Monochorionic Monoamniotic Twin Pregnancy Research Articles

Monochorionic Monoamniotic Twin Pregnancy: Shared but Not Equal.

Monochorionic Monoamniotic Twin Pregnancy: Shared but Not Equal.

Umbilical Cord Abnormality in a Monochorionic-Monoamniotic Twin Pregnancy.

Umbilical Cord Abnormality in a Monochorionic-Monoamniotic Twin Pregnancy.

The management of Monochorionic Monoamniotic (MCMA) twin pregnancy

HIGHLIGHTS Monochorionic monoamniotic (MCMA) twin pregnancy has a significant risk of perinatal morbidity and mortality, including intrauterine fetal death (IUFD). The risk of prematurity, the risk of death due to MCMA complications, the availability of the NICU, also high costs on preterm care were factors in deciding to terminate the pregnancy. The ideal time to deliver monochorionic twins in order to reduce the risks of cord entanglement, growth discrepancies, and intrauterine fetal death is still a point of controversy. Early diagnosis, intensive antenatal monitoring, patient and family decision would contribute to antenatal mortality reduction. ABSTRACT Objectives: To present the management of monochorionic monoamniotic (MCMA) twin pregnancy. Case Report: Advanced prenatal treatment has improved the prognosis for Monochorionic Monoamniotic (MCMA) pregnancies; however, there is still no agreement on how to handle MCMA twins. The authors report 2 cases of monoamniotic monochorionic twin pregnancies. In the first case, a 30-years-old primi pregnant woman detected MCMA at 14 weeks of gestation; no complications related to MCMA were found; she planned delivery at 32 weeks, but one of the babies died in the womb at 31/32 weeks pregnant, a live baby born by cesarean section. The second case was a 36-year-old pregnant woman, on her third pregnancy, diagnosed with MCMA after 12 weeks of pregnancy, no complications related to MCMA, the baby was born at 32 weeks pregnant, and both babies survived. The management was the same in both cases, but different outcomes were obtained; in case 1, the baby died allegedly due to cord entanglement, which could not be detected during pregnancy.

Evaluation of clinical features and outcome of eight fetuses with ectopia cordis; A study from a fetal cardiology center.

We aim to evaluate the clinical course and outcome of cases with a prenatal diagnosis of ectopia cordis in our center. In this retrospective study, we analyzed clinical variables including gestational age at diagnosis, maternal age, associated cardiac, extracardiac, genetic anomalies and, outcome in prenatally diagnosed ectopia cordis cases in our tertiary referral center. Eight ectopia cordis cases from seven pregnancies were included in the study. All fetuses had complete type of ectopia cordis and pentalogy of Cantrell. Five multiple pregnancies were found, four were twin pregnancies (three dichorionic diamniotic, one monochorionic monoamniotic) and one was triplet (trichorionic triamniotic). In the monochorionic monoamniotic twin pregnancy, both fetuses have pentalogy of Cantrell. Two cases had intracardiac structural defects including Tetralogy of Fallot and hypoplastic right heart syndrome. Three pregnancies were terminated, four cases delivered alive could not survive beyond the neonatal period. The striking feature in our study is its association with multiple pregnancies.

Monochorionic monoamniotic twin pregnancies.

Monochorionic monoamniotic (MCMA) twin pregnancy is rare and associated with increased complication rates when compared with singletons, dichorionic and monochorionic diamniotic pregnancy in general. Monoamnionicity presents an enormous challenge following its accurate diagnosis, where the absence of an inter-twin membrane subsequently results in cord entanglement and consistently fluctuating foetal position. Furthermore, the detection of twin-twin transfusion syndrome (TTTS) in MCMA pregnancy can be challenging in the absence of amniotic fluid volume discordance without the presence of the inter-twin dividing membrane. Early surveillance of foetal anatomy permits early recognition of foetal structural anomalies, the twin reversed arterial perfusion (TRAP) sequence and conjoined twins. However, the evidence on how best to monitor MCMA pregnancies remains inadequate, though observational studies have demonstrated that once surveillance is initiated, the potential risk of foetal death decreases significantly. In-utero foetal demise can be acute and unpredictable in MCMA pregnancies, despite close surveillance. Elective preterm delivery is usually advocated when the risk of foetal loss upon continuing the pregnancy outweighs the risk of prematurity - around 33 weeks' gestation by caesarean section. Nevertheless, the optimal prenatal surveillance regimen and prompts for delivery have yet to be defined.

