Uncomplicated Monochorionic Diamniotic Twins Research Articles

Long-Term Neurodevelopmental Outcome After Selective Fetoscopic Laser Therapy for Stage I Twin-Twin Transfusion Syndrome.

Twin-twin transfusion syndrome (TTTS) is a serious complication in monochorionic (MC) pregnancies. Fetoscopic laser surgery (FLS) is the primary treatment for advanced TTTS, but managing Quintero stage I TTTS is still controversial. We conducted an observational study evaluating the 2-year neurodevelopment of fetuses, which underwent FLS for stage I TTTS, compared with advanced TTTS and uncomplicated monochorionic diamniotic twins (MCDTs). The study included 156 children: 14 in stage I TTTS group, 28 in advanced TTTS group, and 114 in uncomplicated twin group. In stage I TTTS, 92.9% showed normal neurodevelopment, with no severe neurological impairments observed. These results were comparable with uncomplicated twins (92.1% normal neurodevelopment, P = .921, adjusted odds ratio [aOR] = 1.56, 95% confidence interval [CI] = 0.42-5.79; 1.8% severe impairment, P = .617). Advanced TTTS had a non-significant lower rate of normal neurodevelopment (89.3%, P = .710, aOR = 1.31, 95% CI = 0.12-14.87). In conclusion, FLS for stage I TTTS shows favorable long-term neurodevelopmental outcomes, similar to uncomplicated MC pregnancies.

Развитие острой фето-фетальной трансфузии при родоразрешении монохориальных диамниотических двоен

Objective. To determine the incidence and characteristics of acute feto-fetal transfusion (FFT) in patients with an uncomplicated monochorionic diamniotic (MCDA) twin pregnancy who had a vaginal delivery and to compare their perinatal outcomes with those patients who underwent elective cesarean section. Patients and methods. This retrospective study included data on perinatal outcomes of 92 births in patients with MCDA twins delivered at the Maternity Hospital No 17 between 2019 and 2021. All patients were divided into two groups according to the mode of delivery: the study group (n = 49) – vaginal delivery, the control group (n = 43) – elective cesarean section before the onset of labor. Results. No diagnostically significant signs of acute FFT were found among newborns delivered by cesarean section. Acute FFT was detected in four neonates born to two (4%) patients delivered vaginally. These neonates had the Apgar score at 1 minute and 5 minutes greater than 7. Only one of these four neonates required phototherapy for neonatal jaundice caused by polycythemia and transfer to a pediatric hospital for stage 2 neonatal nursing. When comparing perinatal outcomes in patients in both groups delivered after 36 weeks’ gestation, no statistically significant differences in Apgar scores at 1 minute and 5 minutes and differences in hemoglobin levels in newborns were found regardless of delivery. In case of delivery before 36 weeks’ gestation, Apgar scores at 1 minute and 5 minutes were statistically significantly higher in the vaginal delivery group than in the cesarean section group. Conclusion. The data obtained show a low incidence of acute FFT in neonates born through vaginal delivery in an uncomplicated MCDA twin pregnancy and the absence of this complication in newborns delivered by cesarean section. When this specific complication of MCDA twin pregnancy developed among newborns, no perinatal losses were detected, and subsequent postnatal outcomes were favorable. It appears that further studies to clarify the diagnostic criteria and risk factors for the development of acute FFT in labor and the long-term health outcomes for newborns in an uncomplicated MCDA twin pregnancy may reduce the rate of cesarean delivery without worsening perinatal outcomes. Key words: monochorionic twins, acute feto-fetal transfusion, twin-to-twin transfusion syndrome, twin anemia polycythemia sequence

Two Year Neurodevelopmental Outcome after Fetoscopic Laser Therapy for Twin-Twin Transfusion Syndrome: Comparison with Uncomplicated Monochorionic Diamniotic Twins.

