Monochorionic Diamniotic Pregnancies Research Articles

Outcomes of twin neonates and association with chorionicity and modes of conception

Objective To investigate the pregnancy and neonatal outcomes in twin pregnancies and the association with chorionicity and modes of conception in order to provide evidence for early prevention and reduction of complications and life quality improvement of twin neonates. Methods This study retrospectively enrolled 756 women with twin pregnancies who gave birth at Peking University Third Hospital from January 1, 2014 to December 31, 2015. Clinical features of the mothers and newborns were collected, the pregnancy and neonatal outcomes were analyzed. Impacts of chorionicity and different modes of conception on the outcomes were also evaluated. Two independent-sample t test and Chi-square test were used as statistical methods. Results Twin pregnancies accounted for 6.7% (756/11 169) of all deliveries in the hospital during the study period and the preterm birth rate was 59.4% (449/756). Twenty five women underwent fetal reduction (3.3%, 25/756) and intrauterine death occurred in 85 pregnancies (11.2%, 85/756). Eventually 1 400 babies were born alive (92.6%, 1 400/1 512). Subgroup analysis suggested that compared with dichorionic diamniotic (DCDA) pregnancies, monochorionic diamniotic (MCDA) cases showed younger maternal age at conception [(30.5±4.2) vs (32.9±4.0) years, t=-7.412], smaller gestational age at delivery [(34.1±3.1) vs (35.7±2.2) weeks, t=-7.325] and higher preterm birth rate [78.4% (174/222) vs 51.5% (263/511), χ2=46.554], all P<0.05. Moreover, the incidence of neonatal complications, including respiratory distress syndrome [18.3% (40/219) vs 8.0% (21/261), χ2=11.210], neonatal pneumonia [18.3% (40/219) vs 8.8% (23/261), χ2=9.331] and sepsis [6.8% (15/219) vs 1.5% (4/261), χ2=8.854], etc. was higher in the MCDA group than those in the DCDA group, resulting in a higher mortality rate [7.8% (17/219) vs 1.1% (3/261), χ2=13.042] in the MCDA pregnancies, all P<0.05. Compared with spontaneously conceived twin pregnancies, women underwent in vitro fertilization-embryo transfer were older at conception [(33.4±3.8) vs (30.6±4.4) years, t=-6.095], delivered at a greater gestational age [(35.8±2.1) vs (35.2±2.6) weeks, t=-2.452] and had a lower preterm birth rate [49.2% (206/419) vs 63.5% (54/85), χ2=5.838] in the DCDA group, all P<0.05. No significant differences in the incidence of neonatal diseases were observed between the two subgroups. Conclusions The incidence of preterm birth is high in twin pregnancies. Compared with DCDA twin pregnancies, MCDA twin pregnancies are associated with more adverse outcomes due to higher incidence of neonatal diseases. In vitro fertilization-embryo transfer does not increase the incidence of preterm birth and the neonatal outcomes were comparable to those of spontaneously conceived ones. Key words: Pregnancy, twin; Pregnancy outcome; Premature birth; Infant, newborn, diseases; Incidence; Fertilization in vitro; Embryo transfer

Perinatal outcomes of monochorionic diamniotic triplet pregnancies: a case series

BackgroundTriplet pregnancies are associated with higher fetal morbidity and mortality rates as well as life-threatening maternal complications. Monochorionic diamniotic (MCDA) triplet pregnancies are very rare compared to other types of triplet pregnancies.Case presentationWe report three cases of MCDA triplet pregnancies between January 2012 and December 2017. Two of these MCDA triplet pregnancies received regular and intensive prenatal care, were diagnosed by ultrasonography during the first trimester or early second trimester, and had good perinatal outcomes. The case with irregular perinatal care had poor outcomes, and the MCDA triplet pregnancy was diagnosed intrapartum.ConclusionsThe possibility of continuing an MCDA triplet pregnancy should be recognized. Early diagnosis, regular antenatal care, close prenatal monitoring, and sufficient communication are recommended to obtain better perinatal outcomes in MCDA triplet pregnancies.

