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.     

Perinatal morbidity and mortality rates in severe twin-twin transfusion syndrome: results of the International Amnioreduction Registry

OBJECTIVE: Serial aggressive amnioreduction is the most widely used therapy for pregnancies that are complicated by twin-twin transfusion syndrome. Survival rates reported with this therapy are 33% to 83%, the wide range attributable to the small number of patients in these case series. Similarly, data on morbidity in survivors are imprecise. We instituted the international twin-twin transfusion syndrome registry to determine the perinatal survival and morbidity rates and the factors that influence perinatal outcome in patients with twin-twin transfusion syndrome who were treated with serial aggressive amnioreduction from 1990 to 1998. STUDY DESIGN: A total of 223 sets of twins who were diagnosed with twin-twin transfusion syndrome before 28 weeks' gestation from 20 fetal medicine referral centers were analyzed, with follow-up data until 4 weeks after birth. RESULTS: Three hundred forty-six twins (78%; 182 recipients and 164 donors) were born alive. Two hundred sixty-six twins (60%; 144 recipients and 122 donors) were alive 4 weeks after birth. Both fetuses survived to 4 weeks in 108 pregnancies (48.4%), whereas, at least 1 fetus survived in 158 pregnancies (70.8%). The interval between the last amnioreduction and delivery ranged from zero to 138 days (median, 17.5 days). In the infants who survived to 4 weeks after birth, abnormalities on neonatal cranial scan were diagnosed in 24% of recipients and in 25% of donors. Logistic regression analysis indicated that the survival rate was significantly related to gestational age at diagnosis, presence of end-diastolic blood flow in the umbilical artery velocity waveforms, presence of hydrops, mean volume of amniotic fluid removed per week, larger birth weight, and gestational age at delivery. The hemoglobin level difference at birth was the only significant parameter to predict abnormal cranial ultrasonography in newborns. CONCLUSION: These data document perinatal survival and neonatal morbidity rates in severe twin-twin transfusion syndrome that were treated by serial aggressive amnioreduction. Outcome was influenced by several perinatal risk factors, which may be used to counsel patients before and during therapy.     

Obstetric and perinatal outcomes from the australian and new zealand twin-twin transfusion syndrome registry

OBJECTIVE: Our purpose was to investigate the antepartum characteristics and perinatal outcomes of twin-twin transfusion syndrome cases from a multicenter national registry. STUDY DESIGN: Perinatal centers in Australia and New Zealand voluntarily notified a central evaluation registry with information on identified pregnancies with twin-twin transfusion syndrome during 1995 through 1998. RESULTS: One hundred twelve cases of twin-twin transfusion syndrome were registered. The median gestation at diagnosis was 21.5 weeks (range, 14.4-34.6 weeks). Oligohydramnios-polyhydramnios sequence was the most common presentation, with 84% of cases involving "stuck" twinning. Therapeutic amnioreduction was used in 92 cases (82.1%), with the median number of procedures per case being 2 (range, 1-23). The median gestation at delivery was 29 weeks (range, 18-38 weeks). The overall perinatal survival rate was 62.5%. Abnormal findings on cranial ultrasonography were present in 27.3% of live neonates, and periventricular leukomalacia was reported in 10.8%. Increased gestational age at delivery, the presence of umbilical artery diastolic flow, and a prolonged interval from final amnioreduction to delivery were positively associated with the delivery of live fetuses without complications. CONCLUSION: The majority of antenatally identified cases of twin-twin transfusion syndrome are managed with serial amnioreduction. Despite contemporary obstetric and neonatal management strategies, perinatal mortality and morbidity rates are high.     

