Perinatal outcome of forty-nine pregnancies complicated by acardiac twinning

Acardiac twinning affects 1 in 100 monozygotic twin pregnancies and 1 in 35,000 pregnancies overall. The presence of an acadiac twin requires the normal (or "pump") twin to provide circulation for itself, as well as the acardiac sibling. In many cases the acardiac twin is almost equal to the normal twin. The principal perinatal problems associated with acardiac twinning are pump-twin congestive heart failure, maternal hydramnios, and preterm delivery. We reviewed the perinatal courses of 49 acardiac twin pregnancies to identify factors prognostic of favorable outcome. The overall perinatal mortality was 55%, primarily associated with prematurity. Mean (+/- SD) gestational age at delivery was 29 +/- 7.3 weeks, with a mean (+/- SD) normal twin weight of 1378 +/- 1047 gm. The acardiac weight averaged 651 +/- 571 gm. However, the occurrence of hydramnios, the occurrence of preterm labor, and perinatal outcome were strongly related to the ratio of the acardiac and pump-twin's weight. The mean overall ratio of the twin weights was 52% +/- 42%. However, the mean weight ratio for patients delivered before 34 weeks was 60% versus 29% (p less than 0.04). Preterm delivery was strongly associated with the development of hydramnios and congestive heart failure in the pump twin (p less than 0.01). If the twin-weight ratio was above 70% (25% of cases), the incidence of preterm delivery was 90%; hydramnios, 40%; and pump-twin congestive heart failure, 30% compared with 75%, 30%, and 10%, respectively, when the ratio was less (p less than 0.05). Regression of the weight of the acardiac twin against its longest dimension (L) resulted in this equation for prediction of acardiac weight: Weight (grams) = 1.2 L2-1.7L; r = 0.79, p less than 0.01. These data suggest that estimation of the relative weights in acardiac twins provides prognostic information regarding outcome. Poor outcome occurs with congestive heart failure and hydramnios in the normal twin. Use of the above data may assist in counseling patients and determining optimal management.     

Utility of Doppler velocimetry in predicting outcome in twin reversed-arterial perfusion sequence

OBJECTIVE: The aim of this study was to describe Doppler velocimetric findings in pregnancies complicated by the twin reversed-arterial perfusion sequence and to determine the association of these findings with pregnancy outcome. STUDY DESIGN: Six twin pregnancies complicated by twin reversed-arterial perfusion sequence had ultrasonographic and Doppler studies performed between 1990 and 1997. Pulsatile vessels in the umbilical cords of the pump and acardiac twins were insonated, and reversal of flow was confirmed in all cases. Resistive index values were calculated, and the difference in resistive index between the pump and acardiac twin in each pair was evaluated as a marker of pregnancy outcome. RESULTS: Five of 6 pump twins survived the immediate neonatal period. Although 5 of the acardiac twins had abnormally elevated Doppler index values, no ratio of systolic to diastolic velocity or resistive index value of the acardiac twin alone was associated with either a good or poor prognosis for the pump twin. Among the 3 pump twins with good outcomes, all had a resistive index difference >0.20. Among the 3 pump twins with poor outcomes, all had small resistive index differences (<0.05). CONCLUSION: We found larger differences in resistive index to be associated with improved outcome of the pump twin in pregnancies complicated by twin reversed-arterial perfusion sequence. Smaller resistive index differences were associated with poor outcome, including cardiac failure and central nervous system hypoperfusion.     