Fœtus in fœtu de siège rétropéritonéal

Fetus in Fetu (FIF) is an extremely rare congenital anomaly defined as a mass containing a vertebral axis often associated with other organs or limbs around this axis. We report the case of a female fetus aged 4 months presenting with retroperitoneal mass measuring 7x6x4cm, suggesting teratoma on computerized tomography (CT) scan. The mass was resected. Macroscopic examination showed fetiform mass covered by skin tissue and extending into upper and lower limb buds (A). Sectional views showed that it was centered by several osteocartilaginous fragments arranged in a linear fashion reminding the vertebral axis (B). Histological examination objectified the presence of glial tissue around a cerebral ventricle as well as skin, muscle and bone tissue. The diagnosis of FIF was retained. FIF is mainly reported at the level of the retroperitoneum followed by the sacro-caudal, intra-abdominal, cranial, buccal, mediastinal, pulmonary, renal and scrotal area. Diagnosis is made during the antenatal period in 15% of cases. The etiopathogenesis of FIF includes both the theory of monochorionic diamniotic monozygotic pregnancy in which an aberrant asymmetric twin becomes internalized in the other twin and the theory of a defective embryo implantation in the mesenchyme of its twin instead of the uterine wall. The differential diagnosis includes teratoma, meconium pseudocyst and ectopic pregnancy.

OC22.03: Apparent diffusion coefficient differences between normal and complicated monochorionic diamniotic pregnancy

OC22.03: Apparent diffusion coefficient differences between normal and complicated monochorionic diamniotic pregnancy

Spontaneous triplet pregnancy and trap sequence, case report

BackgroundSpontaneous multiple pregnancies are rare, and the incidence of spontaneous triplet pregnancy is about 1/4000. TRAP (Twin Reversed Arterial Perfusion) sequence has acardiac foetus with non-viable multiple anomalies, and there is a pump foetus which feeds this foetus with placental anastomoses. TRAP sequence phenomena is quite rare in triplet pregnancies.Case presentationThe patient who applied to our clinic was 30 years old. Monochorionic diamniotic triplet pregnancy was detected by ultrasonographic examination. First amniotic sac had one foetus (Foetus A). Ultrasonographic evaluation of Foetus A revealed gestational age of 31 weeks, adequate amniotic fluid and no fetal structural anomalies. The second amniotic sac contained 2 foetuses and polyhydromnios. Ultrasonic measurements of Foetus B were consistent with 32 weeks gestational age. Color flow doppler indicated Foetus B was the pump foetus. Foetus C was an acardiac foetus with no sonographic visualization of cranium, thoracic organs or extremities, but abdominal circumference consistent with 28 weeks. Pregnancy was followed conservatively and evaluated regularly by ultrasonography twice a week. When prolonged bradycardia was detected in fetus B at 35 4/7 weeks, emergency cesarean section was performed. Two healthy fetuses weighing 2 kg were delivered each with an 8/10 APGAR score (Appearance, Pulse, Eye Insertion, Activity, Respiration).ConclusionThis case was managed without any invasive procedures and demonstrates that treatment of TRAP sequence cases can be individualized considering clinical conditions, the size of the acardia twin and extent of placental venous anastomoses.

