Umbilical cord entanglement in monoamniotic twin preganacy--case presentation and literature review

Monoamniotic twins are at most increased risk of perinatal complications with perinatal mortality of 28-60 % reported in literature. The most specific complication to monoamniotic twins is entanglement and (or) knotting of the cords leading to intrauterine death of both (more often) or one twin. In first presented case 1, 23-year-old primigravida in 33wks of twin monoamniotic gestation was reffered to our Institute due to intrauterine death of one co-twin caused by umbilical cord entanglement. In second case, 26-year-old multigravida in monoamniotic twin gestation was admitted to our institution. A serious umbilical cord entanglement was observed and a presence of true knot of umbilical cord was suspected. Presented cases indicate that establishing a chorionicity and amniocity in twin pregnancy is an essential part of ultrasound examination. The diagnosis of cord entanglement in monoamniotic twin pregnancy enables a forecasting of possible complications. According to the established diagnosis future protocols of perinatal management could be proposed. Due to possible complications counseling and management of monoamniotic twins should be performed in tertiary medical centers.     

The aggressive approach to the management of monoamniotic twins

A series of five sets of monoamniotic twins are presented. The sonographic diagnostic criteria are outlined, with special emphasis on entanglement of the cord. The management protocol included: early hospitalisation, frequent sonographic, electronic fetal heart monitoring and early delivery by caesarean delivery when indicated. This management resulted in survival of all 10 neonates in the series.     

Monoamniotic twins: a retrospective controlled study

Monoamniotic twins are uncommon but are at high risk (reportedly 50%) for perinatal death, commonly from cord accidents. Until recently the diagnosis of monoamniotic twinning was seldom made before delivery, but modern ultrasound technology permits diagnosis during prenatal care, creating a management dilemma. This is a report of the experience with monoamniotic twins of 20 or more weeks' gestation at the University of Iowa Hospitals from 1961-1989. Twenty monoamniotic twin pregnancies were compared with 40 monochorionic, diamniotic controls regarding antepartum and intrapartum complications. Overall, monoamniotic twins were delivered earlier, were more likely to die in utero, and had lower birth weights than diamniotic twins. When only live-born twins were considered, however, there were no differences in gestational age at delivery, birth weight, or 5-minute Apgar scores. No fetal death occurred after 32 weeks, suggesting that prophylactic preterm delivery may not be indicated in all cases. Labor and vaginal delivery were not associated with an increased risk of fetal death.     

Antepartum rupture of the intertwin-dividing membrane in monochorionic diamniotic twins: a case report and review of the literature

We report a case of monochorionic diamniotic twin gestation confirmed by ultrasound visualization of the thin intertwin-dividing membrane at 32 weeks' gestation. Ultrasound at 36 weeks failed to demonstrate the thin dividing membrane. The pregnancy ended a few days later with spontaneous vaginal delivery of the first twin. The second twin was in transverse lie with no membranes that could be felt around. Severe fetal heart rate deceleration developed, prompting delivery by emergency caesarean section. Cord entanglement was noted at the time of delivery, which resulted in severe perinatal morbidity of the second twin. The antepartum rupture of the dividing membrane must have happened some time between 32 and 36 weeks. The etiology for this intrauterine disruption is unknown. A review of the literature about the antepartum rupture of the intertwin-dividing membrane is described, along with its possible causes and complications. In addition, we discuss possible causes of incorrect amnionicity determination, and thus how to minimize these pitfalls. We conclude that antepartum disruption of the intertwin-dividing membrane is more common than previously thought. Moreover, prenatal ultrasonographic visualization of a dividing membrane in a diamniotic twin pregnancy does not rule out future change in this environment to a monoamniotic one, with all its perinatal morbidity and mortality complications, which result mainly from cord entanglement. This suggests a modification in the method and frequency of the prenatal fetal well-being follow-up, as well as the time and mode of delivery.     

