Prevalence and management of late fetal complications following successful selective laser coagulation of chorionic plate anastomoses in twin-to-twin transfusion syndrome

Arterial and Venous Doppler in Evaluation of the "At-risk" Fetus

Our practice utilizes Doppler ultrasound as one of the most objective and effective methods to assess at-risk pregnancies. This review will discuss the application of arterial and venous Doppler techniques in assessing and managing various diseases and conditions for high-risk fetuses.

Placental Vascular Anastamoses and Associated Pathologies in Dichorionic Twin Gestations

Placental vascular anastomoses are traditionally thought to exist exclusively in monochorionic pregnancies. However, they have been reported in dichorionic twin pregnancies as well. In turn, twin to twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS) have also been noted to impact some of these gestations. Through discussion of one such case at our institution along with a review of the available literature, we review the proposed pathophysiology of placental vascular anastamoses in dichorionic twin gestations, and aim to raise awareness of the possibility of associated pathologies in dichorionic gestations. This is an emerging area of literature that will require future study to guide prenatal surveillance and mitigate morbidity.

Society for Maternal-Fetal Medicine Consult Series #72: Twin-twin transfusion syndrome and twin anemia-polycythemia sequence

Thirty percent of spontaneously occurring twins are monozygotic, of which two-thirds are monochorionic, possessing a single placenta. A common placental mass with shared intertwin placental circulation is key to the development and management of complications unique to monochorionic gestations. In this Consult, we review general considerations and a contemporary approach to twin-twin transfusion syndrome and twin anemia-polycythemia sequence, providing management recommendations based on the available evidence. The following are the Society for Maternal-Fetal Medicine recommendations: (1) we recommend routine first-trimester sonographic determination of chorionicity and amnionicity (GRADE 1B); (2) we recommend that ultrasound surveillance for twin-twin transfusion syndrome begin at 16 weeks of gestation for all monochorionic-diamniotic twin pregnancies and continue at least every 2 weeks until delivery, with more frequent monitoring indicated with clinical concern (GRADE 1C); (3) we recommend that routine sonographic surveillance for twin-twin transfusion syndrome minimally include assessment of amniotic fluid volumes on both sides of the intertwin membrane and evaluation for the presence or absence of urine-filled fetal bladders, and ideally incorporate Doppler study of the umbilical arteries (GRADE 1C); (4) we recommend fetoscopic laser surgery as the standard treatment for stage II through stage IV twin-twin transfusion syndrome presenting between 16 and 26 weeks of gestation (GRADE 1A); (5) we recommend expectant management with at least weekly fetal surveillance for asymptomatic patients continuing pregnancies complicated by stage I twin-twin transfusion syndrome, and consideration for fetoscopic laser surgery for stage I twin-twin transfusion syndrome presentations between 16 and 26 weeks of gestation complicated by additional factors such as maternal polyhydramnios-associated symptomatology (GRADE 1B); (6) we recommend an individualized approach to laser surgery for early- and late-presenting twin-twin transfusion syndrome (GRADE 1C); (7) we recommend that all patients with twin-twin transfusion syndrome qualifying for laser therapy be referred to a fetal intervention center for further evaluation, consultation, and care (Best Practice); (8) after laser therapy, we suggest weekly surveillance for 6 weeks followed by resumption of every-other-week surveillance thereafter, unless concern exists for post-laser twin-twin transfusion syndrome, post-laser twin anemia-polycythemia sequence, or fetal growth restriction (GRADE 2C); (9) following the resolution of twin-twin transfusion syndrome after fetoscopic laser surgery, and without other indications for earlier delivery, we recommend delivery of dual-surviving monochorionic-diamniotic twins at 34 to 36 weeks of gestation (GRADE 1C); (10) in twin-twin transfusion syndrome pregnancies complicated by posttreatment single fetal demise, we recommend full-term delivery (39 weeks) of the surviving co-twin to avoid complications of prematurity unless indications for earlier delivery exist (GRADE 1C); (11) we recommend that fetoscopic laser surgery not influence the mode of delivery (Best Practice); (12) we recommend that prenatal diagnosis of twin anemia-polycythemia sequence minimally require either middle cerebral artery Doppler peak systolic velocity values >1.5 and <1.0 multiples of the median in donor and recipient twins, respectively, or an intertwin Δ middle cerebral artery peak systolic velocity >0.5 multiples of the median (GRADE 1C); (13) we recommend that providers consider incorporating middle cerebral artery Doppler peak systolic velocity determinations into all monochorionic twin ultrasound surveillance beginning at 16 weeks of gestation (GRADE 1C); and (14) consultation with a specialized fetal care center is recommended when twin anemia-polycythemia sequence progresses to a more advanced disease stage (stage ≥II) before 32 weeks of gestation or when concern arises for coexisting complications such as twin-twin transfusion syndrome (Best Practice).

Treatment of Twin Anemia Polycythemia Sequence with Donor Transfusion and Partial Recipient Exchange Transfusion: Procedural Considerations and Outcomes

Background: Intrauterine transfusion (IUT) of the donor and partial exchange (pET) of the recipient is a temporizing treatment for pregnancies with Twin Anemia Polycythemia Sequence (TAPS). We aimed to provide a detailed description of the procedural approach and outcomes for sequential donor IUT and recipient pET in TAPS. Methods: Retrospective study of spontaneous TAPS referred to the Johns Hopkins Center for Fetal Therapy treated with donor IUT followed by recipient pET utilizing a double-syringe setup. Procedural characteristics and outcomes as well as the accuracy of existing transfusion formulas were analyzed and compared with the literature. Results: 5 of 78 patients with spontaneous TAPS underwent a total of 19 combined IUT/pET procedures (median first procedure to delivery interval 5.6 weeks [interquartile range IQR 1.9-6.0]). One pET was stopped due to fetal deceleration. The patients were delivered at 33.0 weeks [IQR 31.9-33.3] with two survivors and no neonatal transfusion requirements. The IUT volume was 48 mL [IQR 39-63 mL] and the pET volume was 32 mL [IQR 20-50], utilizing aliquots of 5-20 mL for the latter (p = 0.021). For the IUTs, the assumption of a fetal blood volume below 150 mL/kg underestimated the required transfusion volume. For the pETs, all formulas required adjustment of the dilution volume based on bedside testing (p < 0.05 for all). Conclusions: Donor transfusion followed by partial exchange in the recipient can prolong pregnancy in spontaneous TAPS and obviate the need for neonatal transfusion. A double-syringe setup facilitates efficient saline exchange. Because the accuracy of volume formulas is limited, bedside testing is recommended to achieve the target hemoglobin.

Elevated middle cerebral artery peak systolic velocity and risk of death in donor twin affected by twin-twin transfusion syndrome but not twin anemia-polycythemia sequence

OBJECTIVES

To determine the association between elevated (> 1.5 multiples of the median (MoM)) middle cerebral artery (MCA) peak systolic velocity (PSV) and fetal demise of the donor twin in pregnancies complicated by twin-twin transfusion syndrome (TTTS) in the absence of twin anemia-polycythemia sequence (TAPS). Secondary objectives were to evaluate if donor or recipient MCA-PSV is associated with a risk for their corresponding fetal death, and to compare the proportion of donor fetuses with low MCA pulsatility index (PI) among donor twins with high MCA-PSV and those with normal MCA-PSV to evaluate the contribution of blood-flow redistribution to the fetal brain in donor twins with high MCA-PSV.

METHODS

This prospective cohort study included TTTS cases that underwent laser surgery between 2011 and 2022 at a single center. TAPS cases were excluded from the study. Multivariable and Poisson regression analysis were performed to explore the association between isolated elevated donor MCA-PSV and fetal demise, adjusted for TTTS stage, selective fetal growth restriction (sFGR) and other confounders.

RESULTS

Of 660 TTTS cases, donor MCA-PSV was not recorded in 48 (7.3%) cases. Of the remaining 612 patients, nine (1.5%) were lost to follow-up and 96 TAPS cases were excluded; thus, 507 cases were included in the study. High donor MCA-PSV was seen in 6.5% (33/507) of cases and was an independent risk factor for donor fetal demise (adjusted relative risk (aRR), 4.52 (95% CI, 2.72-7.50)), after adjusting for confounders. Regression analysis restricted to each Quintero TTTS stage demonstrated that high donor MCA-PSV was an independent risk factor for fetal demise of the donor in Quintero Stage II (aRR, 14.21 (95% CI, 1.09-186.2)) and Quintero Stage III (aRR, 3.41 (95% CI, 1.82-6.41)). Donor MCA-PSV in MoM was associated with fetal demise of the donor (area under the receiver-operating-characteristics curve (AUC), 0.69; P < 0.001), but recipient MCA-PSV in MoM was not associated with fetal demise of the recipient (AUC, 0.54; P = 0.44). A higher proportion of donor twins in the group with high MCA-PSV had a low MCA-PI compared to the group with normal MCA-PSV (33.3% vs 15.5%; P = 0.016).