CEPHALOTHORACOPHAGUS JANICEP MONOSYMETROS

To report a case of cephalo-thoracophagus janicep monosymmetros. A 30 year old female of child bearing age came to the department of radiology for routine obstetric ultrasonography with gestational age of 30 weeks. Patient had never conceived previously. In the current pregnancy patient had complaints in relation with the pregnancy. Routine ultrasonography was performed to obtain diagnostic output. Radiological evaluation revealed conjoined monochorionic monoamniotic twin pregnancy. Detailed screening revealed fusion of head (cephalophagus) with two sided face of which single eye on one ventral side (cyclops) and two eyes on the dorsal side (Janicep) along with fusion of the thorax (thoracophagus). 'Janicep' is derived from the word Janus, the two faced roman God. The presence of this prototype makes the case report of a rare variety. Cephalothoracophagus janicep monosymmetros has a prevalence 1:50,000 to 1:200,000 with a male:female ratio of 1:3. However post caesarean delivery of the conjoined twin revealed female sex making the case report more rare.

Outcomes of Monoamniotic Twin Pregnancies from the First Trimester Onward

Introduction: Monochorionic monoamniotic (MCMA) twins are rare, and information is lacking on pregnancy outcomes from the first trimester onward. This study compares the pregnancy and neonatal outcomes between MCMA and monochorionic diamniotic (MCDA) twin pregnancies from the first trimester onward. We also report on the outcomes of MCMA twin pregnancies continuing after 28 weeks and on the neurodevelopmental outcomes of MCMA twins. Methods: A retrospective single-center cohort study of MCMA and MCDA twin pregnancies followed from the first trimester with a fortnightly ultrasound scan. We excluded pregnancies with a major anomaly diagnosed on the first-trimester ultrasound scan. MCMA twin pregnancies were offered inpatient monitoring from 28 weeks onward, and an elective cesarean section was advised between 32 and 33 weeks. MCDA pregnancies were managed as inpatients only if medically indicated, and an elective birth between 36 and 37 weeks was recommended. Results: We analyzed the outcomes of 52 MCMA and 671 MCDA twin pregnancies. In MCMA twins, the fetal and neonatal survival rate was 81/104 (78%) versus 1,192/1,342 (89%) in MCDA twins (p = 0.016). Double intrauterine demise (IUD) was more common in MA than in DA pairs (13% vs. 3%) (p = 0.002). No IUD occurred in the 40 MCMA pregnancies that continued after 28 weeks, but five women (13%) required an urgent cesarean section for fetal distress. Thirty-eight of 52 eligible infants (73%) underwent a neurodevelopmental assessment. Thirty-three (87%) had cognitive and motor development scores within normal limits. Four infants had mild cognitive or motor impairment, and one infant was diagnosed with spastic diplegia. Conclusion: MCMA twins are associated with decreased survival rates compared to MCDA due to increased rates of double IUD. After 28 weeks, about one in eight women required an urgent delivery for fetal distress. Most infants had normal neurodevelopmental outcomes.

A cohort of five cases with asymmetric conjoined twining and literature review

Asymmetric conjoined twining (ACT) is a form of conjoined twining which is a rare malformation of monochorionic monoamniotic twin pregnancy. Most publications were single case reports. We reported a cohort of five cases with ACT from a single tertiary medical center and reviewed the case reports of ACT over the last decade to enrich the clinical research of this disease and summarized the clinical features of the disease. We reviewed five cases of ACT admitted in Tianjin Children's Hospital from 17 March, 2008, through 7 March 2017. The cohort was analysed from general information, imaging manifestations, separation surgery, histopathological findings, outcome and follow-up. We searched the English literatures on case reports of ACT over the past decade from the PubMed database and presented details about the clinical characteristics, treatment, and prognosis of all cases. There were four males and one female in our cohort. Among the five cases, two parasites were located in epigastrium, two in rachis, and one in retroperitoneum (fetus in fetu, FIF). All of the parasites were separated successfully by operation in five cases and were confirmed to be ACT by histopathology reports. Four patients made an uneventful recovery except for one case of wound infection. All of them were doing well in follow-up. In the literature review, we found 41 cases of exoparasitic heteropagus twining (EHT) and 63 cases of FIF. ACT is very rare and usually diagnosed by prenatal ultrasonography (US). Computed tomography (CT) and magnetic resonance imaging (MRI) examinations are essential imaging examinations before separation surgery to delineate the anatomical relationship between the autosite and the parasite. Ingeneral, the separation surgery of ACT is less complicated and the prognosis is better compared with the symmetric conjoined twining (SCT).

