associated with a higher risk of early pregnancy loss; however, if the pregnancy progresses, it is associated with lower risks of preterm birth and neurological disabilities in the survivors.

Outcomes of fetal reduction versus expectant management in dichorionic triamniotic triplets

OBJECTIVE

To compare the outcomes of dichorionic triamniotic (DCTA) triplets who underwent fetal reduction (FR) to singletons or twins with those managed expectantly.

METHODS

We conducted a retrospective study of DCTA triplets with three living fetuses at 11-14 weeks over a 7-year period. Pregnancy outcomes were compared following different management strategies.

RESULTS

Of 108 included patients, 22 underwent expectant management (EM), 28 were reduced to dichorionic diamniotic twins, and 58 to singletons. The median gestational age at birth for EM, FR to twins, and singletons was 33.1 weeks, 37.0 weeks, and 38.6 weeks, respectively (P < 0.001). Prematurity before 37 and 34 weeks was less common following FR to singletons and twins than in ongoing triplets (18.9%, 46.2% and 90.5%, P < 0.001; 13.2%, 26.9% and 57.1%, P < 0.001). Neonatal birth weight was higher in triplets reduced to singletons and twins compared with EM cases (3140g, 2315g, and 1860g, P < 0.001). However, rates of miscarriage, pregnancies with ≥1 survivor, maternal complications, and adverse neonatal outcomes were comparable among the three groups.

CONCLUSIONS

In our experience, FR in DCTA triplets could reduce prematurity risk compared to EM, but it confers no survival advantage. Fetal reduction to singletons may result in more favorable outcomes than those reduced to dichorionic twins.

Directive clinique no 440 : Prise en charge de la grossesse gémellaire monochoriale

OBJECTIF

Cette directive clinique passe en revue les données probantes sur la prise en charge de la grossesse gémellaire monochoriale normale et compliquée.

POPULATION CIBLE

Les femmes menant une grossesse gémellaire ou multiple de haut rang. BéNéFICES, RISQUES ET COûTS: L'application des recommandations de cette directive devrait améliorer la prise en charge des grossesses gémellaires (ou multiples de haut rang) monochoriales compliquées et non compliquées. Ces recommandations aideront les fournisseurs de soins à surveiller adéquatement les grossesses gémellaires monochoriales ainsi qu'à détecter et prendre en charge rapidement les complications associées de façon optimale afin de réduire les risques de morbidité et mortalité périnatales. Ces recommandations impliquent une surveillance échographique plus fréquente en cas de grossesse monochoriale qu'en cas de grossesse bichoriale. DONNéES PROBANTES: La littérature publiée a été colligée par des recherches dans les bases de données PubMed et Cochrane Library au moyen de termes MeSH pertinents (Twins, Monozygotic; Ultrasonography, Prenatal; Placenta; Fetofetal Transfusion; Fetal Death; Fetal Growth Retardation). Les résultats ont été restreints aux revues systématiques, aux essais cliniques randomisés et aux études observationnelles. Aucune date limite n'a été appliquée, mais les résultats ont été limités aux contenus en anglais ou en français. MéTHODES DE VALIDATION: Les auteurs principaux ont rédigé le contenu et les recommandations et ils se sont entendus sur ces derniers. Le conseil d'administration de la SOGC a approuvé la version définitive aux fins de publication. Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations Assessment, Development and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et conditionnelles [faibles]). PROFESSIONNELS CONCERNéS: Spécialistes en médecine fœto-maternelle, obstétriciens, radiologues, échographistes, médecins de famille, infirmières, sages-femmes, résidents et autres fournisseurs de soins de santé qui s'occupent de femmes menant une grossesse gémellaire ou multiple de haut rang. RéSUMé POUR TWITTER: Directive canadienne (SOGC) pour le diagnostic, la surveillance échographique et la prise en charge des complications de la grossesse gémellaire monochoriale (p. ex., STT, TAPS, retard de croissance sélectif, cojumeau acardiaque, monoamnionicité et mort d'un jumeau). DÉCLARATIONS SOMMAIRES: RECOMMANDATIONS.

Guideline No. 440: Management of Monochorionic Twin Pregnancies

OBJECTIVE

This guideline reviews the evidence-based management of normal and complicated monochorionic twin pregnancies.

TARGET POPULATION

Women with monochorionic twin or higher order multiple pregnancies.

BENEFITS, HARMS, AND COSTS

Implementation of these recommendations should improve the management of both complicated and uncomplicated monochorionic (and higher order multiple) twin pregnancies. They will help users monitor monochorionic twin pregnancies appropriately and identify and manage monochorionic twin complications optimally in a timely manner, thereby reducing perinatal morbidity and mortality. These recommendations entail more frequent ultrasound monitoring of monochorionic twins compared to dichorionic twins.

EVIDENCE

Published literature was retrieved through searches of PubMed and the Cochrane Library using appropriate MeSH headings (Twins, Monozygotic; Ultrasonography, Prenatal; Placenta; Fetofetal Transfusion; Fetal Death; Fetal Growth Retardation). Results were restricted to systematic reviews, randomized controlled clinical trials, and observational studies. There were no date limits, but results were limited to English or French language materials.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the principal authors. The Board of the SOGC approved the final draft for publication. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

Maternal-fetal medicine specialists, obstetricians, radiologists, sonographers, family physicians, nurses, midwives, residents, and other health care providers who care for women with monochorionic twin or higher order multiple pregnancies.

TWEETABLE ABSTRACT

Canadian (SOGC) guidelines for the diagnosis, ultrasound surveillance and management of monochorionic twin pregnancy complications, including TTTS, TAPS, sFGR (sIUGR), acardiac (TRAP), monoamniotic twins and intrauterine death of one MC twin.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Timing of intra-fetal laser therapy for twin reversed arterial perfusion (TRAP) sequence: Retrospective series and systematic review and meta-analysis

OBJECTIVE

To estimate the neonatal survival rate after intra-fetal laser (IFL) treatment for twin reversed arterial perfusion (TRAP) sequence, and to investigate the effect of gestational age at the time of procedure.