Monoamniotic twin pregnancy: a review of contemporary practice

Monoamniotic twins represent an uncommon manifestation of the monozygotic twinning process (1% of monozygotic twins). They are the result of ovum division beyond 8 days postconception and are characterised by a single amnion and a single yolk sac. There may be two or one (conjoined twins) embryos present. This form of twinning is notable for an increase in perinatal loss (10-15% in contemporary series of prenatally recognised cases). Congenital anomalies, umbilical cord entanglement/accidents, preterm birth and intrauterine growth restriction primarily account for this increased perinatal mortality rate. Diagnosis is most typically by ultrasound, with the inability to distinguish a dividing membrane between the fetuses the most typical feature. There are diagnostic pitfalls (oligohydramnios in one twin with closely adherent membrane) and accuracy in diagnosis is central to appropriate pregnancy management. Obstetric management protocols are based on several retrospective case series, and there is a paucity of large well-controlled studies to provide guidance in the management of monoamniotic twin pregnancies. The prevention of antepartum death from umbilical cord entanglement is one of the central management issues; however, the available techniques of antepartum surveillance have a variable performance in predicting this event.     

Entrecruzamiento de cordones en la gestación gemelar monocorial monoamniótica

Monochorial monoamniotic twins are at high risk of fetal death due to the general complications seen in multiple gestations, as well as those specific to this type of pregnancy. The most severe complication in these pregnancies is fetal death due to cord entanglement, which occurs in almost all cases.Early ultrasonographic diagnosis and intensive prenatal surveillance are essential for the early detection of cord entanglement and the prevention of fetal death.The need for in-hospital management and the exact gestational age for delivery continue to generate controversy in the literature.     

3D color Doppler of monoamniotic twin cord entanglement

Cord entanglement is a leading cause of mortality of monochorionic monoamniotic twins. Few studies focused on entanglement features/structure itself. Three-dimensional color Doppler ultrasound was conducted to evaluate the cord entanglement in monoamniotic twins at 30 weeks of gestation. Ultrasound revealed detailed features: the two cords were entangled at several points with a chain-like appearance and this complicated structure led us to closely monitor fetal well-being. Seven days later, non-reassuring fetal heart rate pattern was observed, and cesarean section was performed at 30 6/7 pregnancy week, yielding female infants without neurological sequelae. Three-dimensional color Doppler clearly delineated the features of entanglement, and thus was useful for evaluating cord entanglement in monoamniotic twins.     

Notching of the umbilical artery waveform associated with cord entanglement in a monoamniotic twin pregnancy

Abstract

Cord accidents are the principal cause of the high rates of morbidity and mortality associated with monoamniotic twins. Observation of an umbilical artery notch might be a highly specific sign for cord entanglement involving a tight cord knot. It thus justifies the implementation of intense surveillance and should be one of the factors taken into account in deciding on early delivery of the twins.     

Monochorionic monoamniotic twins--the most precarious of twin pregnancies.

Monochorionic monoamniotic twins have a high perinatal mortality rate. Death usually occurs before 24 weeks' gestation, mainly because of cord entanglement, prematurity, congenital anomalies or twin-to-twin transfusion. These possibilities should be taken into account when twin pregnancies are detected at the ultrasound screening between 17 and 20 weeks' pregnancy. We report here a case where monochorionic monoamniotic twins were born at 34 weeks, with massive cord entanglement and we describe the antenatal care at our clinic.     

Monochorionic Diamniotic Triplet Pregnancy With Prenatal Diagnosis of Cord Entanglement

BackgroundMonozygotic monochorionic triplet pregnancies in which triplets share an amniotic cavity (di- or monoamniotic) are very rare. In addition to the other risks of high-order multiple pregnancy, such triplets are at risk for cord entanglement and therefore cord accident and intrauterine demise.CaseA 32-year-old primigravid woman was found on ultrasound at 25 to 26 weeks’ gestation to have a monochorionic diamniotic triplet pregnancy, a short dilated cervix, one fetus with biometry < 10th centile, and cord entanglement. The woman was hospitalized, ultrasound assessment was performed three times per week, and elective Caesarean section was performed at 30 weeks. The triplets subsequently did well.ConclusionMonochorionic diamniotic triplet pregnancy with cord entanglement can be successfully managed by admission, close inpatient monitoring, and elective delivery.     