Twin-twin transfusion syndrome: etiology, severity and rational management

The twin-twin transfusion syndrome is a serious complication of monochorionic twin pregnancies. Partly as a result of an inadequate understanding of the pathophysiology of the syndrome, there is a lack of consensus in clinical management. We sought to review the available information on the etiology of twin-twin transfusion syndrome, to identify parameters that contribute to the severity of the syndrome, and propose a rational management plan based on pathophysiology, clinical presentation and the efficacy of therapies. We therefore amalgamated recent advances in twin-twin transfusion syndrome computer modelling and clinical studies, particularly on therapeutic outcomes. We found that the oligo-polyhydramnios sequence that defines twin-twin transfusion syndrome prenatally represents a wide continuum of severity in the imbalance between the fetoplacental circulations of both twins. In severe twin-twin transfusion syndrome cases, in which the circulatory imbalance deteriorates beyond fetal control, fetoscopic laser therapy of all anastomoses along the placental vascular equator is predicted to have significantly better survival rates and fewer neurological sequelae than amnioreduction. In contrast, mild twin-twin transfusion syndrome cases have better outcomes after one or at most a few amnioreductions than laser therapy, as a result of significantly fewer procedure-related risks. In conclusion, optimal individual therapy may possibly achieve an 85% survival rate in twin-twin transfusion syndrome, but requires advancement in non-invasive criteria that predict the severity of the syndrome. Identifying such criteria is a future challenge. For the interim, twin-twin transfusion syndrome diagnosed before 26 weeks' gestation has significantly better survival rates and fewer neurological sequelae after laser therapy than amnioreduction. Twin-twin transfusion syndrome diagnosed after 26 weeks can best be treated by amnioreduction, or delivery. Contrary to previous claims, fetoscopic laser therapy has outgrown its experimental status. Although improvements in technique and technology are likely, laser placental ablation has a firm scientific and clinical basis.     

Amnioreduction versus septostomy in twin-twin transfusion syndrome.

OBJECTIVE: The purpose of this study was to compare treatment outcomes in pregnancies affected with twin-twin transfusion syndrome. Treatment consisted of serial amnioreduction or septostomy. STUDY DESIGN: A retrospective review of patients who were diagnosed with twin-twin transfusion syndrome from June 1998 to June 2000 was conducted. Diagnosis was based on polyhydramnios (maximal vertical pocket, >8 cm) in conjunction with an enlarged fetal bladder, oligohydramnios (maximal vertical pocket, <2 cm) with nonvisualization of the fetal bladder, and documentation of a single placenta. Data evaluated were gestational age at enrollment and delivery, prolongation of gestation, and number of surviving fetuses by treatment modality. RESULTS: There were 7 patients in the amnioreduction group and 7 patients in the septostomy group. The mean gestational age at enrollment for amnioreduction was 21.0 weeks and for septostomy was 18.0 weeks (P =.01). There were 67% 2-twin survivors in the septostomy group (P = not significant), but an overall equal number of survivors (78%) in both treatment groups. The rate of no surviving twins was equal (14%) in both groups. Pregnancy was prolonged an average of 12 weeks in the septostomy group and 6.5 weeks in the amnioreduction group (P =.007). The average gestational age at delivery was 27.5 weeks for the amnioreduction group and 30.0 weeks for the septostomy group (P =.08). CONCLUSION: The prolongation of pregnancy from diagnosis to delivery was statistically significant for septostomy when compared to amnioreduction. Although not statistically significant, there appears to be a trend toward increasing gestational age at delivery with septostomy. Further randomized studies are warranted for septostomy as a treatment modality in twin-twin transfusion syndrome.     

Brain natriuretic peptide and endothelin-1 in the pathogenesis of polyhydramnios-oligohydramnios in monochorionic twins