METHODS

Retrospective cohort study of TRAP sequences followed at our institution from 2013-2020. Systematic review and meta-analysis of the neonatal survival rate after IFL was conducted. Both diamniotic and monoamniotic monochorionic pregnancies were included. A subgroup analysis to compare outcomes according to gestational age at procedure (<16⁺⁰ weeks or ≥16⁺⁰ weeks) was planned.

RESULTS

Thirteen pregnancies were followed at our center and seven were treated with IFL: the survival rate was 57%. Ten studies published between 2008 and 2020 for a total of 156 cases were included in the meta-analysis. The overall neonatal survival after IFL was 79% (95% CI 0.72-0.86, I² 22%). A random-effects model comparing neonatal survival for IFL performed <16⁺⁰ weeks versus ≥16⁺⁰ weeks showed no significant difference between the two groups (OR = 0.93; 95% CI 0.37-2.33).

CONCLUSION

IFL is a safe and minimally invasive technique for the treatment of TRAP sequence, with a survival rate of 79%. Gestational age at treatment (before or after 16 weeks) does not seem to affect neonatal survival rate.

Outcome of TRAP Sequence Treated in the First Trimester - A Ten-Year Single-Center Experience

PURPOSE

 To evaluate the outcome of first trimester intervention by intrafetal laser (IFL) in pregnancies complicated by twin reversed arterial perfusion (TRAP).

MATERIALS AND METHODS

 For a 10-year study period, all patients with TRAP diagnosed < 14.0 weeks of gestation were retrospectively analyzed for intrauterine course and outcome. Monoamniotic pregnancies were excluded. Patients were offered either intervention by IFL in the first trimester, expectant management, or termination of pregnancy (TOP). Adverse outcome was defined as either intrauterine death (IUD), neonatal death, or preterm birth.

RESULTS

 In 45 cases TRAP was diagnosed. 17 monoamniotics were excluded. The cohort was divided into two groups according to management. Group A: 24 cases underwent IFL and group B: 4 cases were managed expectantly. No patient opted for TOP. In group A, 70.8 % of pump twins were born alive, including one preterm delivery, and 29.2 % died within four days after the intervention. All 4 expectantly managed cases in group B had an adverse outcome (1 preterm delivery, 3 IUDs < 15.0 weeks). There were no neonatal deaths. In cases treated by IFL, a comparison of survivors and non-survivors identified no significant differences in gestational age at IFL or any of the assessed biometrical and functional parameters. There was a trend towards better outcome in the second half of the study period.

CONCLUSION

 IFL in first trimester TRAP sequence is technically feasible but is associated with significant mortality, albeit less than previously reported. No risk stratification is possible using the investigated parameters. However, there seems to be a learning curve.

Twin reversed arterial perfusion (TRAP) sequence: A case report and a brief literature review

Twin reversed arterial perfusion (TRAP) sequence is rare in monochorionic twin pregnancies. TRAP sequence is distinct from other multifetal pregnancies in that one of the twins has normal anatomy while the other twin has a varied amount of characteristic abnormal features. In the literature, mortality is reported 100% in the abnormal twin. We report 1 case of TRAP sequence at our institution in which the diagnosis of TRAP sequence was missed in the first trimester at another hospital. The patient, a 33-year-old G1P0A0, did not have any follow-up after her first scan until the routine second-trimester ultrasound at our institution. Both the radiologist and the sonographer did not appreciate the differential diagnosis of TRAP sequence in their clinical decision-making. The TRAP diagnosis was established after the ultrasound performed at the fetal assessment unit in our hospital. Radiofrequency ablation (RFA) procedure was performed to give the normal twin a chance to survive, but unfortunately, the prognosis was poor in this case. We conclude that diagnosing a TRAP sequence is very important early in the pregnancy for a positive outcome in the normal twin. A robust collaboration among radiologists and obstetricians is vital for the best outcome of the normal twin.

Twin reversed arterial perfusion sequence managed by bipolar cord coagulation and amniopatch: Case report

Introduction and importance

Twin Reversed Arterial Perfusion (TRAP) Sequence is a rare condition that occurs in monochorionic twin pregnancies, resulting in the coexistence of a normal “pump” twin and an acardiac twin. Indonesia is implementing fetal therapy centers that are starting to treat fetal cases such as TRAP Sequence.

Case presentation

An 18 years old pregnant woman with monochorionic diamniotic pregnancy was detected by ultrasonographic examination. A live fetus with normal fetal heart rate estimated fetal weight was 661 g, and consistent with 25 w gestational age. Additionally, an acardiac twin with polyhydramnios and EFW of 1829 g. Bipolar cord coagulation, amniopatch, and amnioinfusion were performed. The patient's condition was stable and managed closely.

Clinical discussion

This is the first procedure reported in Indonesia for TRAP sequence case. It reduces cardiac strain on the pump twin and increases the chance of survival.

Conclusion

The patient was diagnosed with TRAP Sequence and bipolar cord coagulation to interrupt blood supply to the non-viable twin, amniopatch with autologous platelet concentrate followed by cryoprecipitate amnioinfusion were reported for the first time in Indonesia.

•

The first case of bipolar cord coagulation and amniopatch in the TRAP sequence was reported in Indonesia.

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The first case report in Indonesia informs the success in the management of TRAP Sequence.

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Increase the survival of infant

Long-term neurodevelopmental outcomes of the pump twin in twin reversed arterial perfusion sequence treated by radiofrequency ablation

Objectives

To assess long‐term neurodevelopmental outcomes in children after radiofrequency ablation (RFA) for twin reversed arterial perfusion (TRAP) sequence.

Methods

This cross‐sectional study included children who underwent RFA for the TRAP sequence between 2012 and 2018. We assessed neurodevelopment in children using the Kinder Infant Development Scale, a validated questionnaire. The developmental quotient (DQ) assessed in nine subscales was calculated as the developmental age divided by the chronological age. Neurodevelopmental delay (NDD) was defined as a DQ of <70 points.

