Neonatal cranial ultrasonographic findings in preterm twins complicated by severe fetofetal transfusion syndrome

Fetal and neonatal neuroimaging in twin-twin transfusion syndrome

OBJECTIVES

To describe the types of brain injury and subsequent neurodevelopmental outcome in fetuses and neonates from pregnancies with twin-twin transfusion syndrome (TTTS). Additionally, to determine risk factors for brain injury and to review the use of neuroimaging modalities in these cases.

METHODS

This was a retrospective cohort study of consecutive TTTS pregnancies treated with laser surgery in a single fetal therapy center between January 2010 and January 2020. The primary outcome was the incidence of brain injury, classified into predefined groups. Secondary outcomes included adverse outcome (perinatal mortality or neurodevelopmental impairment), risk factors for brain injury and the number of magnetic resonance imaging (MRI) scans.

RESULTS

Cranial ultrasound was performed in all 466 TTTS pregnancies and in 685/749 (91%) liveborn neonates. MRI was performed in 3% of pregnancies and 4% of neonates. Brain injury was diagnosed in 16/935 (2%) fetuses and 37/685 (5%) neonates and all predefined injury groups were represented. Four fetal and four neonatal cases of cerebellar hemorrhage were detected. Among those with brain injury, perinatal mortality occurred in 11/16 (69%) fetuses and 8/37 (22%) neonates. Follow-up was available for 29/34 (85%) long-term survivors with brain injury and the mean age at follow-up was 46 months. Neurodevelopmental impairment was present in 9/29 (31%) survivors with brain injury. Adverse outcome occurred in 28/53 (53%) TTTS individuals with brain injury. The risk of brain injury was increased after recurrent TTTS/post-laser twin anemia-polycythemia sequence (TAPS) (odds ratio (OR), 3.095 (95% CI, 1.581-6.059); P = 0.001) and lower gestational age at birth (OR per 1-week decrease in gestational age, 1.381 (95% CI, 1.238-1.541); P < 0.001).

CONCLUSIONS

Based on dedicated neurosonography and limited use of MRI, brain injury was diagnosed in 2% of fetuses and 5% of neonates with TTTS. Adverse outcome was seen in over half of cases with brain injury. Brain injury was related to recurrent TTTS/post-laser TAPS and a lower gestational age at birth. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Additional benefits of three-dimensional ultrasound for prenatal assessment of twins

Three-dimensional ultrasound (3DUS) may provide additional information for prenatal assessment of twins. It may improve the diagnostic confidence of dating, nuchal translucency (NT) and chorionicity assignment in twin pregnancies. The "virtual 3DUS placentoscopy" can guide selective fetoscopic laser photocoagulation (SFLP) to treat twin-twin transfusion syndrome (TTTS). Volumetric assessment of the dysmorphic acardiac twin with the Virtual Organ Computer-aided Analysis (VOCAL) software is more accurate than the conventional ultrasound measurement. Twin anemia polycythemia (TAP) sequence and selective intrauterine growth restriction (sIUGR) may be clinically monitored with 3DUS placental volume (PV) and power Doppler vascular indices. Congenital anomalies are more common in twins. Evaluation of fetal anomalies with 3DUS could assist perinatal management. The 3DUS power Doppler can provide a better understanding of true and false umbilical cord knots, which are commonly found in monoamniotic (MA) twins. Single demise in monochorionic (MC) twin pregnancies can cause severe neurologic morbidity in the surviving co-twin. Prenatal prediction of brain injury in the surviving co-twin with unremarkable neurosonographic examination is difficult. The 3DUS power Doppler may aid in prenatal detection of subtle abnormal cerebral perfusion. Prenatal assessment of conjoined twins with 3DUS is important if emergency postnatal surgical separation is anticipated. There is no significant additional advantage in using real-time 3DUS to guide prenatal interventions. Assessment of the cervix and pelvic floor during twin pregnancies is enhanced with 3DUS. Due to lack of high-quality studies, routine prenatal 3DUS in twin pregnancies needs to be balanced with risks of excessive ultrasound exposure.

Early postnatal cardiac manifestations are associated with perinatal brain injury in preterm infants with twin to twin transfusion syndrome

Altered hemodynamics associated with twin to twin transfusion syndrome (TTTS) can be manifested in the fetal and neonatal heart. This study evaluated the association between cardiac manifestations immediately after birth and brain injury in preterm infants with TTTS. Medical records of preterm infants who were born at <35 weeks of gestation with TTTS and admitted to the neonatal intensive care unit at Seoul National University Children's Hospital between January 2011 and January 2018 were reviewed. TTTS was prenatally diagnosed and staged according to the Quintero criteria. Echocardiographic findings, brain ultrasound and MRI imaging findings were analyzed. Fifty-three infants were enrolled in this study. Thirty-two infants (60.3%) were treated by fetoscopic laser coagulation. Brain injury developed in 15 infants (28.3%). Hypotension within the first week and immediate postnatal cardiac manifestations were more prevalent in the brain injury group. In the multivariate analysis, acute kidney injury and cardiac manifestations, such as ventricular dysfunction and tricuspid regurgitation, were statistically associated with brain injury in the study population. Immediate postnatal cardiac manifestations, such as ventricular dysfunction and tricuspid regurgitation, can serve as surrogate markers for perinatal hemodynamic disturbance, which are associated with early neonatal brain injury in preterm infants with TTTS.

Impact of Twin-to-Twin Transfusion Syndrome, Preterm Birth, and Vision Loss on Development

This study compared the developmental outcomes of twin boys (one who is blind and one who is sighted) who were born prematurely and diagnosed with twin-to-twin transfusion syndrome (TTTS) at age 24 months. The results indicate a disparity in the developmental outcomes of the twins. Although the medical risk factors that are associated with TTTS and preterm births, as well as vision loss, appear to have a negative impact on developmental outcomes, it is impossible to determine the degree to which any factor is responsible for this result.

Outcomes of extremely premature infants with twin-twin transfusion syndrome treated by laser therapy

OBJECTIVE

To compare short-term and long-term outcomes of preterm infants born at <29 weeks of gestational age (GA) with twin-twin transfusion syndrome (TTTS) treated with laser therapy to preterm twin infants without TTTS.

DESIGN

Retrospective case-control study comparing 33 preterm TTTS twins to 101 preterm diamniotic-dichorionic (di-di) twins born at our institution between 2006 and 2015.

RESULTS

GA at birth were 26.4 ± 1.4 weeks (TTTS) and 26.9 ± 1.6 weeks (di-di) (p = 0.07). TTTS premature newborns were less exposed to antenatal steroids (p = 0.01), more frequently born by C-section (p = 0.005), received more surfactant therapy (p = 0.004, and were smaller for GA (p < 0.001). When adjusted for antenatal steroids and birth weight, TTTS status was not associated with increased mortality (HR 1.66, 95% CI 0.77-3.56, p = 0.20). No differences were found on neurodevelopmental outcomes at 18 months of corrected GA.