CONCLUSIONS

Elevated donor MCA-PSV without TAPS prior to laser surgery for TTTS is associated with a 4-fold increased risk for donor fetal demise, adjusted for sFGR, TTTS stage and other confounders. Doppler evaluation of donor MCA-PSV prior to laser surgery may help stratify TTTS staging to evaluate the risk of donor fetal demise. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Neurological morbidity in monochorionic twins with selective fetal growth restriction

The increased risks of various obstetric, maternal and fetal comorbidities of monochorionic twin pregnancies are widely known. However, despite its high prevalence and significance, the assessment of neurological morbidity as more commonly in selective fetal growth restriction (sFGR) is concerned with more health care. This literature review aims to provide more information about such an assessment. To this end, retrospective cases of sFGR were studied in monochorionic twins, already diagnosed, classified and who had the recommended management, published between 2001 and 2018 in 17 scientific articles. In the assessment of fetal mortality, the highest risk of death of the restricted fetus was found in type 3 of sFGR, while type 2 sFGR was responsible for the highest death rates of both fetuses and also the lowest mean gestational age at delivery, 30.9 weeks. Regarding neurological morbidity, however, studies have shown a higher risk of brain damage in the habitually growing twin compared to the restricted one in the case of sFGR. This may be due to prematurity or intermittent diastolic flow on Doppler in type 2 and 3 of sFGR, however, statements about its pathophysiology still lack further studies.

Monochorionic Twins: TTTS, TAPS, and Selective Fetal Growth Restriction

With an increasing incidence of twin gestations, understanding the inherent risks associated with these pregnancies is essential in modern obstetrics. The unique differences in placentation in monochorionic twins leads to unique complications, including twin-to-twin transfusion syndrome, the twin anemia-polycythemia sequence, and selective fetal growth restriction. Not only does the understanding of the monochorionic placenta lead to an understanding of the pathophysiology of the complications of monochorionic twins, but it also has led to the development of highly effective directed fetal therapy via fetoscopic laser coagulation used in twin-to-twin transfusion syndrome.

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.

The High-Risk Profile of Selective Growth Restriction in Monochorionic Twin Pregnancies

The present review aims to provide a critical appraisal of the sonographic diagnosis and follow-up and to evaluate the optimal clinical management of monochorionic twin pregnancies where one of the twins is complicated by selective fetal growth restriction (sFGR). The classification is based on the umbilical artery (UA) diastolic flow reflecting the outcome. If the sFGR twin has positive diastolic flow (Type I) then the prognosis is good, and it does not require close surveillance. Biweekly or weekly sonographic and Doppler surveillance and fetal monitoring are recommended strategies to detect unpredictable complications in type II and type III forms, which are defined by persistently absent/reverse end-diastolic flow (AREDF) or cyclically intermittent absent/reverse end-diastolic flow (iAREDF) in the umbilical waveforms, respectively. The latest forms are associated with an increased risk of unexpected fetal demise of the smaller twin and 10-20% risk of neurological injury in the larger twin in addition to the overall risk of prematurity. The clinical course can be affected by elective fetal therapy ('dichorinization' of the placenta with laser or selective fetal reduction) or elective delivery in the presence of severe fetal deterioration. The prediction of the clinical outcome in complicated cases of type II and III sFGR cases remains elusive. Novel routines in fetal and placental scans in order to predict neurological impairments and unexpected fetal death to optimize the delivery time-point are needed.

Solomon versus selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome: A systematic review and meta-analysis

This meta-analysis aims to compare the perinatal outcome of twin-twin transfusion syndrome (TTTS) pregnancies undergoing selective versus vascular equator (Solomon) fetoscopic laser photocoagulation (FLP). We performed a systematic search in PubMed and Web of Science from inception up to 25 July 2021. Studies comparing the Solomon and selective techniques of FLP for treatment of TTTS pregnancies were eligible. Random-effects or fixed-effect models were used to pool standardized mean differences (SMD) and log odds ratio. Seven studies with a total of 1664 TTTS pregnancies (n = 671 undergoing Solomon and n = 993 selective techniques) were included. As compared to the selective FLP, Solomon was associated with a lower risk of recurrent TTTS compared to the selective technique (Log odds ratio [OR]: -1.167; 95% credible interval [CrI]: -2.01, -0.33; p = 0.021; I² : 67%). In addition, Solomon was significantly associated with a higher risk of placental abruption than the selective technique (Log [OR]: 1.44; 95% CrI: 0.45, 2.47; p = 0.012; I² : 0.0%). Furthermore, a trend for the higher risk of preterm premature rupture of membranes was observed among those undergoing Solomon (Log [OR]: 0.581; 95% CrI: -0.43, 1.49; p = 0.131; I² : 17%). As compared to selective FLP, the Solomon technique for TTTS pregnancies is associated with a significantly lower recurrence of TTTS; however, it significantly increases the risk of placental abruption.

Fetal anemia in monochorionic twins: a review on diagnosis, management, and outcome

INTRODUCTION

Monochorionic twins may develop fetal anemia when blood is unequally distributed via the placental vascular anastomoses. This review focuses on the causes of fetal anemia in complicated monochorionic twins and highlights the differences in management and outcome.

AREAS COVERED

Fetal anemia can occur in the context of twin anemia polycythemia sequence (TAPS), chronic twin-twin transfusion syndrome (TTTS) and acute peripartum TTTS, and in cotwins after single fetal demise. Diagnosis of fetal anemia is based on abnormal Doppler ultrasound measurements. Management options include fetoscopic laser surgery, intrauterine blood transfusion, or expectant management, depending on the type of complication and the severity of the disease. In all complications, fetal anemia may lead to perinatal mortality, neonatal morbidity, severe cerebral injury, and long-term neurodevelopmental impairment. In TAPS specifically, anemic donors may also show bilateral deafness.

EXPERT OPINION

Knowledge on the diagnosis and optimal treatment in TTTS is nowadays widespread, but caregivers often fail to distinguish TAPS from acute peripartum TTTS at birth. A full blood count including reticulocyte count is required, and placental dye injection is extremely helpful to reach the correct diagnosis and establish the optimal management.

Twin Anemia-Polycythemia Sequence (TAPS): From Basic Research to Clinical Practice

Twin pregnancy is associated with an increased risk of perinatal and maternal complications, and early establishment of the chorionicity type defines this risk. In monochorionic (MC) pregnancies, the fetuses share the same placental mass and exhibit vascular anastomoses crossing the intertwin membrane, and the combination and pattern of anastomoses determine the primary clinical picture and occurrence of future complications. Twin Anemia-Polycythemia Sequence (TAPS) was first described in 2006 after fetoscopic laser surgery in twin-to-twin transfusion syndrome (TTTS) twins, and in 2007, the first spontaneous cases were reported, recognizing TAPS as an individualized vascular identity in fetofetal transfusion syndromes. There are two types of TAPS: spontaneous (3-5%) and iatrogenic or postlaser (2-16%). TAPS consists of small diameter arteriovenous anastomoses (<1 mm) and low-rate, small-caliber AA anastomoses in the absence of amniotic fluid discordances. There are certain antenatal and postnatal diagnostic criteria, which have progressively evolved over time. New, additional secondary markers have been proposed, and their reliability is being studied. The best screening protocol for TAPS in MC twins is still a matter of debate. This review provides a survey of the relevant literature on the epidemiology, vascular pathophysiology, underlying hemodynamic factors that regulate mismatched vascular connections, and diagnostic criteria of this condition. The aim is to increase awareness and knowledge about this recently identified and frequently unrecognized and misdiagnosed pathology.

The Value of Delta Middle Cerebral Artery Peak Systolic Velocity for the Prediction of Twin Anemia-Polycythemia Sequence-Analysis of a Heterogenous Cohort of Monochorionic Twins

Introduction: Twin anemia-polycythemia sequence (TAPS) is a complication in monochorionic-diamniotic (MCDA) twin pregnancies. This study analyzes whether the prenatal diagnosis using delta middle cerebral artery-peak systolic velocity (MCA-PSV) > 0.5 multiples of the median (MoM) (delta group) detects more TAPS cases than the guideline-based diagnosis using the MCA-PSV cut off levels of >1.5 and <1.0 MoM (cut-off group), in a heterogenous group of MCDA twins. Methods: A retrospective analysis of 348 live-born MCDA twin pregnancies from 2010 to 2021 with available information on MCA-PSV within one week before delivery and hemoglobin-values within 24 h postnatally were considered eligible. Results: Among postnatal confirmed twin pairs with TAPS, the cut-off group showed lower sensitivity than the delta group (33% vs. 82%). Specificity proved higher in the cut-off group with 97% than in the delta group at 86%. The risk that a TAPS is mistakenly not recognized prenatally is higher in the cut-off group than in the delta group (52% vs. 18%). Conclusions: Our data shows that delta MCA-PSV > 0.5 MoM detects more cases of TAPS, which would not have been diagnosed prenatally according to the current guidelines. In the collective examined in the present study, TAPS diagnostics using delta MCA-PSV proved to be a more robust method.

Solomon technique vs selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome: systematic review and meta-analysis of maternal and perinatal outcomes

OBJECTIVE

To ascertain maternal and perinatal outcomes of monochorionic twin pregnancies complicated by twin-twin transfusion syndrome (TTTS) treated with the Solomon technique compared with selective fetoscopic laser photocoagulation (SFLP) of placental anastomoses.

METHODS

MEDLINE, EMBASE and The Cochrane Library were searched to identify relevant studies. The outcomes observed were perinatal loss and survival, preterm prelabor rupture of membranes (PPROM), preterm birth (PTB), gestational age (GA) at delivery, interval between laser treatment and delivery, maternal bleeding, septostomy or chorioamniotic separation, placental abruption, twin anemia-polycythemia sequence (TAPS), recurrence of TTTS, neonatal morbidity and neurological morbidity. Random-effects head-to-head meta-analyses were used to analyze the data. Pooled odds ratios (OR) and mean differences (MD) and their 95% CIs were calculated.