Results

In total, 38 children from 37 pregnancies underwent RFA for the TRAP sequence during the study period; 6 fetuses died in utero. We sent the questionnaire to the parents of the 32 surviving children and obtained answers for 27 (84%). The median age at the assessment was 2 years and 5 months old. The median total DQ was 111 (80–150). Most median DQs in the nine subscales were above 70. The incidence of NDD was 0% (0/27). There were no marked differences in DQ by chorionicity.

Conclusions

Children who survived after RFA for TRAP sequence showed favorable long‐term neurodevelopmental outcomes. Radiofrequency ablation seems to rarely affect fetal neurodevelopment. Pregnant women with TRAP sequence are encouraged to be treated by RFA.

What's already known about this topic?

Radiofrequency ablation (RFA), which induces the coagulation of tissue, is commonly used to treat twin reversed arterial perfusion (TRAP) sequence because of the minimal invasiveness of the technique.

The survival rate of the pump twin of TRAP sequence treated by RFA is more than 80%; however, the long‐term neurodevelopmental outcomes of survivors have rarely been investigated.

What does this study add?

Pump twins of TRAP sequence who survived after RFA showed favorable long‐term neurodevelopmental outcomes with a median developmental quotient of more than 100.

Radiofrequency ablation in fetal surgery itself seems to rarely affect fetal neurodevelopment.

Outcome of radiofrequency ablation for selective fetal reduction before vs at or after 16 gestational weeks in complicated monochorionic pregnancy

OBJECTIVE

To investigate whether gestational age at intervention (< or ≥ 16 weeks) and other factors affect the risk of loss of the cotwin after selective fetal reduction using radiofrequency ablation (RFA) in monochorionic (MC) pregnancy.

METHODS

This was a single-center retrospective analysis of 63 consecutive RFA procedures performed at our institution from January 2011 to October 2019 for selective fetal reduction in complicated MC pregnancies. Indications for RFA were twin reversed arterial perfusion sequence (13 cases), twin-to-twin transfusion syndrome (12 cases), twin anemia-polycythemia sequence (two cases), selective fetal growth restriction (10 cases), discordant anomalies (17 cases) and multifetal pregnancy reduction in triplets or quadruplets with a MC pair (nine cases). Twenty-six (41.3%) of these procedures were performed before and 37 (58.7%) after 16 weeks. Potential factors that could affect the risk of loss of the cotwin, including gestational age at RFA, order of multiple pregnancy, amnionicity, indication for RFA and number of ablation cycles, were assessed first by univariate analysis and then by multivariate analysis.

RESULTS

There were 17 (27.0%) cotwin losses. Ablation cycles numbering four or more was the only factor among those investigated to be associated with loss of the cotwin after RFA (P = 0.035; odds ratio, 5.21), while the indication for RFA, order of multiple pregnancy, amnionicity and gestational age at RFA had no effect. Comparing RFA performed at < 16 vs ≥ 16 weeks, there was no difference in the rate of cotwin loss (23.1% vs 29.7%; P = 0.558) or preterm prelabor rupture of the membranes before 34 weeks (7.7% vs 5.4%; P = 0.853), or in the median gestational age at delivery (36.2 vs 37.3 weeks; P = 0.706).

CONCLUSIONS

RFA is a promising tool for early selective fetal reduction in MC pregnancy before 16 weeks. Four or more ablation cycles is a major risk factor for cotwin loss. Careful assessment pre- and post-RFA, together with proficient operative skills to minimize the number of ablation cycles, are the mainstay to ensure that this procedure is effective and safe. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Double Trouble: Complications in Twin Pregnancies

With the increasing rate of twin pregnancies due to increase in maternal age and use of assisted reproduction, it is important to be aware of unique diseases which occur specifically to twin pregnancies, especially in monochorionic twin pregnancies. These entities include twin to twin transfusion syndrome, twin anemia polycythemia sequence, twin reversed arterial perfusion, cotwin demise, and conjoined twins. Early evaluation and documentation are imperative to guide management which ultimately leads to better patient outcomes.

Controversies in the management of twin pregnancy

Despite many advances in antenatal care, twin pregnancies still experience more adverse outcomes, in particular perinatal morbidity and mortality. They also pose a multitude of challenges and controversies, as outlined in this Review. Moreover, they are less likely to be included in clinical trials. Many issues on classification and management remain under debate. Efforts at standardizing diagnostic criteria, monitoring protocols, management and outcome reporting are likely to reduce their perinatal risks. The top 10 most important research uncertainties related to multiple pregnancies have been identified by both clinicians and patients. More robust research in the form of randomized trials and large well-conducted prospective cohort studies is needed to address these controversies. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Intrafetal laser therapy in a monochorionic diamniotic triplet pregnancy with two acardiac fetuses: a case report and literature review

Background

Monochorionic diamniotic triplet pregnancies are rare. Twin reversed arterial perfusion sequence in monochorionic triplet pregnancies is extremely rare, and it is associated with high perinatal morbidity and mortality rates in the “pump fetus.”

Case presentation

We reported a case of monochorionic diamniotic triplet pregnancy with twin reversed arterial perfusion sequence, including two acardiac fetuses sharing a single amniotic sac and a normal fetus in another amniotic sac. Due to rapid growth of the acardiac fetuses, intrafetal laser therapy was performed in both of them under ultrasound guidance at 15 weeks +5 days. Subsequently, regular and careful antenatal care including fetal ultrasonography and doppler and fetal echocardiography was conducted. At 37 weeks +4 days, a healthy female baby weighing 2510 g was delivered. The baby was followed up and now at 11 months old is in good health.

Conclusions

Twin reversed arterial perfusion sequence in monochorionic triplet pregnancy should be diagnosed early by ultrasound imaging during pregnancy. Individualized management should be based on clinical conditions to improve the perinatal outcome of the pump twin. Intrafetal laser therapy could be an alternative procedure when intrauterine intervention is required.