CONCLUSION

Premature TTTS newborns treated with fetal laser therapy had similar survival and neurodevelopmental outcomes compared to preterm di-di twins without TTTS.

Fetal stroke and cerebrovascular disease: Advances in understanding from lenticulostriate and venous imaging, alloimmune thrombocytopaenia and monochorionic twins

Fetal stroke is an important cause of cerebral palsy but is difficult to diagnose unless imaging is undertaken in pregnancies at risk because of known maternal or fetal disorders. Fetal ultrasound or magnetic resonance imaging may show haemorrhage or ischaemic lesions including multicystic encephalomalacia and focal porencephaly. Serial imaging has shown the development of malformations including schizencephaly and polymicrogyra after ischaemic and haemorrhagic stroke. Recognised causes of haemorrhagic fetal stroke include alloimmune and autoimmune thrombocytopaenia, maternal and fetal clotting disorders and trauma but these are relatively rare. It is likely that a significant proportion of periventricular and intraventricular haemorrhages are of venous origin. Recent evidence highlights the importance of arterial endothelial dysfunction, rather than thrombocytopaenia, in the intraparenchymal haemorrhage of alloimmune thrombocytopaenia. In the context of placental anastomoses, monochorionic diamniotic twins are at risk of twin twin transfusion syndrome (TTTS), or partial forms including Twin Oligohydramnios Polyhydramnios Sequence (TOPS), differences in estimated weight (selective Intrauterine growth Retardation; sIUGR), or in fetal haemoglobin (Twin Anaemia Polycythaemia Sequence; TAPS). There is a very wide range of ischaemic and haemorrhagic injury in a focal as well as a global distribution. Acute twin twin transfusion may account for intraventricular haemorrhage in recipients and periventricular leukomalacia in donors but there are additional risk factors for focal embolism and cerebrovascular disease. The recipient has circulatory overload, with effects on systemic and pulmonary circulations which probably lead to systemic and pulmonary hypertension and even right ventricular outflow tract obstruction as well as the polycythaemia which is a risk factor for thrombosis and vasculopathy. The donor is hypovolaemic and has a reticulocytosis in response to the anaemia while maternal hypertension and diabetes may influence stroke risk. Understanding of the mechanisms, including the role of vasculopathy, in well studied conditions such as alloimmune thrombocytopaenia and monochorionic diamniotic twinning may lead to reduction of the burden of antenatally sustained cerebral palsy.

Neonatal cerebral lesions predict 2-year neurodevelopmental impairment in children treated with laser surgery for twin-twin transfusion syndrome

OBJECTIVE

The objective of this study is to assess whether postnatally detected cerebral abnormalities are predictive of neurodevelopmental impairment (NDI) in survivors of twin-twin transfusion syndrome (TTTS) that underwent laser surgery.

MATERIALS AND METHODS

Ninety-nine children treated for TTTS had neurodevelopmental assessment at age 2-years (±6 weeks). 'High-risk survivors' had cerebral imaging in the neonatal period. 'High-risk survivors' were defined as (1) delivered at <32 weeks; or (2) cerebral imaging clinically indicated. NDI was a composite outcome of: Battelle Developmental Inventory 2nd edition (BDI-2) score <70, cerebral palsy, blindness, and/or deafness. Multilevel logistic regression with robust standard errors was used to evaluate associations between cerebral lesions and NDI.

RESULTS

Fifty-six children were 'high-risk survivors' and had neonatal cerebral imaging. Ten twins (18%) had at least one cerebral lesion, including grade 1-2 intraventricular hemorrhage (8), cystic periventricular leukomalacia (2), ventriculomegaly (1), and bilateral subependymal cyst (1). The risk of NDI in the 'high-risk survivors' was 7% (4/56) compared with 0% (0/43) in the remaining group. Among 'high-risk survivors', cerebral lesions were a significant risk factor for NDI (OR = 19.28, p < .001).

CONCLUSIONS

Among 'high-risk survivors' of TTTS treated with laser surgery, cerebral lesions identified on neonatal imaging were associated with NDI at 2-years.

Fetal and postnatal brain MRI in premature infants with twin-twin transfusion syndrome

OBJECTIVE

To describe the findings on fetal and postnatal magnetic resonance imaging (MRI) in premature infants with twin-twin transfusion syndrome (TTTS) and to determine whether currently used staging systems and other fetal and postnatal factors correlate with brain injury in this population.

STUDY DESIGN

We performed a prospective study of 22 premature infants with TTTS whose mothers had fetal MRIs. Postnatal brain MRI was performed at term equivalent age (38 to 44 weeks) and medical records were reviewed. Brain injury was scored on fetal and postnatal MRIs using an injury scale incorporating hemorrhagic and nonhemorrhagic injury.

RESULT

The median (range) gestational age (GA) was 31 weeks (26 to 35) and birth weight (BW) was 1296 g (762 to 2330). In all, 5/22 patients (23%) had brain injury seen on fetal MRI and 15/22 patients (68%) had brain injury seen on postnatal MRI. Quintero stage was the only predictor variable that was significantly correlated with the total brain injury score (P=0.05).

CONCLUSION

Postnatal brain injury in premature infants with TTTS is correlated with Quintero stage. GA and BW are not predictive of brain injury in this cohort of infants.

Prognosis and long-term neurodevelopmental outcome in conservatively treated twin-to-twin transfusion syndrome

Background

Amnioreduction remains a treatment option for pregnancies with twin-to-twin transfusion syndrome (TTTS) not meeting criteria for laser surgery or those in which it is not feasible. Amnioreduction is a relatively simple treatment which does not require sophisticated technical equipment. Previous reports of conservative management have indicated that major neurodevelopmental impairment occurs in 14.3-26% of survivors. The purpose of this study was to investigate long-term neurodevelopmental outcome in conservatively treated TTTS.

Methods

During the nine-year study period from January 1996 to December 2004, all pregnancies with TTTS who were admitted to our center were investigated. TTTS was diagnosed by using standard prenatal ultrasound criteria, and staged according to the criteria of Quintero et al. We reviewed gestational age at diagnosis, gestational age at delivery, the stage of TTTS at diagnosis, and diagnosis to delivery interval. Neonatal cranial ultrasound findings were reviewed and the neurodevelopmental outcomes were evaluated.

Results

Twenty-one pregnancies with TTTS were included. Thirteen pregnancies (62%) were treated with serial amnioreduction. The mean gestational age at delivery was 28 weeks (22 - 34 weeks). The perinatal mortality rate was 42.9%. Twenty survivors were followed up until at least 3 years of age. The mean age at follow-up was 6.3 years (3 - 12 years). Six children (30%) had neurodevelopmental impairment. Four children (20%) had major neurodevelopmental impairment and two children (10%) had minor neurodevelopmental impairment. Children with neurodevelopmental impairment were delivered before 29 weeks of gestation.