The impact of chorionicity and the type of twin growth on the early neonatal outcome in twin pregnancies – 20 years of experience from one tertiary perinatal center

ObjectiveTwin pregnancies are associated with higher neonatal mortality and morbidity. Growth discordance and monochorionicity are among the factors that worsen the course of pregnancy. The study aimed to assess neonatal conditions and mortality in relation to growth type and chorionicity. Materials and methodsData from 820 pregnant women with twin pregnancies and their 1640 newborns were analyzed. The Apgar score and umbilical artery blood pH, as well as the rate of complications, were compared between dichorionic diamniotic (DCDA) and monochorionic diamniotic (MCDA) twins with symmetric and discordant growth. The Student's t-test and the Pearson chi-square test were used for comparisons. ResultsThere were 576 (70.2%) DCDA pregnancies, including 421 (73.1%) with symmetric growth and 155 (26.9%) with discordant growth, and 244 (29.8%) MCDA pregnancies, including 110 (45.1%) with symmetric growth and 134 (54.9%) with discordant growth. A significantly greater percentage of twins with discordant growth occurred in women older than 34 years than in those that were younger. An Apgar score of ≤7 was significantly more common among MCDA discordant twins, while an arterial umbilical blood pH of <7.2 was more common among MCDA twins with symmetric growth. Early neonatal deaths (n = 29; 1.8%), respiratory disorders, and a birth weight of <1500 g were significantly more common in MCDA twins than in DCDA twins. ConclusionMCDA twins with growth discordance are burdened with a higher risk of neonatal morbidity and mortality than symmetric DCDA twins. Chorionicity and growth discordancy are important determinants of the outcome of twin pregnancy.

Visualizing Prenatal Twin Anatomy: A Parent Education Resource for Twin‐Twin Transfusion Syndrome

Twin‐twin transfusion syndrome (TTTS) is a complication occurring in 10–20% of monochorionic diamniotic multiple pregnancies characterized by unequal circulation due to placental anastomoses. Left untreated, chronic TTTS has an 80–100% mortality rate, with sequelae including cardiovascular, neurodevelopmental and renal anomalies in surviving infants. Prognosis is improved by timely diagnosis and intervention, with selective fetoscopic laser photocoagulation emerging as the front‐line treatment. Considering poor prognosis and the urgent need for invasive treatment, TTTS announcement is a traumatic event for expectant parents regardless of survival outcome, thus adequate support from their providers is essential. Parent perception of their care relies on receiving ample information, and while antenatal multidisciplinary consultations at fetal centers provide space for parent education, parents often have difficulty understanding the fetal and placental anatomy. Currently, at the Colorado Fetal Care Center, supplemental educational resources include 2D images and literature intended for a scientific audience. The objective of this project was to develop and implement an interactive 3D virtual model of TTTS during antenatal consultations to facilitate parent education. The model was developed from deidentified fetal MRI Digital Imaging and Communications in Medicine (DICOM) data demonstrating TTTS (COMIRB # 18‐1955). A total of 10 MRI datasets (6 with selective intrauterine growth restriction (SIUGR), 4 without SIUGR) were identified as possible candidates. One dataset was selected for model construction based on representation of the pathology. The DICOM data was segmented on 3D Slicer. The segmentations were imported into Blender for 3D rendering and to smooth artifacts, then published onto Sketchfab for user interaction. The tool was assessed by obstetric and surgical specialists for accuracy. By providing an anatomically accurate fetal, placental, and pathologic anastomosis visualization, this model can assist providers in demonstrating the diagnosis, explaining prognosis, and discussing potential treatment options. The new 3D, interactive virtual TTTS model has the potential to improve parents' experience by increasing patient knowledge and engaging them in the intervention planning required to optimize fetal outcomes. Further investigation is required to determine the efficacy and educational value of the model.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Postnatal condition of the second twin in respect to mode of delivery, chorionicity and type of fetal growth.