Twin Reversed Arterial Perfusion Sequence: Current Treatment Options

Twin reversed arterial perfusion (TRAP) sequence is a specific and severe complication of monochorionic multiple pregnancy, characterized by vascular anastomosis and partial or complete lack of cardiac development in one twin. Despite its rarity, interest in the international literature is rising, and we aimed to review its pathogenesis, prenatal diagnostic features and treatment options. Due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin, the management of these pregnancies aims to maximize the pump twin's chances of survival. If treatment is needed, the best timing of intervention is still debated, although the latest studies encourage intervention in the first trimester of pregnancy. As for the technique of choice to interrupt the vascular supply to the acardiac twin, ultrasound-guided laser coagulation and radiofrequency ablation of the intrafetal vessels are usually the preferred approaches.

Morphology, intrafetal vascular pattern, and umbilical artery Doppler indices of acardiac twins

BACKGROUND

Twin reversed arterial perfusion (TRAP) sequence consists of acardiac twin (A) paradoxically perfused by pump twin (P) through an umbilical artery (UA). We proposed characterization of acardiac twins with intrafetal vascular pattern (IVP), and assessed its correlation with morphology and UA Doppler indices.

METHODS

We prospectively evaluated 21 cases of TRAP sequence. Morphology (acardia vs hemicardia) and IVP (simple vs complex) of acardiac twins were characterized with ultrasound and color Doppler. Twins weight ratio (A/P Wt) and UA Doppler indices of acardiac and pump twins including (1) difference of systolic/diastolic ratio (UA ∆S/D), (2) difference of resistance index (UA ∆RI), and (3) ratio of pulsatility index (UA PI A/P) were calculated.

RESULTS

The median (min, max) gestational age at diagnosis was 18 (11, 27) weeks. Acardia (n = 14) were associated with simple IVP (n = 16) (P < .05). After exclusion of acardia with complex IVP (n = 1), the A/P Wt, UA ∆S/D, UA ∆RI, and UA PI A/P of acardia with simple IVP (n = 13), hemicardia with simple IVP (n = 3), and hemicardia with complex IVP (n = 4) were not significantly different (P > .05).

CONCLUSIONS

Most of acardiac twins were acardia with simple IVP. Morphology and IVP of acardiac twins were not associated with UA Doppler indices.

Intrafetal laser for midtrimester TRAP sequence-experience from a single center

OBJECTIVE

To report our experience and evaluate outcomes in monochorionic pregnancies with Twin Reversed Arterial Perfusion sequence with intrafetal laser therapy.

METHODS

Retrospective review of records of all pregnancies with TRAP sequence treated by intrafetal laser therapy between 2011 January and 2015 December that were retrieved and analysed.

RESULTS

Electronic search of the scan database retrieved 57 cases of TRAP sequence during the study period, 7 triplets and 50 monochorionic twins. Intrafetal laser was done in 27 cases, 22 cases of twins and 5 cases of triplets. In the twins group, median gestational age at intervention was 22.5 weeks, the earliest done at 16.3 weeks. The median gestational age at delivery and birth weight was 37 weeks and 2.5 Kgs. The median procedure and delivery interval was 14 weeks. Live birth rate was 17/22 (77%) the pump survival rate was 16/22 (73%). Pregnancies with non-surviving pump were 5 in numbers (5/22). A repeat procedure was warranted in one case. In the triplet group, median gestational age at intervention, delivery and procedure delivery interval was 18, 35 and 17 weeks.

CONCLUSION

Intrafetal laser is simple, effective and the treatment of choice to interrupt the vascular supply to acardiac twin.

Twin pregnancy with two live fetuses at 11-13 weeks: effect of one fetal death on pregnancy outcome

OBJECTIVES

First, to compare the incidence of single and double fetal death between monochorionic (MC) and dichorionic (DC) twin pregnancies with two live fetuses at 11-13 weeks' gestation and no major abnormalities. Second, to investigate the relationship between gestational age at single fetal death and interval to delivery of the cotwin. Third, to determine the rate of early preterm birth in DC and MC twin pregnancies with two live fetuses and those with single fetal death.

METHODS

This was a retrospective analysis of prospectively collected data on twin pregnancies undergoing routine ultrasound examination at 11-13 weeks' gestation between 2002 and 2019. The outcome measures, which were stratified by chorionicity, were: first, death of both fetuses at presentation or death of one fetus followed by delivery of a live or dead cotwin within the subsequent 3 days at < 34 weeks' gestation; second, in pregnancies with single fetal death at < 34 weeks' gestation and a live cotwin ≥ 3 days later, the subsequent risk of fetal death and gestational-age distribution at birth of the cotwin; and, third, the gestational-age distribution at birth in pregnancies with two live fetuses.

RESULTS

The main findings of this study of 4896 DC and 1329 MC twin pregnancies with two live fetuses at 11-13 weeks' gestation were: first, the rate of death of both twins or death of one fetus and delivery of the live or dead cotwin within 3 days was higher in MC than in DC twin pregnancies; second, the rate of single fetal death with a live cotwin ≥ 3 days later was higher in MC than in DC twin pregnancies, but the rate of subsequent cotwin death in MC twin pregnancies was not significantly different from that in DC twin pregnancies; third, in pregnancies with two live fetuses, the rate of early preterm birth was significantly higher in MC than in DC twin pregnancies; fourth, the rate of early preterm birth in pregnancies with single fetal death and a live cotwin ≥ 3 days later was not significantly different between MC and DC twin pregnancies but the rates were substantially higher than in those with two live fetuses; and, fifth, in both MC and DC pregnancies with single fetal death and a live cotwin ≥ 3 days later, there was a significant inverse association between gestational age at death and interval to delivery (mean interval of 19 weeks for death at 15 weeks and mean interval of 2.5 weeks for death at 30 weeks).