Conclusions

Our study showed a high rate of perinatal mortality and a high rate of major neurodevelopmental impairment in conservatively treated TTTS. The long-term outcomes for the survivors with TTTS were good when survivors were delivered after 29 weeks of gestation.

Retinopathy of prematurity in twin-twin transfusion syndrome

The authors present the first reported case of retinopathy of prematurity in twin-twin transfusion syndrome. A 31-year-old woman gave birth to twins at 31 weeks' gestation. The pregnancy had been complicated by twin-twin transfusion syndrome and had been managed with two amnioreductions and laser ablation of the interplacental blood vessels. The donor twin, born at 1,310 g, had threshold retinopathy of prematurity and underwent argon laser retinal photocoagulation treatment. The recipient twin (1,775 g) did not show any evidence of retinopathy of prematurity.

Twin-to-twin transfusion syndrome: a comprehensive update

Twin-to-twin transfusion syndrome (TTTS) is a serious complication in about 10% to 20% of monozygous twin gestations with an incidence of 4% to 35% in the United States. Severe TTTS is reported to occur in 5.5% to 17.5% of cases. TTTS is a progressive disease in which sudden deteriorations in clinical status can occur, leading to death of a co-twin. Up to 30% of survivors may have abnormal neurodevelopment as a result of the combination of profound antenatal insult and the complications of severe prematurity. This article presents an overview of what is known about the pathophysiology and the diagnosis of TTTS, the role of echocardiography in TTTS, treatment options available for TTTS, complications of treatment for TTTS, and short- and long-term outcomes of TTTS.

Sonographic findings in severe fetomaternal transfusion

Fetomaternal hemorrhage (FMH) or fetomaternal transfusion syndrome is the leakage of fetal red blood cells into the maternal circulation. Massive FMH can cause substantial fetal morbidity and mortality. Sonographic evidence of severe FMH syndrome includes fetal hydrops and other fetal anemia-related findings. The peak systolic velocity in the middle cerebral artery has extensively been used for the prediction of fetal anemia and for the timing of the first intrauterine intravascular transfusion (IIVT). We present a case of severe FMH syndrome that was diagnosed during the 24th week of pregnancy. A total of eight IIVT were performed. The actual increase in the fetal Hb after each transfusion was much lower than the expected. At 27 weeks of gestation, sonographic evaluation revealed areas of echogenicity around the posterior horns of the lateral ventricles suggesting ischemic damage. Due to these findings, no further IIVTs were offered and the fetus died a week later. The management of fetal anemia caused by severe FMH is difficult, and the anemic fetuses do not respond well to serial IIVTs as the transfer of blood to the maternal circulation continues.

Increased perinatal mortality and morbidity in monochorionic versus dichorionic twin pregnancies: clinical implications of a large Dutch cohort study

OBJECTIVE

To evaluate mortality and morbidity in a large cohort of twin pregnancies according to chorionicity. We aimed to estimate the optimal time of delivery.

DESIGN

Historical cohort design. Setting Two teaching hospitals.

POPULATION

Twin pregnancies delivered in the University Medical Centre, Utrecht, and the St Elisabeth Hospital, Tilburg (1995-2004), The Netherlands (n = 1407).

METHODS

Pregnancy outcomes were documented according to chorionicity. Mortality >/=32 weeks was reviewed carefully with special attention to antenatal fetal monitoring, autopsy and placental histopathology to find an explanation for adverse outcome.

MAIN OUTCOME MEASURES

Perinatal mortality and morbidity in monochorionic (MC) and dichorionic (DC) twins.

RESULTS

Perinatal mortality was 11.6% in MC twin pregnancies and 5.0% in DC twin pregnancies. After 32 weeks, the risk of intrauterine death (IUD) was significantly higher in MC twins than in DC twins (hazard ratio 8.8, 95% CI 2.7-28.9). In most of these cases of IUD, no antenatal signs of impaired fetal condition had been present. Median gestational age was 1 week longer in DC twins than in MC twins, and the mean birthweight was 221 g higher. Severe birthweight discordancy (>20%) occurred more often in MC twins than in DC twins (OR 1.23, 95% CI 0.97-1.55). The incidence of necrotising enterocolitis (NEC) was higher in MC twins, after adjustment for age and weight at birth (OR 4.05, 95% CI 1.97-8.35). There was a trend towards higher neuromorbidity in MC twins.

CONCLUSIONS

This is the largest cohort study of twin pregnancies evaluating outcome according to chorionicity thus far. MC twins are at increased risk for fetal death (even at term), NEC and neuromorbidity. Current antenatal care is insufficient to predict and prevent this excess perinatal mortality and morbidity. Planned delivery at or even before 37 weeks of gestation seems to be justified for MC twins.

Twin-to-twin transfusion syndrome after 26 weeks of gestation: is there a role for fetoscopic laser surgery?

OBJECTIVE

To compare fetoscopic laser surgery with amniodrainage in the treatment of twin-to-twin transfusion syndrome (TTTS) diagnosed after 26 weeks of gestation.

DESIGN

A retrospective cohort study.

SETTING

Leiden University Medical Centre, a tertiary referral hospital for fetal therapy.

POPULATION

Between January 1991 and February 2006, 21 TTTS cases were diagnosed and treated after 26 weeks of gestation.

METHODS

Treatment of TTTS consisted of either amniodrainage or fetoscopic laser coagulation of vascular anastomoses.

MAIN OUTCOME MEASURES

PRIMARY OUTCOME

adverse outcome (intrauterine or neonatal death, major neonatal morbidity and/or severe cerebral injury). Secondary outcome: gestational age at birth.

RESULTS

Eleven TTTS cases were treated with amniodrainage and ten with laser surgery. Median gestational age at birth in the amniodrainage group and in the laser surgery group was 29 and 31 weeks, respectively (P = 0.17) All infants were born alive. Major neonatal morbidity occurred more often in the amniodrainage group than in the laser surgery group, 27% (6/22) and 0% (0/20), respectively (P = 0.02). Severe cerebral injury in the amniodrainage group and in the laser surgery group occurred in 23% (5/22) and 15% (3/20) of infants, respectively (P = 0.70). Neonatal mortality in the amniodrainage group and in the laser surgery group was 14% (3/22) and 0% (0/20), respectively (P = 0.23). Overall adverse outcome was 36% (8/22) in the amniodrainage group and 15% (3/20) in the laser surgery group (P = 0.17).

CONCLUSION

In TTTS diagnosed after 26 weeks of gestation, amniodrainage and laser surgery both result in 100% survival. However, infants born after laser surgery have less major neonatal morbidity.