The increased use of assisted reproductive techniques (ART) contributes to the increased rate of twin pregnancies, which are burdened with a higher risk of complications. Factors that affect the condition of the second twin are understudied. The objective of this study was to assess the impact of the delivery mode, chorionicity, amnionicity, and the type of fetal growth on the postnatal condition of the second twin. The study included data from 475 pregnant women with twin pregnancies. Maternal age, parity, chorionicity, amnionicity, type of fetal growth, mode of delivery, gestational weeks at delivery, Apgar score, and umbilical arterial blood pH were retrospectively analyzed. Data normality was checked with the Kolmogorov-Smirnov test. The paired Wilcoxon signed-rank test and χ2 test were used for comparisons between groups. To check predictive value of the analyzed variables multiple linear regression was used. The mean maternal age was 29.22 (standard deviation (SD) ±5.19) years. The maternal age and gestational age at delivery did not differ significantly between women who delivered by cesarean section (CS) and vaginal delivery (VD). In the second twin, the Apgar score and values of arterial umbilical blood pH were lower in infants delivered by VD than in those delivered by CS (6.30 ±2.83 and 7.30 ±0.12; p = 0.0209 and 7.26 ±0.12 and 7.30 ±0.11; p = 0.0236, respectively). In monochorionic diamniotic twins with asymmetric growth, the second twin achieved significantly lower outcome than the first twin. Vaginal delivery was a predictive factor for a lower Apgar score and lower values of umbilical arterial blood pH in second twins, while not in first twins. Symmetrical fetal growth of twins was a predictive factor for better postnatal condition for both twins. In twin pregnancies, VD, but not CS, is associated with increased risk of worse postnatal condition of the second twin. In monochorionic diamniotic pregnancies complicated by growth discordance, CS seems to be a reasonable mode of delivery.

Twin anemia-polycythemia sequence and routine monitoring practices amongst maternal-fetal medicine specialists in the United States: an initial investigation.

Background The purpose of this initial investigation was to begin to understand the routine twin anemia-polycythemia sequence (TAPS) monitoring practices of maternal-fetal medicine specialists (MFM specialists) in the United States in the absence of a formal guideline. Methods This study used an anonymous, online survey of 90 MFM specialists who were practicing in the United States. A $5 gift card to an online store was used to incentivize participants. Descriptive statistics were calculated. Results All MFM specialists reported at least some familiarity (100.00%) with TAPS. Most participants (92.94%) were familiar with methods for monitoring patients for TAPS and nearly all (97.50%) responded that they use 'Doppler MCA-PSV' to make a prenatal TAPS diagnosis. Nearly two-thirds of MFM specialists surveyed (65.06%) reported performing regular TAPS monitoring for patients with monochorionic-diamniotic (MCDA) pregnancies. Conclusion Despite no formal guidelines, the majority of American MFM specialists surveyed are using routine TAPS screening in their management of MCDA twin pregnancies, suggesting that the MFM specialists included in this study consider it a valuable diagnostic tool. Future research should further explore this possible trend toward routine TAPS monitoring amongst MFM specialists in the United States, as well as the potential value of routine TAPS monitoring in MCDA pregnancy.

Cirugía fetal en Brasilia

Brasilia es la capital de Brasil. Existen en la actualidad dos hospitales públicos en la ciudad que tienen la posibilidad de realizar cirugía fetal: el Hospital Materno-Infantil de Brasília (HMIB) y el Hospital Universitário de Brasília (HUB). En el presente artículo presentamos la información del HUB. En los últimos cinco años, diez pacientes fueron sometidos a procedimientos invasivos durante la gestación. Hubo una transfusión intrauterina (cordocentesis) y ninguna ablación láser por embarazo diamniótico monocoriónico u oclusión endotraqueal del feto por hernia diafragmática. La escasez de casos se debe principalmente a la falla en los diagnósticos y la demora en la referencia a los centros terciarios.

The incidence of unexpected critical complications in monochorionic diamniotic twin pregnancies according to the interval period between ultrasonographic evaluations.