Fused yolk sacs in a case of forked umbilical cord in monochorionic diamniotic twin pregnancy: sonoembryological implications

Forked cord (FC), which presents as a fused insertion of two umbilical cords into a monochorionic placenta, is a rare entity, especially in monochorionic diamniotic (MCDA) twin pregnancies. Herein, we describe a case of a MCDA pregnancy with FC, which showed characteristic findings on first-trimester ultrasound examination. A healthy 29-year-old nulliparous woman presented at 8 weeks of gestation following a positive result on pregnancy self-testing. Transvaginal ultrasound revealed two fetuses with active heartbeats and both had their own amniotic membrane, suggesting a MCDA pregnancy (Figure 1a). Noteworthy was that the two yolk sacs were completely fused (Figure 1b) and the connecting stalks, which are the site of the future umbilicus, were located in close proximity to one another (Figure 1c). On transabdominal ultrasound screening at 16 weeks of gestation (Figure 2a), FC was diagnosed but no other abnormalities were detected. The pregnancy course was uneventful and healthy female babies, weighing 2285 g and 2345 g, were born vaginally at 36 weeks. The umbilical and placental inspection revealed that each umbilical cord had two arteries and one vein, which fused near the placental surface, where the amniotic membranes divided the amniotic cavities (Figure 2b). Most cases of previously reported FC were observed in monochorionic monoamniotic (MCMA) twin pregnancies, which were frequently accompanied by an acardiac twin1, 2. Thomas et al. was the first to report an antenatally diagnosed case of FC in an otherwise uncomplicated MCDA pregnancy, in which FC was recognized at 30 weeks, and healthy infants (weighing 2460 g and 2490 g) were delivered at 35 weeks3. Frisch et al. reported a case of FC in a MCMA pregnancy diagnosed at 10 weeks, in which the twin pair (weighing 1169 g and 935 g) was delivered at 29 weeks because of abnormal fetal heart rate patterns4. In our case, which is the third report in the literature of liveborn twins with prenatal diagnosis of FC, the unique findings were the fused yolk sacs, with the amniotic membranes dividing the two fetuses as early as 8 weeks of gestation, in addition to the closely located connecting stalks. From an embryological viewpoint, the folding of the embryo and the expansion of the amniotic cavity, which bring the connecting stalk and yolk sac together to form the umbilical cord, occur after 9 weeks of gestation5. We postulate that our findings at 8 weeks of the fused yolk sacs and the closely located connecting stalks might be forecasting subsequent FC, even when the amniotic membranes dividing two embryos are visualized. As for the blood volume balance between the twins, we agree with the speculation of Thomas et al. and Frisch et al. that a fenestration between the two umbilical vein walls may have had a protective effect on the hemodynamic status of the twins3 and that FC itself in MCMA and MCDA pregnancies does not necessarily cause adverse perinatal outcome4. Our first-trimester findings provide new insights into sonoembryology, especially in relation to umbilical cord development from connecting stalks.

Early Ultrasound Identification of Cord Entanglement in Monochorionic Monoamniotic Twin Pregnancy.

Monochorionic monoamniotic pregnancy are considered high risk gestations and the fetal outcome is at times unpredictable. Correct diagnosis and counselling are extremely important, especially regarding the risk of unexpected fetal demise. We present the rare case of a monochorionic monoamniotic twin pregnancy with early identification of cord entanglement and the characteristic ultrasound findings in the first trimester of pregnancy.

Management of Monochorionic Monoamniotic Twin Pregnancy Experience of a Tertiary CenterPP

Amaç: Monokoryonik monoamniyotik ikiz gebeliklerin (MKMA) kliniğimizdeki uyguladığımız yönetim şekli ile gebelik sonuçlarının değerlendirilmesi, bu gebeliklerdeki komplikasyonların tanımlanması.Materyal ve metod: Çalışmaya üç yıllık süreçte kliniğimizde takip edilen ve sonuçlandırılan MKMA ikiz gebelikler dahil edildi. Veriler retrospektif olarak toplandı, çalışmaya dahil edilen gebeliklerin gebelik sonuçları, monokoryonisiteye spesifik gebelik komplikasyonlar ve bu gebeliklerdeki konjenital malformasyonlar kaydedildi. Bulgular: Üç yıllık süreçte toplam 12 MKMA ikiz gebeliğin kliniğimizde takip ve yönetimi uygulanmıştır. Üç olguda ikiz eşi doğum öncesi dönemde intrauterin fetal kayıp ile komplike olmuştur. Bir olguda her iki fetüsün intrauterin kaybı ile sonuçlanmıştır. Hiçbir olguda monokoryonisite spesifik komplikasyon ile karşılaşılmadı. Bir olguda her ikizde diskordan konjenital malformasyonlar mevcuttu.Sonuç: MKMA gebelikler nadir fakat perinatal tıpta en karmaşık ve yönetim açısından tartışmalı konulardandır. Nasıl yönetilmesi ve ne zaman teslim edileceği konusunda henüz netlik yoktur. Bu çalışmada kliniğimizdeki yönetim protokolümüzle ilgili deneyimimizi bildirdik.Anahtar Kelimeler: Monokoryonisite, Monoamniyotik ikiz, Monozigosite

