Nutritional supplementation in monochorionic diamniotic twin pregnancies: impact on twin-twin transfusion syndrome

Twin-to-twin transfusion syndrome (TTTS) has been related to unbalanced unidirectional arteriovenous anastomoses in the placenta of monochorionic diamniotic (DiMo) twin gestations. As maternal malnutrition accounting for hypoproteinemia and anemia has been detected in severe cases of TTTS, the purpose of this study was to evaluate the impact of early diet supplementation on TTTS. Fifty-one DiMo twin pregnancies were given commercially available oral nutritional diet supplements and then compared in a retrospective cohort study to 52 twin gestations with the same chorionicity but not subjected to nutritional supplementation. Diet supplementation was associated with lower overall incidence of TTTS (20/52 versus 8/51, P = 0.02) and with lower prevalence of TTTS at delivery (18/52 versus 6/51, P = 0.012) when compared with no supplementation. Nutritional intervention also significantly prolonged the time between the diagnosis of TTTS and delivery (9.4 +/- 3.7 weeks versus 4.6 +/- 6.5 weeks; P = 0.014). The earlier nutritional regimen was introduced, the lesser chance of detecting TTTS ( P = 0.001). Although not statistically significant, dietary intervention was also associated with lower Quintero stage, fewer invasive treatments, and lower twin birth weight discordance. Diet supplementation appears to counter maternal metabolic abnormalities in DiMo twin pregnancies and improve perinatal outcomes in TTTS when combined with the standard therapeutic options.     

Successful selective termination at 17 weeks' gestation in monochorionic monoamniotic twin pregnancy affected by twin-twin transfusion syndrome and discordant for hypoplastic left heart syndrome

OBJECTIVES: To report a successful selective feticide in a complicated monochorionic monoamniotic (MCMA) pregnancy. METHODS: A case of MCMA pregnancy with severe twin-twin transfusion syndrome and discordant for hypoplastic left heart syndrome was diagnosed at 16 weeks' gestation. A complete ultrasound and fetoscopic surveillance was performed, ruling out cord entanglement and, thus, precluding the necessity of transecting the cord. RESULTS: The selective feticide was successfully performed by bipolar coagulation of the umbilical cord of the abnormal fetus under ultrasound guidance. The survivor twin developed normally during the rest of the pregnancy and was born at term. At 6 months of age, the infant was healthy. CONCLUSION: Selective feticide in complicated monoamniotic pregnancies can be safely performed. Cord entanglement can be confidently excluded by both ultrasound and fetoscopy, thus making the systematic transection of the umbilical cord unnecessary.     

Search for hemodynamic compromise at 11-14 weeks in monochorionic twin pregnancy: is abnormal flow in the ductus venosus predictive of twin-twin transfusion syndrome?

BACKGROUND AND OBJECTIVES: Twin-twin transfusion syndrome is a devastating complication of monochorionic twin pregnancies. The presence of increased nuchal translucency thickness (NT) in one of the monochorionic twins has been associated with an increased risk of developing this syndrome. One of the most plausible mechanisms for increased nuchal translucency is heart failure, indirectly manifested by abnormal blood flow in the ductus venosus. We aimed to clarify the pathophysiology of increased NT found more frequently in monochorionic twins prone to develop twin-twin transfusion syndrome. DESIGN: We present 50 cases of monochorionic twin pregnancies in which nuchal translucency thickness was measured and ductus venosus blood flow evaluation was performed at 11-14 weeks of gestation. RESULTS: Whenever the fetuses of a twin pregnancy were found to have discrepant nuchal translucency thickness measurements and abnormal flow in the ductus venosus was found in the fetus with increased nuchal translucency thickness, twin-twin transfusion syndrome eventually developed. Progression to twin-to-twin transfusion syndrome was not observed in the twins displaying no intertwin difference in nuchal translucency thickness measurements and it was not observed in those with discrepant nuchal translucency thickness but normal flow in the ductus venosus of both fetuses. In the two cases which developed twin-to-twin transfusion syndrome, fetoscopic laser coagulation of the vascular anastomoses was successfully carried out at 18 weeks and normalization of the venous return was recorded. CONCLUSIONS: Both increased nuchal translucency and abnormal flow in the ductus venosus in monochorionic twins may be early manifestations of haemodynamic imbalance between donor and recipient. The combined evaluation of both parameters in monochorionic twin pregnancies may constitute an effective method for identifying those at risk of developing twin-to-twin transfusion syndrome.     

Monoamniotic-versus diamniotic-monochorionic twin placentas: anastomoses and twin-twin transfusion syndrome

Objective

The purpose of this study was to compare monoamniotic-monochorionic and diamniotic-monochorionic twin placentas and to estimate the incidence of twin-twin transfusion syndrome in monoamniotic-monochorionic twin pregnancies.