RESULTS

Nine studies were included in the systematic review. There was generally no difference in the main maternal and pregnancy characteristics between pregnancies treated using the Solomon technique and those treated using SFLP of placental anastomoses. The risks of fetal loss (pooled OR, 0.69 (95% CI, 0.50-0.95); P = 0.023), neonatal death (pooled OR, 0.37 (95% CI, 0.16-0.84); P = 0.018) and perinatal loss (pooled OR, 0.56 (95% CI, 0.38-0.83); P = 0.004) were significantly lower in pregnancies treated using the Solomon technique than in those treated with SFLP. Likewise, pregnancies treated using the Solomon technique had a significantly higher chance of survival of at least one twin (pooled OR, 2.31 (95% CI, 1.03-5.19); P = 0.004) and double survival (pooled OR, 2.18 (95% CI, 1.29-3.70); P = 0.001). There was no difference in the risk of PPROM (P = 0.603), PPROM within 10 days from laser surgery (P = 0.982), PTB (P = 0.207), maternal bleeding (P = 0.219), septostomy or chorioamniotic separation (P = 0.224) or chorioamnionitis (P = 0.135) between the two groups, while the risk of placental abruption was higher in pregnancies treated using the Solomon technique (pooled OR, 2.90 (95% CI, 1.55-5.44); P = 0.001). In the Solomon technique group, pregnancies delivered at a significantly earlier GA than did those treated with SFLP (pooled MD, -0.625 weeks (95% CI, -0.90 to -0.35 weeks); P < 0.001), while there was no difference in the interval between laser treatment and delivery (P = 0.589). The rate of recurrence of TTTS was significantly lower in pregnancies undergoing the Solomon technique (pooled OR, 0.43 (95% CI, 0.22-0.81); P < 0.001), while there was no difference in the risk of TAPS between the two groups (P = 0.792). Finally, there was no difference in the overall risk of neonatal morbidity (P = 0.382) or neurological morbidity (P = 0.247) between the two groups.

CONCLUSIONS

Monochorionic twin pregnancies complicated by TTTS undergoing laser treatment using the Solomon technique had a significantly higher survival rate and lower recurrence rate of TTTS but were associated with an increased risk of placental abruption and earlier GA at delivery compared to those treated with SFLP. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Clinical Value and Treatment Progress of Prenatal Ultrasonography in Twin Pregnancy: A Systematic Review

Assisted reproductive technology has continued to develop in recent years, the technology has become more and more mature, and it has improved the total gestational age of the population. Assisted reproductive technology has improved twin pregnancy rates with the use of ovulation-inducing drugs. The risk factor of twins is much higher than singletons, and adverse pregnancy outcomes such as stillbirth and premature birth are more likely to occur than singletons, especially the special complications of monochorionic twins (MC), and the neonatal mortality and morbidity are also increased. Prenatal diagnosis and prognosis of twin pregnancy, as well as therapeutic interventions, are of current concern. Ultrasound can realize the understanding of intrauterine growth and development of twin pregnancy fetuses during pregnancy, can more accurately determine gestational age, organ function, and maturity, and timely detect fetal growth and development abnormalities in twin pregnancy, while the prognosis and treatment still need further improvement. The purpose of this study was to investigate the clinical value and treatment progress of prenatal ultrasound monitoring in twin pregnancy.

Fetal and neonatal brain injury in twins complicated by twin anemia polycythemia sequence

OBJECTIVES

To determine the rate of fetal and neonatal brain lesions and define risk factors for such lesions in pregnancies complicated by Twin Anemia Polycythemia Sequence (TAPS).

METHODS

A retrospective cohort study of monochorionic twin pregnancies which were diagnosed with TAPS in a single tertiary medical center between 2013 and 2021. Pregnancies were followed with fetal brain neurosonogram every 2 weeks and fetal brain MRI (magnetic resonance imaging) was performed when indicated at 28-32 weeks of gestation; post-natal brain imaging included neonatal brain ultrasound. Pregnancies with pre- and post-natal brain lesions were compared to those without such findings.

RESULTS

Overall, 23 monochorionic diamniotic pregnancies were diagnosed with TAPS over the study period resulting in perinatal survival of 91.3% (42/46). In 6/23 (26%) pregnancies and 7/46 (15.2%) fetuses pre- or post-natal brain lesions were detected, of whom five were the polycythemic twins and two were the anemic twins. Brain findings included intra-cerebral hemorrhage and ischemic lesions and were diagnosed prenatally in 6/7 (85.7%) cases. No risk factors for severe brain lesions were identified.

CONCLUSIONS

TAPS may place the fetuses and neonates at increased risk for cerebral injuries. Incorporation of fetal brain imaging protocols may enhance precise prenatal diagnosis and allow for accurate parental counseling and post-natal care.

Perinatal outcomes of pregnancies with twin-anemia polycythemia sequence complicating twin-to-twin transfusion syndrome using different twin-anemia polycythemia sequence diagnostic criteria

OBJECTIVE

To investigate whether the presence of twin-anemia polycythemia sequence (TAPS) with twin-to-twin transfusion syndrome (TTTS) or post-laser TAPS would change outcomes using different TAPS diagnostic criteria.

METHODS

TTTS cases undergoing laser surgery between 2012 and 2020 were included. Groups included pre-laser TTTS-only compared to TTTS + TAPS, and no post-laser TAPS compared to post-laser TAPS. Three prenatal TAPS diagnostic criteria were used: group A: middle cerebral artery-peak systolic velocity (MCA-PSV) > 1.5 MoM in one twin and <1 MoM in the other twin, group B: inter-twin MCA-PSV difference >1 MoM, and group C: inter-twin MCA-PSV difference >0.5 MoM. Perinatal outcomes including survival and severe cerebral injury were investigated.

RESULTS

174 laser procedures were included. TTTS + TAPS cases were 16 in group A, 17 in group B, and 29 in group C. Post-laser TAPS cases were 11 in group A, 6 in group B, and 12 in group C. There were no differences in preoperative, operative variables and outcomes including survival and severe cerebral injury between groups using all three TAPS diagnostic criteria. The incidence of TTTS + TAPS was highest in group C (16.7%), then group B (9.8%), followed by group A (9.2%). The incidence of post-laser TAPS was highest in group C (9%), then group A (8.3%), followed by group B (4.5%).

CONCLUSION

Presence of TAPS complicating TTTS and presence of post-laser TAPS do not seem to be associated with worse perinatal outcomes including postnatal-ultrasound detected cerebral injury using three different TAPS criteria. Collaborative studies are needed to investigate the validity and the performance of different TAPS criteria.

Selective vs complete fetoscopic coagulation of vascular equator: a matched comparative study

BACKGROUND

Complete coagulation of the vascular equator (as in the Solomon technique) has been suggested to reduce postoperative complications such as twin anemia polycythemia syndrome and the recurrence of twin-twin transfusion syndrome following fetoscopic laser coagulation of chorionic vessels for twin-twin transfusion syndrome.

OBJECTIVE

We aimed to evaluate the benefit of this technique on perinatal outcomes compared with selective ablation of anastomoses.

STUDY DESIGN

We conducted a monocentric retrospective study comparing selective laser coagulation of anastomoses to the Solomon technique from January 2006 to August 2020. To adjust for potential confounders, the cases operated by selective surgery were matched to the cases operated with the Solomon technique according to the gestational age at laser therapy, placental localization, and Quintero stage using propensity score matching.

RESULTS

With a total of 994 cases, 399 matched pairs were included in the analysis. Compared with selective ablation, the Solomon technique was associated with significantly improved survival: the overall twin survival at delivery and discharge was 72% vs 79% (P=.003) and 69% vs 75% (P=.006), respectively; the double twin survival rate at discharge was 55% vs 65% (P=.02), respectively, and the rate of intrauterine death dropped from 18% to 12% (P=.003), respectively. The Solomon technique significantly reduced the rate of twin anemia polycythemia syndrome (10% vs 4%; P=.02), leading to fewer secondary rescue procedures (13% vs 7.3%; P=.01). However, the Solomon technique was associated with an increased risk of preterm rupture of membranes, especially at early gestational ages (3.8% vs 11%; P<.001 for preterm rupture of membranes <24 weeks). Among the survivors at delivery, both the groups had similar gestational ages at birth. Both neonatal mortality and severe neurologic morbidity were similar in both the groups. However, an increased risk of bronchopulmonary dysplasia was found in the Solomon group (4.5% vs 12%; P<.001).

CONCLUSION

Although the risk of preterm premature rupture of membranes has increased, the introduction of the Solomon technique has significantly improved perinatal outcomes in pregnancies affected with twin-twin transfusion syndrome.

Neonatal management and outcome in complicated monochorionic twins: What have we learned in the past decade and what should you know?

Monochorionic (MC) twin pregnancies are at increased risk of neonatal morbidity and mortality due to the shared placenta with vascular connections that can give rise to various complications, including twin-twin transfusion syndrome, twin anemia polycythemia sequence (TAPS), selective fetal growth restriction, and other hematological imbalances at birth. Each complication presents its own challenges and considerations in the neonatal period. Measurement of hemoglobin levels and reticulocyte count is required to establish a correct diagnosis. Placenta dye injection is needed to properly distinguish between the various conditions. Risk factors for adverse outcome in MC twins include prematurity, severe cerebral injury, and the type of MC pregnancy complication. We, therefore, recommend cerebral ultrasound examinations in all complicated MC twins at birth to rule out a severe brain injury. Lastly, we strongly encourage screening for hearing loss using automated auditory brainstem response in all spontaneous TAPS donors to prevent permanent speech development delay.