Intrafetal alcohol chemosclerosis of acardiac twins: a multicenter experience

OBJECTIVE: To report a multicenter experience with intrafetal alcohol chemosclerosis in the treatment of pregnancies complicated with the twin reversed arterial perfusion sequence. METHODS: Percutaneous injection of 1- 2 ml of absolute alcohol into the intra-abdominal segment of the single umbilical artery was performed in 8 acardiac twins. Cases were collected from 5 centers following a standardized protocol. The procedure was performed under continuous ultrasound control, using color Doppler ultrasound to identify the main arterial vessel entering the abdomen of the acardiac twin and passing a 20-gauge spinal needle into the targeted vessel. Intraoperative and short-term complications were noted. Information on pregnancy outcome was obtained by reviewing the medical records or contacting the referring obstetrician. RESULT: At the time of the procedure, the acardiac twin was severely hydropic and the size exceeded 70% of the size of the pump twin in all cases. In addition, there were associated complications in all the pump twins including polyhydramnios in 8 cases (100%), cardiac insufficiency in 5 (63%), and fetal growth restriction in 1 (13%). The procedure was performed at a mean gestational age of 24.7 weeks (range 20-32), and it was technically successful in all cases. However, it was complicated with thrombosis of the umbilical vessels of the pump twin in 1 case, and transient bradycardia in 2 others. These 3 pump twins died in utero as a result of the procedure. The other 5 procedures were technically and clinically successful, resulting in an overall survival rate of 63%. In 4 pregnancies, the pump twin was delivered after 35 weeks and had no neonatal complications. CONCLUSIONS: Intrafetal alcohol chemosclerosis is a simple procedure that can be performed in any fetal medicine center around the world to stop the vascular supply to acardiac twins. However, the main concern with this technique is intravascular transfer of the ablative material to the circulation of the pump twin. The use of this technique should therefore be restricted to those pregnancies with poor prognostic factors and in countries where more sophisticated methods for the treatment of this condition are not available.     

Term birth after midtrimester hysterotomy and selective delivery of an acardiac twin.

OBJECTIVE: Our aim was to determine whether hysterotomy and selective removal of an acardiac twin could improve the outcome of the "pump" twin. STUDY DESIGN: A literature and case review of the outcome of the acardiac twin malformation was performed. When an acardiac malformation was diagnosed at 19 weeks' gestation the patient was monitored with weekly ultrasonographic examinations. At 23 weeks' gestation, no blood flow could be demonstrated to the acardiac twin and it was thought that the continued presence of the acardiac twin posed a risk to the "pump" twin. A midtrimester hysterotomy was performed and the acardiac twin was delivered. RESULTS: After the midtrimester hysterotomy, the pregnancy progressed to term and a healthy female infant was delivered by elective cesarean section at 37 weeks' gestation. CONCLUSION: Midtrimester hysterotomy may be a useful intervention in cases of twinning when one fetus is a threat to the health of the other.     

The natural history of twin–twin transfusion syndrome stratified by Quintero stage*

Objective: To describe the natural history of expectantly managed twin–twin transfusion syndrome (TTTS) specific to disease stage.

Methods: This was a retrospective study of monochorionic diamniotic pregnancies diagnosed with TTTS and delivered between 1997 and 2013. Staging was based on Quintero’s criteria, with sonogram images reviewed to confirm findings specific to stage. Progression and outcomes were evaluated in pregnancies that did not receive any form of therapy.

Results: Thirty-eight pregnancies were diagnosed with TTTS and delivered at our institution, representing 1.6 per 10 000 births. Twenty were expectantly managed, of which 50% were stage I at presentation. Progression occurred in 45% of pregnancies, including 50% initially diagnosed with stage I TTTS. Seventy percent of pregnancies experienced survival of at least one twin, with no stillbirths or neonatal deaths if TTTS resolved. Pregnancies in which TTTS was either stable or improved had higher overall survival, compared with pregnancies that experienced progression, 86% versus 22%, p?<?0.001, as well as more frequent survival of one or both twins, 91% versus 44%, p?=?0.02.

Conclusions: Among expectantly managed pregnancies with TTTS, most had early disease at diagnosis. Although 45% of cases progressed, which conferred poor prognosis, the majority experienced disease stabilization or improvement.     