OBJECTIVE: We investigated the association between amniotic fluid levels of human brain natriuretic peptide, endothelin-1, and abnormal amniotic fluid volume in monochorionic twins with and without chronic twin-twin transfusion syndrome. STUDY DESIGN: Amniotic fluid and fetal blood samples were obtained in utero or at cesarean delivery from monochorionic twins with (n = 20) or without chronic twin-twin transfusion syndrome (n = 10). Concentrations of atrial natriuretic peptide, human brain natriuretic peptide, and endothelin-1 (in picograms per milliliters) were determined by radioimmunoassay. RESULTS: The amniotic fluid concentrations of human brain natriuretic peptide (P <.001) and endothelin-1 (P <.001) in the recipient fetuses were higher than the donor twins but were similar in the twins with no twin-twin transfusion syndrome. In the donor twins, amniotic fluid concentrations of human brain natriuretic peptide (P <.001) and endothelin-1 (P <.001) were lower than the twin pairs with no twin-twin transfusion syndrome. In both chronic twin-twin transfusion syndrome fetuses (P <.01) and fetuses with no twin-twin transfusion syndrome (P <.001), the amniotic fluid concentrations of human brain natriuretic peptide were high, although the concentrations of the endothelin-1 were lower than the fetal plasma concentrations. A positive association was present between amniotic fluid levels of human brain natriuretic peptide and endothelin-1 (R (2) = 0.51, P <.001, n = 60). Amniotic fluid human brain natriuretic peptide (r = 0.67, P <.001) and endothelin-1 (r = 0.57, P <.01) levels of the recipient twins correlated with the amniotic fluid index. CONCLUSION: These data suggest that amniotic fluid concentrations of human brain natriuretic peptide and endothelin-1 were highest in the twins with polyhydramnios and lowest in the twins with oligohydramnios, which suggests the importance of these hormones in the regulation of amniotic fluid volume.     

Natriuretic peptides in the pathogenesis of cardiac dysfunction in the recipient fetus of twin-twin transfusion syndrome.

OBJECTIVE: Although serial amnioreduction has substantially improved the prognosis of twin-twin transfusion syndrome, the majority of recipient twins develop cardiac dysfunction in utero and some have structural abnormalities in the neonatal period. The mechanism of cardiac dysfunction is unclear. To test the hypothesis that this occurs as a result of preload or pressure overload, we determined atrial natriuretic peptide and brain natriuretic peptide levels and their association with endothelin-1 in monochorionic pregnancies with or without chronic twin-twin transfusion syndrome. PATIENTS AND METHODS: Matched maternal and fetal blood samples were obtained in utero from monochorial twin pregnancies complicated with (n = 14) and without twin-twin transfusion syndrome (n = 6). Serial fetal echocardiography assessment included cardiac anatomy, chamber size, cardiothoracic ratio, ventricular thickness, and the presence and severity of atrioventricular valve regurgitation. Postnatal echocardiograms were obtained on the surviving twins. The plasma levels of atrial natriuretic peptide, brain natriuretic peptide, and endothelin-1 were measured by use of radio-immunoassay. RESULTS: Levels of fetal atrial natriuretic peptide (P <.001), brain natriuretic peptide (P <.001), and endothelin-1 (P <.001) in the recipient fetuses were higher than in donor twins. Fetal concentrations of atrial natriuretic peptide, brain natriuretic peptide, and endothelin-1 in the donor twins were similar to those concentrations in twins that did not have twin-twin transfusion syndrome. Fetal brain natriuretic peptide (P <.01) and endothelin-1 (P <.01) levels were significantly higher in the recipient fetuses when compared to those without severe cardiac dysfunction. A significant positive correlation was present between levels of fetal brain natriuretic peptide and endothelin-1 (y = 230.9 LOG(x) - 264.1, r =.82; P <.01). In contrast, there was no association between levels of fetal atrial natriuretic peptide and the severity of cardiac dysfunction, or with levels of fetal brain natriuretic peptide and endothelin-1. CONCLUSION: Fetal natriuretic peptide levels were higher in the recipient twins than the co-twins, and the severity of cardiac dysfunction was related to levels of brain natriuretic peptide. These data, thereby, suggest that brain natriuretic peptide is a sensitive surrogate biochemical marker of cardiac dysfunction in the recipient twin.     