This study aimed to evaluate the incidence of unexpected critical complications (UCC) in monochorionic diamniotic (MCDA) twin pregnancies according to ultrasonographic scan interval. This retrospective single-center cohort study, conducted between January 2005 and April 2015, investigated the incidence of UCC in patients with MCDA twin pregnancies undergoing weekly ultrasound (Group A) and those undergoing biweekly ultrasound (Group B). We also examined the incidence of predictable critical complications according to ultrasound interval. Of all 385 cases, the total incidence of UCC was 20 (5.2%), including 14 cases of twin-twin transfusion syndrome and 6 cases of intrauterine fetal death. The incidence of UCC was 3.9% in Group A and 9.0% in Group B (P = 0.046). In contrast, the incidence of predictable critical complications was 6.7% in Group A and 9.0% in Group B (P = 0.440). The incidence of UCC in patients with MCDA twin pregnancies was significantly lower in patients undergoing weekly ultrasound. Our results suggest that weekly ultrasound evaluation for patients with MCDA pregnancy is more effective for early detection of UCC such as intrauterine fetal death and twin-twin transfusion syndrome ; however, further investigations are needed to determine whether weekly ultrasound evaluation can improve clinical outcomes.

Secuencia perfusión arterial reversa. Reporte de caso

La secuencia de perfusión arterial reversa en gemelos es una complicación del embarazo gemelar monocoriónico, en la que un gemelo muestra anomalías mortales, incluyendo acardia, y es perfundido por el otro gemelo ‘bomba’ a través de anastomosis arteriales placentarias, produciendo el crecimiento y las anomalías características del gemelo acárdico, con posible insuficiencia cardíaca en el gemelo bomba. Los mecanismos fisiopatológicos exactos que conducen a este fenómeno devastador no son bien conocidos. Ocurre en aproximadamente 1% de los embarazos monocoriónicos y en 1 de cada 35 000 embarazos. La mortalidad se debe generalmente a anemia y complicaciones cardíacas que pueden conducir a insuficiencia cardíaca, que aparecen temprano durante el embarazo y causan la muerte del gemelo bomba. Se presenta un caso de perfusión arterial reversa en gemelos en paciente de 28 años de edad con un embarazo monocoriónicodiamniótico de 12 semanas quien fue referida por ausencia de actividad cardíaca de uno de los gemelos. La ecografía mostró un gemelo acárdico con reversión de flujo visto en arteria-vena umbilical y un segundo gemelo normal. A las 28 semanas se realizó una cesárea de emergencia debido a parto pretérmino y situación transversa del segundo gemelo, obteniendo el primer gemelo marcadamente malformado y un segundo gemelo vivo que murió dos días después de las complicaciones de la prematuridad. El diagnóstico prenatal exacto secuencia de perfusión arterial reversa en gemelos es esencial para mejorar el pronóstico de esta rara entidad.

Significance of placental cord insertion site in twin pregnancy.