Monoamniotic twins: case series and proposal for antenatal management

Objective: To present a case series of antenatally suspected monoamniotic twin gestations managed by a similar set of guidelines.Methods: Eight women with antenatally suspected monoamniotic twins were identified between 1994 and 1996 in a single perinatal referral area. All were diagnosed sonographically. Management included serial ultrasound studies, frequent nonstress testing, and weekly steroid therapy. Elective cesarean delivery was recommended at 32 weeks unless obstetrically indicated at an earlier age.Results: Monochorionic monoamniotic twins were confirmed at delivery in six women, and one had a pseudomonoamniotic twin. One woman was found to have a monochorionic diamniotic pregnancy at delivery. Of the eight women, three were delivered by elective cesarean at 32 weeks, including the falsely diagnosed case. Three were delivered before 32 weeks because of nonreassuring fetal testing. One was delivered at 25 weeks secondary to hemolysis, elevated liver enzymes, low platelets, and disseminated intravascular coagulation. One was delivered at 33 weeks, after declining elective delivery at 32 weeks, because of death of one twin and nonreassuring testing of the other twin. Morbidity among the live-born infants included severe bronchopulmonary dysplasia (25-week twins), large-bowel perforation (30-week infant), and respiratory distress syndrome and mild bronchopulmonary dysplasia (one 32-week pair).Conclusion: Monoamniotic twin pregnancies can be diagnosed reliably by ultrasound alone in most cases. Frequent antenatal testing may show signs of cord compression that may prompt delivery but will not prevent sudden fetal death. Fetal death can occur at greater than 32 weeks’ gestation despite intensive fetal surveillance. Elective preterm delivery could be considered to eliminate the uncertain risk of fetal death.     

Discordant lower urinary tract obstruction in early twin gestations: management and outcome

OBJECTIVE: To report our experience with the management of twin pregnancies discordant for lower urinary tract obstruction. METHODS: Cases of twin pregnancies discordant for lower urinary tract obstruction were identified from our fetal medicine database. Information on ultrasonographic findings, antenatal course, pregnancy complications, and perinatal outcome was obtained by reviewing medical records or contacting the referring obstetricians. RESULTS: Five twin pregnancies discordant for lower urinary tract obstruction were diagnosed between 11 and 15 weeks of gestation. There were 3 dichorionic and 2 monochorionic pregnancies (1 diamniotic and 1 monoamniotic). The dichorionic pregnancies were managed conservatively, resulting in a pregnancy loss of both twins in 1 case, a single fetal death at 29 weeks in 1 case, and an early neonatal death due to lung hypoplasia of the affected twin in 1 case. On the other hand, both monochorionic twin pregnancies were managed with serial vesicocenteses. In both cases, the prenatal course was complicated, 1 by premature rupture of the membranes and the other by cord entanglement, requiring delivery at 29 and 31 weeks, respectively. Among the 4 continuing pregnancies with complete perinatal outcome, none of the affected twins survived, and the structurally normal twins were delivered between 29 and 36 weeks and discharged from the hospital in good condition. CONCLUSION: Twin pregnancies discordant for lower urinary tract obstruction are at high risk of perinatal death and premature delivery. Prenatal intervention seems not to be associated with an improved perinatal outcome of the affected twin, but it may be beneficial in selected cases to attain viability of the unaffected twin.     

Prenatal diagnosis and outcome of multiple pregnancies with reversed arterial perfusion (TRAP-sequence)

Objectives

We analyse the prenatal detection and pregnancy outcome of twin reversed arterial perfusion syndrome (TRAP-sequence) in monochorionic twin pregnancies.

Methods

We included all cases in which the prenatal diagnosis of a TRAP-sequence had been established and reviewed the prenatal, obstetrical, and pathological records of the acardiac twin as well as the neonatal/pediatric records of the donor twin. Minimal follow-up for the donor twin after birth was 6?months.

Results

We detected six cases of TRAP-sequence in 412 examined monochorionic multiple pregnancies (incidence 1.46%) Mean gestational age at diagnosis was 20.4 (13.1?C28.0) gestational weeks. All donor twins survived without detectable mid- or long-term sequelae. There was neither missed prenatal diagnosis nor a false-positive diagnosis of TRAP-sequence. Mean birthweight of the acardiac twins was 1,400?g (830?C2800?g). There was an uneventful medical history in the maternal records of all included women. Fetal karyotype was available for 5/6 twin-pairs, all revealing a normal distribution of the chromosomes. All acardiac twins had post-mortem examination with specification of the subtypes of acardiac twin displaying 3/6 acardius acephalus, 2/6 acardius amorphus, and 1/6 acardius anceps.