Antenatal factors at diagnosis that predict outcome in twin-twin transfusion syndrome

OBJECTIVE: We sought to identify clinical factors at diagnosis that predict outcome in twin-twin transfusion syndrome. STUDY DESIGN: In this retrospective series 23 patients with twin-twin transfusion syndrome were seen in a tertiary referral fetal medicine center over a 3-year period. Ten antenatal factors were assessed to determine their ability to predict outcome by use of ordered logistic regression. These factors were the following: (1) absent or reversed end-diastolic flow in the umbilical artery, nonvisible bladder, anhydramnios, and estimated fetal weight of <3rd percentile in the donor; (2) pulsatile umbilical vein, either absent or reversed end-diastolic flow in the ductus venosus, or both, and tricuspid-mitral valve regurgitation in the recipient; and (3) gestational age at presentation, estimated fetal weight discordancy, absent arterioarterial anastomosis, and spontaneous rupture of the membranes or cervical change as pregnancy factors. Management comprised serial amnioreduction (n = 10), selective feticide (n = 5; 4 also had amnioreduction), septostomy (n = 4; 1 also had amnioreduction), and delivery (n = 2). Two patients miscarried before treatment. RESULTS: The chance of survival of both twins fell and double deaths increased linearly with increasing number of adverse factors (P =.026). A low chance of survival was independently associated with absent or reversed end-diastolic flow in the donor umbilical artery (P =.02) and with a pulsatile umbilical vein or absent or reversed end-diastolic flow in the ductus venosus (P =.03) of the recipient. The probability of at least one twin surviving was only 33% if there was absent or reversed end-diastolic flow in the donor umbilical artery or 37% when abnormal venous recordings were seen in the recipient. An arterioarterial anastomosis detected at diagnosis also influenced prognosis, with all twins surviving when an arterioarterial anastomosis was identified (P =.04). CONCLUSIONS: Three factors identified at diagnosis independently predict poor survival in twin-twin transfusion syndrome-absent or reversed end-diastolic flow in the donor umbilical artery, abnormal pulsatility of the venous system in the recipient, and absence of an arterioarterial anastomosis. These may have a role in the counseling of parents and in selecting the appropriate treatment strategy.     

Long-term outcome in twin-twin transfusion syndrome treated with serial aggressive amnioreduction

OBJECTIVE: The purpose of this study was to determine long-term outcomes among pregnancies complicated by twin-twin transfusion syndrome and treated in a tertiary center with serial aggressive amnioreduction. STUDY DESIGN: Thirty-three pregnancies with a diagnosis of twin-twin transfusion syndrome were treated with > or =1 amnioreduction. The perinatal outcome was assessed according to 15 parameters, whereas the main outcome at age > or =2 years was the absence of cerebral palsy. RESULTS: Gestational age at diagnosis ranged from 14.5 to 33 weeks' gestation (median, 20.6 weeks' gestation), whereas gestational age at delivery was between 18.5 and 37 weeks' gestation (median, 30.5 weeks' gestation). The number of amnioreductions per pregnancy ranged from 1 to 15 (median, 2). At initial examination hydrops of the recipient and absence of the end-diastolic velocity of the umbilical artery in one of the twins were associated with poor prognosis. Fifty-one (77%) twins were born alive. At 24 months after birth both infants from 57% of the pregnancies (19/33) were alive, whereas at least one infant from 70% of the pregnancies (23/33) was alive. Thirty-three infants (78% of the survivors) were older than 36 months at last follow-up. Cerebral palsy was diagnosed in 2 of 42 infants (4.7%). One of the affected infants was born after the fetal death of the cotwin; the other infant was born with congenital cardiac malformations. CONCLUSIONS: In the group of fetuses in which both twins were delivered alive after 27 weeks' gestation without congenital malformations and survived the neonatal period, no major neurologic handicaps developed in any of the infants. At initial examination both hydrops of the recipient and absence of end-diastolic flow velocity waveforms of the umbilical artery in one of the twins were poor prognostic signs.     

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.     