To investigate the association between abnormal cord insertion and the development of twin-specific complications, including birth-weight discordance, selective fetal growth restriction (sFGR) and twin-to-twin transfusion syndrome (TTTS). This was a single center retrospective cohort study of twin pregnancies. Abnormal cord insertion was defined as either marginal (umbilical cord attachment site less than 2 cm to the nearest margin of the placental disc) or velamentous (cord attached to the membrane before reaching the placental disc with clear evidence of vessels traversing the membranes to connect with the placental disc), as described in placental pathology reports. Twins with major structural or chromosomal abnormalities and monochorionic monoamniotic twins were not included in the study. Information on the pregnancies, ultrasound findings, prenatal investigations and interventions was obtained from the electronic ultrasound database, while data on placental histopathological findings, pregnancy outcome, mode of delivery, birth weight, gestational age at delivery and admission to the neonatal intensive care unit were obtained from maternity records. Categorical variables were compared using the chi-square or Fisher's exact test, while continuous variables were compared using the Student's t-test, ANOVA for multiple comparisons and the Kruskal-Wallis test. Of the 497 twin pregnancies included in the analysis, 351 (70.6%) were dichorionic and 146 (29.4%) were monochorionic. The incidence of birth-weight discordance of 25% or more was significantly higher in pregnancies with velamentous and those with marginal cord insertions compared to those with normal cord insertion (24.0%, 15.3% vs 7.6%, P< 0.001 and P= 0.020, respectively). In pregnancies with birth-weight discordance of 25% or more, the smaller twins had significantly higher prevalence of velamentous (13.8%) and marginal (34.2%) cord insertions compared with the larger twins (1.8% and 18.5%, respectively, P< 0.001). The smaller twins of the monochorionic diamniotic pregnancies showed an even higher prevalence of velamentous (29.5%) and marginal (40.9%) cord insertions compared with the larger twins (2.3% and 31.5%, respectively, P< 0.001). Compared with the normal cord insertion group, only velamentous insertion was associated significantly with the risk of sFGR (odds ratio (OR), 9.24 (95% CI, 2.05-58.84), P< 0.001) and birth-weight discordance of 20% or more (OR, 4.34 (95% CI, 1.36-14.61), P= 0.007) and 25% or more (OR, 6.81 (95% CI, 1.67-34.12), P= 0.003) in monochorionic twin pregnancies. There was no significant association between velamentous cord insertion and TTTS (P= 0.591), or between marginal cord insertion and the development of sFGR (P= 0.233), birth-weight discordance of 25% or more (P= 0.114) or TTTS (P= 0.487). Subgroup analysis of dichorionic twins showed that abnormal cord insertion was not associated with the risk of birth-weight discordance (P= 0.999), sFGR (P= 0.308), composite neonatal adverse outcome (P= 0.637) or intrauterine death (P= 0.349). Monochorionic twins with velamentous cord insertion are at increased risk of birth-weight discordance and sFGR. Sonographic delineation of placental cord insertion could be of value in the antenatal stratification of twin pregnancies. Prospective studies are required to assess the value and predictive accuracy of this potential screening marker. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Longitudinal reference ranges for serial measurements of myocardial performance index (MPI) by conventional and pulsed-wave tissue Doppler in monochorionic diamniotic twins at 17 to 26weeks of gestation.

To describe the longitudinal changes of fetal myocardial performance index (MPI) measured by conventional Doppler (MPI) and by pulsed-wave tissue Doppler (MPI') based on a prospective cohort of uncomplicated monochorionic diamniotic twin. Single-center observational study. We measured MPI and MPI' in the right and left ventricles 3 times between 17 and 26weeks of gestation. Second-degree fractional polynomials were built to obtain the best fitting curves in relation to gestational age (weeks) for each parameter. Gestational age-specific reference values were estimated by using two-level hierarchical models. Eighty-three uncomplicated monochorionic pregnancies were included in our study with a total of 249 observations. Fetal cardiac function was measured as MPI RV and LV, MPI' RV and LV at a mean gestational age of 18+3 (range 17+1 to 19+2 ), 22+3 (21+1 to 23+5 ), and 24+3 (22+6 to 26+2 ) weeks. The reference ranges for MPI LV, MPI RV, MPI' LV, and MPI' RV at 17 to 26weeks were constructed and conditional percentiles calculated. The present study provides additional data on fetal cardiac function in uncomplicated monochorionic diamniotic twin gestations, describing the evolution of MPI and MPI' in both ventricles in uncomplicated monochorionic diamniotic pregnancies.