Medicolegal issues in multiple pregnancy

Any discussion of multiple pregnancy figures prominently in the consideration of the medicolegal aspects of placental pathology. Multiple gestations are common and becoming more so with assisted reproductive techniques, and multiples are associated with a disproportionate share of complications that may result in disputes over quality of care. Higher rates of intrauterine growth retardation, prematurity, stillbirth, morbidity, mortality, cerebral palsy, anomalous development, and malformation as compared with singletons are well documented in multiple pregnancy and should be anticipated. Monochorionic placentation and complications of vascular anastomosis are important factors contributing to poor outcome. Other factors, although occurring in all gestations, are relevant because they are more common in multiple gestations.

Lenticulostriate vasculopathy in twin-to-twin transfusion syndrome

Intracranial pathology is a common and important complication in extremely low birth weight babies. Lenticulostriate vasculopathy (LSV) is an abnormal finding on cranial ultrasounds of sick babies and has been associated with congenital infection, chromosomal aberration and twin-to-twin transfusion. We describe a previously unreported situation of LSV being detected in both donor and recipient twin. This pair of monochorionic, diamniotic twins was admitted to the Neonatal Intensive Care Unit at 28 weeks of gestation. The mother underwent an emergency caesarean section because ultrasound and Doppler studies showed stage III twin-to-twin transfusion syndrome. The first twin weighed 998 g and second twin weighed 600 g. The first twin had an uneventful stay, whereas the second twin needed prolonged continuous positive airway pressure and indomethacin for patent ductus arteriosus. Both of them developed LSV. The clinical significance of this condition on the neuro-developmental outcome of a neonate has not yet been fully determined.

Incidence, origin, and character of cerebral injury in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery

OBJECTIVE

The objective of the study was to determine the incidence, origin, and character of cerebral lesions in monochorionic twins with twin-to-twin transfusion syndrome treated with fetoscopic laser surgery.

STUDY DESIGN

This was a prospective study of monochorionic twins with twin-to-twin transfusion syndrome treated with fetoscopic laser surgery and monochorionic twins without twin-to-twin transfusion syndrome delivered at our center between June 2002 and September 2005, using cranial ultrasonography.

RESULTS

Incidence of antenatally acquired severe cerebral lesions in the twin-to-twin transfusion syndrome group was 10% (8/84) and 2% (2/108) in the non-twin-to-twin transfusion syndrome group (P = .02). Incidence of severe cerebral lesions at discharge was 14% (12/84) in the twin-to-twin transfusion syndrome group and 6% (6/108) in the non-twin-to-twin transfusion syndrome group (P = .04). Antenatal injury was responsible for severe cerebral lesions in 67% (8/12) of the twin-to-twin transfusion syndrome group.

CONCLUSION

Incidence of severe cerebral lesions in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery is high and results mainly from antenatal injury.

Instability of Doppler cerebral blood flow in monochorionic twins

OBJECTIVE

The purpose of this study was to evaluate Doppler flow velocity changes in cerebral vessels of monochorionic twins with twin-twin transfusion syndrome (TTTS).

METHODS

Repeated Doppler umbilical and cerebral blood flow studies were performed in 7 twin pairs with TTTS. Eight monochorionic twin pairs and 11 dichorionic twin pairs served as control groups. The following Doppler parameters were assessed: umbilical artery pulsatility index (PI), middle cerebral artery (MCA) PI, cerebroplacental ratio, delta PI between the umbilical artery and MCA, and peak systolic velocity (PSV) in the MCA.

RESULTS

Significant variations in PSV in the MCA and cerebral indices were found in the study group of monochorionic twins with TTTS. Periods of high PSV with low PI in the MCA were followed by lower PSV in the same fetus. Repeated measurements in the comparison groups were stable without significant variations. The delta cerebroplacental ratio was significantly higher in the study group (0.38 versus 0.09 and 0.19 in the comparison groups; P < .02).

CONCLUSIONS

Significant changes in Doppler flow velocity and indices suggest instability of cerebral blood flow with episodes of "hyperperfusion" in monochorionic twins with TTTS. Further studies are needed to elucidate the relationship of these transient changes to neurologic sequelae in the neonate.

Twin-to-twin transfusion: update on management options and outcomes

PURPOSE OF REVIEW

The diagnosis and treatment of twin-to-twin transfusion syndrome has progressed to a staging system to allow directed therapy with the addition of laser to traditional serial amnioreduction. The management options and outcomes are reviewed here.

RECENT FINDINGS

In three observational and one randomized controlled trial, laser photocoagulation of chorionic plate vessels at the intertwin membrane improved perinatal survival of at least one fetus and reduced neurological morbidity. Cerebral palsy continues to be a major contributor to adverse outcome with rates of around 20% for survivors.

SUMMARY

Treatment strategies for this condition have remained controversial, but two main approaches have been commonly used. Serial, aggressive amnioreduction and fetoscopic laser photocoagulation of the chorionic plate vascular anastomoses at the intertwin membrane. Using the former technique, survival rates of between 18 and 83% have been described. However, 5-58% neurological morbidity has been demonstrated in the surviving infants treated by serial amnioreduction alone. Laser photocoagulation has been advocated in a few specialist centres. Such treatment has been associated with survival rates of between 55 and 69% and potentially reduced neurological morbidity of between 5 and 11% in surviving infants.

[Neurological outcome of children from twin pregnancies]

The neurological outcome is an important issue regarding twin pregnancies. In fact, twin pregnancy is clearly associated with an important neurological morbidity, roughly 4 times higher than singleton pregnancy. It is possible to distinguish some high-risk situations, making it possible to calculate more accurately the individual risk. The different aetiologies are analysed: hypotrophy, prematurity, malformations, prenatal occurrence of anoxic and ischemic lesions, and particularly the link with monochorionicity. The neurological outcome is mainly depending on hypotrophy and prematurity. However, the rate of long-term neurological complications is not different between twins and singletons after adjustment for term and birth weight. An increased risk of malformation is associated with twin pregnancies, essentially a high rate of abnormal neural tube closing (RR=2). Monochorionic pregnancies have a specific morbidity, not related to these aetiologies, with characteristic anoxic and ischemic lesions. Cerebral palsy is observed in 10-20% of the monochorionic pregnancies, vs 3.7% of the bichorionic ones. These complications are linked to the constant vascular anastomoses, between the circulations of the two monochorionic twins. When the twin-to-twin transfusion syndrome is severe, a poor neurological outcome is observed in 4 to 18% of the surviving children. However, this rate depends on studies, treatments, and methods of neurological evaluation. The laser destruction of anastomoses could decrease this morbidity. The stillbirth rate, either associated or not with twin to twin transfusion syndrome, is increased by monochorionicity. The death of one of the twins is associated with a 20% higher risk of neurological sequelae for the surviving co-twin.

Neonatal outcome in twin-to-twin transfusion syndrome treated with fetoscopic laser occlusion of vascular anastomoses

OBJECTIVE

To determine neonatal mortality and morbidity rates in monochorionic twins with chronic twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser occlusion of vascular anastomoses.