Morbidity associated with prenatal disruption of the dividing membrane in twin gestations

We report eight cases of intrauterine rupture of the dividing membranes in diamniotic twin gestations and the resulting perinatal morbidity and mortality. The poor outcomes associated with these intrauterine amniotic ruptures included fetal and neonatal death secondary to cord entanglement, preterm rupture of the membranes, preterm labor and delivery, and amniotic band syndrome. The overall perinatal mortality rate was 44% (seven of 16), and the mean gestational age at delivery was 29 weeks (range 22-34). Possible etiologies for this intrauterine diamniotic rupture include fetal trauma to the dividing membranes, amniocentesis, infection, and developmental disturbances. A new theory is examined to explain the surviving twin's morbidity associated with intrauterine death of the co-twin. This study suggests that intrauterine rupture of diamniotic twin membranes carries a perinatal mortality consistent with that of true monoamniotic gestations and that, in fact, this entity may be more common than previously thought. Finally, a suspected monoamniotic gestation cannot be ruled out by the historic presence of a dividing membrane on previous ultrasound examination.     

Endoscopic ligation of umbilical cord at 19 week's gestation in monoamniotic monochorionic twins discordant for hypoplastic left heart syndrome

We report the first attempt of reduction of monoamniotic twins, discordant for hypoplastic left heart syndrome, using a new fetoscopic technique. Employing sonographic guidance and endoscopic visualization, cord ligation was accomplished, but significant cord entanglement, not previously appreciated, resulted in the ligation of the umbilical cord of the normal fetus. Cord entanglement may frustrate endoscopic techniques in monoamniotic twins.     

Management of other complications specific to monochorionic twin pregnancies

Monochorionic (MC) twins have a 3-10-fold higher perinatal mortality and morbidity than dichorionic twins. This is largely attributable to their common vascular architecture and the high rate of discordant fetal growth, growth restriction and congenital abnormalities. In the event of a single intrauterine death (IUD), intertwin agonal transfusion results in up to a 38% risk of death and a 46% risk of neurological injury to the co-twin. This chapter addresses the management of complications unique to MC twins. The primary aim of management is to prevent single IUD or, if inevitable, prevent agonal transfusion occurring by vascular occlusive selective feticide. Older fetoscopic techniques have been replaced by the simpler ultrasound-guided techniques of interstitial laser and bipolar cord occlusion. Their application in twin reversed-arterial perfusion sequence has been associated with a 50% reduction of perinatal mortality in the pump twin. Moreover, prophylactic interstitial laser therapy in early pregnancy might obviate the technical and clinical difficulties in the presence of fetal decompensation in later pregnancy. Recent strategies to reduce the high perinatal mortality due to cord entanglement in antenatally diagnosed monoamniotic twins including medical amnioreduction and elective caesarean delivery at 32 weeks, are also discussed.     

Iatrogenic Monoamniotic Twins as a Complication of Therapeutic Amniocentesis

Background: Therapeutic amniocentesis has been accepted widely as a safe and efficacious way to treat the polyhydramnios-oligohydramnios sequence associated with twin–twin transfusion syndrome.Case: A 28-year-old woman, gravida 2, para 1, diagnosed with twin–twin transfusion syndrome at 28 weeks’ gestation was treated with serial amniocenteses. The dividing membrane was ruptured inadvertently during therapeutic amniocentesis, with subsequent complete disruption of the amniotic membrane. Iatrogenic monoamniotic twins with cord entanglement and knotting resulted.Conclusion: Creation of monoamniotic twins by disruption of the dividing membrane can be a complication of therapeutic amniocentesis for twin–twin transfusion syndrome. Such disruption may result in the same morbidity and mortality that are seen in naturally occurring monoamniotic twins.     