Twin-twin Transfusion Syndrome (TTTS) represents a significant complication in monochorionic twin pregnancies, caused by an unbalanced shunting of blood through intertwin placental vascular anastomoses. Despite advances in fetoscopic laser surgery, TTTS is still associated with a high rate of cerebral injury. However, there are no studies comparing these pregnancies with uncomplicated monochorionic diamniotic (MCDA) twin pregnancies, establishing the baseline risk of neurodevelopmental impairment. The aim of this study is to evaluate the odds of neurodevelopmental impairment in MCDA twins who undergo fetoscopic laser surgery for twin-twin transfusion syndrome, in comparison to a cohort of uncomplicated MCDA twin pregnancies. This is a retrospective cohort study of children born from MCDA twin pregnancies at a single center between 2008 and 2019. A routine, standardized follow-up assessment was conducted at a minimum of 2 years after delivery. The primary outcome of this was a 2 year neurodevelopmental impairment. Neurological, motor, and cognitive development was assessed by using the revised Brunet-Lézine scale. 176 children met the enrolment criteria. Of these, 42 (24%; TTTS group) underwent fetoscopic laser surgery for TTTS during pregnancy, and 134 (76%; uncomplicated MCDA group) were uncomplicated MCDA pregnancies. The primary outcome was found in four children (9.52%) in the TTTS group and ten children (7.46%) in the uncomplicated MCDA group (p = 0.67, aOR 2.82, 95% CI 0.49-16.23). Major neurologic impairment was found in 2.38% after fetoscopic laser surgery and 1.49% in uncomplicated MCDA twins (p = 0.70, aOR 0.97, 95% CI 0.22-4.24). The data were adjusted by birth order, birth weight, and gestational age at birth. The outcome in MCDA twins who underwent fetoscopic laser surgery for TTTS is comparable to the outcome in uncomplicated MCDA twins. Our findings emphasize the need for long-term neurodevelopmental follow-ups in all children from monochorionic twin gestations.

Comparative Study of Perinatal Outcome in Uncomplicated Monochorionic Diamniotic versus Dichorionic Diamniotic Twins at a Specialized Twin Clinic—A Prospective Study

Abstract Background Monochorionic twins have higher perinatal morbidity and mortality than dichorionic twins. However, there is conflicting data on outcomes of uncomplicated monochorionic twins. Purpose of the Study The aim of this study is to compare the outcomes of apparently uncomplicated monochorionic twins to dichorionic twins. Methods This is a prospective study conducted from August 2019 to December 2020 at a specialized twin clinic. All twins, whose chorionicity was determined before 14 weeks with two live fetuses at 24 weeks, were recruited. Complicated monochorionic diamniotic (MCDA) twins with twin-to-twin transfusion syndrome, twin anemia polycythemia syndrome, selective fetal growth restriction before 24 weeks and single or double fetal demise before 24 weeks were excluded. Other exclusion criteria were major congenital and chromosomal abnormalities, higher order multiples, monoamniotic twins, and twins with undetermined chorionicity antenatally. Both the groups were followed till delivery and neonates followed till 28 days. Maternal and neonatal outcomes were studied and compared. Results One-hundred forty-eight mothers with dichorionic diamniotic (DCDA) and 74 with uncomplicated MCDA were studied. Mean gestational age at delivery was 35 weeks in both the groups. Maternal, fetal, and neonatal morbidities were similar in both, except early onset preeclampsia that was higher in the DCDA group. Prospective risk of stillbirth for DCDA and MCDA after 24 weeks was 1.35 and 4.05%, respectively. Prospective risk of stillbirth for DCDA and MCDA after 30 weeks was 1.49 and 0%, respectively. Conclusion The maternal and perinatal outcomes in uncomplicated MCDA twins are similar to DCDA twins. Prospective risk of stillbirth after 30 weeks is extremely low. Hence, uncomplicated MCDA twins should not be delivered electively before 36 weeks.

Angiogenic factors (sFlt-1, PlGF) in twin pregnancy with placentaassociated complications

Aim : to determine reference values of angiogenic factors dynamics in pregnancy for female patients with twins and different types of placentation for early diagnostics and assessment of preeclampsia (PE) severity. Materials and Methods . There was conducted 2020–2021 prospective study enrolling 93 females with twin pregnancy to examine 68 with dichorionic diamniotic (DCDA) twins and 25 with monochorionic diamniotic (MCDA) twins. All patients were divided into 2 groups: group I consisted of 65 women with twin pregnancy without PE, group II included 28 women with twin pregnancy complicated by PE. In blood serum of pregnant women the level of soluble fms-like tyrosine kinase 1 (sFlt-1), placental growth factor (PlGF) and their ratio were studied for diagnosing and predicting PE severity at 4 time points of gestation (20.0–23.6 weeks, 24.0–28.6 weeks, 29.0–33.6 weeks, 34.0–36.6 weeks). Results . No significant difference was found in angiogenic factors level and their ratio in pregnant women with uncomplicated DCDA and MCDA twins. Regardless of placentation type, sFlt-1/PlGF ratio in women with twin pregnancy and PE at 24 weeks of gestation was 103.3, by 20-fold exceeding this level than in uncomplicated twin pregnancy. Cut-off values for sFlt-1/PlGF ratio were determined allowing highly reliable to rule out diagnosis PE (sFlt-1/PlGF < 21.85; sensitivity 100 %, specificity 85 %) and to diagnose PE (sFlt-1/PlGF > 49.4; sensitivity 71.1 %, specificity 100 %). The sFlt-1/PlGF ratio was higher in pregnant women with severe PE compared with the moderate degree of the disease throughout pregnancy (р < 0.05). In pregnant women with early PE, the angiogenic factors ratio exceeded the upper threshold value from 24 weeks of gestation, with late PE – from 34.0–36.6 weeks. Significantly higher sFlt-1 level (18359 ± 8656 pg/ml vs. 5526 ± 2808 pg/ml; р < 0.001) and the sFlt-1/PlGF ratio (118,0 ± 65,2 vs. 32,8 ± 18,6; р < 0.03) as well as severe degree of PE were noted in patients with induced twin pregnancy from 24.0–28.6 weeks of gestation compared with spontaneous multiple pregnancy (42,2 and 22,2 % respectively; p < 0,05). Conclusion . The developed reference values of the sFlt-1/PlGF ratio in pregnant women with twins and different types of placentation can be used not only to diagnose PE, but also to assess the severity and timing of the disease manifestation.