STUDY DESIGN

In a prospective study of monochorionic twins delivered at our center between June 2002 and December 2004, neonatal outcome was assessed in 40 monochorionic twin pairs with TTTS treated with laser compared with 46 monochorionic twin pairs without TTTS.

RESULTS

The neonatal mortality rate in the TTTS and no-TTTS group was 8% (6/76) and 3% (3/90), respectively. The rate of severe cerebral lesions on ultrasound scanning in the TTTS and no-TTTS group was 14% (10/72) and 6% (5/82), respectively. The incidence of adverse neonatal outcome (neonatal death, major neonatal morbidity, or severe cerebral lesions) in the TTTS and no-TTTS group was, respectively, 26% (20/76) and 13% (12/90) (RR = 1.97, 95% CI = 1.03 to 3.77).

CONCLUSIONS

Although perinatal outcome in TTTS has improved after laser therapy, neonatal mortality and morbidity rates remain high. Relative risk for adverse neonatal outcome is increased 2-fold in TTTS treated with laser relative to monochorionic twins without TTTS.

Twin-twin transfusion syndrome: where do we go from here?

Management of Twin-Twin Transfusion Syndrome (TTTS) is one of the most challenging clinical problems concerning multiple gestations. The pathophysiology of TTTS and Quintero staging system are described. The importance of fetal echocardiograms in assessing prognosis and response to therapy is highlighted. Treatment modalities, particularly amnioreduction, microseptostomy, and fetoscopic laser photocoagulation, are discussed. Questions still remain as to how various treatment options affect short- and long-term cardiac and neurodevelopmental outcomes and which patients will benefit most from selective laser photocoagulation therapy.

Management of Multiple Pregnancy

Over the past 20 years, the number and rate of multiple births have dramatically increased in the United States. The rise in multiple births is mainly attributable to the increased use of ovulation-inducing drugs and the newly developed assisted reproductive technologies such as in vitro fertilization. Multifetal gestation is associated with an increased risk of perinatal morbidity and mortality. Multiple births account for an increasing percentage of low-birth-weight infants, preterm births, and infant mortality. In this article, the unique complications of multiple gestation and their management are reviewed. Also, selective termination and multifetal reduction in multiple gestation are discussed.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader should be able to describe the effects of the rising rate of multiple pregnancies on perinatal morbidity and mortality, to recall the complications of diagnosing and treating abnormalities of multiple pregnancies, to list the multiple severe complications associated with multiple gestations, and to describe the difficulty in managing these complications.

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.

Long-term outcomes in multiple gestations

Children born from a multiple gestation are at increased risk for cerebral palsy, learning disability, and language and neurobehavioral deficits. With the increased incidence of multiple pregnancies and use of assisted reproductive technology (ART), these issues are more commonly affecting parents. Long-term outcomes are a critical part of preconceptual and early pregnancy counseling for parents faced with a multiple gestation or considering ART, and the provider should be well versed on issues surrounding zygosity, gestational age, higher-order multiples, and the effects of options such as multifetal pregnancy reduction.

Management of fetofetal transfusion syndrome

Feto-fetal transfusion syndrome contributes heavily to high rates of perinatal mortality and morbidity in monochorionic multiple pregnancies. Its prenatal management has been controversial for at least 25 years. We review the recent literature in order to present the basis for a pragmatic reappraisal of the management of this condition. Laser surgery of the chorionic plate inter-twin anastomoses is the best first-line treatment when the syndrome develops before 26 weeks' gestation. Survival (including quality of survival) and gestational age at delivery are improved when compared to serial amnioreduction. Second-line treatment options include repeat-laser, intra-uterine blood transfusion, serial amnioreduction, selective feticide using bipolar cord coagulation or elective delivery, depending upon gestational age and the severity of the disease and its complications. We have found that fetoscopic placental surgery has proven itself over simplicity of amnioreduction. There is no evidence that treatment should be customized according to the stage of the disease at diagnosis. Early recognition of the syndrome through fortnightly serial ultrasound follow-up of all monochorionic pregnancies should ensure timely referral and make up for geographical constraints. Laser surgery should now be available in fetal medicine units that are managing at least 20 cases per year.

Insights into the pathophysiology of twin–twin transfusion syndrome

Twin-twin transfusion syndrome (TTTS) is attributed to trans-anastomotic transfusion between twins. Anastomoses are ubiquitous in monochorionic (MC) placentae, yet TTTS develops in only 15%. Although ex vivo and in vivo studies fail to identify a unique anastomotic signature, TTTS placentae are typically associated with an imbalance in unidirectional arteriovenous anastomoses with absent bidirectional anastomoses. Doppler detection of an artery-artery anastomosis reduces the chance of TTTS, whereas, in those that develop the disease, it improves stage-independent survival. Selective laser is often curative, but an increasingly recognized risk of persistent or reverse TTTS may be attributable to atypical arteriovenous anastomoses not identifiable from the chorionic plate. Simple dysvolaemia fails to explain several phenotypic features, including haematological concordancy, recipient hypertension, and reversibly absent end diastolic flow in the donor. The renin-angiotensin system is upregulated in the donor and downregulated in the recipient's kidneys, while paradoxically raised renin levels in the recipient may contribute to raised afterload along with endothelin. Although research is limited in humans by therapy and the lack of a suitable experimental model, further studies of placental and vascular pathophysiology may not only refine current treatment modalities but may also, in addition, suggest further avenues for downstream management such as genetic predisposition testing or pharmacological intervention.

Endoscopic laser surgery versus serial amnioreduction for severe twin-to-twin transfusion syndrome

BACKGROUND

Monochorionic twin pregnancies complicated by severe twin-to-twin transfusion syndrome at midgestation can be treated by either serial amnioreduction (removal of large volumes of amniotic fluid) or selective fetoscopic laser coagulation of the communicating vessels on the chorionic plate. We conducted a randomized trial to compare the efficacy and safety of these two treatments.

METHODS

Pregnant women with severe twin-to-twin transfusion syndrome before 26 weeks of gestation were randomly assigned to laser therapy or amnioreduction. We assessed perinatal survival of at least one twin (a prespecified primary outcome), survival of at least one twin at six months of age, and survival without neurologic complications at six months of age on the basis of the number of pregnancies or the number of fetuses or infants, as appropriate.

RESULTS

The study was concluded early, after 72 women had been assigned to the laser group and 70 to the amnioreduction group, because a planned interim analysis demonstrated a significant benefit in the laser group. As compared with the amnioreduction group, the laser group had a higher likelihood of the survival of at least one twin to 28 days of age (76 percent vs. 56 percent; relative risk of the death of both fetuses, 0.63; 95 percent confidence interval, 0.25 to 0.93; P=0.009) and 6 months of age (P=0.002). Infants in the laser group also had a lower incidence of cystic periventricular leukomalacia (6 percent vs. 14 percent, P=0.02) and were more likely to be free of neurologic complications at six months of age (52 percent vs. 31 percent, P=0.003).