Monoamnotic twin pregnancy. Multicenter study

OBJECTIVE: The purpose of this study was to evaluate of perinatal mortality and morbidity of monoamniotic twins. STUDY DESIGN: This was a multicenter retrospective analysis of 26 monoamniotic twin gestations identified between 1985 and 2004 in a 3 perinatal departments. Of these 26 pregnancies, 11 women were admitted electively for inpatient fetal monitoring. Overall mortality rates, the risk of intrauterine fetal death and neonatal mortality and morbidity, pregnancy complications and fetal anomalies were calculated. RESULTS: Monoamniotic twin pregnancies were diagnosed reliably prenatally by ultrasound in 22 women and at delivery in 4 cases. Of the 26 gestations, spontaneous fetal losses before 22 weeks of gestation were 4 cases. The overall loss rate and the perinatal mortality rate were 52% and 19.4%, respectively. Twenty-two women had both twins alive at 24 weeks of gestation; 11 women were admitted electively for inpatient fetal monitoring at 26-27 week of gestation. In this group there were 2 neonatal deaths. No intrauterine fetal death occurred in any hospitalized patient. In our series there were 100% incidence of prematurity, 38,5% of umbilical cord entaglement, 23% of TTTS, 3.6% of TRAP and 9.6% fetal congenital anomalies. CONCLUSION: Monoamniotic twins are at extremly risk of pregnancy complications and fetal loss. These pregnancies can be diagnosed reliably by ultrasound in most cases. Electively admitted women for inpatient fetal monitoring could be improved neonatal survival and decreased perinatal morbidity.     

An Unusual Complication in a Binovular Twin Pregnancy — Umbilical Cord of Twin 2 Around the Neck of Twin 1

Summary: A case of cord entanglement involving the cord of twin 2 being around the neck of twin 1 is presented. The unusual feature of this case is that the twins were binovular, being male and female, refuting previous statements that for this complication to occur, the twins must be monoamniotic.     

Fetal asphyxia due to cord entanglement in a monochorionic diamniotic twin pregnancy complicated by 2nd-trimester single intrauterine demise

Usually, fetal asphyxia/demise because of umbilical cord entanglement and secondary cord occlusion is a unique characteristic of monoamniotic twin pregnancies. We present here a rare case of fetal asphyxia due to cord entanglement in a monochorionic diamniotic twin pregnancy complicated by 2nd-trimester single intrauterine demise. In this case, there was no amniocentesis or any other invasive intrauterine procedure performed during pregnancy.     

Antepartum and intrapartum management of multiple pregnancy.

In antepartum management of multiple gestation, this review discusses studies covering the outcome of bedrest, use of ultrasound to assess fetal outcome, management of monoamniotic twins, and outcome of higher-order gestation. Studies comparing modes of delivery are also discussed.     

Multiple gestations: timing of indicated late preterm and early-term births in uncomplicated dichorionic, monochorionic, and monoamniotic twins

In this work we review the indications for late preterm and early-term birth in uncomplicated dichorionic, monochorionic, and monoamniotic twin gestations. Uncomplicated dichorionic twins have optimal outcomes when delivered at 38 weeks' gestation. Monochorionic twins, however, are at greater risk for unexpected stillbirth, and a management plan of late preterm delivery (34-37 weeks) after informed consent is reasonable. Monoamniotic twins are at even greater risk for sudden intrauterine fetal demise, and it is recommended that these expectant mothers be managed by inpatient hospitalization with fetal testing 1-3 times per day and delivery between 32 and 34 weeks' gestation. Recommendations are also provided for the circumstance of single intrauterine fetal demise in a twin gestation.     

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.