The heart after surviving twin-to-twin transfusion syndrome

The persistent changes in cardiac structure and function in children who survived twin-to-twin transfusion syndrome remain a matter of concern and controversy. Current fetal echocardiographic parameters and their postnatal evolution can help improve our understanding of the subject. To describe the echocardiographic changes of monochorionic fetuses affected by twin-to-twin transfusion syndrome, the recipient and the donor, before and after laser photocoagulation and to determine their evolution in the third trimester and during their first year of life. An observational study was conducted including 55 uncomplicated monochorionic diamniotic twins and 78 pairs with twin-to-twin transfusion syndrome, 44 stage I-II and 34 stage III-IV, prospectively enrolled from 2015 until 2018. Comprehensive echocardiography was performed at 4 time periods: before laser photocoagulation, at 24 to 72 hours after surgery, at 28 to 30 weeks of gestation, and at 6 to 12 months after birth. Echocardiographic parameters were transformed to z-scores or indexed for heart area, estimated fetal weight, or body mass surface. At diagnosis, recipients in all stages presented larger hearts (cardiothoracic ratio z-score: 2.77 [0.8] vs controls:-0.03 [0.5]; P<.001) and signs of ventricular hypertrophy (left end-diastolic ventricle wall thickness: 2.68 [0.7] vs controls-0.03 [0.7]; P<.001), along with systolic (cardiac index recipients: 317 [114] mL/min/kg vs controls: 400 [120] mL/min/kg, P<.001) and diastolic impairment (isovolumetric relaxation time z-score: 2.76 [0.6] vs controls: 0.05 [0.6]; P<.001). Donors presented smaller ventricular areas and diameters when compared with controls (left end-diastolic ventricle area z-score:-1.48 [1] vs 0.03 [0.9]; P<.001), along with decreased longitudinal motion (tricuspid annular plane systolic excursion z-score:-0.9 [1] vs controls-0.04 [1]; P<.001) and shorter ejection time z-score (-1.5 [0.7] vs controls: 0.0 [0.7]; P<.001). After surgery, an improvement in functional parameters was observed in both fetuses, whereas most morphometric changes prevailed in donors and recipients in the prenatal period. Postnatally, cardiac remodeling persisted in recipients (left relative wall thickness: 0.34 [0.02] vs controls: 0.30 [0.02]; P<.001), whereas donors mainly presented a decreased longitudinal motion in infancy (tricuspid annular plane systolic excursion z-score:-0.72 [0.7] vs controls: 0.23 [0.9]; P<.05). Cardiac remodeling is present in both fetuses at the twin-to-twin transfusion syndrome diagnosis, whereas diastolic dysfunction is only significant in the recipient. Fetal therapy improves most echocardiographic parameters, although postnatally, the echocardiographic changes persist in both fetuses.

Mode of delivery, perinatal outcome and neurodevelopment in uncomplicated monochorionic diamniotic twins: a single-center retrospective cohort study