Twin reversed arterial perfusion sequence in a monochorionic monoamniotic twin pregnancy: a very rare condition

BackgroundTwin reversed arterial perfusion sequence (TRAP) is a very rare congenital anomaly. We present sonographic findings of TRAP sequence in the case of a multiparous woman with a monochorionic monoamniotic twin pregnancy who was referred to our unit for blood sugar control.Case presentationThe patient had a history of co-twin demise at 13 weeks of gestation without appropriate fetal surveillance afterwards. We found a monochorionic placentation with a normal appearing pump twin, an abnormal appearing co-twin without obvious cardiac activity and reversed arterial flow toward instead of away from the anomalous acardiac fetus. Therefore, the sonographic diagnosis of TRAP sequence was confirmed.ConclusionsWe recommend considering the potential rare complications of monochorionic twin pregnancy which necessitates proper surveillance and intervention to monitor suitable growth of pump twin.

Clinical characteristics and outcomes of monochorionic monoamniotic twin pregnancy

Objective: To investigate the clinical characteristics and outcomes of monochorionic monoamniotic (MCMA) twin pregnancy. Methods: The clinical data of 60 MCMA twin pregnant women who were terminated in Peking University Third Hospital from January 2011 to December 2019 were collected, and the general clinical data, prenatal examination and pregnancy outcomes were analyzed retrospectively. Results: The age of 60 MCMA twin pregnant women was (31.0±4.1) years old, among which 44 cases were primiparas (73%, 44/60) and 16 cases were multiparas (27%, 16/60). Fifty-eight cases were diagnosed as MCMA twin pregnancy prenatally and were confirmed after delivery. Median ultrasonic diagnosis of gestational age was 12 weeks (range: 8-30 weeks). In the 60 MCMA twin pregnancies, 6 cases were conjoined twins, 5 cases were complicated with twin reversed arterial perfusion sequence (TRAPS), and 10 cases were diagnosed as other fetal malformation by prenatal ultrasound examination. Among the 60 MCMA twin pregnant women, 19 cases had spontaneous abortion or induced abortion due to fetal malformation, fetal death or other reasons within 28 weeks of pregnancy, 41 cases entered the perinatal period, a total of 70 newborns survived. The main cause of perinatal fetal or neonatal death was fetal dysplasia. Conclusions: There is a high incidence of fetal abnormality and perinatal mortality in MCMA twin pregnancy. Accurate early diagnosis, enhanced management and monitoring during pregnancy, and individualized treatment are the keys to improve MCMA twin pregnancy outcomes.

Neonatal Morbidity of Monoamniotic Twin Pregnancies: A Systematic Review and Meta-analysis.

This study was aimed to report the incidence of neonatal morbidity in monochorionic monoamniotic (MCMA) twin pregnancies according to gestational age at birth and type of management adopted (inpatient or outpatient). Medline and Embase databases were searched. Inclusion criteria were nonanomalous MCMA twins. The primary outcome was a composite score of neonatal morbidity, defined as the occurrence of at least one of the following outcomes: respiratory morbidity, overall neurological morbidity, severe neurological morbidity, and infectious morbidity, necrotizing enterocolitis at different gestational age windows (24-30, 31-32, 33-34, and 35-36 weeks). Secondary outcomes were the individual components of the primary outcome and admission to neonatal intensive care unit (NICU). Subanalysis according to the type of surveillance strategy (inpatient compared with outpatient) was also performed. Random effect meta-analyses were used to analyze the data. A total of 14 studies including 685 MCMA twin pregnancies without fetal anomalies were included. At 24 to 30, 31 to 32, 33 to 34, and 35 to 36 weeks of gestation, the rate of composite morbidity was 75.4, 65.5, 37.6, and 18.5%, respectively, the rate of respiratory morbidity was 74.2, 59.1, 35.5, and 12.2%, respectively, while overall neurological morbidity occurred in 15.3, 10.2, 4.3, and 0% of the cases, respectively. Infectious morbidity complicated 13, 4.2, 3.1, and 0% of newborns while 92.1, 81.6, 58.7, and 0% of cases required admission to NICU. Morbidity in pregnancies delivered between 35 and 36 weeks of gestation was affected by the very small sample size of cases included. When comparing the occurrence of overall morbidity according to the type of management (inpatient or outpatient), there was no difference between the two surveillance strategies (p = 0.114). MCMA pregnancies are at high risk of composite neonatal morbidity, mainly respiratory morbidity that gradually decreases with increasing gestational age at delivery with a significant reduction for pregnancies delivered between 33 and 34 weeks. We found no difference in the occurrence of neonatal morbidity between pregnancies managed as inpatient or outpatient. · MCMA pregnancies are at high risk of composite neonatal morbidity, mainly respiratory morbidity.. · Neonatal morbidity gradually decreases with increasing GA at delivery, mostly between 33 and 34 weeks.. · There is no difference in the occurrence of neonatal morbidity between in- or outpatient management..

