Diagnosis of umbilical cord entanglement of monoamniotic twins by first-trimester color Doppler imaging

Ultrasound diagnosis of first trimester umbilical cord entanglement in monochorionic monoamniotic twins - case report and review of the literature

BACKGROUND

Diagnosis of umbilical cord entanglement (UCE) by ultrasound (US) in monochorionic monoamniotic (MCMA) twins in the second and third trimesters is common. However, only a few cases have been reported on the diagnosis of UCE as early as the first trimester. Herein, we report a case of the earliest-ever sonographic diagnosis of UCE and demonstrate the feasibility of its diagnosis by US.

CASE PRESENTATION

A 32-year-old gravida 2 para 1 woman conceived after assisted reproductive technology (ART) treatment. In transvaginal US examination at 8.5 gestational weeks, two embryos with regular heartbeats in the same amniotic sac and with only one yolk sac were demonstrated. The fetal crown-rump lengths were 20 and 21 mm, appropriate for 8.4 and 8.5 gestational weeks, respectively. HD-flow power Doppler 2D and 3D US demonstrated two tightly entangled umbilical cords of the two fetuses. Spectral Doppler US showed two different heart rates (162 and 167 beats per minute) and blood flow in opposite directions from the point of entanglement of the two umbilical cords. This was consistent with a diagnosis of a first-trimester MCMA pregnancy with UCE. Missed abortion of the two embryos was diagnosed by US examination at 10.5 weeks, and the pregnancy was terminated by dilatation and curettage without further complications.

CONCLUSIONS

UCE in the first trimester may occur as early as eight gestational weeks, and its diagnosis by ultrasound is feasible. UCE diagnosed in the first trimester may be a poor prognostic factor.

Complex Twisted Knots of Umbilical Cord in a Monochorionic-Diamniotic Twin Gestation: A Case Report

Background:

True knots and tight loops of umbilical cord can cause serious fetal complications in monochorionic-monoamniotic twins but are usually unexpected in Monochorionic-diamniotic twins because of the presence of the intertwin membrane. This report presents a case of monochorionic-diamniotic twin gestation with a complex cord knots.

Case report:

A 31-year-old G2Ab1 with monochorionic-diamniotic twin pregnancy in the gestational age of 30 weeks presented with ruptured membrane since 3weeks before delivery. At the delivery time, multiple umbilical cord knots was found.

Conclusion:

Premature ruptured membrane can cause septostomy of the intertwin membrane, multiple umbilical cord knots and its complications. Therefore, these cases should be considered for evaluation of the presence of intertwin membrane and umbilical cord knots in each sonography examination.

Current Perspectives of Prenatal Sonographic Diagnosis and Clinical Management Challenges of True Knot of the Umbilical Cord

Umbilical cord accidents preceding labor are rare. Single and multiple nuchal cords, and true knot(s) of the umbilical cord, are often incidental findings noted at delivery of non-hypoxic non-acidotic newborns without any evidence of subsequent adverse neonatal outcome. In contrast to single nuchal cords, true knots of the umbilical cord, which occur in between 0.04% and 3% of all deliveries, have been associated with a reported 4 to 10 fold increased risk of stillbirth. First reported with real-time ultrasound, current widespread application of color Doppler, power Doppler and three-dimension sonography, has enabled increasingly more accurate prenatal sonographic diagnoses of true knot(s) of the umbilical cord. Reflecting the inability to visualize the entire umbilical cord at prenatal ultrasound assessment, despite detailed second and third-trimester scanning, many occurrences of incidental true knot of the umbilical cord remain undetected and are noted only at delivery. Although prenatal sonographic diagnostic accuracy is increasing, false positive sonographic diagnosis of true knot of the umbilical cord cannot be ruled out with certainty, and must continue to be considered clinically. Notwithstanding the inability to diagnose all true knots, currently there is a clear absence of clinical management guidelines by governing bodies regarding patients in whom prenatal sonographic diagnosis of true knot(s) of the umbilical cord is / are suspected. As a result, in many prenatal ultrasound units, suspected sonographic findings suggestive of or consistent with true knot of the umbilical cord are often disregarded, not documented, and patients are not uniformly informed of this potentially life-threatening condition, which carries an associated considerable risk of stillbirth. This commentary will address current perspectives of prenatal sonographic diagnostic and management challenges associated with true knot(s) of the umbilical cord in singleton pregnancies.

Three-dimensional ultrasound for prenatal assessment of conjoined twins: additional advantages?