BackgroundThere is no agreement on the effect of planned mode of delivery in the perinatal morbidity and neurodevelopment in uncomplicated monochorionic diamniotic as well as regarding the safest mode of delivery. In this paper we have aimed to analyze the impact of the mode of delivery in uncomplicated monochorionic diamniotic twins ≥ 32 weeks of gestation.Material and methodsThis study included 72 women, followed and attended at our department, with uncomplicated monochorionic diamniotic pregnancies who had a birth between 32.0 and 37.6 weeks of gestation from January 2012 to December 2018. Outcomes were recorded in women who underwent planned vaginal delivery (induced or spontaneous onset of labor), and women who underwent a planned cesarean section for any reason that excluded vaginal delivery. Primary outcomes included: (1) A composite of any of the following: neonatal death, 5-min Apgar score < 4, respiratory distress syndrome, bronchopulmonary dysplasia, sepsis, periventricular leukomalacia, intraventricular hemorrhage, and necrotizing enterocolitis. (2) Neurodevelopmental status at 2 years of corrected age.ResultsIn this period, 42 women (58.3%) had a planned vaginal delivery, and 30 women (41.7%) had a planned cesarean section. In the first group, 64.3% had a vaginal delivery. The rate of successful vaginal delivery was similar regardless the onset of labor. We did not find a higher composite perinatal morbidity in the planned vaginal delivery group (planned vaginal delivery: 3.6% vs. planned cesarean section: 8.3%, aOR 1.36, 95% CI 0.24–7.81). Considering the onset of labor, it was more frequent in the spontaneous subgroup (8.3% vs. 0%). The rate of neurodevelopmental impairment was higher in the planned cesarean section group, without reaching statistical significance [10.2% vs. 4.9%, aOR 1.53 (95% CI 0.37–6.29)].ConclusionsIn uncomplicated monochorionic diamniotic twins at ≥ 32 weeks of gestation, when the first twin is in vertex presentation, our results suggest that planned vaginal delivery is safe, with a successful outcome as well as high vaginal delivery rate.

The Delphi definition for selective fetal growth restriction may not improve detection of pathologic growth discordance in monochorionic twins

A consensus definition of selective fetal growth restriction in monochorionic diamniotic twins was recently proposed following a Delphi procedure involving an international panel of experts. The new definition augments the traditional definition with additional sonographic criteria. We sought to determine whether the augmentations of the "Delphi definition" identified additional morbidity and mortality compared with a traditional definition. Furthermore, we sought to determine the benefit of each definition in identifying pathologic growth restriction relative to uncomplicated monochorionic diamniotic twins. This was a retrospective analysis of unselected monochorionic diamniotic twins that underwent fortnightly ultrasound surveillance at a single center between 2011 and 2020. Patients with concomitant twin-to-twin transfusion syndrome, twin anemia polycythemia sequence, or twin reversed arterial perfusion sequence at the time of diagnosis of selective fetal growth restriction were excluded. The diagnosis of selective fetal growth restriction using the Delphi definition required either an estimated fetal weight of <3rd percentile or presence of 2 of 4 observations in the smaller twin: (1) estimated fetal weight of <10th percentile, (2) estimated fetal weight discordance of >25% compared with the larger twin, (3) abdominal circumference of <10th percentile, (4) umbilical artery pulsatility index of >95th percentile. Diagnosis using the traditional definition required an estimated fetal weight of <10th percentile and an estimated fetal weight discordance of >25%. To determine the efficacy of the augmentations in the Delphi definition, 3 groups were compared: group I, uncomplicated monochorionic diamniotic twins; group II, twins with selective fetal growth restriction using the traditional definition (and therefore the Delphi definition); and group III, twins with selective fetal growth restriction solely using the Delphi definition. Demographic characteristics, subsequent development of twin-to-twin transfusion syndrome or twin anemia polycythemia sequence, pregnancy outcomes, and neonatal outcomes were compared. There were 325 patients with monochorionic diamniotic twins that met inclusion criteria. Of these, 213 (66%; group I) were uncomplicated, 37 (11%; group II) met the traditional definition for selective fetal growth restriction, and 112 (35%) met the Delphi definition for selective fetal growth restriction with 75 (67%) meeting solely the Delphi definition (group III). Demographic characteristics were similar between groups. Patients in group II delivered earlier than uncomplicated twins (32.1 vs 35.7 weeks of gestation; P<.01) and patients in group III (32.1 vs 35.6 weeks of gestation; P<.01). Furthermore, they were more likely to have critical umbilical artery Doppler abnormalities (38% vs 4%; P<.01) and be delivered for deteriorating fetal status (30% vs 5%; P<.01) than those in group III. Overall, survival was lower in group II than groups I and III (89% vs 96% and 100%, respectively; P=.04). Moreover, composite neonatal morbidity and mortality were greater in group II (30%) than either group I (6%; P<.01) or group III (9%; P<.01). The rates of composite neonatal morbidity and mortality were similar between groups I and III (P=.28). The addition of abdominal circumference and umbilical artery pulsatility index thresholds and isolated estimated fetal weight of <3%, as proposed by the Delphi definition, increased the diagnosis of selective fetal growth restriction; however, there was no added benefit in the identification of growth discordant pregnancies at risk of adverse outcomes. Prospective analysis of monochorionic diamniotic twins is required to contextualize these findings.