Pathophysiology, diagnosis, and management of twin anemia polycythemia sequence in monochorionic multiple gestations

Twin anemia polycythemia sequence (TAPS) is a consequence of unequal sharing of red blood cells between monochorionic twins resulting in anemia in the donor and polycythemia in the recipient twin. Prenatally TAPS can occur spontaneously or complicate incomplete laser surgery for twin transfusion syndrome. While there may be clinical overlap with twin transfusion syndrome or selective fetal growth restriction, diagnosis relies on Doppler measurement of middle cerebral artery peak systolic velocities. Significantly discordant velocities are diagnostic, while severity staging is based on signs of cardiovascular compromise. Conservative management, fetoscopic laser coagulation, selective twin reduction, fetal blood and exchange transfusion, and delivery may be selected guided by the gestational age of diagnosis, the severity of the condition, the likelihood of success, and the patients' priorities. Prenatal curative treatment that minimizes the risk for prematurity and residual morbidity at birth is most likely to offer the greatest short-term and long-term benefits.

Perinatal outcome of pregnancy complicated by twin anemia-polycythemia sequence: systematic review and meta-analysis

OBJECTIVE

To report the perinatal outcome of monochorionic diamniotic (MCDA) twin pregnancies complicated by twin anemia-polycythemia sequence (TAPS), according to the type of TAPS (spontaneous or postlaser) and the management option adopted.

METHODS

MEDLINE, EMBASE and The Cochrane Library databases were searched for studies reporting on the outcome of twin pregnancies complicated by TAPS. Inclusion criteria were non-anomalous MCDA twin pregnancies with a diagnosis of TAPS. The primary outcome was perinatal mortality; secondary outcomes were neonatal morbidity and preterm birth (PTB). The outcomes were stratified according to the type of TAPS (spontaneous or following laser treatment for twin-twin transfusion syndrome) and the management option adopted (expectant, laser surgery, intrauterine transfusion (IUT) or selective reduction (SR)). Random-effects meta-analysis of proportions was used to analyze the data.

RESULTS

Perinatal outcome was assessed according to whether TAPS occurred spontaneously or after laser treatment in 506 pregnancies (38 studies). Intrauterine death (IUD) occurred in 5.2% (95% CI, 3.6-7.1%) of twins with spontaneous TAPS and in 10.2% (95% CI, 7.4-13.3%) of those with postlaser TAPS, while the corresponding rates of neonatal death were 4.0% (95% CI, 2.6-5.7%) and 9.2% (95% CI, 6.6-12.3%), respectively. Severe neonatal morbidity occurred in 29.3% (95% CI, 25.6-33.1%) of twins after spontaneous TAPS and in 33.3% (95% CI, 17.4-51.8%) after postlaser TAPS, while the corresponding rates of severe neurological morbidity were 4.0% (95% CI, 3.5-5.7%) and 11.1% (95% CI, 6.2-17.2%), respectively. PTB complicated 86.3% (95% CI, 77.2-93.3%) of pregnancies with spontaneous TAPS and all cases with postlaser TAPS (100% (95% CI, 84.3-100%)). Iatrogenic PTB was more frequent than spontaneous PTB in both groups. Perinatal outcome was assessed according to the management option adopted in 417 pregnancies (21 studies). IUD occurred in 9.8% (95% CI, 4.3-17.1%) of twins managed expectantly and in 13.1% (95% CI, 9.2-17.6%), 12.1% (95% CI, 7.7-17.3%) and 7.6% (95% CI, 1.3-18.5%) of those treated with laser surgery, IUT and SR, respectively. Severe neonatal morbidity affected 27.3% (95% CI, 13.6-43.6%) of twins in the expectant-management group, 28.7% (95% CI, 22.7-35.1%) of those in the laser-surgery group, 38.2% (95% CI, 18.3-60.5%) of those in the IUT group and 23.3% (95% CI, 10.5-39.2%) of those in the SR group. PTB complicated 80.4% (95% CI, 59.8-94.8%), 73.4% (95% CI, 48.1-92.3%), 100% (95% CI, 76.5-100%) and 100% (95% CI, 39.8-100%) of pregnancies after expectant management, laser surgery, IUT and SR, respectively.

CONCLUSIONS

The present meta-analysis provides pooled estimates of the risks of perinatal mortality, neonatal morbidity and PTB in twin pregnancies complicated by TAPS, stratified by the type of TAPS and the management option adopted. Although a direct comparison could not be performed, the results from this systematic review suggest that spontaneous TAPS may have a better prognosis than postlaser TAPS. No differences in terms of mortality and morbidity were observed when comparing different management options for TAPS, although these findings should be interpreted with caution in view of the limitations of the included studies. Individualized prenatal management, taking into account the severity of TAPS and gestational age, is currently the recommended strategy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Predicting Adverse Outcomes in Monochorionic-Diamniotic Twins: The Role of Intertwin Discrepancy in Middle Cerebral Artery Doppler Measurements and the Cerebroplacental Ratio

OBJECTIVE

This study was aimed to evaluate the role of intertwin discrepancy in middle cerebral artery peak systolic velocity (MCA-PSV) and cerebroplacental ratio (CPR) for the prediction of adverse outcomes in monochorionic-diamniotic (MCDA) twin pregnancies.

STUDY DESIGN

A retrospective cohort study of MCDA pregnancies that underwent ultrasound surveillance at a perinatal referral center from 2007 to 2017. Intertwin MCA-PSV discrepancy (MCA-Δ_PSV-MoM) was defined as the absolute difference of MCA-PSV multiple of the median (MoM) for gestational age between twins. Intertwin CPR discrepancy (CPR-Δ) was defined as the absolute difference of CPR between twins. The maximum MCA-Δ_PSV-MoM and CPR-Δ before and after 26 weeks of gestation were assessed as predictors of pregnancy and neonatal outcomes through simple logistic regression models and Pearson's correlation coefficients. Receiver operating characteristic (ROC) curves were generated to determine the predictive value of maximum MCA-Δ_PSV-MoM and CPR-Δ.

RESULTS

A total of 143 MCDA pregnancies met inclusion criteria. There was a significant association between MCA-Δ_PSV-MoM at <26 weeks and the development of twin anemia-polycythemia sequence (TAPS; p = 0.007), intrauterine fetal demise (IUFD; p = 0.009), and neonatal intensive care unit (NICU) admission (p < 0.05). MCA-Δ_PSV-MoM at ≥26 weeks was associated with the development of TAPS (p < 0.001). CPR-Δ at <26 weeks was associated with the development of twin-twin transfusion syndrome (TTTS; p = 0.03) and NICU admission (p = 0.02). MCA-Δ_PSV-MoM at ≥26 weeks was highly predictive of TAPS (area under curve [AUC] = 0.92). A cut-off of 0.44 would identify TAPS with 100% sensitivity and 73% specificity.

CONCLUSION

In MCDA pregnancies, intertwin MCA and CPR discrepancies are associated with adverse pregnancy and neonatal outcomes, including TAPS, TTTS, IUFD, and NICU admission. Evaluation of intertwin MCA and CPR differences demonstrated the potential for clinical predictive utility in the surveillance of MCDA twin pregnancies.

KEY POINTS

· Intertwin discrepancy of MCA-PSV and CPR is associated with adverse pregnancy outcomes.. · Intertwin differences in Doppler ultrasound may occur prior to meeting diagnostic criteria for TTTS or TAPS.. · There is potential clinical predictive utility in MCA and CPR surveillance of MCDA twin pregnancies..

Dual demise following laser surgery for twin-twin transfusion syndrome: Analysis of 52 cases at a single fetal surgery center

OBJECTIVE

To evaluate all individual cases of dual twin demise following laser surgery for twin-twin transfusion syndrome (TTTS).

METHOD

This is an analysis of all monochorionic diamniotic twin gestations with TTTS complicated by dual demise following laser surgery from 2006 to 2019. Cases were reviewed by (1) a fetal surgeon researcher and (2) a panel of independent experienced maternal-fetal medicine specialists to code an etiology of demise for the donor and recipient, and to assess for possible preventability.

RESULTS

Of 753 twins that underwent laser surgery for TTTS, 52 (6.9%) had postoperative dual demise. In this subgroup, gestational age at surgery was 19.5 (16.1-24.9) weeks, and 36 (69.2%) patients were Quintero stage III and IV. The most common etiology was the spectrum of disorders leading to preterm delivery, which included cervical insufficiency, preterm premature rupture of membranes, and preterm labor (44.2% and 48.1%, donor and recipient, respectively). Some degree of preventability was estimated for 23.1% of dual demises.

CONCLUSIONS

The most common cause of dual demise post laser surgery for TTTS was preterm birth, reinforcing the need for studies regarding the etiology and prevention of post-fetoscopy prematurity. Nearly one-quarter of dual demise cases were deemed potentially preventable.

Pregnancy and parenting experiences of women with twin-to-twin transfusion syndrome: a qualitative study

Background

Qualitative research can reflect the actual thoughts and experience of research subjects and can be used to explore the experiences of women presenting with twin-to-twin transfusion syndrome (TTTS) to facilitate the provision of targeted psychological support.

Methods

A semi-structured interview method was used to assess the pregnancy and parenting experiences of women with TTTS. Colaizzi method was used for data analysis.

Results

Eighteen women participated in the study. We found that women with TTTS during pregnancy experienced persistent worry about their children’s health from the disease diagnosis to the subsequent parenting processes, even in case of minor changes in their children’s health. The lack of an efficient referral process and health information increased their uncertainty about their children’s health.

Conclusion

In addition to the children’s health, other difficulties encountered during pregnancy and parenting may aggravate the pressure. Clinicians in the first-visit hospital and foetal medicine centre should improve the referral process and establish a follow-up system to provide women with health information and psychological support.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04057-0.