Study design

We analyzed the angioarchitecture and cord insertion distance in 24 monoamniotic-monochorionic and 200 diamniotic-monochorionic placentas.

Results

Compared with diamniotic-monochorionic placentas, monoamniotic-monochorionic placentas had significantly more arterioarterial anastomoses (20/20 vs 159/200, respectively; P = .013), significantly less opposite arteriovenous anastomoses (10/20 vs 165/200, respectively; P = .002), similar venovenous anastomoses (6/20 vs 46/200, respectively; P = .323), and arteriovenous anastomoses (20/20 vs 187/200 respectively; P = .279) and significantly shorter umbilical cord distances (median [±SD], 5.0±6.9 cm vs 17.5±6.8 cm; P<.001).

Conclusion

Monoamniotic-monochorionic and diamniotic-monochorionic placentas have different anastomotic patterns. The (virtually) 100% incidence of arterioarterial anastomoses in monoamniotic-monochorionic placentas explains the reason that twin-twin transfusion syndrome rarely occurs in monoamniotic-monochorionic twin pregnancies and predicts that twin-twin transfusion syndrome manifestations are approximately 5 times less often recognized in monoamniotic-monochorionic pregnancies than in diamniotic-monochorionic pregnancies.     

Arterio-arterial vascular anastomoses in monochorionic placentas with and without twin-twin transfusion syndrome

We performed a matched case-control study to analyze the placental angioarchitecture, in particular the diameter of arterio-arterial (AA) anastomoses in monochorionic placentas from pregnancies with twin-twin transfusion syndrome (TTTS) compared to a control group of uncomplicated monochorionic placentas. Placental angioarchitecture was analyzed using colored dye injection. AA anastomoses were detected in 37% (14/38) of TTTS placentas versus 91% (209/228) in control placentas (p < 0.001). The median diameter of AA anastomoses in the group with and without TTTS was 1.9 mm and 2 mm, respectively (p = 0.711). In conclusion, our findings show that AA anastomosis occur less frequently in TTTS placentas, supporting the concept of the protective role of AA anastomoses in TTTS. However, the size of the AA anastomosis, when present, does not appear to influence the pathophysiology of the disease.     

Ductus venosus blood flow evaluation at 11-14 weeks in the anticipation of twin-twin transfusion syndrome in monochorionic twin pregnancies

Twin-twin transfusion syndrome (TTTS) is a serious complication, occurring in about 15% of monochorionic twin pregnancies. Strong evidence suggests that increased fetal nuchal translucency thickness (NT) in one of the monochorionic twins is highly predictive of TTTS. One of the most plausible mechanisms for increased NT is heart failure, which can be indirectly manifested by abnormal blood flow in the ductus venosus. We present 20 cases of monochorionic twin pregnancies in which both NT thickness and ductus venosus blood flow evaluation were performed at 11-14 weeks. Whenever both fetuses showed discrepant NT, and abnormal ductal flow was found in the fetus with increased NT, TTTS eventually developed. In none of the twins displaying similar NT measurements, and in those with discrepant NT but normal flow in the ductus venosus of both fetuses, was the progression to TTTS observed. In the two cases that developed TTTS, fetoscopic laser coagulation of the vascular anastomoses was successfully carried out at 18 weeks, and normalization of the venous return was recorded. Increased NT and abnormal flow in the ductus venosus in monochorionic twins may be early manifestations of hemodynamic imbalance between donor and recipient The combined evaluation of both parameters in monochorionic twin pregnancies could be an effective screening method.     

Bipolar coagulation of the umbilical cord in complicated monochorionic twin pregnancy

OBJECTIVES: In monochorionic twin pregnancy in which one twin is a nonviable fetus, selective feticide may be considered. We aimed to occlude the umbilical cord with a bipolar forceps for doing so. STUDY DESIGN: This was a multicenter experience in 10 consecutive patients either with twin-to-twin transfusion syndrome and one fetus affected by a condition not compatible with normal extrauterine life or with acardiac twinning. RESULTS: There were no intraoperative problems, and the mean procedure time was 17.5 minutes. The flow was stopped in all 10 cases. Two cases were complicated by rupture of the fetal membranes within 2 days, and the pregnancies were terminated. The other 8 pregnancies resulted in the live birth of a healthy baby. The mean interval between procedure and birth was 15.1 weeks (range, 7-20 weeks). In one patient emergency cesarean delivery for abruptio placentae was done at 26 weeks, 7 weeks after the procedure. The other 7 patients were delivered beyond the 36th week of gestation. All 8 children are alive and well, with a mean follow-up of at least 1 year. CONCLUSION: Bipolar coagulation is a safe, effective, and simple procedure for cord coagulation that is feasible through a single port and can be performed solely under ultrasonographic guidance.     