Reference values for fetal Doppler-based cardiocirculatory indices in monochorionic-diamniotic twin pregnancy

BackgroundPlacental anastomoses in monochorionic diamniotic (MCDA) twin pregnancy have a major impact on fetal circulation. This study was designed to define reference ranges of cardiac and vascular Doppler indices in MCDA twin pregnancies.MethodsThis cross-sectional study included 442 uncomplicated MCDA twin fetuses undergoing Doppler ultrasonography at 18–35 weeks of gestation. Left and right myocardial performance index (LV-MPI, RV-MPI), E/A ratio of atrioventricular valves, pulsatility indices of umbilical artery, middle cerebral artery (MCA), and ductus venosus (DV), cerebroplacental ratio, peak systolic velocity of MCA, S/a ratio of DV, and early diastolic filling time of ductus venosus (DV-E) were evaluated under standardized settings. The equation models between Doppler indices and gestational age (GA) were fitted. After adjustment for GA, the correlations between MPI and fetal heart rate (FHR), and between MPI and DV indices were analyzed.ResultsEstimated centiles of Doppler indices were derived as a function of GA, being distinct in values from those of singletons. There was no correlation between GA-adjusted MPI and FHR. DV-E was inversely related to LV-MPI.ConclusionsMCDA twins showed significant changes in some Doppler indices throughout gestation with quantitative differences from singletons, emphasizing the importance of MC twin-specific reference values for clinical application. Further adjustment of MPI for FHR was unnecessary. DV-E is a vascular index indirectly representing fetal diastolic function.

Left myocardial performance index in monochorionic diamniotic twin pairs complicated by selective fetal growth restriction with abnormal umbilical artery Doppler

To evaluate left myocardial performance index (MPI) and its time intervals in monochorionic diamniotic (MCDA) twin pairs complicated by selective fetal growth restriction (sFGR) with abnormal (persistent -type II- or intermittent -type III- absent or reversed end-diastolic flow) umbilical artery Doppler. Retrospective study including 16 MCDA twin pairs with sFGR type II, 26 MCDA twin pairs with sFGR type III and 42 gestational age-matched uncomplicated MCDA twin pairs in a single tertiary center. Left isovolumetric contraction time (ICT), ejection time (ET), and isovolumetric relaxation time (IRT) were measured and MPI calculated by conventional Doppler at diagnosis of sFGR. In sFGR type II, the smaller twin had shorter ET and prolonged IRT and MPI, while the larger twin showed prolonged ICT and MPI as compared to uncomplicated MCDA twins. In sFGR type III, the smaller twin had shorter ICT and ET, while the larger twin showed prolonged ICT, IRT, and MPI in comparison to controls. A differential pattern of MPI time intervals could be observed in MCDA twins with sFGR type II and III. All twins had echocardiographic signs of pressure/volume overload, except the smaller twin type III with shorter systolic times probably reflecting reduced volume load.

Prescriptive standards of echocardiographic morphometric and functional parameters in uncomplicated monochorionic diamniotic fetuses.

To create prescriptive standards of cardiac morphometric and functional parameters in a cohort of uncomplicated monochorionic diamniotic (MCDA) twins. Fetal echocardiography was performed in a cohort of uncomplicated monochorionic twin fetuses scanned longitudinally, including comprehensive morphometric and functional parameters, using 2-D imaging, M-mode and conventional Doppler. A multilevel polynomial hierarchical model adjusted by gestational age and estimated fetal weight was used to fit each cardiac parameter. The global heart dimensions including the atrial and ventricular areas, the ventricles dimensions and myocardial wall thicknesses and most of the functional parameters, such as the longitudinal myocardial motion and the biventricular cardiac output showed a positive quadratic increment throughout pregnancy. On the other hand, the left ejection fraction, shortening fraction and right fractional area change decreased with gestational age. Scatterplots for the main structural and functional parameters and ratios by gestational age, with mean, 5th, 10th, 90th, and 95th percentiles are provided. Regression equations by estimated fetal weight are also created. We provide specific comprehensive echocardiographic prescriptive standards for uncomplicated MCDA twin fetuses following current standardized methodology. The implementation of these charts will potentially help to better identify abnormal cardiovascular parameters associated to monochorionic complications.

Cardiac time intervals and myocardial performance index for prediction of twin-twin transfusion syndrome.