CONCLUSIONS

Endoscopic laser coagulation of anastomoses is a more effective first-line treatment than serial amnioreduction for severe twin-to-twin transfusion syndrome diagnosed before 26 weeks of gestation.

Doppler for Artery–Artery Anastomosis and Stage-Independent Survival in Twin–Twin Transfusion

OBJECTIVE

Treatment selection in twin-twin transfusion syndrome is increasingly determined by disease severity. We investigated whether detection of arterio-arterial anastomoses predicts perinatal survival.

METHODS

An artery-artery anastomosis was sought by Doppler and disease stage was determined in 105 cases of twin-twin transfusion syndrome at presentation, first treatment, and worst stage. Outcome measures were perinatal, double, and any (1 or more babies) survival rates.

RESULTS

After exclusion of 10 noninformative pregnancies, perinatal, double, and any survival rates were 61%, 44%, and 77%, respectively. When an anastomosis was detected at each of the 3 time points, perinatal and double survival rates were higher than when one was not (at first treatment, perinatal survival 83% versus 53%, respectively, P =.003; double survival 78% versus 33%, P <.001). Perinatal and double survival (P < or =.01) were poorer with more advanced stage, but any survival rates were not influenced by stage or anastomosis detection. Multiple logistic regression demonstrated that anastomosis detection at treatment increased the chance of perinatal (odds ratio [OR] 5.1, 95% confidence interval [CI] 1.6, 15.9) and double survival (OR 19.3, 95% CI 2.7, 138), independently of stage. For stages I-III at treatment, anastomosis detection predicted better perinatal (100% versus 63%, 100% versus 59%, and 83% versus 44%, respectively) and double survival rates (100% versus 52%, 100% versus 46%, and 78% versus 26%). Stage III, with anastomoses detected, had better perinatal (83% versus 63%) and double survival (78% versus 52%) than did stage I without detection.

CONCLUSION

Antenatal detection of artery-to-artery anastomosis predicts higher perinatal and double survival in twin-twin transfusion syndrome, independently of disease stage.

LEVEL OF EVIDENCE

II-3

Long-term neurodevelopmental outcome in twin-to-twin transfusion syndrome

OBJECTIVE

The purpose of this study was to determine the long-term neurodevelopmental outcome in children after twin-to-twin transfusion syndrome.

STUDY DESIGN

Maternal and neonatal medical records of all twin-to-twin transfusion syndrome patients who were admitted to our center between 1990 and 1998 were reviewed. Neurologic and mental development at school age was assessed during a home visit in all twin-to-twin transfusion syndrome survivors.

RESULTS

A total of 33 pregnancies with twin-to-twin transfusion syndrome were identified. Four couples opted for termination of pregnancy. All other pregnancies were treated conservatively, 18 pregnancies (62%) with serial amnioreductions and 11 pregnancies (38%) without intrauterine interventions. Mean gestational age at delivery was 28.6 weeks (range, 20-37 weeks). The perinatal mortality rate was 50% (29/58 infants). The birth weight of the donor twins was less than the recipient twins (P<.001). Systolic blood pressure at birth was lower in donors than in recipients (P=.023), and donors required inotropic support postnatally more frequently than did recipients (P=.008). The incidence of hypertension at birth was higher in recipients than in donors (P=.038). Abnormal cranial ultrasonographic findings were reported in 41% of the neonates (12/29 neonates). All long-term survivors (n=29 neonates) were assessed during a home visit. Mean gestational age at birth of the surviving twin was 31.6 weeks (range, 25-37 weeks). The mean age at follow-up was 6.2 years (range, 4-11 years). The incidence of cerebral palsy was 21% (6/29 infants). Five of 6 children with cerebral palsy had an abnormal mental development. The incidence of cerebral palsy in the group of survivors who were treated with serial amnioreduction was 26% (5/19 infants). Four children were born after the intrauterine fetal demise of their co-twin, 2 of which had cerebral palsy.

CONCLUSION

The incidence of adverse neurodevelopmental outcome in twin-to-twin transfusion syndrome survivors is high, especially after the intrauterine fetal demise of a co-twin.

Mean arterial pressure in very low birth weight (801 to 1500 g) concordant and discordant twins during the first day of life

OBJECTIVE

To determine retrospectively mean arterial pressure (MAP) for stable and unstable concordant and discordant very low birth weight (VLBW: 801 to 1500 g) twins during the first 24 hours of life.

BACKGROUND

Morbidity and mortality are much higher for extremely low birth weight (ELBW < or =800 g) than for VLBW twins. Recently, we reported MAP trends and reference values in concordant and discordant ELBW twins. No comparable information is available for VLBW infants.

DESIGN

Retrospective cohort study.

METHODS

We studied 48 sets of concordant and 40 sets of discordant (birth weight difference > or =20%) consecutively born VLBW twins. Stable patients were defined as having umbilical cord hemoglobin > or =14 g/dl, nonacidotic blood gases, never treated for hypotension and survived at least 7 days. MAPs (Torr) were measured by oscillometry in 3163 and by transducer via umbilical artery in 2028 instances.

RESULTS

Concordant and discordant twins were similar in demographics, history of twin-twin transfusion (TTTX), antenatal steroids, chorioamnionitis, pre-eclampsia, cesarean delivery, cord hemoglobin, normal head ultrasounds or I to II intracranial hemorrhage (97 and 99%) and neonatal mortality (4 and 5%), but were different in incidence of preterm labor (83 and 58%), birth weight (1227 and 1509 g) and gestational age (GA) (30 and 32 weeks). In all, 66 (69%) concordant twins and 61 (76%) discordant twins were stable. Stable concordant twins, whether small or large, had comparable MAP on admission that increased to 24 hours. Twins of < or =32 weeks GA had lower MAP throughout than those of > or =33 weeks GA. Although their mean birth weights were similar (1262 and 1274 g), 23 stable concordant males had significantly higher MAP than 43 concordant females. Stable discordant twins were divided into 31 small (1241 g) and 30 large (1845 g); their MAPs were different (p<0.05): 35 and 39 (admission), 35 and 39 (1 hour), 36 and 46 (6 hours), 38 and 41 (12 hours), 40 and 41 (18 hours) and 42 and 42 (24 hours) Torr. In all, 88% of small discordant twins were IUGR and 91% of large discordant twins had normal growth. TTTX syndrome occurred in 12 monochorionic sets. Nine of 12 donors were IUGR while 10 of 12 recipients had normal growth. Four of 12 donors had grades III to IV intracranial hemorrhage, eight donors and all 12 recipients had normal ultrasounds. Although their cord hemoglobin levels were similar, donor and recipient MAPs were higher than in any other group and, opposite to concordant and discordant twins, their values decreased from birth to 24 hours.