Ultrasound findings in Pseudoamniotic band syndrome after fetoscopic surgery: Antenatal description of three cases and review of literature

INTRODUCTION

Pseudoamniotic Bands Syndrome (PABS) was described as iatrogenic complication from in utero procedure as fetoscopy.

OBJECTIVE

The aim of our study was to identify the ultrasound findings in PABS diagnosed prenatally METHODS: First, we reported cases of PABS following fetoscopic surgery that were diagnosed prenatally in our institution. We collected all ultrasound data with fetal and neonatal issues. Then, a literature review was conducted by searching the Medline and Cochrane Library computer databases until 2020 to find publications that involve PABS diagnosed prenatally or postnatally. The following keywords were selected and combined: "pseudoamniotic bands syndrome", "fetoscopy", "fetal surgery".

RESULTS

We collected three cases of PABS diagnosed prenatally in our center following fetoscopic procedures for complicated monochorionic pregnancies. Among these cases, we reported the following ultrasound findings: floating membrane, amniotic bands, striction of limbs, perilesional edema, reduced member size and anomalies of Doppler flow. Including our cases, we reported 23 published PABS of which eight (35%) were prenatally diagnosed. When it was diagnosed, mean GA at PABS diagnosis was 23 weeks (mean interval from fetoscopic to diagnosis was 4 weeks). Three fetoscopic release of amniotic bands were described. The principal parts affected were the limbs, more particularly the extremities.

CONCLUSION

PABS was accessible to an antenatal diagnosis, as well as ABS. Although it is a rare complication of fetoscopic surgery, ultrasound examinations after procedure should focus on PABS signs to improve prognosis of the neonates.

Intrauterine fetoscopic laser surgery versus expectant management in stage 1 twin-to-twin transfusion syndrome: an international randomized trial

BACKGROUND

Selective fetoscopic laser coagulation of the intertwin anastomotic chorionic vessels is the first-line treatment for twin-twin transfusion syndrome. However, in stage 1 twin-twin transfusion syndrome, the risks of intrauterine surgery may be higher than those of the natural progression of the condition.

OBJECTIVE

This study aimed to compare immediate surgery and expectant follow-up in stage 1 twin-twin transfusion syndrome.

STUDY DESIGN

We conducted a multicentric randomized trial, which recruited from 2011 to 2018 with a 6-month postnatal follow-up. The study was conducted in 9 fetal medicine centers in Europe and the Unites States. Asymptomatic women with stage 1 twin-twin transfusion syndrome between 16 and 26 weeks' gestation, a cervix of >15 mm, and access to a surgical center within 48 hours of diagnosis were randomized between expectant management and immediate surgery. In patients allocated to immediate laser treatment, percutaneous laser coagulation of anastomotic vessels was performed within 72 hours. In patients allocated to expectant management, a weekly ultrasound follow-up was planned. Rescue fetoscopic coagulation of anastomoses was offered if the syndrome worsened as seen during a follow-up, either because of progression to a higher Quintero stage or because of the maternal complications of polyhydramnios. The primary outcome was survival at 6 months without severe neurologic morbidity. Severe complications of prematurity and maternal morbidity were secondary outcomes.

RESULTS

The trial was stopped at 117 of 200 planned inclusions for slow accrual rate over 7 years: 58 women were allocated to expectant management and 59 to immediate laser treatment. Intact survival was seen in 84 of 109 (77%) expectant cases and in 89 of 114 (78%) (P=.88) immediate surgery cases, and severe neurologic morbidity occurred in 5 of 109 (4.6%) and 3 of 114 (2.6%) (P=.49) cases in the expectant and immediate surgery groups, respectively. In patients followed expectantly, 24 of 58 (41%) cases remained stable with dual intact survival in 36 of 44 (86%) cases at 6 months. Intact survival was lower following surgery than for the nonprogressive cases, although nonsignificantly (78% and 71% following immediate and rescue surgery, respectively).

CONCLUSION

It is unlikely that early fetal surgery is of benefit for stage 1 twin-twin transfusion syndrome in asymptomatic pregnant women with a long cervix. Although expectant management is reasonable for these cases, 60% of the cases will progress and require rapid transfer to a surgical center.

Feasibility of fetal left modified myocardial performance index in twin anemia polycythemia sequence and perinatal outcomes after antenatal intervention

OBJECTIVE

To evaluate the feasibility and clinical value of fetal left modified myocardial performance index (Mod-MPI) in assessment and management of prenatal twin anemia polycythemia sequence (TAPS).

METHODS

We retrospectively reviewed fetuses with TAPS diagnosed prenatally between 2015 and 2019 at Asan Medical Center. Doppler ultrasound evaluation including the peak systolic velocity (PSV) of the middle cerebral artery (MCA) and fetal echocardiography including left Mod-MPI were evaluated and followed up after antenatal management.

RESULTS

Among 10 cases of fetal twin pregnancies with prenatal TAPS, six were spontaneous and four were post-laser TAPS. Left Mod-MPI was abnormal in one or both twins of nine cases (90%) including all post-laser TAPS (n = 4) and 83.3% of spontaneous TAPS (n = 5). Three recipients, one donor and three former recipients/new donors had elevated left Mod-MPI values, and one donor, one recipient, two former donors/new recipients had decreased values. Antenatal intervention was performed in eight cases with intrauterine transfusion (n = 4), fetoscopic laser surgery (n = 2), radiofrequency ablation (n = 1), and intrauterine transfusion followed by radiofrequency ablation (n = 1). The remaining two cases were either delivered or managed expectantly. MCA-PSV and left Mod-MPI became normal on the follow-up scans in all cases except the delivered case. There were four fetal deaths: two occurred spontaneously and two were selectively terminated by radiofrequency ablation. Overall perinatal survival per fetus was 80% (16/20) and the median gestational age at delivery was 34.4 (range, 29.2-37.4) weeks. Neither postnatal death nor neurodevelopmental delay occurred during a median follow-up of 13 months (range, 0.25-60 months).

CONCLUSION

Fetal left Mod-MPI was useful for assessment of compromised fetal cardiac function in cases with prenatal TAPS. Application of fetal left Mod-MPI in prenatal staging of TAPS might help evaluate the severity of TAPS and decide timely antenatal intervention.

Risk Profiling of the Solomon Technique versus Selective Technique of Fetoscopic Laser Surgery for Twin-Twin Transfusion Syndrome

We evaluated the outcomes and adverse events after fetoscopic laser surgery (FLS) for twin-twin transfusion syndrome (TTTS) using the Solomon technique in comparison to the selective technique. A retrospective analysis of a single-center consecutive cohort of FLS-treated TTTS using the selective (January 2010 to July 2014) and Solomon (August 2014 to December 2017) techniques was performed. Among 395 cases, 227 underwent selective coagulation and 168 underwent the Solomon technique. The incidence rates of recurrent TTTS (Solomon vs. selective: 0% vs. .9%, p = .510) and twin anemia-polycythemia sequence (.6% vs. .4%, p = .670) were very low in both groups. The incidence rates of placental abruption (Solomon vs. selective: 10.7% vs. 3.5%, p = .007) and preterm premature rupture of the membranes (pPROM) with subsequent delivery before 32 weeks (20.2% vs. 7.1%, p < .001) were higher in the Solomon group. The median birth recipient weight was significantly smaller in the Solomon group (1790 g vs. 1933 g, p = .049). The rate of survival of at least one twin was significantly higher in the Solomon group (98.2% vs. 93.8%, p = .046). The Solomon technique and total laser energy were significant risk factors for pPROM (odds ratio: 2.64, 1.07, 95% CI [1.32, 5.28], [1.01, 1.13], p = .006, p = .014, respectively). These findings suggest that the Solomon technique led to superior survival outcomes but increased risks of placental abruption, pPROM and fetal growth impairment. Total laser energy was associated with the occurrence of pPROM. Close attention to adverse events is required for perinatal management after FLS to treat TTTS using the Solomon technique.

Perinatal outcomes and factors affecting the survival rate of fetuses with twin-to-twin transfusion syndrome treated with fetoscopic laser coagulation: a single-center seven-year experience

OBJECTIVES

This single-center study aimed to assess the perinatal outcomes and its associated factors in fetuses with twin-to-twin transfusion syndrome (TTTS) treated by fetoscopic laser coagulation (FLC).

METHODS

In this retrospective study, we included fetuses prenatally diagnosed with TTTS at Asan Medical Center, Seoul, Korea, between October 2011 and December 2018. All patients with TTTS stage II or higher and those with stage I TTTS coupled with symptomatic polyhydramnios or cardiac dysfunction were eligible for FLC.

RESULTS

A total of 172 cases of monochorionic diamniotic twins and one case of dichorionic triamniotic triplets were prenatally diagnosed with TTTS and treated with FLC. The median gestational ages (GAs) at diagnosis and FLC were 20.3 and 20.5 weeks, respectively. The median GA of survivors at delivery was 32.5 weeks. The overall at least one twin- and double-survival rates within 28 days after birth were 82.1% and 55.5%, respectively. The GAs at diagnosis and FLC, Quintero stage, inter-twin weight discordance, associated selective intrauterine growth restriction (sIUGR), procedure time, volume of amnioreduction, preterm prelabor rupture of membranes (PPROM) within one week after FLC, intraoperative intrauterine bleeding, and chorioamnionitis were significant predictive factors of perinatal death. Associated sIUGR, absent end-diastolic flow of umbilical artery, and abnormal cord insertion were significantly associated with donor demise in utero, whereas lower GA at diagnosis and FLC, smaller twins at FLC, pulsatile umbilical vein, and presence of mitral regurgitation were significantly associated with recipient demise in utero. Since the application of the Solomon technique, the survival rate has improved from 75.4% to 88.8%. The FLC before 17 weeks was associated with PPROM within one week after FLC and lower survival rate, whereas that after 24 weeks was associated with twin anemia-polycythemia sequence and higher survival rate. We reached a survival rate of 82% for at least one survival with only 12 procedures.