ObjectivesTo explore whether intertwin discordance in myocardial performance index (MPI) or cardiac time intervals enables the prediction of twin–twin transfusion syndrome (TTTS) in monochorionic diamniotic (MCDA) pregnancies with amniotic fluid discordance.MethodsProspective cohort study of MCDA pregnancies with amniotic fluid discordance ≥4 cm. Serial ultrasound examinations consisted of evaluation of amniotic fluid, fetal Dopplers and fetal cardiac function.ResultsWe included 21 “future‐TTTS” (group I), 18 selective fetal growth restriction (sFGR; group II) and 20 uncomplicated MCDA twin pairs (group III). Group I had a higher intertwin difference in left ventricle (LV) MPI and right ventricle (RV) MPI compared to group II and III. The intertwin difference in global heart relaxation time was significantly higher in group I compared to group III. Future recipient twins had significantly higher contraction times of the global heart and RV and lower relaxation times of the global heart and RV compared to the “expected recipients” in group II and III.ConclusionIntertwin discordance in LV‐MPI and RV‐MPI differentiate between TTTS and MCDA pregnancies with transient discordant amniotic fluid volume. Cardiac time intervals identify future recipient twins. The clinical utility of cardiac time intervals and MPI should be investigated in large prospective studies.

Twin-twin transfusion syndrome is associated with alterations in the metabolic profile of maternal plasma in early gestation: a pilot study.

Twin-twin transfusion syndrome (TTTS) causes perinatal mortality and morbidity in monochorionic twins. The early recognition of and interventional therapy for TTTS is associated with a more favorable overall prognosis. However, the prediction by the use of ultrasound in the first trimester has relatively poor sensitivity and specificity. This study aimed to identify metabolic biomarkers to aid in ultrasound screening of TTTS. Maternal plasma was prospectively collected between 11 and 15weeks of gestation in apparently uncomplicated monochorionic-diamniotic twin pregnancies. This cohort was divided into: (i) patients who were subsequently diagnosed with TTTS by using ultrasound; (ii) uncomplicated matched controls. Metabolome was profiled by using gas chromatography-mass spectrometry. The levels of fatty acids, organic acids, oxaloacetic acid, and beta-alanine were significantly lower in the TTTS maternal plasma at 11-15weeks of gestation, and methionine and glycine were also higher (p<0.05, FDR<0.12). Generally, in TTTS pregnancies, the metabolisms of amino acid, carbohydrate, cofactors, vitamins, and purine were "down-regulated"; whereas bile secretion and pyrimidine metabolism were "upregulated." The metabolomics scanning of early gestation maternal plasma may identify those pregnancies that subsequently develop TTTS; in particular, downregulated fatty acid levels may be biologically plausible to be implicated in the pathogenesis of TTTS.

Uncomplicated Monochorionic Twins: Two Normal Hearts Sharing One Placenta.

Cardiovascular dysfunction has been reported in complicated monochorionic diamniotic (MCDA) pregnancies; however, little is known whether hemodynamic changes occur in uncomplicated MCDA twins. A prospective observational study was conducted including 100 uncomplicated MCDA twins matched by gestational age to 200 low-risk singletons. Echocardiography was performed at 26–30 weeks gestation and cord blood B-type natriuretic peptide (BNP) was measured at delivery. In both groups, z-scores for echocardiographic parameters were within normal ranges; however the monochorionic group had larger atrial areas (mean (standard deviation) right atria-to-heart ratio: 17.0 (2) vs. 15.9 (1); p = 0.018; left atria-to-heart ratio: 17.0 (3) vs. 15.8 (2); p < 0.001) and signs of concentric hypertrophy (right relative wall thickness: 0.66 (0.12) vs. 0.56 (0.11); p < 0.001; left relative wall thickness: 0.69 (0.14) vs. 0.58 (0.12); p < 0.001). Longitudinal function was increased in twins, leading to higher tricuspid annular plane systolic excursion (6.9 mm (0.9) vs. 5.9 mm (0.7); p < 0.001) and mitral annular plane systolic excursion (4.9 mm (0.8) vs. 4.4 mm (1.1); p < 0.001. BNP levels at birth were also higher in MCDA twins (median [interquartile range]: 20.81 pg/mL [16.69–34.01] vs. 13.14 pg/mL [9.17–19.84]; p < 0.001). Thus, uncomplicated MCDA fetuses have normal cardiac shape and function, but signs of cardiac adaptation were identified by echocardiographic and biochemical parameters, when compared with singletons.

Fetal ventricular strain in uncomplicated and selective growth-restricted monochorionic diamniotic twin pregnancies and cardiovascular response in pre-twin-twin transfusion syndrome.