Physical examination–indicated cerclage in twin pregnancy: a randomized controlled trial

Women with twin pregnancies and a dilated cervix in the second trimester are at increased risk of pregnancy loss and early preterm birth; there is currently no proven therapy to prevent preterm birth in this group of women. This study aimed to determine whether physical examination-indicated cerclage reduces the incidence of preterm birth in women with a diagnosis of twin pregnancies and asymptomatic cervical dilation before 24 weeks of gestation. Multicenter, parallel group, open-label, randomized controlled trial of women with twin pregnancies and asymptomatic cervical dilation of 1 to 5 cm between 16 weeks 0/7 days of gestation and 23 weeks 6/7 days of gestation were enrolled from July 2015 to July 2019 in 8 centers. Eligible women were randomized in a 1:1 ratio into either cerclage or no cerclage groups. We excluded women with monochorionic-monoamniotic twin pregnancy, selective fetal growth restriction, twin-twin transfusion syndrome, major fetal malformation, known genetic anomaly, placenta previa, signs of labor, or clinical chorioamnionitis. The primary outcome was the incidence of preterm birth at <34 weeks of gestation. Secondary outcomes were preterm births at <32, <28, and <24 weeks of gestation, interval from diagnosis to delivery, and perinatal mortality. Data were analyzed by intention-to-treat methods. After an interim analysis was performed, the Data and Safety Monitoring Board recommended stopping the trial because of a significant decrease in perinatal mortality in the cerclage group. We randomized 34 women, with 4 women being excluded because of expired informed consent. A total of 17 women were randomized to physical examination-indicated cerclage and 13 women to no cerclage. Whereas 4 women randomized to cerclage did not receive the surgical procedure, no women in the no cerclage group received cerclage. Maternal demographics were not significantly different. All women in the cerclage group also received indomethacin and antibiotics. When comparing the cerclage group vs the no cerclage group, the incidence of preterm birth was significantly decreased as follows: preterm birth at <34 weeks of gestation, 12 of 17 women (70%) vs 13 of 13 women (100%) (risk ratio, 0.71; 95% confidence interval, 0.52-0.96); preterm birth at <32 weeks of gestation, 11 of 17 women (64.7%) vs 13 of 13 women (100%) (risk ratio, 0.65; 95% confidence interval, 0.46-0.92); preterm birth at <28 weeks of gestation, 7 of 17 women (41%) vs 11 of 13 women (84%) (risk ratio, 0.49; 95% confidence interval, 0.26-0.89); and preterm birth at <24 weeks of gestation, 5 of 17 women (30%) vs 11 of 13 women (84%) (risk ratio, 0.35; 95% confidence interval, 0.16-0.75). The mean gestational age at delivery was 29.05±1.7 vs 22.5±3.9 weeks (P<.01), respectively; the mean interval from diagnosis of cervical dilation to delivery was 8.3±5.8 vs 2.9±3.0 weeks (P=.02), respectively. Perinatal mortality was also significantly reduced in the cerclage group compared with the no cerclage group as follows: 6 of 34 women (17.6%) vs 20 of 26 women (77%) (risk ratio, 0.22; 95% confidence interval, 0.1-0.5), respectively. In women with twin pregnancies and asymptomatic cervical dilation before 24 weeks of gestation, a combination of physical examination-indicated cerclage, indomethacin, and antibiotics significantly decreased preterm birth at all evaluated gestational ages. Most importantly, cerclage in this population was associated with a 50% decrease in early preterm birth at <28 weeks of gestation and with a 78% decrease in perinatal mortality.

Outcome of twin-to-twin transfusion syndrome in monochorionic monoamniotic twin pregnancy: systematic review and meta-analysis.