CONCLUSIONS

First, in MC twin pregnancies, the risk of single or double fetal death is higher than in DC twins. Second, in both MC and DC twin pregnancies, the rate of early preterm birth is higher in those with one fetal death than in those with two live fetuses. Third, in both MC and DC twins with one fetal death, the interval to delivery is related inversely to gestational age at fetal death. These data should be useful in counseling parents as to the likely outcome of their pregnancy after single fetal death and in defining strategies for surveillance in the management of these types of twin pregnancy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Diagnosis of fetal defects in twin pregnancies at routine 11-13-week ultrasound examination

OBJECTIVES

To examine the performance of the routine 11-13-week scan in detecting fetal defects in twin pregnancies and to examine if, in pregnancies with a fetal defect, compared to those with normal fetuses, there is increased incidence of nuchal translucency thickness (NT) ≥ 95^th and ≥ 99^th percentiles or intertwin discordance in crown-rump length (CRL) ≥ 10% and ≥ 15%.

METHODS

This was a retrospective analysis of prospectively collected data in twin pregnancies undergoing routine ultrasound examination for fetal anatomy, according to standardized protocols, at 11-13 weeks' gestation between 2002 and 2019. Pregnancies with known chromosomal abnormality were excluded. The final diagnosis of fetal defect was based on the results of postnatal examination in cases of live birth and on the findings of the last ultrasound examination in cases of pregnancy termination, miscarriage or stillbirth. The performance of the 11-13-week scan in the detection of fetal defects was determined.

RESULTS

The study population of 6366 twin pregnancies with two live fetuses at 11-13 weeks' gestation included 4979 (78.2%) dichorionic (DC) and 1387 (21.8%) monochorionic (MC) twin pregnancies. The main findings were: first, the overall incidence of fetal defects was higher in MC than in DC twins (2.8% vs 1.3%); second, the proportion of defects diagnosed in the first trimester was higher in MC than in DC twins (52.6% vs 27.1%); third, the pattern of defects in relation to detectability at the 11-13-week scan (always detectable, sometimes detectable and never detectable) was similar to that reported previously in singleton pregnancies; fourth, always-detectable defects included acrania, alobar holoprosencephaly, encephalocele, pentalogy of Cantrell, exomphalos, body-stalk anomaly, twin reversed arterial perfusion sequence and conjoined twins; fifth, the incidence of fetal NT ≥ 95^th percentile was higher in those with than in those without a defect (16.5% vs 4.5% in DC twins and 19.2% vs 5.9% in MC twins) and this was also true for NT ≥ 99^th percentile (8.3% vs 1.0% in DC twins and 15.4% vs 2.0% in MC twins); and sixth, the incidence of CRL discordance ≥ 10% was higher in those with than in those without a defect (20.2% vs 7.9% in DC twins and 33.8% vs 9.3% in MC twins) and this was also true for CRL discordance ≥ 15% (10.1% vs 1.9% in DC twins and 28.2% vs 2.8% in MC twins).

CONCLUSIONS

First, fetal defects are more common in MC than in DC twin pregnancies. Second, first-trimester detection of fetal defects in DC twin pregnancies is similar to that in singleton pregnancies. Third, first-trimester detectability of defects in MC twins is higher than in DC twins. Fourth, in twin pregnancies with a fetal defect, there is higher intertwin discordance in CRL and incidence of increased NT, but the predictive performance of screening by these markers is poor. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Fetal therapies as standard prenatal care in Japan

With recent advances in fetal medicine, various attempts have been made to save fetuses facing perinatal death or devastating consequences despite optimal management after birth. The concept of the fetus as a patient has been established through the application of in utero treatments. This paper reviews fetal therapies in order to highlight the role of perinatal medicine as standard prenatal care. Fetal therapies consist of medical therapy, percutaneous ultrasound-guided surgery, fetoscopic surgery, and open fetal surgery. In the 1980s, with advances in ultrasound imaging, percutaneous ultrasound-guided surgeries such as vesicoamniotic shunting for lower urinary tract obstruction and thoracoamniotic shunting (TAS) for fetal hydrothorax (FHT) were started. In the 1990s, fetoscopic laser surgery (FLS) for twin-twin transfusion syndrome (TTTS) was introduced, and later, a fetoscopic approach for congenital diaphragmatic hernia was also established. The revival of open fetal surgery, introduced in the 1980s by pediatric surgeons, began in the 2010s after a successful clinical study for myelomeningocele. Although many fetal therapies are still considered experimental, some have proven effective, such as FLS for TTTS, TAS for primary FHT, and radiofrequency ablation (RFA) for twin reversed arterial perfusion (TRAP) sequence. These three fetal therapies have been approved for coverage by Japan National Health Insurance as a result of clinical studies performed in Japan. FLS for TTTS, TAS for primary FHT, and RFA for TRAP sequence have become standard prenatal care approaches in Japan. These three minimally invasive fetal therapies will help improve the perinatal outcomes of fetuses with these disorders.

Outcome of Pregnancies Diagnosed with TRAP Sequence Prenatally: A Single-Centre Experience

INTRODUCTION

Twin reversed arterial perfusion (TRAP) sequence is a phenomenon seen in 1-3% of monochorionic twin pregnancies, where the acardiac fetus is found to have multiple anomalies. The normal pump twin maintains its own perfusion in addition to that of its acardiac co-twin. As a result, if the acardiac twin increases in size, the burden on the pump twin is increased, leading to cardiac failure, hydrops fetalis, polyhydramnios, premature delivery, and perinatal death. The outcome of pregnancy is largely dependent on the growth of the acardiac twin. In view of high perinatal loss, surgical techniques to interrupt the blood flow to the acardiac twin have been evaluated.

METHODS

We evaluated interstitial laser therapy, which is the main mode of therapy in our unit, of TRAP pregnancies referred over a 5-year period. Interstitial laser was offered if the blood flow in the acardiac twin was found to be persistent at 2 consecutive examinations or if there were cardiac or hydropic changes in the pump twin at the first examination.