Conjoined twins are a rare, but serious, complication of monozygotic twins. Early prenatal diagnosis of conjoined twins is increasingly made with transvaginal ultrasound and color Doppler studies. Most prenatally diagnosed conjoined twins are terminated due to the high perinatal mortality, but advancement in pediatric surgery has allowed for successful postnatal separation in a small number of cases, and some parents may consider this option over termination of pregnancy. It is important to get a detailed prenatal ultrasound for the site and extent of fusion for an accurate categorization. Three-dimensional ultrasound (3DUS) provides images that can facilitate counselling for the parents. Additional information that impacts on diagnosis, prognostication, and perinatal management of conjoined twins could be obtained from selective use of 3DUS, particularly those with atypical fetal union. Most of the proposed additional benefits of 3DUS are based on case reports. Magnetic resonance imaging (MRI) has been increasingly used for the purpose of identifying intricate organ sharing. Because of the rarity of this condition, and the heterogeneity of fetal fusion, added benefits of either 3DUS or MRI for prenatal diagnosis and perinatal management of conjoined twins have not been demonstrated by well-conducted clinical trials. This article aims to review clinical application of various 3DUS display modes in prenatal assessment of conjoined twins, focusing on their potential additional benefits, risks and misuses. 3DUS may help detecting additional findings that are not possible with 2DUS, but, it has not been scientifically shown to improve the survival rate of the twins or reduce maternal morbidity.

Diagnosis of umbilical cord entanglement in a monochorionic diamniotic twin pregnancy with spontaneous septostomy of the dividing membranes using dual-gate Doppler imaging

Umbilical cord entanglement is the leading cause of fetal mortality in monoamniotic twin pregnancies and a pseudo monoamniotic environment. Published methods for detecting this complication include color Doppler and pulsed Doppler sonography; however, no method provides an absolute diagnosis. In this case, we report the diagnosis of umbilical cord entanglement using dual-gate Doppler imaging. A 35-year-old woman was referred to our hospital at 28 weeks of gestation for prenatal management because of diagnosis of a monochorionic diamniotic twin pregnancy with spontaneous septostomy of the dividing membranes. Each fetus displayed normal fetal growth without obvious discordance and anatomical abnormalities. However, the dividing membrane was not detected, and an entangled cord was suspected. Dual-gate Doppler examination was carried out. Two regions of interest were considered at different areas of the umbilical arteries, and when each Doppler image showed two different heart rates at the same time, we considered this to be evidence of umbilical cord entanglement. Cesarean section was performed at 32 weeks of gestation and twins were delivered. The delivered umbilical cords had sixfold entanglement. In this case, dual-gate Doppler seems to have been more accurate than conventional single-gate Doppler for the diagnosis of cord entanglement because we confirmed two different heart rates at the same time with dual-gate Doppler.

Twins--twice more trouble?

Twin gestations are fascinating and are also high-risk pregnancies. They account for approximately 3% of all pregnancies in the United States. Major obstetrical complications associated with twin pregnancies include hypertensive disorders of pregnancy, gestational diabetes, and preterm delivery. In addition, the death rate for twins and the rate of severe handicap in very low birth weight survivors of twin pregnancies is greater than that for singleton pregnancies. Ultrasound allows for stepwise evaluations at any time during a twin gestation. Current evidence suggests that uncomplicated diamniotic twins with concordant and appropriate growth beyond 24 weeks' gestation should be managed conservatively and the time and mode of delivery should be determined on the basis of obstetrical history and fetal presentations. Perinatal management of the remaining twin pregnancies depends on good clinical judgment, which is improved by the use of ultrasound imaging.

Monoamniotic twins with one fetal anencephaly and cord entanglement diagnosed with three dimensional ultrasound at 14 weeks of gestation

A 29-year-old pregnant woman with parity 0-0-0-0 was diagnosed with monoamniotic twin pregnancy discordant for anencephaly at 14 weeks gestation. Umbilical cord entanglement, which is an important cause of fetal death in monoamniotic twins, was confirmed by three-dimensional ultrasound. Cesarean section was performed at 34 weeks of gestation, and the normal newborn infant was discharged without any complications. We report a case of monoamniotic twin pregnancy discordant for anencephaly and diagnosed with cord entanglement by three-dimensional ultrasound at 14 weeks of gestation, and now report it along with a literature review.

Cord entanglement of monochorionic diamniotic twins following spontaneous antepartum septostomy sonographically simulating a true knot of the umbilical cord

Spontaneous antepartum septostomy occurring in monochorionic diamniotic twins is extremely rare. We present a case in which prenatal sonography at 26 weeks' gestation depicted a monochorionic diamniotic twin gestation with concordant fetal growth and findings suggestive of a true knot of the umbilical cord. At Cesarean delivery at 34 weeks' gestation, spontaneous antepartum septostomy with entanglement of the two separate umbilical cords was noted. This case suggests that the differential diagnosis of findings considered consistent with a true knot of the umbilical cord in monochorionic diamniotic twin gestations, should include spontaneous antepartum septostomy and umbilical cord entanglement.

Diagnosis and management of obstetrical complications unique to multiple gestations

Obstetrical complications unique to multiple gestations pose a number of unique challenges. The presence of more than one fetus complicates the diagnosis and management of a pregnancy when one fetus has a structural or chromosomal abnormality, intrauterine demise, preterm premature rupture of the membranes, or delivers prematurely. Similarly, the diagnosis and management of monoamniotic twins and conjoined twins is challenging. These obstetrical complications that are unique to multiple gestations require thorough counseling of the expectant parents, as well as care by physicians with expertise in the management of multiple gestations.