Fetal magnetic resonance imaging, ultrasound, and echocardiography findings in twin reversed arterial perfusion sequence.

BACKGROUND: Twin reversed arterial perfusion (TRAP) sequence is a rare complication of monochorionic multiple gestation pregnancies, in which the pump twin provides hemodynamic support to a nonviable co-twin (acardius). Fetal magnetic resonance imaging (MRI) is used to detect pump twin abnormalities, particularly brain ischemia, prior to fetal intervention to interrupt umbilical blood flow to the acardius. OBJECTIVE: To summarize the imaging findings of TRAP sequence pregnancies in a large series. MATERIALS AND METHODS: A single-center retrospective review was performed of all TRAP sequence pregnancies referred for fetal MRI (2004-2021). Fetal MRI, ultrasound, and echocardiography data were collected. RESULTS: Eighty-eight TRAP sequence pregnancies with MRI were included (mean gestational age, 19.8±2.8 weeks). Demise of the pump twin was noted in two pregnancies at the time of MRI. By MRI, 12% (10/86) of live pump twins had abnormalities, including 3% (3/86) with brain abnormalities and 9% (8/86) with extra-cranial abnormalities. By echocardiography, 7% (6/86) of pump twins had structural cardiac abnormalities. Three acardius morphological subtypes were identified by MRI: acephalus (55%, 48/88), anceps (39%, 34/88), and amorphous (7%, 6/88). The mean ultrasound acardius to pump twin ratio A/P ratio, calculated for each twin pair as the ratio of the acardius trunk (and head, if present) plus limb volume to the pump twin estimated fetal weight) differed among the three acardius subtypes (P=.03). The mean A/P ratio moderately correlated with pump twin cardiothoracic ratio and combined cardiac output (Pearson's r=0.45 and 0.48, respectively, both P<.001). CONCLUSION: Fetal MRI of TRAP sequence pregnancies found anomalies in a substantial number of pump twins. The three acardius subtypes differed in A/P ratio, which moderately correlated with the pump twin cardiothoracic ratio and combined cardiac output.

Ultrasound Doppler findings of a Twin Reversed Arterial Perfusion Sequence (TRAP).

Twin reversed arterial perfusion (TRAP) sequence is a rare pregnancy complication occurs in an identical twin pregnancy that share a single placenta. TRAP sequence is a twin's pregnancy includes a normal-developed viable pump fetus and an abnormal usually nonviable acardiac fetus. The nonviable acardiac fetus depends on the pump fetus for his blood supply and put the pump fetus at risk of high cardiac output heart failure and congenital anomalies with high mortality rate. Gray-scale ultrasound and color and pulsed Doppler imaging is a noninvasive accessible imaging modality for the diagnosis of TRAP sequence. Early diagnosis of such conditions is mandatory in order to apply the proper therapeutic measures and to help the normal developed pump fetus to survive. The main goal of management is to interrupt blood supply to the nonviable acardiac fetus to reduce the strain on the heart of the pump fetus thus, increase the chance of survival.

Doppler Waveform Analysis of Intertwin Venous Blood Flow in Twin Reversed Arterial Perfusion (TRAP) Sequence with a Rudimentary Heart.

Twin reversed arterial perfusion (TRAP) sequence is a rare anomaly in 1% of monochorionic twin pregnancies. Few TRAP sequence cases have a rudimentary heart with cardiac motion in the acardiac twins. Herein, we investigated the venous Doppler waveform in two cases of TRAP sequence with a rudimentary heart with cardiac motion in the acardiac twin. Although both cases had veno-venous anastomoses, the venous Doppler waveforms of the umbilical vein differed. A comparison of the characteristics of the cases indicated that the existence of a ductus venosus, or greater heart pulse power, in the acardiac twin might impact the venous Doppler waveform in the pump twin.

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.

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.

Radiofrequency ablation for selective fetal reduction in complicated Monochorionic twins; comparing the outcomes according to the indications.

BACKGROUND: To evaluate the perinatal outcomes in women with complicated monochorionic diamniotic twins who underwent selective reduction using radiofrequency ablation (RFA). METHODS: This retrospective study included patients with complicated monochorionic diamniotic twins between 16 to 28 weeks who underwent selective reduction using RFA. RESULTS: During the study period, 143 women with complicated monochorionic twins underwent RFA including 52 with selective fetal growth restriction (sFGR), 48 with twin to twin transfusion syndrome (TTTS), 33 with major fetal anomalies in one of the twins, and 10 with reversed arterial perfusion sequence (TRAP). The overall survival was 71.3% (102/143). The procedures were technically successful in achieving selective termination in all cases. The mean ± SD of gestational age at the time of the procedure was 21.0 ± 2.3 weeks. The mean ± SD of gestational age at delivery was 34.6 ± 3.3 weeks. The mean ± SD of overall procedure-to-delivery time was 12 ± 1.7 weeks. The pregnancy success rates among sFGR, TRAP, TTTS and anomaly groups were 82.7, 80, 73 and 60.7% respectively. There were no maternal complications. CONCLUSION: Radiofrequency ablation for fetal reduction in complicated monochorionic twin pregnancies appears to be a reasonable option. The pregnancy success rate following RFA selective reduction was highest among sFGR and TRAP groups and lowest in the anomaly group.