Conclusions

The antenatal diagnosis of TRAP-sequence is feasible and can be established during the first-trimester-screening. The discrimination of the adequate time to end the pregnancy, though a crucial concern, remains a challenging question. Future studies should address this topic.     

Multifetal pregnancy reductions of triplets to twins: comparison with nonreduced triplets and twins.

OBJECTIVE: Multifetal pregnancy reduction has been shown to improve survival rates in high-order multifetal pregnancies (>/=4). There is, however, some controversy as to whether multifetal pregnancy reduction improves pregnancy outcomes of triplets reduced to twins. The purpose of this study was to evaluate this issue by comparing outcomes of triplet gestations undergoing reduction to twins with outcomes of nonreduced twin gestations and expectantly managed triplet gestations. STUDY DESIGN: The study included 143 triplet pregnancies that underwent reduction to twins over a 10-year period at a single center. These were compared with 12 nonreduced triplet pregnancies from the Wayne State University Perinatal Database and with 2 groups of twin pregnancies: 605 from the Wayne State University Perinatal Database and 207 from the Quest Diagnostics Database. RESULTS: The miscarriage rate for expectantly managed triplets was 25%, compared with 6.2% for triplets reduced to twins. This rate was similar to the rates for both groups of nonreduced twins: 5.8% (Quest) and 6.3% (Wayne State University). Severe prematurity occurred in 25% of nonreduced triplets compared with 4. 9% of twins after reduction. This rate was also similar to that of nonreduced twins: 7.7% (Quest) and 8.4% (Wayne State University). The mean gestational age at delivery for expectantly managed triplets (32.9 +/- 4.7 weeks) was significantly shorter than for triplets reduced to twins (35.6 +/- 3.1 weeks). By comparison, nonreduced twins had a mean gestational age at delivery of 35.8 +/- 3.9 weeks for Quest and 34.4 +/- 3.6 weeks for Wayne State University. Mean birth weights were significantly lower in expectantly managed triplets as compared with triplets undergoing reduction to twins (1636 +/- 645 g vs 2381 +/- 602 g, respectively). Nonreduced twins had a mean birth weight of 2254 +/- 653 g for Quest and 2123 +/- 634 g for Wayne State University. Pregnancy loss rates, mean length of gestation, and mean birth weight did not vary significantly between triplets who underwent reduction to twins and nonreduced twins. CONCLUSIONS: Reduction of triplets to twins significantly reduces the risk for prematurity and low birth weight and may also be associated with a reduction in overall pregnancy loss. This suggests that multifetal pregnancy reduction of triplets to twins is a medically justifiable procedure not only from an actuarial viewpoint but also from the ethical perspective of supporting patients' autonomy and respect for patients' individual circumstances.     

Intensive management and early delivery reduce antenatal mortality in monoamniotic twin pregnancies

BACKGROUND: Intensive management and elective delivery between 32 and 35 weeks of monoamniotic twin pregnancies were suggested as improving perinatal outcome. We sought to evaluate this management as viewed by the outcome of monoamniotic twin pregnancies in our population. METHODS: A retrospective systematic chart review of all monoamniotic twin pregnancies, diagnosed from January 1986 to June 2002, was performed in three medical centers. Demographics, pregnancy course, and perinatal outcome were evaluated. The management and outcome were compared between the group of survivors and the groups of intrauterine fetal demise (IUFD) and miscarriage. RESULTS: Thirty-three pairs of monoamniotic twins were identified. Excluded were three women, who chose to terminate the pregnancy. Total survival rate was 60% (of 60 fetuses, 36 were born alive, but one neonate died due to sepsis). None of the IUFD occurred in hospitalized patients, and two pairs of twins died after 32 weeks. In the 10 twin pairs who died in utero, cord entanglement was documented in eight (80%). There were two cases of twin discordance and two cases of twin-to-twin transfusion syndrome. One twin of the live-born group had congenital transposition of the great arteries. Furthermore, one of the hospitalized patients was delivered by means of an emergency cesarean section because of a non-reassuring non-stress test at 30 weeks. CONCLUSIONS: Women with monoamniotic twin pregnancies should be advised about the very high mortality and morbidity rate. Early diagnosis, close in-hospital antenatal surveillance starting at fetal viability, and elective delivery at 32 weeks would reduce the antenatal mortality.     