ABSTRACTObjectivesOur primary aim was to confirm whether intertwin discordance in ventricular strain and ductus venosus (DV) time intervals predicts twin–twin transfusion syndrome (TTTS). Secondary aims were to create gestational‐age ranges for ventricular strain in uncomplicated monochorionic diamniotic (MCDA) twin pregnancies without selective intrauterine growth restriction (sIUGR) and to characterize the relationship of ventricular strain with gestational age in MCDA twin pregnancies with sIUGR that did not develop TTTS.MethodsIn the period 2015–2018, we enrolled 150 MCDA twin pregnancies consecutively into this prospective, blinded study of global longitudinal left and right ventricular strain. With the observer blinded to twin pairing and pregnancy outcome, videoclips of the four‐chamber view, which had been recorded during ultrasound surveillance in the usual window for development of TTTS (16–26 completed gestational weeks), underwent offline measurement of strain. Uncomplicated MCDA twin pregnancies, without sIUGR, were used to test the association between strain, gestational age and estimated fetal weight using mixed‐effects multilevel regression. Inter‐rater reliability was tested in 208 strain measurements in 31 fetuses from pregnancies which did not develop TTTS and within‐fetus variation was assessed in 16 such fetuses, in which multiple four‐chamber views were taken on the same day. The effect of sIUGR on strain in otherwise uncomplicated MCDA twin pregnancy was analyzed. MCDA twin pregnancies were defined as ‘pre‐TTTS’ when, having been referred for TTTS evaluation, they did not satisfy Quintero staging criteria, but subsequently developed TTTS requiring laser treatment. MCDA pregnancies which did not develop TTTS comprised the ‘non‐TTTS’ group. Cardiovascular parameters measured in these cases included tissue Doppler parameters and DV early filling time as a percentage of the cardiac cycle (DVeT%). Intertwin strain and DVeT% discordance was compared between non‐TTTS and pre‐TTTS cases, matched for gestational age.ResultsPaired strain data were available for intertwin comparison in 127/150 MCDA twin pregnancies, comprising 14 pre‐TTTS and 113 non‐TTTS pregnancies, after exclusions. Scans were collected at a median frame rate of 97 (range, 28–220) Hz. Laser therapy was performed at a median gestational age of 20.6 (range, 17.2–26.6) weeks. There were no group differences in right (RV) or left (LV) ventricular strain discordance between 68/113 non‐TTTS and 13/14 pre‐TTTS MCDA twin pregnancies < 20 completed gestational weeks (RV, P = 0.338; LV, P = 0.932). DVeT% discordance > 3.6% was found in eight of 13 pre‐TTTS pregnancies. In non‐TTTS pregnancies, the estimated variability in ventricular strain within each twin during the day was high (RV, 19.7; LV, 12.9). However, within each pair (intertwin variation), variability was low (RV, 5.5; LV, 2.9). Interclass correlation reflecting the proportion of total variability represented by the variability between twin pairs was low (RV, 0.22; LV, 0.18). Both RV (P < 0.001) and LV (P = 0.025) strain showed a negative association with gestational age. Among non‐TTTS MCDA twin pregnancies, LV strain was, on average, higher by 1.83 in sIUGR compared with normally grown fetuses (P = 0.023), with no statistically significant difference in RV strain (P = 0.271).ConclusionsAlthough ventricular strain has been reported previously as a possible predictor of developing TTTS, in this blinded, prospective study, we found no significant intergroup differences in ventricular strain in pre‐TTTS compared with age‐matched non‐TTTS MCDA twin pregnancies. We recommend using DVeT% discordance as a more practical screening tool in MCDA twin pregnancies. This study also provides new information on the changes with gestational age, and the biological and technical variation, of global longitudinal ventricular strain in uncomplicated MCDA twin pregnancies and those with isolated sIUGR. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

VP18.07: Mid‐trimester left ventricular modified myocardial performance index of selective intrauterine growth restriction in monochorionic pregnancies

To evaluate the left ventricular modified myocardial performance index (LV mod-MPI) of early-onset selective intrauterine growth restriction (sIUGR) in monochorionic diamniotic (MCDA) twins. This retrospective study consisted of MCDA twins diagnosed at Asan Medical Center between 2014 and 2019. Isovolumetric contraction time (ICT), isovolumetric relaxation time (IRT), and ejection time (ET) were measured between 16.0 and 24.6 weeks of gestational age. MPI was calculated as (ICT + IRT)/ET. Cases with Twin–twin transfusion syndrome and major anomalies were excluded. sIUGR was defined as an intertwin weight discordancy of >25% and weight of the smaller fetus of less than the 10th percentile. The LV mod-MPI and its components were compared using the Mann-Whitney U test. During the study period, 38 uncomplicated MCDA twins and 26 twins with sIUGR were included. Although the LV mod-MPI and IRT were slightly higher in the larger twins in those with sIUGR than in those among twins without complications (0.44 vs. 0.50, and 41 vs. 45, respectively), differences were within the normal ranges. The ICT and ET of the larger twins did not show significant differences between twins without complications and those with sIUGR. There were no significant differences in LV mod-MPI and its components in the smaller twins between the two groups. Mid-trimester LV mod-MPI and its components may not be significantly different between twins with uncomplicated MCDA and those with sIUGR.