Influence of indications on perinatal outcomes after radio frequency ablation in complicated monochorionic pregnancies: a retrospective cohort study.

BACKGROUND: Radiofrequency ablation (RFA) is recommended to prevent potential neurological injury or intrauterine foetal death (IUFD) of the co-twin(s) in complicated monochorionic (MC) pregnancies. However, the impacts of various indications on the pregnancy outcome following RFA remain unclear. This study aimed to determine how the indications influence the perinatal outcomes in complicated MC pregnancies undergoing radiofrequency ablation. METHODS: This was a retrospective cohort study performed in a single centre. All consecutive MC pregnancies treated with RFA between July 2011 and July 2019 were included. The adverse perinatal outcomes and the survival rate were analysed based on various indications. The continuous variables with and without normal distribution were compared between the groups using Student's t-test and Mann-Whitney U test, respectively, and for categorical variables, Chi-square and Fisher's exact tests were used. P < 0.05 indicated a significant difference. RESULTS: We performed 272 RFA procedures in 268 complicated MC pregnancies, including 60 selective intrauterine growth restriction (sIUGR), 64 twin-twin transfusion syndrome (TTTS), 12 twin reversed arterial perfusion sequence (TRAPs), 66 foetal anomaly and 66 elective foetal reduction (EFR) cases. The overall survival rate of the co-twin was 201/272 (73.9%). The overall technical successful rate was determined at 201/263 (76.7%). The IUFD rate in the co-twin was 20/272 (7.4%). The TTTS group had recorded the lowest survival rate (37/64, 57. 8%), and the survival rate was significantly correlated with Quintero stages (P = 0.029). Moreover, the sIUGR III subgroup had a lower survival rate compared with sIUGR II (55.6%, versus 84.3%). The subgroup of foetal anomaly of gastroschisis or exomphalos had the highest IUFD rate (4/10, 40%), followed by sIUGR III (2/9, 22.2%) and dichorionic triamniotic (DCTA) subgroup (8/46, 17.9%). In EFR group, eight IUFD cases were all coming from the DCTA subgroup and received RFA before 17 weeks. CONCLUSIONS: The perinatal outcome of RFA was correlated with the indications, with the lowest survival rate in TTTS IV and the highest IUFD incidence in abdominal wall defect followed by sIUGR III. Elective RFA after 17 weeks may prevent IUFD in DCTA pregnancies.

Outcome of Monochorionic Monoamniotic Twin Reversed Arterial Perfusion Sequence Diagnosed in the First Trimester.

INTRODUCTION: The aim of this study is to evaluate the outcome of pregnancies complicated by monochorionic monoamniotic twin reversed arterial perfusion sequence (MOMA TRAP) diagnosed in the first trimester. METHODS: All patients diagnosed with MOMA TRAP sequence <14.0 weeks of gestation in a 10-year study period were retrospectively analyzed for intrauterine course and outcome. All patients were offered either expectant management or intrauterine intervention. Adverse outcome was defined as either intrauterine death (IUD), neonatal death or preterm birth <34.0 weeks of gestation. RESULTS: In the study period, 17 cases with MOMA TRAP sequence were diagnosed. Of these, 2 couples opted for termination of pregnancy. The remaining 15 were divided into 2 groups depending on the management: group A (n = 8) with expectant management and group B (n = 7) with intrauterine intervention. All fetuses in group A died before 20 weeks. Survival in group B was significantly better with 4/7 (57.1%) life births at a median of 39.6 weeks of gestation (p = 0.0256). The reasons for IUD in the 3 cases in group B were hemodynamic, strangulation, and bleeding complications during intervention. CONCLUSIONS: Intrauterine intervention in MOMA TRAP pregnancies significantly improves neonatal survival, although it is still associated with a substantial risk for IUD by hemodynamic complications or entanglement.

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.

Successful use of fetoscopic laser surgery as treatment for a monochorionic-triamniotic triplet pregnancy complicated by twin-reversed arterial perfusion sequence and severe selective fetal growth restriction: A case report.