Management of twin pregnancies discordant for anencephaly

Objective To examine options of management and outcome of twin pregnancies discordant for anencephaly.
Design Retrospective study.
Setting Research Centre for Fetal Medicine.
Population Twenty-four twin pregnancies discordant for anencephaly.
Methods A computer search was made of our database for twin pregnancies discordant for anencephaly. The data were reviewed for gestation at presentation, chorionicity, management and pregnancy outcome.
Main outcome measures Pregnancy outcome in relation to chorionicity and management.
Results There were 13 dichorionic and 11 monochorionic twin pregnancies discordant for anencephaly. In the dichorionic group five pregnancies had selective fetocide at 17 to 21 weeks; one pregnancy resulted in spontaneous abortion but in the others a healthy infant was born at a median gestation of 37 weeks. The other eight dichorionic pregnancies were managed expectantly, but three developed polyhydramios at 26 to 30 weeks; in one case amniodrainage was performed and in another selective fetocide was carried out. In this group the median gestation at delivery was 35 weeks. All 11 monochorionic pregnancies were managed expectantly and in three there was intrauterine death of both fetuses. In the other eight cases the normal twin was liveborn at a median gestation of 34 weeks; in four of these pregnancies polyhydramnios developed and two were managed by amniodrainage.
Conclusions In monochorionic pregnancies, expectant management is associated with a high rate of intrauterine lethality of the normal twin. In dichorionic pregnancies selective fetocide in the second trimester prevents the development of polyhydramnios and is associated with a lower risk of preterm delivery but can cause miscarriage.     

Acardiac twins: pathophysiology, diagnosis, outcome and treatment. Six cases and review of the literature

Twin gestation is often a hazardous pregnancy and especially the monochorionic twin pregnancy significantly contributes to fetal morbidity and mortality. Among the serious complications with twins, the twin-twin transfusion syndrome complicates 5-35% of monozygotic twin pregnancies with monochorionic placentation. Acardiac twinning, earlier known as chorioangiopagus parasiticus, is the most extreme manifestation of this condition. An acardiac twin is a rare complication of multifetal pregnancy, in the literature reported at an incidence of 1% of monochorionic twin pregnancies, i.e. 1 of 35,000 pregnancies. In the following paper we review the literature on the subject and report 6 cases, 5 twins and 1 triplet, that were diagnosed at our department during the period of 1993-1997 and treated conservatively. Only 1 child survived.     

Treatment of acardiac-acephalus twin gestations by hysterotomy and selective delivery.

The acardius syndrome is a rare complication of monozygotic twin pregnancies, occurring once in 35,000 births. The outcome is invariably fatal for the acardiac twin and for 50-75% of the normal twins. We present a surgical approach to the treatment of this problem involving hysterotomy and selective delivery of the acardiac twin, which we have used in five cases. In the first case, placental abruption shortly after the procedure led to fetal death. The next two cases resulted in cesarean delivery of the remaining healthy singleton at 35 weeks' gestation. The fourth and fifth cases were delivered at 27 and 28 weeks' gestation, respectively, the first because of preterm rupture of membranes 2 weeks after the procedure and the second because of partial placental abruption 8 weeks after surgery; both of these infants are now doing well. There were no residual maternal complications. We conclude that hysterotomy has direct applicability in the management of these high-risk pregnancies.     