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To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester screening for spontaneous preterm birth in asymptomatic monochorionic diamniotic versus dichorionic diamniotic twin pregnanciesThis was a multicenter retrospective cohort study. Study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7–23 6/7 weeks gestation. We excluded women that received progesterone, pessary, or cerclage. Distribution of CL was determined and normality was examined. Mean of TVU CL were compared between monochorionic diamniotic and dichorionic diamniotic pregnancies. The relationship of TVU CL with gestational age (GA) at delivery and incidence of spontaneous preterm birth (SPTB) at different TVU CL cut offs were assessed. Incidence of short TVU CL, defined as TVU CL ≤30 mm, was also calculated in the two groups.580 women with diamniotic twin pregnancies underwent TVU CL screening between 18 0/6 and 23 6/7 weeks. 175 (30.2%) were monochorionic diamniotic pregnancies, and 405 (69.8%) were dichorionic pregnancies. The demographic characteristics were similar on both groups. The mean GA at TVU CL was about 20 week in both groups. The mean TVU CL was significantly lower in the monochorionic diamniotic (32.8 ± 10.1) compared to the dichorionic (34.9 ± 8.6) group (MD −2.10 mm, 95% CI −3.91 to −0.29). TVU CL ≤30 mm was 16.6% (29/175) in the monochorionic group, and 11.9% (48/405) in the dichorionic group (aOR 1.48, 95% CI 1.03–2.43). Twins with a monochorionic diamniotic pregnancy had a significantly higher incidence of SPTB (53.1% vs 44.9%; aOR 1.22, 95% CI 1.22–1.79). For any given CL measured between 18 0–7 and 23 6/7 weeks, gestational age at delivery for monochorionic diamniotic pregnancies was about 2 weeks earlier compared to dichorionic pregnancies (MD -2.1 weeks; ANCOVA P < 0.001).Monochorionic diamniotic twin pregnancies had a higher rate of spontaneous preterm birth than dichorionic diamniotic pregnancies. The higher rate of spontaneous preterm delivery in monochorionic pregnancies is associated with lower midtrimester TVU CL when compared to dichorionic pregnancies.

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To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester screening for spontaneous preterm birth in asymptomatic monochorionic diamniotic versus dichorionic diamniotic twin pregnanciesThis was a multicenter retrospective cohort study. Study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7–23 6/7 weeks gestation. We excluded women that received progesterone, pessary, or cerclage. Distribution of CL was determined and normality was examined. Mean of TVU CL were compared between monochorionic diamniotic and dichorionic diamniotic pregnancies. The relationship of TVU CL with gestational age (GA) at delivery and incidence of spontaneous preterm birth (SPTB) at different TVU CL cut offs were assessed. Incidence of short TVU CL, defined as TVU CL ≤30 mm, was also calculated in the two groups.580 women with diamniotic twin pregnancies underwent TVU CL screening between 18 0/6 and 23 6/7 weeks. 175 (30.2%) were monochorionic diamniotic pregnancies, and 405 (69.8%) were dichorionic pregnancies. The demographic characteristics were similar on both groups. The mean GA at TVU CL was about 20 week in both groups. The mean TVU CL was significantly lower in the monochorionic diamniotic (32.8 ± 10.1) compared to the dichorionic (34.9 ± 8.6) group (MD −2.10 mm, 95% CI −3.91 to −0.29). TVU CL ≤30 mm was 16.6% (29/175) in the monochorionic group, and 11.9% (48/405) in the dichorionic group (aOR 1.48, 95% CI 1.03–2.43). Twins with a monochorionic diamniotic pregnancy had a significantly higher incidence of SPTB (53.1% vs 44.9%; aOR 1.22, 95% CI 1.22–1.79). For any given CL measured between 18 0–7 and 23 6/7 weeks, gestational age at delivery for monochorionic diamniotic pregnancies was about 2 weeks earlier compared to dichorionic pregnancies (MD -2.1 weeks; ANCOVA P < 0.001).Monochorionic diamniotic twin pregnancies had a higher rate of spontaneous preterm birth than dichorionic diamniotic pregnancies. The higher rate of spontaneous preterm delivery in monochorionic pregnancies is associated with lower midtrimester TVU CL when compared to dichorionic pregnancies.

Cardiac pathophysiology in twin-twin transfusion syndrome: new insights into its evolution.