Monochorionic triplet pregnancy is a rare condition, and twin-reversed arterial perfusion (TRAP) sequence and severe selective fetal growth restriction (FGR) are associated with high perinatal morbidity and mortality rates. We report a case of TRAP sequence and selective FGR typeIIconcurrently complicating a monochorionic triplet pregnancy. Fetoscopic laser surgery (FLS) was performed at 16 + 1 weeks of gestation and was technically successful. Inter-fetus placental anastomoses were coagulated. The pregnancy continued until 28 + 4 weeks of gestation, when the patient presented with preterm rupture of membranes and preterm labor. Two live female newborns were delivered by a cesarean section, and their postnatal course of the neonates was uneventful and in accordance with their gestational age at birth. To our knowledge, this is the first case report of FLS resulting in favorable outcomes for a monochorionic triplet pregnancy concurrently complicated with TRAP sequence and selective FGR type II.

Acardiac twin pregnancies part III: Model simulations.

BACKGROUND: Acardiac monochorionic twins lack cardiac function but grow by passive perfusion of the pump twin's deoxygenated arterial blood through placental arterioarterial (AA) and venovenous (VV) anastomoses and by hypoxia-mediated neovascularization. Pump twins therefore must continuously increase their cardiac output which may cause heart failure. Our aims were: to adapt our twin-twin transfusion syndrome model for acardiac twin pregnancies, to simulate pump and acardiac twin development, and to examine the model for early prognostic markers of pump twin survival. METHODS: We used an infinite acardiac placental resistance, based on placental dye injection studies and simulations, suggesting the AA-Acardiac-VV series resistance determines the pump twin's excess cardiac output. Pump and acardiac development were expressed by the pump's excess cardiac output versus its normal value, represented by pump/acardiac umbilical venous diameter (UVD) ratios. RESULTS: UVD ratios distinguish between AA-VV anastomoses that do and do not cause hydropic pump twins. Pump twins can handle relative larger acardiac perfusion at later than earlier gestation. Both VV and acardiac resistances are significantly smaller than the AA resistance, based on respectively clinical data and acardiac blood volumetric growth. CONCLUSION: Our simulations support clinical results which show that UVD ratios aid in the prediction of pump twin risk. The AA anastomosis controls the future of both the pump and the acardiac. Correlation between acardiac size and pump twin risk is secondary to the AA size but remains clinically usable. These factors may aid in the development of methods for pump twin prognosis and the promotion of selective clinical interventions.Birth Defects Research (Part A), 2016.© 2016 Wiley Periodicals, Inc. Birth Defects Research (Part A) 106:1008-1015, 2016. © 2016 Wiley Periodicals, Inc.

Hypothesis acardiac twin pregnancies: Pathophysiology-based hypotheses suggest risk prediction by pump/acardiac umbilical venous diameter ratios.

BACKGROUND: A total of 75% of monozygotic twins share 1 monochorionic placenta where placental anastomoses cause several serious complications, for example, acardiac twinning. Acardiac twins lack cardiac function but grow by perfusion of arterial blood from the pump twin. This rare pregnancy has 50% natural pump twin mortality but accurate risk prediction is currently impossible. Recent guidelines suggest prophylactic surgery before 18 weeks, suggesting 50% unnecessary interventions. We hypothesize that (1) adverse pump twin outcome relates to easy-to-measure pump/acardiac umbilical venous diameter (UVD) ratios, representing acardiac perfusion by the pump's excess cardiac output. This hypothesis suggests that (2) UVD-ratios are large, mildly varying in cases without complications but small and decreasing when complications develop, thus predicting that (3) UVD-ratios may allow risk prediction of pump twins. In this exploratory clinical pilot, we tested whether UVD-ratio measurements support these predictions. METHODS: We included 7 uncomplicated (expectant management), 3 elective surgical, and 17 complicated cases (pump decompensation, emergency intervention/delivery or demise). Nine UVD-ratios were measured sonographycally and 18 by pathology. RESULTS: Uncomplicated cases have larger, two serial measurements showing mildly varying UVD-ratios; elective surgical cases show larger UVD-ratios; complicated cases have smaller, two serial measurements showing decreasing UVD-ratios. There were no false-positives, no false-negatives and noncrossing linear trendlines of uncomplicated and complicated cohorts. CONCLUSION: Our data provide first evidence that UVD-ratios allow risk prediction of pump twins. More early uncomplicated and late complicated cases are needed, for example, in a prospective trial, before the separation between uncomplicated and complicated cohorts is accurate enough to support a well-founded decision on (early) intervention.

Twin Reversed Arterial Perfusion Sequence (TRAPS): An Illustrative Series of 13 Cases.