Selective reduction of acardiac twin by radiofrequency ablation

OBJECTIVE: Acardiac/acephalic twinning is a rare anomaly in which a normal "pump" twin perfuses an acardiac twin, which results in twin reversed arterial perfusion sequence. A novel technique for selective reduction and obliteration of blood flow in the acardiac twin is described. STUDY DESIGN: Thirteen consecutive cases of monochorionic twin gestation with twin reversed arterial perfusion sequence underwent selective reduction of the abnormal twin with the use of radiofrequency ablation. Under direct real-time sonographic guidance, a 3-mm (14-gauge) radiofrequency ablation needle was percutaneously inserted through the maternal abdominal wall into the intrauterine fetal abdomen at the level of the cord insertion site of the acardiac twin. Energy was applied until termination of blood flow to the acardiac fetus was documented by Doppler ultrasound scanning. RESULTS: All 13 mothers tolerated the procedure without major complications. All 13 "pump" fetuses have been delivered. Twelve of 13 infants are alive and well. The first patient in this series was delivered at 24.4 weeks and the infant subsequently died from complications of prematurity. Average gestational age at intervention was 20.7 weeks, and the average gestational age at delivery was 36.2 weeks. CONCLUSION: Radiofrequency ablation is a minimally invasive, percutaneous technique that can effectively obliterate blood supply to an acardiac twin to preserve and protect the pump twin.     

Percutaneous ultrasonographically guided ablation of an acardiac twin

Acardiac twinning is caused by twin reversed arterial perfusion (TRAP). Normal "pump" twins may face early delivery and cardiac decompensation and have a high perinatal mortality. A primagravid patient had serial evaluation of a TRAP pregnancy beginning early in the second trimester. Rapid growth of the acardiac sibling, high diastolic velocity Doppler waveforms in the perfusing vessel, and early hydramnios prompted ablation of blood flow by a percutaneous ultrasonographically guided infusion of absolute alcohol. A term birth of a normal pump twin was the outcome. Ablation of blood flow into an acardiac sibling of a TRAP pregnancy may be indicated in cases with a poor prognosis by use of an effective percutaneous ultrasonographically guided technique.     

Monoamniotic twin pregnancies: antenatal management and perinatal results of 19 consecutive cases

Objective   To describe the obstetric management and perinatal outcome of antenatally diagnosed monoamniotic twin pregnancies (MATP) in a tertiary level maternity unit.
Setting   Port-Royal Maternity Hospital, Paris, France.
Population   MATP that progressed beyond 22 weeks seen from 1993 to 2001.
Methods   A retrospective chart review of all twin pregnancies. Diagnosis of MATP was made by ultrasonography and confirmed by placental pathology.
Main outcome measure   Perinatal mortality.
Results   Among the 1242 twins pregnancies delivered during the study period, 19 were monoamniotic. Four fetuses (10% of all births) had malformations. Perinatal mortality was high ( n = 12, 32%) because of fetal deaths (nine cases) and very preterm births (three neonatal deaths). No fetal deaths occurred after 29 weeks. Of the 15 women with at least one live fetus before labour, 6 gave birth by vaginal delivery (40%). No obstetric accidents occurred during vaginal deliveries.
Conclusion   Perinatal mortality of MATP is still very high, even with accurate, early antenatal diagnosis, intensified surveillance and delivery provided in a tertiary level hospital. The main causes of perinatal deaths are cord accidents in utero , congenital anomalies and very preterm births.     

Fetal therapy in twin reserve arterial perfusion sequence pregnancies with alcohol ablation or bipolar cord coagulation

Objective  We aimed to evaluate perinatal outcome of seven pregnancies with twin reserve arterial perfusion sequence. Materials and methods  Study group included seven cases of acardiac twins. Out of seven acardiac twins, two cases were followed without interventions. We performed four alcohol ablation and one bipolar caogulation. For alcohol ablation, a 20-gauge needle guided with color Doppler USG was directed to abdominal insertion site of the single umbilical artery of the acardiac twin, and 1.0–2.0 mL of absolute alcohol was injected. For bipolar coagulation of the umbilical cord, we used 3.5 mm laparoscopic trocar and 3.0 mm bipolar forceps. The procedures were performed under the guidance of transabdominal ultrasonography. Results  Gestational age of the cases at diagnosis and at delivery was 15–32 and 17–38 weeks, respectively. Two cases without intervention were lost at 17 and 32 weeks. The mean time of procedure for bipolar coagulation and alcohol ablation were 30 and 10 min, respectively. One of the four cases of alcohol ablation group was aborted although alcohol ablation was succesful. Another one case was aborted after alcohol ablation due to lost of fetal cardiac activity of the pump fetus. In two other cases, umbilical cord ablation with alcohol was successful, and they delivered live birth at 36 and 38 weeks. In one case, we performed bipolar cord coagulation successfully, and the case delivered live birth at 39 weeks. The overall survival rate for intrauterine surgery was 60% (N 3/5). Conclusion  In twin reserve arterial perfusion sequence pregnancies with findings of poor prognosis, alcohol ablation or bipolar cord coagulation as fetal therapy under the guidance of ultrasonography can be done successfully, and should be offered as a choice to families upon discussion of intervention or follow-up with own complications.     