Contemporary treatments for twin-twin transfusion syndrome

OBJECTIVE: To undertake a systematic review to determine the effects of fetal therapy interventions compared with amniodrainage for twin-twin transfusion syndrome on perinatal survival and outcome. METHODS: Searching MEDLINE (1966-2004), EMBASE (1988-2004), a hand search of specialist journals, and the Cochrane library (2004:2) identified relevant articles. Studies were selected if the effects of fetal therapeutic interventions for twin-twin transfusion syndrome (laser photocoagulation, serial amnioreduction, septostomy, and selective feticide) on perinatal survival, complications, and morbidity were compared. Study selection, quality assessment, and data abstraction were performed independently and in duplicate. RESULTS: Only 3 controlled observational studies (comparing treatment in 306 twins) and 1 randomized controlled trial (of 142 twins) were identified. Laser photocoagulation significantly improved perinatal survival of at least 1 fetus and reduced neurologic morbidity compared with serial amnioreduction. No such differences were observed in the comparison of serial amnioreduction with septostomy. CONCLUSION: In a systematic review of observational and randomized controlled studies, laser photocoagulation of chorionic plate vessels at the intertwin membrane seems to be more effective than serial amnioreduction in the treatment of twin-twin transfusion syndrome with less associated perinatal morbidity and mortality. However, septostomy and selective feticide have not been robustly evaluated.     

Hypothesis: the placental 'steal' phenomenon - a possible hazard of amnioreduction

The twin-twin transfusion syndrome (TTTS) complicates approximately 15% of monochorionic twin pregnancies. Severe TTTS is associated with poor neonatal outcome and a relatively high rate of neurological abnormalities. Some studies have suggested this outcome to be more severe in cases treated by amnioreduction. In this paper we present a hypothesis that radical amnioreduction performed after 24 weeks of gestation might cause a shift of blood from the fetus into the placenta. This could explain some of the severe neurological outcomes, such as hypoxic ischemic brain damage, seen in these cases.     

Validation of the Quintero staging system for twin-twin transfusion syndrome

OBJECTIVE: To validate an established staging system for twin-twin transfusion syndrome. METHODS: Prospective observational study in a tertiary referral fetal medicine center of 52 consecutive cases of twin-twin transfusion syndrome. Each pregnancy was assessed longitudinally for a variety of prognostic factors including fetal biometry, amniotic fluid volume, arterial and venous Doppler sonogram abnormalities, and the presence of hydrops. Data were used to determine stage at diagnosis and first treatment, and worst stage throughout pregnancy. Perinatal outcome was assessed by stage. Management comprised serial amnioreduction, septostomy, selective reduction, or delivery, alone or in combination. RESULTS: Median gestation at presentation and first treatment were both 21 weeks (range 14-34 and 15-34), and at delivery it was 29 weeks (range 16-40). Sixty-three percent of pregnancies (33 of 52) were at least stage III at presentation. Forty-five percent of pregnancies (22 of 49) progressed to a more advanced stage. Overall survival was 47% (47 of 100), with no difference between donor and recipient fetuses (40% [20 of 50] versus 54% [27 of 50] [chi(2) P =.5]). Survival rates were 58% (15 of 26), 60% (six of ten), 42% (20 of 48), 43% (six of 14), and 0% (none of two) for stages I-V, respectively, with no significant influence of stage at presentation on survival. Survival was poorer where stage increased, versus decreased (27% [12 of 44] versus 94% [17 of 18] chi(2) P <.001). Kaplan-Meier survival curves indicated that staging at presentation identified pregnancies at greater risk of earlier rather than later gestational perinatal loss. CONCLUSION: The Quintero staging system did not distinguish good from bad outcome at presentation, and thus should be used with caution in guiding initial management of twin-twin transfusion syndrome. However, prognosis was influenced by a change in stage, and pregnancies progressing to higher stage disease were at increased risk of earlier perinatal loss. Staging may thus be more useful in monitoring disease progression.     

Amniotic band syndrome following septostomy in management of twin-twin transfusion syndrome: a case report.