Twin reversed-arterial-perfusion sequence (TRAPS) is a rare and severe complication of monochorionic twin pregnancies. It usually occurs in the setting of monochorionic placentation, when the heart of a normal appearing twin serves as the pump for one or more dysmorphic twins whose head, thoracic organs, and upper extremities do not fully develop or do not develop at all and thus lack cardiac activity. Anomalous vascular placental architecture causes a shift in arterial flow towards the acardiac twin(s). The exact physiopathologic mechanisms that lead to this devastating phenomenon are not well known. We reviewed the maternal history and the surgical pathology reports of the fetuses and placentas of 13 different cases of TRAPS that were collected in a 23-year study period at a single institution. Herein we summarize the characteristic findings and illustrate specific mechanical feto-placental circulation issues that appear to be instrumental in the development of TRAPS.

Twin reversed arterial perfusion sequence is more common than generally accepted.

BACKGROUND: Approximately 75% of monozygotic twin pregnancies share one monochorionic placenta where placental anastomoses are virtually always present to connect the two fetoplacental circulations. These anastomoses cause several serious complications such as acardiac twinning. Acardiac twins lack a functional heart but nevertheless show fetal growth because the normal pump twin perfuses the acardiac body through arterioarterial (AA) and venovenous (VV) anastomoses. The widely accepted 1% monochorionic acardiac incidence dates back to 1944 and the associated 1:35,000 pregnancies to 1953. Our aim was to update this analysis. METHODS: We accepted the 1% (actually 1.1%) monochorionic acardiac incidence due to lack of more precise data, included the recently observed 58% early cessation of acardiac development as well as consequences of assisted reproductive technology, and assessed the incidence of acardiac twinning under conditions of AA-VV anastomoses. RESULTS: Early acardiac monochorionic twinning increased from 1.1% to 1.1/(1-0.58) = 2.6%, from 1:35,000 to 1:9,500 to 11,000 pregnancies, depending on number and method of assisted reproductive technology, and occurs in approximately 1:8 AA-VV anastomoses-containing monochorionic placentas. CONCLUSION: Early acardiac twinning is not a rare event. The 1944-based 1% acardiac monochorionic incidence has a weak basis and could therefore be (much) larger. Knowing this incidence more precisely may contribute to our knowledge of embryonic splitting in unequal cell masses.

Experience of fetoscopic laser photocoagulation and cord transection for twin-reversed arterial perfusion sequence.

AIM: The purpose of this study was to evaluate the usefulness of fetoscopic laser photocoagulation of placental communicating vessels or umbilical cord for twin-reversed arterial perfusion (TRAP) sequence. MATERIAL AND METHODS: We report a retrospective case series of all cases of TRAP sequence identified from 2006 to 2014 at out institutions. Fetoscopic laser photocoagulation of placental arterioarterial and venovenous anastomoses was performed in diamniotic twins, and in cases of monoamniotic twins we performed laser photocoagulation and transection of the umbilical cord of the acardiac twin to prevent cord entanglement. Pregnancy and perinatal outcomes were estimated. RESULTS: Ten cases were included in the study. The median gestational age at procedure was 21.3 weeks (range, 16.7-27.3 weeks). All cases completed the procedure. Two cases were treated with laser photocoagulation and transection of the umbilical cord of the acardiac twin. No major immediate complications were noted. Preterm rupture of membranes occurred in four cases (40%). One case resulted in miscarriage. The other fetuses were delivered alive. Median gestational age at delivery was 35.4 weeks (range, 25.6-42.0 weeks). Median interval of treatment to delivery was 85 days (range, 43-153 days). Five out four infants were delivered preterm. The overall neonatal survival was 9/10. CONCLUSION: This case series demonstrated favorable outcome, and fetoscopic laser photocoagulation seems to be a useful treatment for TRAP sequence. In particular, transection of the umbilical cord is effective to prevent cord entanglement of monoamniotic twins.

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.

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 syndrome in a monochorionic monoamniotic twin pregnancy.

OBJECTIVE: Twin-Reversed Arterial Perfusion (TRAP) sequence is a rare complication of monochorionic multiple gestation. Conservative management should be considered if there is no poor prognostic factor. CASE REPORT: This is a 35 year-old female with twin pregnancy with acardiac monster. Under the request of the patient, there was no intervention during the whole pregnancy. We keep regular and close sonography weekly follow up. There was no maternal complication and there was also no heart failure sign or polyhydramnios of the donor twin. Minimal blood flow was noted at the anastomotic vessels under the sonography at late gestational age. Due to breech presentation, cesarean section was performed at gestational age 37 + 1/7 weeks. She delivers a healthy baby smoothly. CONCLUSION: Antenatal sonography is an important tool to evaluate the fetus status. Under special condition, term pregnancy is still possible without any treatment. CASE REPORT: Twin reversed arterial perfusion syndrome in a monochorionic monoamniotic twin pregnancy.

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.