To explore the outcome of monochorionic monoamniotic (MCMA) twin pregnancies affected by twin-to-twin transfusion syndrome (TTTS). MEDLINE and EMBASE databases were searched for studies reporting the outcome of MCMA twin pregnancies complicated by TTTS. The primary outcome was intrauterine death (IUD); secondary outcomes were miscarriage, single IUD, double IUD, neonatal death (NND), perinatal death (PND), survival of at least one twin, survival of both twins and preterm birth (PTB) before 32 weeks' gestation. Outcomes were assessed in MCMA twins affected by TTTS not undergoing intervention and in those treated with amniodrainage, laser therapy or cord occlusion. Subgroup analysis was performed including cases diagnosed before 24 weeks. Random-effects meta-analysis of proportions was used to analyze the data. Fifteen cohort studies, including 888 MCMA twin pregnancies, of which 44 were affected by TTTS, were included in the review. There was no randomized trial comparing the different management options in MCMA twin pregnancies complicated by TTTS. In cases not undergoing intervention, miscarriage occurred in 11.0% of fetuses, while the incidence of IUD, NND and PND was 25.2%, 12.2% and 31.2%, respectively. PTB complicated 50.5% of these pregnancies. In cases treated by laser surgery, the incidence of miscarriage, IUD, NND and PND was 19.6%, 27.4%, 7.4% and 35.9%, respectively, and the incidence of PTB before 32 weeks' gestation was 64.9%. In cases treated with amniodrainage, the incidence of IUD, NND and PND was 31.3%, 13.5% and 45.7% respectively, and PTB complicated 76.2% of these pregnancies. Analysis of cases undergoing cord occlusion was affected by the very small number of included cases. Miscarriage occurred in 19.2%, while there was no case of IUD or NND of the surviving twin. PTB before 32 weeks occurred in 50.0% of these cases. MCMA twin pregnancies complicated by TTTS are at high risk of perinatal mortality and PTB. Further studies are needed in order to elucidate the optimal type of prenatal treatment in these pregnancies. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Weight discordance and perinatal mortality in monoamniotic twin pregnancy: analysis of MONOMONO, NorSTAMP and STORK multiple-pregnancy cohorts.

The primary objective was to quantify the risk of perinatal mortality in non-anomalous monochorionic monoamniotic (MCMA) twin pregnancies complicated by birth-weight (BW) discordance. The secondary objectives were to investigate the effect of inpatient vs outpatient fetal monitoring on the risk of mortality in weight-discordant MCMA twin pregnancies, and to explore the predictive accuracy of BW discordance for perinatal mortality. This analysis included data on 242 MCMA twin pregnancies (484 fetuses) from three major research collaboratives on twin pregnancy (MONOMONO, STORK and NorSTAMP). The primary outcomes were the risks of intrauterine (IUD), neonatal (NND) and perinatal (PND) death, according to weight discordance at birth from ≥ 10% to ≥ 30%. The secondary outcomes were the association of inpatient vs outpatient fetal monitoring with the risk of mortality in weight-discordant pregnancies, and the accuracy of BW discordance in predicting mortality. Logistic regression and receiver-operating-characteristics-curve analyses were used to analyze the data. The risk of IUD was significantly increased in MCMA twin pregnancies with BW discordance ≥ 10% (odds ratio (OR), 2.2; 95% CI, 1.1-4.4; P = 0.022) and increased up to an OR of 4.4 (95% CI, 1.3-14.4; P = 0.001) in those with BW discordance ≥ 30%. This association remained significant on multivariate logistic regression analysis for BW-discordance cut-offs ≥ 20%. However, weight discordance had low predictive accuracy for mortality, with areas under the receiver-operating-characteristics curve of 0.60 (95% CI, 0.46-0.73), 0.52 (95% CI, 0.33-0.72) and 0.57 (95% CI, 0.45-0.68) for IUD, NND and PND, respectively. There was no difference in the risk of overall IUD, single IUD, double IUD, NND or PND between pregnancies managed as an inpatient compared with those managed as an outpatient, for any BW-discordance cut-off. MCMA twin pregnancies with BW discordance are at increased risk of fetal death, signaling a need for increased levels of monitoring. Despite this, the predictive accuracy for mortality is low; thus, detection of BW discordance alone should not trigger intervention, such as iatrogenic delivery. The current data do not demonstrate an advantage of inpatient over outpatient management in these cases. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Intertwin discordance in fetal size at 11-13 weeks' gestation and pregnancy outcome.