RESULTS

A total of 18 cases of TRAP were referred during this period and all were counselled regarding fetal therapy if the situation were to deteriorate; 5 couples (27.7%) opted for termination of pregnancy; of the remaining 13, 7 (53.8%) agreed to perform intervention following confirmation of a normal karyotype. Six (85.7%) and 1 (14.3%) lasers were performed in the second and third trimesters, respectively; all 7 had a normal outcome of the pump twin. There were 6/13 (46.2%) in the expectant group who continued the pregnancy with no intervention, with 2 term live births (33.3%).

CONCLUSIONS

Our study confirms that there is a high risk of spontaneous loss in untreated pregnancies with TRAP, primarily due to polyhydramnios and fetal hydrops. In the pregnancies that underwent interstitial laser, there was a more favourable outcome. Interstitial laser is minimally invasive, safe, and feasible in experienced hands.

Treatment of twin-reversed arterial perfusion sequence using high-intensity focused ultrasound

We describe our experience of high-intensity focused ultrasound (HIFU) for fetal therapy in twin-reversed arterial perfusion (TRAP) sequence. Six pregnant women underwent HIFU therapy, five before 16 weeks and one at 26 weeks. Two types of HIFU system were used: the first-generation system, which comprised a biaxial transducer and continuous exposure pattern, and the second-generation system, which comprised a coaxial transducer and sequential exposure pattern. The first-generation apparatus was used in four cases and the second-generation apparatus was used in two. In three cases, occlusion of the blood vessels mediating flow to the acardiac twin was achieved by HIFU. Two cases experienced intrauterine fetal death despite vessel occlusion. The total survival rate of pump fetuses 2 years after HIFU was 67% and the efficiency rate (the proportion of cases with occlusion or reduced blood flow on ultrasound after HIFU) was 83%. After more than 2 years of follow-up, the surviving infants had no severe clinical complications and no postnatal developmental problems. There was no significant difference in survival rate compared with TRAP cases managed expectantly. Given that complete occlusion of the blood vessels was not achieved in half of the cases, we could not show that HIFU therapy is superior to other treatments. However, HIFU can reduce the cardiac load of the pump fetus and, as it does not require uterine puncture for fetal therapy, there were no fatal complications, such as bleeding, rupture of membranes or infection. Thus, HIFU therapy may represent a less-invasive treatment for TRAP sequence in early pregnancy. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Therapeutic dilemma in twin reversed arterial perfusion sequence

The dissemination of minimally invasive in utero surgery reduced the mortality of twin reversed arterial perfusion sequence, but the mortality of expectantly treated surgical candidates remains high. A 26-year-old, non-parous, Japanese woman at 13 weeks of gestation had been diagnosed with twin reversed arterial perfusion sequence and was judged as a surgical candidate for radiofrequency ablation. However, she did not undergo surgery because of the anatomical location of the acardiac twin. At 18 weeks of gestation, the blood flow to the acardiac twin disappeared spontaneously. The pump twin began to demonstrate fetal growth retardation during the third trimester. The patient delivered a 1891 g female at term. We macroscopically identified the cause of the fetal growth retardation as velamentous insertion of the umbilical cord and microscopically diagnosed the acardiac twin with acardiac acephalus. We should give the same attention to the management of post–twin reversed arterial perfusion sequence as twin reversed arterial perfusion sequence itself.

Integration of imaging and molecular approaches in selective fetal reduction in twin pregnancies with one carrying a pathogenic genomic aberration

BACKGROUND/PURPOSE

With the evolution of assisted fertility and prenatal diagnostic technology, the prevalence of multi-fetal pregnancy increased, followed by the demand for prenatal intervention if genomic aberration was detected. How to distinguish the affected foetus from the normal co-twin before selective fetal reduction is therefore challenging.

OBJECTIVES

We retrospectively reviewed the cases of dichorionic twins at our centre during 2004-2018, where selective fetal reduction was requested because one foetus carried a pathogenic genomic aberration. Five cases were enrolled, including three foetuses with trisomy 21, one foetus with microduplication and one foetus with microdeletion disorders.

METHOD

We labelled the affected foetus by prenatal ultrasound and rapid molecular tools. For the twins without discriminating sonographic features (e.g., the same gender and no distinct placentae), interphase fluorescence in situ hybridization, rapid microarray and short tandem repeat markers were applied to identify the affected foetus.

RESULTS

Selective fetal reduction was allocated accurately for all individuals. Two cases delivered at term, while two delivered preterm, and one developed fetal loss of the co-twin.

CONCLUSION

We proposed a working scheme of integrating imaging and molecular techniques to correctly identify the affected co-twin before selective fetal reduction to ensure the accuracy of the identification.

ACR Appropriateness Criteria® Multiple Gestations

Women with twin or higher-order pregnancies will typically have more ultrasound examinations than women with a singleton pregnancy. Most women will have at minimum a first trimester scan, a nuchal translucency evaluation scan, fetal anatomy scan at 18 to 22 weeks, and one or more scans in the third trimester to evaluate growth. Multiple gestations are at higher risk for preterm delivery, congenital anomalies, fetal growth restriction, placenta previa, vasa previa, and velamentous cord insertion. Chorionicity and amnionicity should be determined as early as possible when a twin pregnancy is identified to permit triage of the monochorionic group into a closer surveillance model. Screening for congenital heart disease is warranted in monochorionic twins because they have an increased rate of congenital cardiac anomalies. In addition, monochorionic twins have a higher risk of developing cardiac abnormalities in later gestation related to right ventricular outflow obstruction, in particular the subgroups with twin-twin transfusion syndrome or selective intrauterine growth restriction. Monochorionic twins have unique complications including twin-to-twin transfusion syndrome, twin embolization syndrome, and acardius, or twin-reversed arterial perfusion sequence. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Ultrasound screening for complications in twin pregnancy

In the decades since the introduction of ultrasound into routine obstetric practice, the advantages of ultrasound have moved beyond the simple ability to identify multiple pregnancies antenatally to the possibility of screening them for fetal anomalies, pre-eclampsia, preterm birth, and the complications specific to monochorionic pregnancies. Screening studies have often excluded twins because physiological differences impact on the validity and sensitivity of the screening tests in routine use in singletons, and therefore, the evidence of screening performance in multiple pregnancy lags behind the evidence from singleton pregnancies. In general, most pregnancy complications are more common in twin pregnancy, but screening tests are less accurate or well validated. In this review article we present the current state of the evidence and avenues for future research relating to the use of ultrasound and screening for complications in twin pregnancies, including the monochorionicity-related pathologies, such as twin-twin transfusion syndrome, selective growth restriction, twin anaemia-polycythaemia sequence and twin reversed arterial perfusion sequence.