双胎输血综合征的治疗进展与妊娠结局

双胎输血综合征（TTTS）是单绒毛膜双胎特有的严重并发症。相比于羊水减量术,胎儿镜激光电凝术（FLP）治疗TTTS可明显改善围产儿结局,已被公认为治疗双胎输血综合征的首选方法。文章主要对FLP的不同术式进行评价,并对接受FLP的TTTS患者的妊娠结局做一综述。     

Stage-based treatment of twin-twin transfusion syndrome

OBJECTIVE: The purpose of this study was to compare the outcomes of patients with twin-twin transfusion syndrome who were treated with either serial amniocentesis or selective laser photocoagulation of communicating vessels according to disease severity (stage). STUDY DESIGN: Centers that were experienced in the treatment of twin-twin transfusion syndrome were invited to share stage-based perinatal outcome data. All patients met basic standard sonographic criteria for twin-twin transfusion syndrome (polyhydramnios maximum vertical pocket, > or =8 cm; oligohydramnios maximum vertical pocket, < or =2 cm). Gestational age at first treatment was <27 weeks of gestation. RESULTS: Three centers submitted stage-based data, for a total of 173 patients (serial amniocentesis, 78 patients from all 3 centers) and 95 selective laser photocoagulation of communicating vessels (1 center). The distribution of patients by stage was similar in the two groups. Successful pregnancy outcome (at least 1 surviving infant) was correlated inversely with stage in the serial amniocentesis but not in the selective laser photocoagulation of communicating vessels group and was significantly lower in the serial amniocentesis (66.7%) than in the selective laser photocoagulation of communicating vessels group (83.2%). Neurologic morbidity was related directly to stage in the serial amniocentesis group but not in the selective laser photocoagulation of communicating vessels group and was significantly higher in the serial amniocentesis (24.4%) than in the selective laser photocoagulation of communicating vessels (4.2%) group. Intact neurologic survival (at least 1 surviving infant without neurologic morbidity) was significantly lower in the serial amniocentesis group than in the selective laser photocoagulation of communicating vessel group (51.3% vs 78.9%), particularly in stage III and stage IV (23.5% vs 72.7% in stage IV). Patients who were treated with selective laser photocoagulation of communicating vessels were 2.4 times more likely to have at least one survivor than those treated with serial amniocentesis. CONCLUSION: Our study suggests a relationship between perinatal morbidity and mortality rates and stage in serial amniocentesis but not in selective laser photocoagulation of communicating vessel-treated twin-twin transfusion syndrome patients. These findings could be used to tailor the treatment of twin-twin transfusion syndrome. A clinical trial to confirm these results is being organized by our research groups.     

Discordant fetal leptin levels in monochorionic twins with chronic midtrimester twin-twin transfusion syndrome

The objective of this study was to determine the plasma leptin concentrations in monochorionic twin fetuses with and without twin-twin transfusion syndrome (TTTS). Paired maternal and fetal blood samples were obtained at birth from monochorionic twin pregnancies complicated with (n=12) or without TTTS (n=12). Amniotic fluid samples were also collected from twin pairs at amnioreduction and/or fetal blood sampling in utero. Plasma and amniotic fluid leptin concentrations were measured by radio-immunoassay. Fetal leptin levels in the growth-restricted donor were lower than the recipient twin of the TTTS group (Delta mean 3.7; CI 2.6 to 4.7 ng/ml; P< 0.001). Fetal leptin levels were comparable between non-TTTS twin pairs (Delta mean 0.9; CI 0.1 to 1.4 ng/ml; P=0.10) and recipient twins of TTTS (P=NS). Maternal plasma concentrations of leptin were comparable between the two groups and were higher than the fetal levels. There was a positive association between cord leptin levels and birthweight of twin pairs (y=0.002x-0.37; r=0.58; P< 0.01; n=48). A significant positive relation was also found between delta leptin levels and percentage discordance in birthweight in the TTTS group (y=0.25x-2.21; r=0.82; P< 0.001, n=12). In conclusion, leptin levels in the recipient twins were three times higher than their growth restricted donor twins. However further studies are warranted to elucidate the underlying mechanism.     

Twin reversed arterial perfusion syndrome in a monochorionic monoamniotic twin pregnancy

ObjectiveTwin-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 reportThis 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.ConclusionAntenatal sonography is an important tool to evaluate the fetus status. Under special condition, term pregnancy is still possible without any treatment.Case reportTwin reversed arterial perfusion syndrome in a monochorionic monoamniotic twin pregnancy.     