CONCLUSIONS

FLC is an effective treatment for TTTS. The learning curve reached the acceptable target faster than in previous studies. Several prenatal parameters are identified as predictive factors of fetal survival in TTTS treated with FLC.

Management of Twin Pregnancies: A Comparative Review of National and International Guidelines

Importance

Twin pregnancies are associated with a higher risk of perinatal mortality and morbidity compared with singleton and require more intensive prenatal care.

Objective

The aim of this study was to review and compare the recommendations from published guidelines on twin pregnancies.

Evidence Acquisition

A descriptive review of guidelines from the Royal College of Obstetricians and Gynaecologists, the International Society of Ultrasound in Obstetrics and Gynecology, the Royal Australian and New Zealand College of Obstetricians and Gynaecologists, the National Institute for Health and Care Excellence, the Institute of Obstetricians and Gynaecologists of the Royal College of Physicians of Ireland, the International Federation of Gynecology and Obstetrics, the Society of Obstetricians and Gynaecologists of Canada, and the American College of Obstetricians and Gynecologists on the management of twin pregnancies was conducted.

Results

All the guidelines highlight the importance of an accurate assessment of chorionicity, amnionicity, and gestational age in the first trimester. They also recommend the performance of nuchal translucency and a detailed anomaly scan. The ultrasound surveillance protocol is similar in all guidelines, that is, every 2 weeks for monochorionic and every 4 weeks for dichorionic twins. On the other hand, there are differences regarding the timing and mode of delivery, especially in monochorionic diamniotic twins, in the definition and management of fetal growth discordance, the use of cervical length to screen for preterm birth, and the timing of corticosteroids' administration.

Conclusions

The differences in the reviewed guidelines on the management of twin pregnancies highlight the need for an adoption of an international consensus, in order to improve perinatal outcomes of twin pregnancies.

Twin Anemia Polycythemia Sequence in a Dichorionic Twin Pregnancy Leading to Severe Cerebral Injury in the Recipient

Twin anemia polycythemia sequence (TAPS) is a form of chronic imbalanced feto-fetal transfusion through minuscule placental anastomoses leading to anemia in the TAPS donor and polycythemia in the TAPS recipient and has been reported only in monochorionic twins. We report a very unusual case of TAPS which developed in a dichorionic twin pair, born at a gestational age of 33+2. Twin 1 (recipient) was polycythemic and had a hemoglobin value of 22.4 g/dL, whereas twin 2 (donor) was anemic with a hemoglobin value of 9.8 g/dL and an increased reticulocyte count (72‰). Color dye injection of the placenta revealed the presence of a deep-hidden small veno-venous anastomosis. Dichorionicity was confirmed on histologic examination. Aside from respiratory distress syndrome, the donor twin had an uncomplicated neonatal course. The recipient twin developed a post-hemorrhagic ventricular dilatation requiring treatment with a ventriculoperitoneal shunt and Rickham reservoir. This report shows that in dichorionic twins, placental anastomoses can be present, which can lead to the development of TAPS with severe consequences. Therefore, when a pale and plethoric dichorionic twin pair is born, a complete diagnostic work-up is required, including a full blood count with reticulocytes and placental injection, to investigate the presence and nature of potential underlying feto-fetal transfusion. Once the diagnosis of TAPS has been established, cerebral ultrasound, hearing screening, and long-term follow-up are strongly recommended as these twins have increased risk for severe cerebral injury, hearing loss, and long-term neurodevelopmental impairment.

Antenatal management and neonatal outcomes of monochorionic twin pregnancies in a tertiary teaching hospital: a 10-year review

Monochorionic (MC) pregnancy is a high risk pregnancy with well-defined specific complications, such as twin-to-twin transfusion syndrome (TTTS) and twin anaemia-polycythaemia sequence (TAPS). Laser photocoagulation (LPC) is an effective treatment for both complications. In the current retrospective study, we determined the incidence of MC pregnancy complications in a tertiary care centre during a 10-year period. Single foetal death (FD) beyond 14 weeks' gestation was significantly higher when complicated by either TTTS, TAPS or selective foetal growth restriction (21.4%, 16.7% and 9.1% versus 1.6%, p<.001, p=.02 and p=.04, respectively). We also demonstrated that twins' weight discordance >20% is an independent risk factor for single or double FD after LPC. Consequently, prior to LPC, patients should be counselled that early diagnosis of TTTS, advanced Quintero stages and weight discordances >20% are potential risk factors for FD. Further studies are needed to identify additional risk factors for TTTS and TAPS outcome after LPC.Impact StatementWhat is already known on this subject? Monochorionic (MC) pregnancy is a high risk pregnancy with well-defined specific complications, such as twin-twin transfusion syndrome (TTTS) and twin anaemia-polycythaemia sequence (TAPS). Laser photocoagulation (LPC) is an effective treatment for both complications.What the results of this study add? The results of the current study determined the incidence of MC pregnancy complications in a tertiary care centre in Brussels, and identified that twins' weight discordance >20% is an independent risk factor for single or double foetal death after LPC.What the implications are of these findings for clinical practice and/or further research? Prior to laser coagulation, patients should be counselled that early diagnosis of TTTS, Quintero stages 3 or 4 and weight discordances >20% are potential risk factors for foetal demise. Further studies are needed to identify additional risk factors for TTTS and TAPS outcome after LPC.

Placental Anatomy and Function in Twin Gestations

With an increasing incidence of twin gestations, understanding the inherent risks associated with these pregnancies is essential in modern obstetrics. The unique differences in placentation in twins contribute to the increased risks. Monochorionic twins are susceptible to complications because of their unique placental architecture, including twin-to-twin transfusion syndrome, the twin anemia-polycythemia sequence, selective intrauterine growth restriction, and the twin reversed arterial perfusion sequence. Knowing the clinical correlations of placental anatomy in these gestations helps perinatal pathologists perform a more informed placental evaluation, allowing for better care for the mother and her children.

Prevalence of Extraplacental Anastomoses in Monochorionic Twin Pregnancies

OBJECTIVES

To evaluate the prevalence of extraplacental anastomoses (EPA) and the factors associated.

METHODS

A retrospective study including 144 placentas from monochorionic diamniotic (MCDA) twins delivering at one institution was performed. EPA were defined as any intertwin anastomosis located outside the chorionic plate on macroscopic inspection. The association with perinatal factors and with umbilical cord insertion site was analyzed.

RESULTS

The prevalence of EPA was 4.9% (7/144). Velamentous cord insertion of both twins was significantly associated with the presence of EPA in the multivariate logistic regression model (p = 0.045).

DISCUSSION

EPA was found in ≈5% of MCDA twin pregnancies.

Treatment and outcome of 370 cases with spontaneous or post-laser twin anemia-polycythemia sequence managed in 17 fetal therapy centers

OBJECTIVE

To investigate the antenatal management and outcome in a large international cohort of monochorionic twin pregnancies with spontaneous or post-laser twin anemia-polycythemia sequence (TAPS).

METHODS

This study analyzed data of monochorionic twin pregnancies diagnosed antenatally with spontaneous or post-laser TAPS in 17 fetal therapy centers, recorded in the TAPS Registry between 2014 and 2019. Antenatal diagnosis of TAPS was based on fetal middle cerebral artery peak systolic velocity > 1.5 multiples of the median (MoM) in the TAPS donor and < 1.0 MoM in the TAPS recipient. The following antenatal management groups were defined: expectant management, delivery within 7 days after diagnosis, intrauterine transfusion (IUT) (with or without partial exchange transfusion (PET)), laser surgery and selective feticide. Cases were assigned to the management groups based on the first treatment that was received after diagnosis of TAPS. The primary outcomes were perinatal mortality and severe neonatal morbidity. The secondary outcome was diagnosis-to-birth interval.

RESULTS

In total, 370 monochorionic twin pregnancies were diagnosed antenatally with TAPS during the study period and included in the study. Of these, 31% (n = 113) were managed expectantly, 30% (n = 110) with laser surgery, 19% (n = 70) with IUT (± PET), 12% (n = 43) with delivery, 8% (n = 30) with selective feticide and 1% (n = 4) underwent termination of pregnancy. Perinatal mortality occurred in 17% (39/225) of pregnancies in the expectant-management group, 18% (38/215) in the laser group, 18% (25/140) in the IUT (± PET) group, 10% (9/86) in the delivery group and in 7% (2/30) of the cotwins in the selective-feticide group. The incidence of severe neonatal morbidity was 49% (41/84) in the delivery group, 46% (56/122) in the IUT (± PET) group, 31% (60/193) in the expectant-management group, 31% (57/182) in the laser-surgery group and 25% (7/28) in the selective-feticide group. Median diagnosis-to-birth interval was longest after selective feticide (10.5 (interquartile range (IQR), 4.2-14.9) weeks), followed by laser surgery (9.7 (IQR, 6.6-12.7) weeks), expectant management (7.8 (IQR, 3.8-14.4) weeks), IUT (± PET) (4.0 (IQR, 2.0-6.9) weeks) and delivery (0.3 (IQR, 0.0-0.5) weeks). Treatment choice for TAPS varied greatly within and between the 17 fetal therapy centers.