Treatment of twin reversed arterial perfusion sequence with radiofrequency ablation and expectant management: A single center study in China

OBJECTIVE

To evaluate the treatment of pregnancies in different stages complicated by TRAP sequence at a single medical center in China.

STUDY DESIGN

A retrospective study evaluating 25 pregnancies with TRAP sequence was performed at Shengjing Hospital in Shenyang, Liaoning between 2012 and 2016. Patients were diagnosed by ultrasound and categorized into three groups (Ia, IIa and IIb) and were expectantly managed or performed RFA (radiofrequency ablation) according to their stage of TRAP sequence. Perinatal outcomes and survival rates were analyzed.

RESULTS

There were four cases in stage Ia, 19 cases in stage IIa, and two cases in stage IIb. Cases in stage Ia were expectantly managed. Among cases in stage IIa, we performed RFA (radiofrequency ablation) in 10 cases and expectant management in 6 cases, with the remainder of the patients refusing intrauterine treatment. We applied RFA to treat one case in stage IIb and the other was managed expectantly. For expectant management group and the RFA group, the survival rates were both 64%(7/11). All pump twins in stage Ia survived and the average gestational age at delivery was 37.9 weeks. In stage IIa, the overall survival rate of the pump twin was 70% (7/10) and the average gestational age at delivery was 35.8 weeks in cases treated by RFA. The survival rate was 50% (3/6) and the average gestational age at delivery was 32.8 weeks in expectantly managed cases in stage IIa. No pump twin survived in stage IIa without treatment (3 cases refused any therapy who were excluded) or in stage IIb.

CONCLUSION

Expectant management is effective for treatment of TRAP sequence in stage Ia. In stage IIa, RFA improves the prognosis of pump twins.

Intrafetal laser ablation for embryo reduction from dichorionic triplets to dichorionic twins

OBJECTIVE

To report the outcome of dichorionic (DC) triplet pregnancies reduced to DC twins by laser ablation of the pelvic vessels of one of the monochorionic (MC) twins.

METHODS

Intrafetal laser embryo reduction (ER) from DC triplets to DC twins was carried out in 61 pregnancies at 11 + 0 to 14 + 3 weeks' gestation. Pregnancy outcome was examined.

RESULTS

Intrafetal laser was successfully carried out in all cases, but ultrasound examination within 2 weeks of the procedure demonstrated that the MC cotwin had died in 28 (45.9%) cases and was alive in the other 33 (54.1%). In the DC group, there was one miscarriage at 23 weeks, one neonatal death after delivery at 26 weeks and in the other 31 cases there were two live births at a median gestational age of 35.3 (range, 30.4-38.4) weeks. In the 28 cases in which both MC fetuses died, there was one miscarriage at 16 weeks and in the other 27 cases the separate triplet was liveborn at a median gestation of 38.2 (range, 32.2-42.1) weeks. The overall rate of miscarriage was 3.3% (2/61) and that of preterm birth (PTB) at < 33 weeks was 6.8% (4/59).

CONCLUSIONS

In the management of DC triplet pregnancies, ER to DC twins by intrafetal laser ablation is associated with lower rates of miscarriage or early PTB, compared with expectant management or ER by fetal intracardiac injection of potassium chloride. However, about half of the pregnancies result in the birth of one rather than two babies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

First-trimester intervention in twin reversed arterial perfusion sequence: does size matter?

OBJECTIVE

To evaluate the outcome of first-trimester intervention (12 + 0 to 14 + 0 weeks of gestation) in pregnancies complicated by twin reversed arterial perfusion (TRAP) sequence.

METHODS

All monochorionic diamniotic twin pregnancies diagnosed with TRAP sequence that underwent intrafetal laser ablation (IFL) of the feeding vessels before 14 + 0 weeks of gestation at the University of Bonn between 2010 and 2015 were analyzed retrospectively for intrauterine course and outcome.

RESULTS

In the study period, 12 pregnancies with TRAP sequence were treated by IFL. Median gestational age at intervention was 13.2 (interquartile range (IQR), 12.6-13.6) weeks. In all cases, one intervention sufficed to disrupt the perfusion of the TRAP twin. There was no case of miscarriage, preterm prelabor rupture of membranes or hemorrhage. In five (41.7%) pregnancies, intrauterine death of the pump twin occurred at a median of 72.0 (IQR, 54.0-90.0; range, 48-96) h after intervention. The remaining seven pregnancies continued uneventfully resulting in birth of a healthy infant at term. A comparison of survivors and non-survivors identified a significant difference in median discordance between crown-rump length (CRL) of the pump twin and upper pole-rump length (URL) of the TRAP twin ((CRL - URL)/CRL ratio, 0.56 vs 0.31; P < 0.05 and URL/CRL ratio, 0.44 vs 0.68; P < 0.05). Survivors were treated at a significantly later gestational age than were non-survivors (median, 13.4 (IQR, 12.9-14.1) vs 12.6 (IQR, 12.5-13.1); P < 0.05). However, none of these parameters independently predicted survival.

CONCLUSIONS

Although technically feasible, IFL performed in the first trimester for TRAP sequence is associated with a significant fetal loss rate. Gestational age at intervention, (CRL - URL)/CRL ratio and URL/CRL ratio are potential predictors of pregnancy outcome. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Procedure-related complications of open vs endoscopic fetal surgery for treatment of spina bifida in an era of intrauterine myelomeningocele repair: systematic review and meta-analysis

OBJECTIVE

To assess and compare the rate of procedure-related complications after intrauterine treatment of spina bifida by endoscopic surgery and by open fetal surgery.