To investigate the value of intertwin discordance in fetal crown-rump length (CRL) at the 11-13-week scan in the prediction of adverse outcome in dichorionic (DC), monochorionic diamniotic (MCDA) and monochorionic monoamniotic (MCMA) twin pregnancies. This was a retrospective analysis of prospectively collected data on twin pregnancies undergoing routine ultrasound examination at 11-13 weeks' gestation between 2002 and 2019. In pregnancies with no major abnormalities, we examined the value of intertwin discordance in fetal CRL in DC, MCDA and MCMA twins in the prediction of fetal loss at < 20 and < 24 weeks' gestation, perinatal death at ≥ 24 weeks, preterm delivery at < 32 and < 37 weeks, birth of at least one small-for-gestational-age (SGA) neonate with birth weight < 5th percentile and intertwin birth-weight discordance of ≥ 20% and ≥ 25%. First, the study population of 6225 twin pregnancies included 4896 (78.7%) DC, 1274 (20.4%) MCDA and 55 (0.9%) MCMA twin pregnancies. Second, median CRL discordance in DC twin pregnancies (3.2%; interquartile range (IQR), 1.4-5.8%) was lower than in MCDA twins (3.6%; IQR, 1.6-6.2%; P = 0.0008), but was not significantly different from that in MCMA twins (2.9%; IQR, 1.2-5.1%; P = 0.269). Third, compared to CRL discordance in DC twin pregnancies with two non-SGA live births at ≥ 37 weeks' gestation, there was significantly larger CRL discordance in both DC and MCDA twin pregnancies complicated by fetal death at < 20 and < 24 weeks' gestation, perinatal death at ≥ 24 weeks, preterm birth at < 32 and < 37 weeks, birth of at least one SGA neonate and birth-weight discordance ≥ 20% and ≥ 25%, and in MCDA twin pregnancies undergoing endoscopic laser surgery. Fourth, the predictive performance of CRL discordance for each adverse pregnancy outcome was poor, with areas under the receiver-operating-characteristics curves ranging from 0.533 to 0.624. However, in both DC and MCDA twin pregnancies with large CRL discordance, there was a high risk of fetal loss. Fifth, in DC twin pregnancies, the overall rate of fetal loss at < 20 weeks' gestation was 1.3% but, in the small subgroup with CRL discordance of ≥ 15%, which constituted 1.9% of the total, the rate increased to 5.3%. Sixth, in MCDA twin pregnancies, the rate of fetal loss or endoscopic laser surgery at < 20 weeks was about 11%, but, in the small subgroups with CRL discordance of ≥ 10%, ≥ 15% and ≥ 20%, which constituted 9%, < 3% and < 1% of the total, the risk was increased to about 32%, 49% and 70%, respectively. Seventh, in MCMA twin pregnancies, there were no significant differences in CRL discordance for any of the adverse outcome measures, but this may be the consequence of the small number of cases in the study population. In both DC and MCDA twin pregnancies, increased CRL discordance is associated with an increased risk of fetal death at < 20 and < 24 weeks' gestation, perinatal death at ≥ 24 weeks, preterm birth at < 37 and < 32 weeks, birth of at least one SGA neonate and birth-weight discordance ≥ 20% and ≥ 25%, but CRL discordance is a poor screening test for adverse pregnancy outcome. However, in DC twins, CRL discordance of ≥ 15% is associated with an increased risk of fetal loss at < 20 and < 24 weeks' gestation and, in MCDA twins, CRL discordance of ≥ 10%, and more so discordance of ≥ 15% and ≥ 20%, is associated with a very high risk of fetal loss or endoscopic laser surgery at < 20 and < 24 weeks and this information is useful in counseling women and defining the timing for subsequent assessment and possible intervention. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Outcome of twin pregnancy with two live fetuses at 11-13 weeks' gestation.