CONCLUSION

In stable concordant, stable discordant, and small and large discordant twins, MAP correlates with birth weight, GA and postnatal age, and increases during the first 24 hours. In recipient and donor twin-twin transfusion infants, MAP is higher throughout and declines over time.

Monochorionic diamniotic twins: complications and management options

PURPOSE OF REVIEW

Monochorionic compared with dichorionic twins have disproportionately high fetal loss rates, perinatal mortality and morbidity. This is because of the unpredictable vascular anastomoses and the often asymmetrical distribution of the single placenta between both twins.

RECENT FINDINGS

The pathophysiology of twin-to-twin transfusion syndrome is usually explained on an angioarchitectural basis, although certain hemodynamic and hormonal factors also may be involved. The results of the large randomized trials on amnioreduction, fetoscopic laser coagulation and septostomy are still awaited. An update is given on hardware and instruments required for fetoscopic laser. Subsequently, the problem of the monochorionic twin set with severe early discordant growth is addressed. Several etiological mechanisms have been proposed, but little is known of its natural history. Also, umbilical artery Doppler waveforms may not have the same predictive value as in singletons. Prophylactic laser coagulation of the vascular anastomoses to protect against the adverse effects of single intrauterine demise, has so far not been shown to confer any benefit in outcome. Finally, pathophysiology and management of discordant structural and chromosomal anomalies in monochorionic twins are discussed. Laser and monopolar coagulation, which can be introduced through a needle, may be used for selective feticide in early pregnancy or low hemodynamic conditions. Bipolar coagulation seems more effective at later gestational ages and normal hemodynamic conditions.

SUMMARY

Our insight into the complications associated with monochorionic twins has increased in recent years. It is hoped that this will lead to better surveillance and ultimately an improved outcome for these high-risk pregnancies.

Myocardial hypertrophy of the recipient twins in twin-to-twin transfusion syndrome and cerebral palsy

OBJECTIVES

This study was performed to determine risk factors for cerebral palsy (CP) in monochorionic twins, especially with twin-to-twin transfusion syndrome (TTTS).

METHODS

In 33 pathologically confirmed monochorionic pregnancies, we analyzed the incidence of cardiovascular and neurological complications.

RESULTS

Seventeen cases were diagnosed as TTTS. Myocardial hypertrophy was detected in seven recipient twins of TTTS, but not found in the donor twins of TTTS or in non-TTTS. CP developed in six out of 29 in TTTS and one out of 32 in non-TTTS. In TTTS, all the cases with CP were seen in the recipient twins. The development of CP was significantly associated with cardiovascular complications such as myocardial hypertrophy and hydropic changes.

CONCLUSIONS

Myocardial hypertrophy found in the recipient twins in TTTS seems to be a risk for developing CP later on, which may have implications in understanding the pathogenesis of CP.

Cerebral infarctions in the fetus and neonate: maternal-placental-fetal considerations

Historical data, clinical examination findings, and laboratory information must be integrated along a variable timeline that includes antepartum, intrapartum, and postnatal time periods when cerebral infarction can occur, in the context of the neonates genetic endowment. Genetic susceptibility or prenatal acquired vulnerabilities regarding stroke syndromes may set in motion a cascade of molecular pathways that ultimately cause or exacerbate brain injury when the vulnerable child experiences adverse medical conditions. The clinician must consider maternal, placental, and fetal conditions on which a stroke syndrome may be superimposed, with or without additional brain injury from other pathogenic mechanisms. Evaluation of fetal and neonatal cerebral infarction requires knowledge of mechanisms of brain injury that cross medical disciplines and may involve consultation with maternal/fetal specialists, placental and pediatric pathologists, neonatologists, geneticists, and other pediatric subspecialties. Comprehensive evaluations of survivors of cerebral infarction are needed to better understand structural and functional plasticity of the developing brain after a cerebrovascular event in the fetal and neonatal periods.

Mean arterial pressure in extremely low birth weight concordant and discordant twins during the first day of life

OBJECTIVE

To determine mean arterial pressure (MAP) values during the first 24 hours for stable concordant and discordant extremely low birth weight (ELBW) twins and to ascertain its association with perinatal factors.

BACKGROUND

In ELBW infants, whether singletons or concordant or discordant twins, hypotension is diagnosed by nonspecific clinical signs together with reference arterial pressure values extrapolated from regression models or from scarce actual observations.

DESIGN

Retrospective cohort study.

METHODS

We studied 26 sets of concordant and 29 sets of discordant twins, one of whom in each set weighed < or = 800 g at birth. Infants with umbilical cord hemoglobin > or = 14 g/dl and who, although mechanically ventilated, had normal acid-base balance, no patent ductus arteriosus, had not received indomethacin, steroids, muscle relaxants, narcotics, were never treated for hypotension, and survived at least 7 days were considered stable. Arterial pressures were determined by oscillometry (OBP) and direct transducer readings using an umbilical line (MAP). All admission and 10 % of the subsequent readings were measured by OBP; the remaining were measured by MAP.

RESULTS

Concordant and discordant twins were similar in demographics, history of chorioamnionitis, preeclampsia, antepartum steroids, cesarean delivery, and neonatal morbidity, but were different in mean birth weight (700 and 789 g), and gestational age (GA) (25 and 27 weeks). Forty-four (82%) of all concordant and 14 (26%) of 58 discordant twins were treated empirically for hypotension. Head ultrasounds were normal or showed Grade I/II in 74% concordant, 81% discordant, and 80% discordant infants with twin-to-twin transfusion syndrome (TTTX). Neonatal mortality was 46%, 45%, and 47%, respectively. There were 14 stable concordant and 22 stable discordant. Their MAPs were different at 1 hour (29 and 34 Torr), 3 hours (29 and 35 Torr), 6 hours (30 and 37 Torr), 12 hours (31 and 36 Torr), 18 hours (33 and 35 Torr), and 24 hours (34 and 36 Torr), respectively. Twenty-six small and 26 large concordant infants had similar MAP from the 1st (27 and 28 Torr) to the 24th hour of life (43 and 43 Torr). Concordant males (often not stable) had lower MAP than concordant females. Seventeen small discordant twins had lower MAP from 1 to 24 hours (28 and 33 Torr) than 17 large discordant twins without TTTX (32 and 38 Torr). Small discordant twins with (donors) and without TTTX had similar trends and MAP values. Large discordant twins with TTTX (recipient) had the highest MAP from birth to 24 hours than any other subgroup of infants and, unlike the others, the MAP trend decreased over time. MAP correlated with GA but not with very low birth weight (< or = 750 g), although with the same GA, those with higher birth weights had higher MAP, and at the same birth weight younger GA twins had lower MAP values.

CONCLUSION

MAP increases from birth to 24 hours in all concordant and discordant twins regardless of condition (stable or unstable), birth weight (large or small) or GA. Recipient TTTX twins had higher MAP throughout but, unlike the other twins, it declined over 24 hours. Small discordant and donor TTTX infants should be considered intrauterine growth restricted and are expected to have MAP commensurable to their GA and not to their birth weight.