双胎输血综合征产前干预二例

<正>病例1患者29岁,孕3产1,本次妊娠为自然受孕,孕期定期产前检查未见异常。孕13~(+1)周在外院超声检查提示单绒毛膜双羊膜囊双胎妊娠,胎儿颈项透明层厚度检查正常,早期唐氏筛查提示21-三体综合征和18-三体综合征低风险;孕21周再次超声检查提示双胎输血综合征,遂转至广州医科大学附属第三医院产前诊断科进行诊治。患者进行     

Fetal urine and amniotic fluid in monochorionic twins with twin-twin transfusion syndrome: simulations of therapy

OBJECTIVE: Therapy for twin-twin transfusion syndrome includes amnioreduction, septostomy, and laser ablation, but there is no accepted standard of care. Mechanisms for the reported improvement in survival are incompletely understood. We sought to model the mechanisms and predict the response of varying severities of twin-twin transfusion syndrome and placental angioarchitectures to current therapies to determine optimal clinical interventions. STUDY DESIGN: We used our mathematic model of twin-twin transfusion syndrome that predicts fetal and amniotic fluid abnormalities that are related to the placental angioarchitecture. Amnioreduction was modeled as reduction in amniotic fluid volume; septostomy was modeled as the merging of donor and recipient amniotic fluid, and laser ablation was modeled as the cessation of all placental anastomotic blood flows. RESULTS: Amnioreduction reduces amniotic fluid pressure, which improves transplacental fluid flow from mother to fetus and increases both donor and recipient blood volume. However, net arteriovenous transfusion increases, because of increased donor arterial pressure, which negates, in part, the benefit of amnioreduction. Septostomy allows amniotic fluid to be swallowed by the donor, with minimal effects on donor growth and blood volume. Laser ablation eliminates anastomotic exchange of blood and reduces discordant fetal growth. CONCLUSION: Amnioreduction may be effective in milder twin-twin transfusion syndrome pregnancies but ineffective in severe cases. Septostomy is unlikely to offer significant therapeutic efficacy. Laser ablation is equally effective in mild and severe twin-twin transfusion syndrome but has a higher spontaneous abortion rate than amnioreduction. The model indicates improved outcomes with the use of amnioreduction in mild twin-twin transfusion syndrome cases and with laser ablation in severe cases.     

Aggressive therapeutic amniocentesis for treatment of twin-twin transfusion syndrome

Acute severe twin-twin transfusion syndrome occurs in about 1% of monochorionic twin gestations. In the most severe form, acute hydramnios develops in the recipient twin's sac and fetal hydrops may be present. The donor twin is anemic and oligohydramnios is present, so that the donor appears "stuck" in a cocoon made by its adherent amnion. In this report, aggressive therapeutic amniocentesis restored amniotic fluid volume to normal in both sacs in all pregnancies. Fetal hydrops resolved in three of five (60%) of the fetuses affected. Pregnancy was extended a mean 80 +/- 33 days (+/- 2 SD) and perinatal survival was 79%. These findings contrast dramatically with the virtual 100% mortality reported in the literature with no therapy. Repeated aggressive amniocentesis effectively reversed the physiology of twin-twin transfusion syndrome and should be the treatment of choice for acute hydramnios, which previously had no recommended therapy.     

Placental angioarchitecture in monochorionic twin pregnancies: relationship to fetal growth, fetofetal transfusion syndrome, and pregnancy outcome

OBJECTIVE: We sought to correlate placental vasculature with fetal growth and outcome in monochorionic twins. STUDY DESIGN: Eighty-two patients with consecutive monochorionic pregnancies underwent biweekly ultrasonography for determination of fetal growth and well-being. After delivery, blinded placental injection studies delineated vascular anastomoses and territory share. Degree of balance in arteriovenous anastomoses equaled the number of arteriovenous anastomoses in one direction minus the number in the other. RESULTS: Pregnancies affected by fetofetal transfusion syndrome (n = 21) had numbers of arteriovenous and venovenous anastomoses that were similar to those in pregnancies without fetofetal transfusion syndrome but fewer arterioarterial anastomoses (P <.0001). Fetofetal transfusion syndrome occurred in 78% of pregnancies with >/=1 arteriovenous and no arterioarterial anastomoses. Birth weight discordancy correlated with placental territory discordancy (P <.0001) and the degree of balance in arteriovenous anastomoses (P =.004). The larger placental share twin had a greater growth velocity than its smaller placental share co-twin (P =.008) for all but one anastomotic pattern. Where arteriovenous anastomoses were aligned with the net venous outflow to the fetus with the smaller territory, co-twins had similar birth weights and growth velocities irrespective of placental share. Fetal survival was higher in pregnancies with an arterioarterial anastomosis (P =.01) but lower with a venovenous anastomosis (P =. 01). Survival of both fetuses was inversely associated with birth weight discordancy (P <.0001). CONCLUSION: Although interrelationships among the various types of anastomoses are complex, our data suggest that the placental territory share and the pattern of arteriovenous anastomoses influence fetal growth, that arterioarterial anastomoses protect against fetofetal transfusion syndrome, and that venovenous anastomoses reduce perinatal survival.