Septostomy, a rupture of the diamniotic membrane separating monozygotic twins essentially creating a monoamniotic gestation, is a potential therapeutic modality for twin-twin transfusion syndrome (TTTS). This may be associated with complications including cord entanglement or complete rupture of the membranes. We report a case of severe amniotic band syndrome with cord amputation after septostomy. A 33-year-old woman with a Mo-Di twin pregnancy was diagnosed with TTTS at 18 weeks of gestation. Septostomy as well as amnioreduction were performed at 24 weeks of gestation. A repeat cesarean delivery was performed at 31 weeks resulting in a live recipient baby of 1340 g and a dead donor with amniotic band syndrome. The donor showed pieces of membrane tightening both legs. The right thigh became entangled in the bands connecting to the umbilical cord of the live fetus. The umbilical cord of the dead twin was completely amputated, whereas the umbilical cord of the live infant was also entrapped within the amniotic band resulting in small diameter and some degree of stricture. This is the first report of a rare but serious complication following septostomy.     

Twin-twin transfusion syndrome treated with serial amniocenteses

BACKGROUND: To evaluate the treatment and neonatal outcome in pregnancies complicated by twin-twin transfusion syndrome (TTS). MATERIAL AND METHODS: Twenty-four women with TTS were identified in the period 1993-99 among 34477 deliveries. We include a retrospective chart review of all twins with TTS. RESULTS: The overall incidence of TTS was 4.75% of all twin pregnancies. The mean gestational age at the time of diagnosing TTS was 23 weeks (range 17.6-38), and the mean gestational age at delivery was 34.6 weeks (range 23.1-38.3). Therapeutic amniocenteses was performed in 21 women. The total volume drained varied from 0.4 to 32.31 with a mean of 2.3 l. Overall perinatal mortality in TTS was 35.4%, as nine donor twins and eight recipient twins died. The main causes for mortality were intrauterine death and prematurity. CONCLUSION: Twin-twin transfusion syndrome is a severe complication in monochorionic diamniotic twin pregnancies, with high perinatal mortality and morbidity even though amnioreduction prolonged the pregnancies leading to better neonatal outcome.     

Empirical report on acute twin-twin transfusion syndrome with single intrauterine death

We report on a case of acute twin-twin transfusion syndrome in a twin pregnancy in the 26 th under primarily unclear conditions. On admission to the hospital, one fetus was not showing signs of life anymore, while the Doppler indices and CTG of the living fetus showed signs of acute distress. On the scan both fetuses showed adequate and symmetric growth as well as symmetric and normal amniotic fluid amounts, indicating a lack of typical signs for chronic twin-twin transfusion syndrome. The emergency cesarean section performed under the assumption of acute twin-twin transfusion syndrome, which unfortunately could not save the second twin, confirmed our suspected diagnosis.     

Failure of amniotic septostomy in the management of 3 subsequent cases of severe previable twin-twin transfusion syndrome

INTRODUCTION: Amniotic septostomy has been described as a method to treat twin-twin transfusion syndrome. A case report of 3 patients treated in this way is described. CASE REPORT: Three subsequent patients, who presented with twin-twin transfusion syndrome, were treated by amniotic septostomy. All 3 showed initial improvement in the amniotic fluid volume and mobility of the donor fetus. However, all three pregnancies were lost within 5 days of the amniotic septostomy due to ruptured membranes and premature labour. CONCLUSION: In our experience, amniotic septostomy did not improve the pregnancy outcome in twin-twin transfusion syndrome. Possible reasons for this are discussed.     

Individual placental territories after selective laser photocoagulation of communicating vessels in twin-twin transfusion syndrome