METHODS

Systematic literature searches in PubMed and SCOPUS databases were performed on 20 September 2015 to identify randomized controlled trials and observational studies on treatment of human spina bifida by endoscopic or open fetal surgery techniques. Only studies with ≥ 10 cases that were published in or after 2000 were included in the meta-analysis in order to reduce the risk of bias. Primary outcomes (complete dehiscence, focal dehiscence and/or markedly thin hysterotomy scar; preterm delivery < 34 weeks; mean gestational age at delivery) and secondary outcomes (oligohydramnios, prelabor rupture of membranes, placental abruption, chorioamnionitis and perinatal death) were assessed for both techniques. Precision of the estimated proportions was evaluated with 95% CIs. Inconsistency was assessed using the I(2) statistic.

RESULTS

The search identified 1080 records that were examined based on title and abstract, of which 28 full-text articles were examined completely for eligibility. Nine records were excluded because cases were also described in other studies, leaving 19 records for analysis. When comparing endoscopic vs open fetal surgery, the rate of complete dehiscence, focal dehiscence and/or markedly thin hysterotomy scar was, respectively, 1% (95% CI, 0-4%) vs 26% (95% CI, 12-42%); preterm delivery < 34 weeks was 80% (95% CI, 41-100%) vs 45% (95% CI, 38-53%); oligohydramnios was 39% (95% CI, 9-75%) vs 14% (95% CI, 7-24%); prelabor rupture of membranes was 67% (95% CI, 12-100%) vs 38% (95% CI, 26-50%); and perinatal death was 14% (95% CI, 1-38%) vs 5% (95% CI, 3-8%).

CONCLUSION

Open fetal surgery for spina bifida seems to show lower rates of procedure-related complications than does endoscopic surgery, but the rate of hysterotomy scar complications is high after open surgery. Because of the low quality of evidence, the conclusions should be interpreted with caution. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Intervention versus a conservative approach in the management of TRAP sequence: a systematic review

OBJECTIVE

In the management of twin reversed arterial perfusion (TRAP) sequence, we wished to (i) determine if intervention is better than a conservative approach and (ii) assess if any of the apparent adverse prognostic indicators could guide intervention.

METHODS

A systematic review was conducted between 1994 and 2014. Data extracted were inspected for heterogeneity. Overall rates and confidence intervals (CIs) for each prognostic factor were calculated. Where there were comparative data, the odds ratio (OR) was calculated.

RESULTS

Twenty-six studies were included in the review. When all cases were considered, intervention either by cord occlusion or by ablation conferred a better survival rate compared with conservative management (OR=2.22, 95% CI 1.23-4.01, heterogeneity I2=37%, P=0.008). This difference was greater in the presence of one or more poor prognostic features (OR=8.58, 95% CI 1.47-49.96, heterogeneity I2=0%, P=0.02). Survival was better using ablative techniques compared to cord occlusion (OR=9.84, 95% CI 1.56-62.00, heterogeneity I2=0%, P=0.01).

CONCLUSION

Intervention either by cord occlusion or by ablation confers a better survival rate compared to conservative management. This appears more compelling if there are one or more poor prognostic features. Ablative techniques are superior to cord occlusion. There were insufficient data to determine which poor prognostic features should guide management.

Forty cases of twin reversed arterial perfusion sequence treated with radio frequency ablation using the multistep coagulation method: a single-center experience

OBJECTIVE

To report the pregnancy outcomes of patients with twin reversed arterial perfusion (TRAP) sequence treated by radiofrequency ablation (RFA).

METHODS

This was a retrospective study of TRAP sequences treated in a single center between March 2002 and February 2015. Forty patients underwent RFA with expandable tines through a multistep coagulation method between 15 and 26 gestational weeks. The primary outcome was neonatal survival to discharge.

RESULTS

The overall survival of the pump twin was 85%. The survival rates in monochorionic-monoamniotic (MCMA) pregnancies and monochorionic-diamniotic pregnancies were 66.7% (4/6) and 87.9% (29/33), respectively. One triplet was treated successfully and delivered at 36 weeks of gestation. One of 35 live births (2.9%) had preterm premature rupture of membranes less than 34 weeks, resulting in infant death. In five intrauterine pump twin deaths, two cases were MCMA twins with cord entanglement, and three cases were MCDA twins with acardius anceps.

CONCLUSIONS

Our study supports the effectiveness of RFA for TRAP sequence after 15 weeks of gestation. The presence of MCMA twins or acardius anceps is associated with a high risk of pump twin death after RFA. © 2016 John Wiley & Sons, Ltd.

Radiofrequency Ablation with an Internally Cooled Electrode for Twin Reversed Arterial Perfusion Sequence

OBJECTIVE

The study aims to evaluate the efficacy of radiofrequency ablation (RFA) with an internally cooled electrode for twin reversed arterial perfusion (TRAP) sequence.

METHODS

From April 2008 through December 2014, we retrospectively reviewed all patients who underwent RFA with an internally cooled electrode for TRAP sequence at 3 tertiary referral centers in Japan.

RESULTS

Twenty-five monochorionic diamniotic twin pregnancies underwent RFA with an internally cooled electrode for TRAP sequence at 16-27 weeks of gestation. In all cases, umbilical cord blood flow cessation in the acardiac twin was confirmed by ultrasonography with color Doppler. There were 2 cases of procedure-related complications: 1 case of unintentional septostomy and 1 case of anemia in a pump twin. Fetal demise of the pump twin occurred in 3 (12%) cases. Twenty-two (88%) of 25 pump twins were delivered alive. The median gestational age at delivery was 36 + 3 weeks (range 25 + 2-40 + 5 weeks). There were 14 cases (64%) of premature deliveries before 37 weeks and 5 (23%) before 32 weeks.

CONCLUSION

RFA with an internally cooled electrode is a feasible and effective procedure for the treatment of TRAP sequence.