To report and compare pregnancy outcome in dichorionic (DC), monochorionic diamniotic (MCDA) and monochorionic monoamniotic (MCMA) twin pregnancies with two live fetuses at 11-13 weeks' gestation and to examine the impact of endoscopic laser surgery for severe twin-twin transfusion syndrome (TTTS) and/or selective fetal growth restriction (sFGR) on the outcome of MCDA twins. This was a retrospective analysis of prospectively collected data on twin pregnancies undergoing routine ultrasound examination at 11-13 weeks' gestation between 2002 and 2019. In pregnancies with no major abnormalities, we compared overall survival, fetal loss at < 24 weeks' gestation, perinatal death at ≥ 24 weeks, delivery at < 37 and < 32 weeks, and birth weight < 5th percentile between DC, MCDA and MCMA twins. The study population of 6225 twin pregnancies with two live fetuses at 11-13 weeks' gestation with no major abnormalities included 4896 (78.7%) DC, 1274 (20.5%) MCDA and 55 (0.9%) MCMA twins. In DC twins, the rate of loss at < 24 weeks' gestation in all fetuses was 2.3%; this rate was higher in MCDA twins (7.7%; relative risk (RR), 3.258; 95% CI, 2.706-3.923) and more so in MCMA twins (21.8%; RR, 9.289; 95% CI, 6.377-13.530). In DC twins, the rate of perinatal death at ≥ 24 weeks in all twins that were alive at 24 weeks was 1.0%; this rate was higher in MCDA twins (2.5%; RR, 2.456; 95% CI, 1.779-3.389) and more so in MCMA twins (9.3%; RR, 9.130; 95% CI, 4.584-18.184). In DC twins, the rate of preterm birth at < 37 weeks' gestation in pregnancies with at least one liveborn twin was 48.6%; this rate was higher in MCDA twins (88.5%; RR, 1.824; 95% CI, 1.760-1.890) and more so in MCMA twins (100%; RR, 2.060; 95% CI, 2.000-2.121). In DC twins, the rate of preterm birth at < 32 weeks was 7.4%; this rate was higher in MCDA twins (14.2%; RR, 1.920; 95% CI, 1.616-2.281) and more so in MCMA twins (26.8%; RR, 3.637; 95% CI, 2.172-6.089). In DC twin pregnancies with at least one liveborn twin, the rate of a small-for-gestational-age neonate among all liveborn twins was 31.2% and in MCDA twins this rate was higher (37.8%; RR, 1.209; 95% CI, 1.138-1.284); in MCMA twins, the rate was not significantly different (33.3%; RR, 1.067; 95% CI, 0.783-1.455). Kaplan-Meier analysis showed a significant difference in survival in MCDA and MCMA twins, compared to DC twins, for both the interval of 12 to < 24 weeks' gestation (log-rank test, P < 0.0001 for both) and that of ≥ 24 to 38 weeks (log-rank test, P < 0.0001 for both). Endoscopic laser ablation of intertwin communicating placental vessels was carried out in 127 (10.0%) MCDA twin pregnancies for TTTS and/or sFGR and, in 111 of these, surgery was performed at < 24 weeks; both fetuses survived in 62 (55.9%) cases, one fetus survived in 25 (22.5%) cases and there were no survivors in 24 (21.6%) cases. On the extreme assumption that, had laser surgery not been carried out in these cases, all fetuses would have died, the total fetal loss rate at < 24 weeks' gestation in MCDA twins would have been 13.5%. The rates of fetal loss at < 24 weeks' gestation, perinatal death at ≥ 24 weeks and preterm birth are higher in MCDA and more so in MCMA twins than in DC twins. In MCDA twins, the rate of fetal loss may have been reduced by endoscopic laser surgery in those that developed early TTTS and/or sFGR. These data would be useful in counseling parents as to the likely outcome of their pregnancy and in defining strategies for surveillance and interventions in the management of the different types of twin pregnancy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Perinatal mortality, timing of delivery and prenatal management of monoamniotic twin pregnancy: systematic review and meta-analysis.

To quantify the rate of perinatal mortality in monochorionic monoamniotic (MCMA) twin pregnancies, according to gestational age, and to ascertain the incidence of mortality in pregnancies managed as inpatients compared with those managed as outpatients. MEDLINE, EMBASE and CINAHL databases were searched for studies on monoamniotic twin pregnancy. The primary outcomes explored were the incidence of intrauterine death (IUD), neonatal death (NND) and perinatal death (PND) in MCMA twins at different gestational-age windows (24-30, 31-32, 33-34, 35-36 and ≥ 37weeks of gestation). The secondary outcomes were the incidence of IUD, NND and PND in MCMA twins according to the type of fetal monitoring (inpatient vs outpatient), and the incidence of delivery ahead of schedule. Random-effects model meta-analyses were used to analyze the data. Twenty-five studies (1628 non-anomalous twins reaching 24 weeks of gestation) were included. Single and double intrauterine deaths occurred in 2.5% (95% CI, 1.8-3.3%) and 3.8% (95% CI, 2.5-5.3%) of cases, respectively. IUD occurred in 4.3% (95% CI, 2.8-6.2%) of twins at 24-30 weeks, in 1.0% (95% CI, 0.6-1.7%) at 31-32 weeks and in 2.2% (95% CI, 0.9-3.9%) at 33-34 weeks of gestation, while there was no case of IUD, either single or double, from 35 weeks of gestation. In MCMA twin pregnancies managed mainly as inpatients, the incidence of IUD was 3.0% (95% CI, 1.4-5.2%), while the corresponding figure for those managed mainly as outpatients was 7.4% (95% CI, 4.4-11.1%). Finally, 37.8% (95% CI, 28.0-48.2%) of MCMA pregnancies were delivered before the scheduled time, due mainly to spontaneous preterm labor or abnormal cardiotocographic findings. MCMA twins are at high risk of perinatal loss during the third trimester of pregnancy, with the large majority of such losses occurring as apparently unexpected events. Inpatient management seems to be associated with a lower rate of mortality, although further studies are needed in order to establish the appropriate type and timing of prenatal assessment in these pregnancies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.