CONCLUSIONS

Antenatal treatment for TAPS differs considerably amongst fetal therapy centers. Perinatal mortality and morbidity were high in all management groups. Prolongation of pregnancy was best achieved by expectant management, treatment by laser surgery or selective feticide. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Consensus diagnostic criteria and monitoring of twin anemia-polycythemia sequence: Delphi procedure

OBJECTIVES

Twin anemia-polycythemia sequence (TAPS) is associated with increased perinatal morbidity and mortality. Inconsistencies in the diagnostic criteria for TAPS exist, which hinder the ability to establish robust evidence-based management or monitoring protocols. The main aim of this study was to determine, by expert consensus using a Delphi procedure, the key diagnostic features and optimal monitoring approach for TAPS.

METHODS

A Delphi process was conducted among an international panel of experts on TAPS. Panel members were provided with a list of literature-based parameters for diagnosing and monitoring TAPS. They were asked to rate the importance of the parameters on a five-point Likert scale. Consensus was sought to determine the cut-off values for accepted parameters, as well as parameters used in the monitoring of and assessment of outcome in twin pregnancy complicated by TAPS.

RESULTS

A total of 132 experts were approached. Fifty experts joined the first round, of whom 33 (66%) completed all three rounds. There was agreement that the monitoring interval for the development of TAPS should be every 2 weeks and that the severity should be assessed antenatally using a classification system based on middle cerebral artery (MCA) peak systolic velocity (PSV), but there was no agreement on the gestational age at which to start monitoring. Once the diagnosis of TAPS is made, monitoring should be scheduled weekly. For the antenatal diagnosis of TAPS, the combination of MCA-PSV ≥ 1.5 MoM in the anemic twin and ≤ 0.8 MoM in the polycythemic twin was agreed. Alternatively, MCA-PSV discordance ≥ 1 MoM can be used to diagnose TAPS. Postnatally, hemoglobin difference ≥ 8 g/dL and intertwin reticulocyte ratio ≥ 1.7 were agreed criteria for diagnosis of TAPS. There was no agreement on the cut-off of MCA-PSV or its discordance for prenatal intervention. The panel agreed on prioritizing perinatal and long-term survival outcomes in follow-up studies.

CONCLUSIONS

Consensus-based diagnostic features of TAPS, as well as cut-off values for the parameters involved, were agreed upon by a panel of experts. Future studies are needed to validate these diagnostic features before they can be used in clinical trials of interventions. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Performance of Antenatal Diagnostic Criteria of Twin-Anemia-Polycythemia Sequence

This study aims to elicit the validation performance of different diagnostic criteria and to evaluate the disease course and perinatal outcomes of pregnancies complicated by twin anemia polycythemia sequence (TAPS). Monochorionic diamniotic (MCDA) twin pregnancies who received serial middle cerebral artery (MCA) peak systolic velocity (PSV) measurements without non-TAPS-related demise or major anomalies were included. Course of disease, antenatal intervention, additional ultrasound features, and perinatal outcomes were compared between each criteria and onset. Forty-nine cases of TAPS and 203 non-TAPS controls were identified. The incidence of TAPS was 19.2%, 15.7%, 7.8%, and 6.3% for ΔPSV MoM > 0.373, ΔPSV MoM > 0.5, traditional, and Delphi consensus criteria, respectively (p < 0.001). The incidence of antenatal intervention was 55.1, 62.5, 75.0, and 87.5%, respectively. Furthermore, cases detected according to the Delphi consensus criteria had a higher rate of progression or intervention compared to cases detected with ΔPSV MoM > 0.373 (87.0 vs. 59.0%, p = 0.037). TAPS had a significantly higher birth weight discordance than uncomplicated MCDA twins (25.3 vs. 7.3%, p < 0.001). Application of four different diagnostic criteria for TAPS leads to significant differences in the incidence, severity, and antenatal intervention. The Delphi criteria identified more severe cases likely to require intervention, and the delta PSV > 0.373 criteria identified milder cases, without a significant impact on neonatal outcomes.

Middle Cerebral Artery Doppler Velocimetry for the Diagnosis of Twin Anemia Polycythemia Sequence: A Systematic Review

Twin anemia polycythemia sequence (TAPS) is a rare complication of monochorionic diamniotic (MCDA) twins. Middle cerebral artery peak systolic velocity (MCA-PSV) measurements are used to screen for TAPS while fetal or neonatal hemoglobin levels are required for definitive diagnosis. We sought to perform a systematic review of the efficacy of MCA-PSV in diagnosing TAPS. Search criteria were developed using relevant terms to query the Pubmed, Embase, and SCOPUS electronic databases. Publications reporting diagnostic characteristics of MCA-PSV measurements (i.e., sensitivity, specificity or receiver operator curves) were included. Each article was assessed for bias using the Quality Assessment of Diagnostic Accuracy Studies II (QUADAS II) tool. Results were assessed for uniformity to determine whether meta-analysis was feasible. Data were presented in tabular form. Among publications, five met the inclusion criteria. QUADAS II analysis revealed that four of the publications were highly likely to have bias in multiple areas. Meta-analysis was precluded by non-uniformity between definitions of TAPS by MCA-PSV and neonatal or fetal hemoglobin levels. High-quality prospective studies with consistent definitions and ultrasound surveillance protocols are still required to determine the efficacy of MCA-PSV in diagnosing TAPS. Other ultrasound findings (e.g., placenta echogenicity discordance) may augment Doppler studies.

Discordant placental oxygenation and autophagy in twin anemia-polycythemia sequence (TAPS)

BACKGROUND

(Macro)autophagy is an important process of self-degradation of macromolecules and organelles that ensures cellular homeostasis and energy preservation during stressful conditions. Dysregulated placental autophagy has been implicated in a wide range of pregnancy complications. Recent studies identified hypoxia as a key regulator of trophoblast autophagy in vitro; however, its effects on placental autophagy in vivo remain incompletely understood. In this study, we evaluated the monochorionic twin anemia-polycythemia sequence (TAPS) placenta as model of discordant placental oxygenation to determine the effects of hypoxia on placental autophagy in utero.

METHODS

We performed a retrospective comparative analysis of tissue oxygenation and autophagy in anemic and polycythemic territories of TAPS placentas (N = 12). Archival tissues were subjected to immunohistochemical, immunofluorescence and Western blot analyses of carbonic anhydrase (CA) IX (hypoxia marker) and key autophagy/lysosomal markers.

RESULTS

CAIX protein levels were significantly higher in anemic twin territories than in corresponding polycythemic territories, consistent with relative tissue hypoxia. Anemic placental shares further displayed significantly higher levels of LC3I/II (autophagosome markers) and LAMP1/2 (lysosome markers), associated with upregulated expression of lysosome/autophagosome activity-associated markers, transcription factor EB and cathepsin D. The accumulation of autophagosomes and lysosomes in anemic shares was accompanied by elevated p62 protein expression, suggestive of inhibition of the downstream autophagy pathway.

CONCLUSIONS

TAPS placentas display striking intertwin discordance in tissue oxygenation and autophagic activity and may provide a suitable model for study of the interrelationship between hypoxia, autophagy, and pregnancy outcome in a monochorionic twin setting.

High risk of long-term neurodevelopmental impairment in donor twins with spontaneous twin anemia-polycythemia sequence

OBJECTIVES

To evaluate the long-term neurodevelopmental and behavioral outcomes in surviving infants of pregnancies with spontaneous twin anemia-polycythemia sequence (TAPS), to compare outcome between donors and recipients, and to investigate potential risk factors for neurodevelopmental impairment (NDI).

METHODS

This was a retrospective study of a consecutive cohort of spontaneous-TAPS survivors delivered between 2005 and 2017 at the Leiden University Medical Center, The Netherlands. Neurological, motor, cognitive and behavioral development were assessed at a median age of 4 years. The primary outcome was NDI, which was a composite outcome of cerebral palsy, deafness, blindness and motor and/or cognitive delay. NDI was subdivided into two grades of severity: mild-to-moderate and severe NDI. Outcome was compared between surviving donor and recipient twins. Logistic regression analysis was used to assess risk factors for NDI.

RESULTS

Forty-nine twin pregnancies complicated by spontaneous TAPS were eligible for inclusion. The perinatal survival rate was 83% (81/98) of twins. Neurodevelopmental assessment was performed in 91% (74/81) of surviving twins. NDI occurred in 30% (22/74) of TAPS survivors, and was found more often in donors (44%; 15/34) than in recipients (18%; 7/40) (odds ratio (OR), 4.1; 95% CI, 1.8-9.1; P = 0.001). Severe NDI was detected in 9% (7/74) of survivors and was higher in donors compared with recipients (18% (6/34) vs 3% (1/40)), although the difference did not reach statistical significance; P = 0.056). Donors demonstrated lower cognitive scores compared with recipients (P = 0.011). Bilateral deafness was identified in 15% (5/34) of donors compared with 0% (0/40) of recipients (P = 0.056). Parental concern regarding development was reported more often for donor than for recipient twins (P = 0.001). On multivariate analysis, independent risk factors for NDI were gestational age at delivery (OR, 0.7; 95% CI, 0.5-0.9; P = 0.003) and severe anemia (OR, 6.4; 95% CI, 2.4-17.0; P < 0.001).