Neonatal and long-term outcomes of very low birth weight infants from single and multiple pregnancies

The revolution in artificial reproductive technologies has resulted in a dramatic rise in the incidence of multiple pregnancies. Many of these infants are born prematurely, often extremely so. Consequently, perinatal morbidity and mortality are highly correlated with plurality. The primary mechanism for this increased risk is prematurity. Studies of the relationship between plurality and outcome are frequently hampered by major differences in case mix between singletons, twins and high multiples. For example, high multiples tend to receive earlier prenatal care, receive more antenatal steroids, are more often delivered by Caesarean section and more often suffer from respiratory distress syndrome. However, recent studies that appropriately account for relevant confounding variables have suggested that very low birth weight infants from high multiple pregnancies are at excess risk for mortality when compared with twins and singletons. This article reviews the current available evidence.

The twin-twin transfusion syndrome

The aetiology of twin-twin transfusion syndrome (TTTS), which affects 10-15% of monochorionic (MC) twin pregnancies, remains poorly understood. Although all MC twins have placental vascular anastomoses, unbalanced intertwin transfusion has been shown by ex vivo injection and in vivo Doppler studies of chorionic plate vasculature to be mediated by > or =1 arterio-venous anastomoses (AVA) in association with absent bi-directional arterio-arterial anastomoses (AAA). TTTS presents in the mid trimester with the oligo-polyhydramnios sequence, the donor may have a small or non-visible bladder and abnormal umbilical artery Doppler, while the recipient has a large bladder and may develop cardiac hypertrophy, triscupid regurgitation, and eventually hydrops. Recently, discordant renal renin angiotensin expression, endothelin and atrial natriuretic peptide have been implicated in the pathogenesis. Survival has increased from <20% to <60-70% with modern treatments, although survivors remain at increased risk of antenatally acquired cerebral white matter injury, and neurodevelopmental sequelae are documented in c.10% (range 5-23%). The recent introduction of a staging system for TTTS facilitates selection of therapy with less invasive amnioreduction and septostomy preferred for early stage disease, and more aggressive modalities such as laser ablation and cord occlusion with their attendant risk of procedure related fetal loss, reserved for advanced stage disease.

Ultrasound-guided umbilical cord occlusion using bipolar diathermy for Stage III/IV twin-twin transfusion syndrome

OBJECTIVES

To evaluate bipolar diathermy as a technique for selective fetocide in the treatment of advanced (Stage III/IV) twin-twin transfusion syndrome (TTTS).

METHODS

A prospective observational study in two tertiary referral fetal medicine centres: Queen Charlotte's Hospital, London, UK and Haemek Hospital, Afula, Israel. Fifteen cases of TTTS (14 twins and one triplet pregnancy) were treated by selective occlusion of either the donor (n=8) or recipient's (n=7) umbilical cord using ultrasound-guided bipolar diathermy. Following each procedure, patients were scanned serially for fetal growth, liquor volume and umbilical Doppler measurements. Procedural complications and obstetric outcome were recorded. Postnatal placental injection studies were performed.

RESULTS

Overall co-twin survival in Stage III/IV TTTS was 13/14 (93%). There were no treatment failures. The incidence of preterm prelabour rupture of membranes (PPROM) within 3 weeks of the procedure was 3/15 (20%). In those cases where pre-procedure umbilical artery Dopplers were abnormal, the Doppler findings normalised post-procedure in all non-cord-occluded fetuses. Growth velocities of surviving donors were similar to those of surviving recipients.

CONCLUSIONS

Bipolar diathermy appears an effective technique for the selective reduction of monochorionic twins complicated by severe as well as preterminal TTTS, with recipient and donor fetuses being equally appropriate choices for fetocide. We suggest that for advanced-stage disease where the parents can contemplate this option, cord occlusion as a single preemptive procedure maximises the opportunity for intact survival of a single survivor.

Freehand three-dimensional Doppler demonstration of monochorionic vascular anastomoses in vivo: a preliminary report

OBJECTIVES

To demonstrate the three-dimensional vascular anatomy of monochorionic placental anastomoses in vivo, both arterioarterial and arteriovenous.

DESIGN

Two-dimensional placental mapping techniques were used to locate arterioarterial and arteriovenous anastomoses. A freehand sweep was performed across the anastomotic site, and multiple images were stored to disk, at 17 Hz. These were then segmented to show only color information (vascular flow) using purpose-designed software (CQ analysis) and the files reconstructed into a three-dimensional volume, for multidirectional viewing and movie generation.

RESULTS

Both arterioarterial and arteriovenous anastomoses could be visualized in detail. Reconstruction of a dual volume of gray-scale and segmented color images allowed recreation of the vascular anatomy within the placental substance, as well as retention of the original directional flow information.

CONCLUSIONS

Detailed anastomotic anatomy can be demonstrated three dimensionally in vivo. Given the increasing evidence implicating various anastomotic configurations in pathological intertwin transfusion, this technique may prove useful in the antenatal assessment and treatment of monochorionic twin pregnancies.

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.

Fetal and neonatal neurologic consultations: identifying brain disorders in the context of fetal-maternal-placental disease

Pediatric neurologists provide an important consultative role for the fetus or neonate with a suspected brain disorder. Although most consultations are initiated after birth, neonatal neurologic dysfunction may be reflective of fetal brain damage or maldevelopment. Maternal or placental/cord disease states can predispose the fetus or neonate to brain disorders during the antepartum, intrapartum, or early postpartum periods. Neurologists must therefore consider maternal, placental, and fetal conditions on which a neonatal encephalopathy may be superimposed, with or without recent brain injury. This review suggests how the pediatric neurologist can contribute more effectively to fetal and neonatal neurologic evaluations regarding etiologies and mechanisms of brain injury; their role will enhance diagnostic services composed of maternal-fetal specialists, placental and pediatric pathologists, neonatologists, neurosurgeons, geneticists, and other pediatric subspecialists. Selected examples of structural markers during fetal life, and functional markers during neonatal life, illustrate the wide spectrum of disease states that are highly dependent on the timing and location of brain injury. The pediatric neurologist has the opportunity to integrate these complementary lines of investigation into a responsive consultative opinion, which is both medically accurate and ethical, responsible to the welfare of the mother and child.

Twin pregnancy: the role of ultrasound in management

Determination of chorionicity is one of the most important issues in the management of twin pregnancy. Modern ultrasound equipment has made it possible to accurately assess placentation already in the first trimester with the lambda sign. With regard to prenatal diagnosis, it is important to know the chorionicity in order to calculate the risk of chromosomally abnormal fetuses. Accurate chorionicity offers the obstetricians the opportunity to observe the monochorionic twins more intensively than is required for twins with dichorionic placentation. This review gives an update of the state of the art for clinicians caring for twin pregnancies.