Management of monoamniotic twin pregnancies: a case series and systematic review of the literature

Objectives To review the experience of the University of Toronto Perinatal Complex, Ontario, Canada concerning antenatally diagnosed monoamniotic twin pregnancies; and to compare our results with cases reported in the literature with respect to antenatal surveillance and perinatal outcome.
Methods A retrospective chart review of all twin gestations from 1993 to April 2000 was performed. A systematic review of the literature, 1966 to April 2000, of perinatal outcome in monoamniotic twin pregnancies was undertaken.
Setting All monoamniotic twin gestations at the University of Toronto.
Results Case-series: 25 prenatally diagnosed monoamniotic twin pregnancies were identified. Seven pregnancies were affected by fetal anomalies. One fetus died at 29 weeks. Neonatal complications occurred below 33 weeks of gestational age and were related to immaturity. Systematic review of the literature: 49 studies met our selection criteria and reported 88 cases diagnosed antenatally. Fourteen pregnancies were affected by major congenital anomalies. Twenty fetuses died after 24 weeks of gestation. Neonatal complications varied widely in severity and depended on gestational age at birth. The risk of intrauterine fetal death was 10% at the University of Toronto and 12% in the review of the literature.
Discussion Our experience, the largest so far, suggests that regular fetal surveillance and appropriate steroid administration leads to a good perinatal outcome. The risk of fetal death (10%–12%) is lower than the previously quoted risk of 30%–70%. A careful review of obstetric interventions and further work examining outpatient surveillance of monoamniotic twin pregnancies are needed. The best treatment of monoamniotic twin pregnancies can only be determined by randomised trials.     

Intrauterine treatment for an acardiac twin with alcohol injection into the umbilical artery

An acardiac twin is a unique complication of monochorionic twinning, in which a normal pump twin perfuses the acardiac twin. The mortality rate of the pump twin is greater than 50%. Herein we present the successful treatment of an acardiac twin with alcoholization as follows. An acardiac twin was diagnosed at 24 weeks gestation. Circulation interruption of the acardiac twin was successfully achieved by injection of absolute alcohol (5 mL) into the intra-abdominal umbilical artery. Serial ultrasound after the procedure revealed normal growth of the pump twin, whereas the acardiac twin was shrinking. Spontaneous premature delivery at 34 weeks gestation resulted in a normal surviving female baby weighing 2410g and an acardiac female fetus weighing 300g. This experience suggests that this simple technique may be an alternative treatment for an acardiac twin.     

Perinatal mortality in twin pregnancies: a 3-year analysis in Seine Saint-Denis (France).

OBJECTIVES: Our purpose was to evaluate perinatal mortality in twins and to investigate factors associated with this mortality. STUDY DESIGN: A prospective study on the perinatal mortality was performed in the department of Seine-Saint-Denis. Out of all the perinatal deaths, we have retrospectively isolated those arising from twin pregnancies. RESULTS: There were 54 twin pregnancies complicated with perinatal death. The perinatal mortality rate in twin pregnancy was 78.0 per 1000 twin babies delivered. Out of 86 twin deaths, 38 (44.2%) were born before 28 weeks gestation and out of 82 twin perinatal deaths, 37 (45.1%) weighed less than 1000 g. Chorionicity was recorded in 44 twin pairs: 21 (47.7%) were dichorionic and 23 (52.3%) monochorionic. Finally, out of 48 twin sets there were four (8.3%) monoamniotic pregnancies. CONCLUSIONS: The present data show that extreme prematurity represents nearly half of perinatal mortality in twins. This study indicates also a significant proportion of monochorionic placentation among twin pregnancies with poor outcome.