CONCLUSION

Surviving donor twins of pregnancies complicated by spontaneous TAPS have four-fold higher odds of NDI compared with recipient cotwins, are at increased risk of cognitive delay and have a high rate of deafness. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Reproductive Outcomes following Laser Surgery for Twin-Twin Transfusion Syndrome

BACKGROUND

There are limited studies describing future reproductive outcomes in women who have had selective fetoscopic laser photocoagulation (SFLP) for twin-twin transfusion syndrome (TTTS).

OBJECTIVE

Our study aims to compare reproductive outcomes following monochorionic multiple gestational pregnancies complicated by TTTS requiring SFLP to those not requiring SFLP.

METHODS

This is a retrospective cohort study that analyzed records of patients who were evaluated at the Cincinnati Fetal Center (2007-2014) for monochorionic multiple gestations. A questionnaire regarding reproductive, obstetric, gynecologic, and psychological outcomes following the index pregnancy was administered to consented participants by electronic distribution. The data was compared between pregnancies with prior SFLP versus no prior SFLP.

RESULTS

There was a higher response rate in the SFLP group (219/474, 46.2%) versus the referent group (62/187, 33.2%). The median interval between the index pregnancy and survey completion was 74 months and 46 months in the SFLP and referent groups, respectively. Approximately 38 and 37% of the women in the SFLP and referent groups attempted conception after the index pregnancy with a >90% pregnancy success rate in both groups. Use of assisted reproductive technology was highly prevalent in both the index and subsequent pregnancies, with no significant difference between the groups. Over 60% of the women in each group did not attempt future pregnancy. Of those, approximately 1 in 3 cited the outcome of the index pregnancy as the primary reason for not pursuing future conception. There were no significant differences in selected maternal-fetal complications and new-onset gynecologic problems. More than 1 in 4 women in both groups were diagnosed with a mental health disorder following the index pregnancy.

CONCLUSION

SFLP does not appear to be associated with adverse reproductive, obstetric, or gynecologic outcomes. The data may help facilitate evidence-based counseling for this patient population.

Handheld Active Add-On Control Unit for a Cable-Driven Flexible Endoscope

The instruments currently used by surgeons for in utero treatment of the twin-to-twin transfusion syndrome (TTTS) are rigid or semi-rigid. Their poor dexterity makes this surgical intervention risky and the surgeon's work very complex. This paper proposes the design, assembly and quantitative evaluation of an add-on system intended to be placed on a commercialized cable-driven flexible endoscope. The add-on system is lightweight and easily exchangeable thanks to the McKibben muscle actuators embedded in its system. The combination of the flexible endoscope and the new add-on unit results in an easy controllable flexible instrument with great potential use in TTTS treatment, and especially for regions that are hard to reach with conventional instruments. The fetoscope has a precision of 7.4% over its entire bending range and allows to decrease the maximum planar force on the body wall of 6.15% compared to the original endoscope. The add-on control system also allows a more stable and precise actuation of the endoscope flexible tip.

Outcomes following selective fetoscopic laser ablation for twin-to-twin transfusion syndrome: a single-centre experience

INTRODUCTION

Fetoscopic laser photocoagulation (FLP), a treatment option for twin-to-twin transfusion syndrome (TTTS) in monochorionic twin pregnancies, is currently the treatment of choice at our centre. We previously reported on our experience of FLP from June 2011 to March 2014. This paper audits our fetal surgery performance since then.

METHODS

15 consecutive patients who underwent FLP for Stage II-III TTTS before 26 weeks of gestation from June 2011 to January 2017 were retrospectively reviewed, consisting of five cases from our initial experience and ten subsequent cases. Perioperative, perinatal and neonatal outcomes were analysed.

RESULTS

Of 15 pregnancies, 10 (66.7%) and 5 (33.3%) were for Stage II and III TTTS respectively, with FLP performed at an earlier Quintero stage in the later cohort. Overall mean gestational ages at presentation, laser and delivery were comparable between the cohorts at 19.7 (15.4-24.3) weeks, 20.3 (16.3-25.0) weeks and 31.2 (27.6-37.0) weeks, respectively. 2 (13.3%) cases had intra-amniotic bleeding and 1 (6.7%) had iatrogenic septostomy. 1 (6.7%) case had persistent TTTS requiring repeat FLP, and another (6.7%) had preterm premature rupture of membranes at seven weeks post procedure. The overall perinatal survival rate was 21 (75.0%) out of 28 infants. One mother underwent termination of pregnancy for social reasons at 1.4 weeks post procedure. Double survival occurred in 8 (57.1%) out of 14 pregnancies, while 13 (92.9%) had at least one survivor.

CONCLUSION

FLP requires a highly specialised team and tertiary neonatal facility. Continual training improves maternal and perinatal outcomes, ensuring comparable standards with international centres.

Cardiomegaly of the larger twin in monochorionic twin pregnancies warrants neonatal intensive care even without twin-to-twin transfusion syndrome

OBJECTIVES

Some monochorionic twin pregnancies need intensive cardiac management even in the absence of twin-to-twin transfusion syndrome after birth. The purpose of this study was to investigate risk factors related to persistent hypotension requiring cardiotonic agent use among monochorionic twin pregnancies without twin-to-twin transfusion syndrome.

STUDY DESIGN

This was a retrospective study of 316 monochorionic twin pregnancies without twin-to-twin transfusion syndrome (632 babies). All cases were treated in the neonatal intensive care unit. Hypotension was defined as mean arterial blood pressure below the norm for gestational age. Decreased left ventricular ejection fraction was defined as a value <60%. Dopamine, dobutamine and phosphodiesterase III inhibitor were used as cardiotonic agents for hypotension persisting even after adequate infusion.

RESULTS

Among the 632 cases, 33 (5.2%) needed cardiotonic agents for persistent hypotension. The frequency of persistent hypotension with decreased left ventricular ejection fraction was significantly higher among larger twins (4.4%) than among smaller twins (0.6%, p = 0.0038). In larger twins, multivariate analysis showed that Z-score for cardiothoracic area ratio (odds ratio, 2.31; p < 0.001), tricuspid regurgitation (odds ratio, 6.34; p = 0.015) and gestational age at delivery (odds ratio, 0.66; p < 0.001) correlated with persistent hypotension. In smaller twins, univariate analysis showed gestational age at delivery, birth weight, Z-score for birth weight and Z-score for cardiothoracic area ratio of the larger twin were related to persistent hypotension. Concentration of brain natriuretic peptide in the umbilical vein in larger and smaller twins were significantly correlated (coefficient of correlation = 0.792, p < 0.001).

CONCLUSIONS

In monochorionic twin pregnancies, attention needs to be given to cardiac size along with amniotic fluid and fetal growth. Both larger and smaller twins carry risks of persistent hypotension after birth. Close observation is needed, especially in cases where the larger twin displays cardiomegaly despite absence of twin-to-twin transfusion syndrome.

Complex multigestational anomalies

The increase in multiple gestation pregnancies has resulted in significant health care implications for both mother and child. Our ability to diagnose and intervene on an at-risk multi-gestation pregnancy has dramatically improved. It is important for the pediatric surgeon to be equipped with a basic fund of knowledge concerning these pregnancies. An understanding of amnionicity and chorionicity will equip the practitioner with the ability to identify which pregnancies are at risk for specific complications. This article highlights multi-gestation pregnancies that are monochorionic (single shared placenta) and can be complicated by twin-twin transfusion syndrome (TTTS), twin reversed arterial perfusion (TRAP) sequence, twin anemia polycythemia sequence (TAPS), or selective fetal intrauterine growth restriction (sIUGR). The risk of fetal demise is significant in these pregnancies. Understanding recommended surveillance and warning signs can alert surgeons to developing complications. Specialized fetal care centers possess the ability to intervene on these pregnancies in utero.

Twin-Twin Transfusion Syndrome with Anemia-Polycythemia: Prevalence, Characteristics, and Outcome

The aim of this study was to estimate the prevalence of co-existing anemia-polycythemia (AP) in twin pregnancies with twin-twin transfusion syndrome (TTTS) prior to laser surgery, and to evaluate the characteristics and outcomes in TTTS twins with and without AP. All TTTS cases treated with laser between 2001 and 2019 were retrospectively reviewed for the presence of AP before surgery. AP was defined as delta middle cerebral artery–peak systolic velocity > 0.5 multiples of the median. The primary outcome was a composite of perinatal survival and severe neurodevelopmental impairment (NDI). Secondary outcomes included procedure-related characteristics, severe neonatal morbidity, and disease-free survival. In total, 66% (461/696) of TTTS twin pregnancies were eligible for analysis. AP was detected in 15% (70/461) of the TTTS twins prior to laser surgery. Gestational age at laser was higher in the TTTS+AP group compared to the TTTS-only group—21.0 weeks (interquartile rage (IQR): 18.8–24.0) versus 19.3 weeks (IQR: 17.3–21.9), respectively (p < 0.0001). Fewer placental anastomoses were detected in the TTTS+AP group than in the TTTS-only group—five (IQR: 4–6) versus six (IQR: 5–8), respectively (p < 0.0001). Perinatal survival was 77% (599/782) in the TTTS-only group and 83% (118/142) in the TTTS+AP group (p = 0.130). Severe NDI was 8% (28/370) in TTTS-only and 3% (2/74) in TTTS+AP. TTTS-only twins showed more severe neonatal morbidity than twins with TTTS+AP—23% (132/575) versus 11% (13/115), respectively (p = 0.005). Disease-free survival was lower in the TTTS-only group compared to the TTTS+AP group—62% (341/548) versus 73% (72/98), respectively (p = 0.046). Thus, AP complicates 15% of TTTS twins prior to laser. TTTS+AP twins show a different placental angioarchitecture, a later time of onset of the disease, and a more favorable outcome.