Performance of Antenatal Diagnostic Criteria of Twin-Anemia-Polycythemia Sequence.

This study aims to elicit the validation performance of different diagnostic criteria and to evaluate the disease course and perinatal outcomes of pregnancies complicated by twin anemia polycythemia sequence (TAPS). Monochorionic diamniotic (MCDA) twin pregnancies who received serial middle cerebral artery (MCA) peak systolic velocity (PSV) measurements without non-TAPS-related demise or major anomalies were included. Course of disease, antenatal intervention, additional ultrasound features, and perinatal outcomes were compared between each criteria and onset. Forty-nine cases of TAPS and 203 non-TAPS controls were identified. The incidence of TAPS was 19.2%, 15.7%, 7.8%, and 6.3% for ΔPSV MoM > 0.373, ΔPSV MoM > 0.5, traditional, and Delphi consensus criteria, respectively (p < 0.001). The incidence of antenatal intervention was 55.1, 62.5, 75.0, and 87.5%, respectively. Furthermore, cases detected according to the Delphi consensus criteria had a higher rate of progression or intervention compared to cases detected with ΔPSV MoM > 0.373 (87.0 vs. 59.0%, p = 0.037). TAPS had a significantly higher birth weight discordance than uncomplicated MCDA twins (25.3 vs. 7.3%, p < 0.001). Application of four different diagnostic criteria for TAPS leads to significant differences in the incidence, severity, and antenatal intervention. The Delphi criteria identified more severe cases likely to require intervention, and the delta PSV > 0.373 criteria identified milder cases, without a significant impact on neonatal outcomes.

881: The optimal timing of induction of labor in uncomplicated twin pregnancy

Recent guidelines recommend the planned delivery in twin pregnancy as 38 weeks for uncomplicated dichorionic twin pregnancies and as 34-37+6 weeks for uncomplicated monochorionic diamniotic twin pregnancies. However, the optimal timing of induction of labor in twin pregnancies has not been well studied. In the current study, we compared the pregnancy and neonatal outcomes between women with induction at 37 weeks and those who were nonintervention at 37 weeks and allowed the pregnancy to progress after the time. The study population consisted of 1228 term twin pregnant women who were candidates for trial of labor. They were divided into 2 groups: group 1, women who were planned as induction of labor at 37-37+6 weeks (induction group, n=488 in dichorionic twin, 143 in monochorionic twin); group 2, women who were nonintervention at 37 weeks and allowed the pregnancy to progress after the time. (expectant management group, n=384 in dichorionic twin, 92 in monochorionic twin). The timing of induction after 38 weeks in group 2 was at the discretion of the attending physician. Women who delivered due to obstetric indication (ex. preeclampsia, oligohydramnios, fetal growth restriction) and cases with fetal death in utero or fetal anomaly were excluded. The primary outcome was cesarean section rate and perinatal outcomes (Apgar scores, neonatal intensive care unit (NICU) admission, umbilical cord blood gases, neonatal morbidity). No significant differences were observed in cesarean delivery rate between two groups regardless of chorionicity. In monochorionic twin pregnancies, neonates born to women in group 2 (expectant management group) had higher risk for admission to NICU and lower pH in cord blood than neonates in group 1. In dichorionic twin pregnancies, the perinatal outcomes were not different between the two groups. Induction of labor at 37 weeks resulted in reduced adverse perinatal outcomes compared to expectant management in monochorionic twin pregnancies. The optimal timing of induction of labor in dichorionic pregnancies beyond 38 weeks needs further studies.

OC22.04: Cardiac morphometry in uncomplicated monochorionic diamniotic twins: comparison to singletons

OC22.04: Cardiac morphometry in uncomplicated monochorionic diamniotic twins: comparison to singletons

EP09.01: Cardiac function in uncomplicated monochorionic diamniotic twins: comparison to singletons

EP09.01: Cardiac function in uncomplicated monochorionic diamniotic twins: comparison to singletons