OBJECTIVE: Intrauterine fetal death of one or both twins after laser therapy (selective photocoagulation of communicating vessels) may occur, in part, from insufficient individual placental mass. The objective of this study was to assess the percentage of individual placental mass (individual placental territory) that is associated with fetal survival in twin-twin transfusion syndrome after selective photocoagulation of communicating vessels. STUDY DESIGN: Placentas from 72 patients with selective photocoagulation of communicating vessels-treated twin-twin transfusion syndrome without intrauterine fetal death and from 61 monochorionic pregnancies without twin-twin transfusion syndrome (control subjects) were assessed. The placentas were weighed fresh (total placental mass) and cut along the vascular equator, which yielded the individual placental mass and the individual placental territory. Patency of anastomoses was ruled out with air-injection. The individual fetoplacental ratio was obtained by dividing birth weight by the corresponding individual placental mass. RESULTS: The 5th percentile individual placental territory that was associated with fetal survival was 27% in control subjects and 18% in cases with twin-twin transfusion syndrome, with a minimum of 10% to 14%, respectively. There were no differences in total placental mass, individual placental mass, individual placental territory, or individual fetoplacental ratio between pregnancies with twin-twin transfusion syndrome and control subjects. However, corrected for gestational age, the birth weight of recipient and donor twins were significantly smaller than control subjects. The individual placental territory of donors was statistically smaller than that of recipients. Individual placental territories were not different within control subjects. CONCLUSION: Fetal survival typically is associated with at least 18% of individual placental territory after selective photocoagulation of communicating vessels for twin-twin transfusion syndrome, but it can occur with as little as 10% to 14% individual placental territory. Decreased birth weight of the donor twin could result from relative decreased percentage of individual placental territory or from the loss of nutrients to the recipient twin. Decreased birth weight of the recipient twin could result from partial deprivation of functional placental tissue after surgery. Our findings may contribute to the understanding of normal and pathologic monochorionic twin gestations, in the counseling of patients, and potentially to the improvement of surgical treatment of twin-twin transfusion syndrome.     

The role of Doppler blood flow velocimetry in multiple pregnancy

This article focuses on Doppler velocimetry in the assessment of fetal growth, placental insufficiency, management of intrauterine growth restriction, discordant growth and twin-twin transfusion syndrome. Problems specific to multiple pregnancy such as twin reversed arterial perfusion, cord entanglement and visualization of anastomoses are also reviewed. Doppler sonography seems to be superior to other tests for early detection of placental insufficiency during surveillance of multiple pregnancies. It is suggested that Doppler sonography helps to select multiple fetuses who are at higher than normal risk, and might reduce perinatal mortality and morbidity. Fetal echocardiography may provide an accurate assessment of cardiovascular adaptation to intertwin transfusion, early recognition of deterioration and evaluation of antenatal management. In the management of the twin-twin transfusion syndrome, Doppler echocardiography and Doppler ultrasound examination of the venous circulation appear to be useful tools for improved perinatal management. Doppler sonography is an important adjunct in monitoring high-risk multiple pregnancies.     

Association of umbilical venous with inferior vena cava blood flow velocities

The fetal cardiac and placental circulations are interconnected through the umbilical venous and arterial vasculature. We hypothesized that alterations in umbilical venous blood flow velocities are present in fetuses with abnormal umbilical arterial circulation, and further, that changes in inferior vena cava blood flow velocities occur with, and might explain, these variations in umbilical venous blood flow velocities. Umbilical venous and inferior vena cava blood flow velocities were examined in 15 normal fetuses and in 59 fetuses with abnormalities that included absent end-diastolic umbilical artery blood flow velocities (N = 21) or abnormal heart rates (N = 27). Inferior vena cava velocities were also analyzed in 11 other fetuses with anomalies or known growth or placental abnormalities who had abnormal umbilical venous blood flow velocities. In normal fetuses, variations in umbilical venous velocities occurred during fetal activity or with fetal breathing; however, no variation in velocity corresponded with heart rate. Eleven of 21 fetuses with absent end-diastolic velocities in the umbilical artery demonstrated decreases in umbilical venous velocities ("venous pulsations") during arterial diastole. Blood flow velocities in the reverse direction, from the right atrium into the inferior vena cava with atrial contraction, were significantly greater in these fetuses than in those without umbilical venous pulsations (27.5 +/- 14.9% and 7.5 +/- 5.7% of total forward flow velocity, respectively; P less than .001). Venous pulsations were also seen in fetuses with abnormally fast or slow heart rates; reverse flow with atrial contraction in the inferior vena cava was likewise greater than normal in these fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)