In twin-twin transfusion syndrome (TTTS), unbalanced transfer of vasoactive mediators and fluid from the donor to the recipient cotwin alters their cardiovascular function. The aims of this study were to describe the impact of TTTS on fetal cardiac function in a large cohort of monochorionic-diamniotic (MCDA) pregnancies, and determine the early hemodynamic response to selective fetoscopic laser photocoagulation (SFLP). Echocardiography was performed in 145 MCDA pregnancies, including 26 uncomplicated MCDA, 61 TTTS Stages I+II and 58 TTTS Stages III+IV pregnancies, prior to SFLP for TTTS. Echocardiographic data after SFLP were available in a subset of 41/119 (34%) TTTS cases at a mean of 1.7 ± 1.9 days. Mitral (MAPSE) and tricuspid (TAPSE) annular systolic excursion, myocardial performance index (MPI), tissue Doppler velocities (E', A', S') and filling pressures (E/E') were measured and transformed into Z-scores. Ventricular pressure was estimated from peak atrioventricular regurgitation velocity. Left ventricular hemodynamics of the recipient twin were affected in early TTTS. In all stages of TTTS, left MPI and E/E' of the recipient twin were elevated in comparison to those of the donor (all P < 0.05), with reduced recipient left S' in TTTS Stages III+IV (P < 0.001). Ventricular pressure was elevated for gestational age (median, 42 mmHg (range, 20-65 mmHg)) in 11 of 14 recipients in which this parameter was measured. Between-group difference in right ventricular E/E' was significant only in TTTS Stages III+IV recipients compared with TTTS Stages I+II (P = 0.007) and uncomplicated MCDA (P = 0.041). Recipient left and right MPI decreased while S', MAPSE and TAPSE increased after SFLP; in donors, left E/E' and cardiac output increased. Cardiac function of the recipient twin in TTTS is abnormal, even in the early stages of the disease. Left ventricular filling pressures are elevated and systolic function is decreased before abnormalities in the right heart become apparent. SFLP produces rapid hemodynamic improvement. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

428: Midtrimester transvaginal ultrasound cervical length in diamniotic twin pregnancies according to chorionicity

To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester screening for spontaneous preterm birth in asymptomatic monochorionic diamniotic versus dichorionic diamniotic twin pregnancies This was a multicenter retrospective cohort study of a prospectively collected database. Study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7 - 23 6/7 weeks gestation. Distribution of CL was determined and normality was examined. Mean of TVUCL were compared between monochorionic diamniotic and dichorionic diamniotic pregnancies. The relationship of TVUCL with gestational age (GA) at delivery and incidence of spontaneous preterm birth (SPTB) at different TVUCL cut offs were assessed. Incidence of short TVUCL, defined as TVUCL ≤30mm, was also calculated in the two groups. We excluded women that received progesterone, pessary, or cerclage. 580 women with diamniotic twin pregnancies underwent TVUCL screening between 18 0/6 and 23 6/7 weeks. 175 (30.2%) were monochorionic diamniotic pregnancies, and 405 (69.8%) were dichorionic pregnancies. The demographic characteristics were similar on both groups. The mean GA at TVUCL was about 20 week in both groups. The mean TVUCL was significantly lower in the monochorionic diamniotic (32.8±10.1) compared to the dichorionic (34.9±8.6) group (MD -2.10 mm, 95% CI -3.91 to -0.29). TVUCL ≤30mm was 16.6% (29/175) in the monochorionic group, and 11.9% (48/405) in the dichorionic group (aOR 1.48, 95% CI 1.03 to 2.43). Twins with a monochorionic diamniotic pregnancy had a significantly higher incidence of SPTB <34 weeks (29.7% vs 20.0%; aOR 1.69, 95% CI 1.13 to 2.54). For any given CL measured between 18 0-7 and 23 6/7 weeks, gestational age at delivery for monochorionic diamniotic pregnancies was about 2 weeks earlier compared to dichorionic pregnancies (MD -2.1 weeks; ANCOVA P<0.001). Monochorionic diamniotic twin pregnancies had a higher rate of spontaneous preterm birth than dichorionic diamniotic pregnancies. The higher rate of spontaneous preterm delivery in monochorionic pregnancies is associated with lower midtrimester TVUCL, as well as by the lower gestational age at birth per any given CL in monochorionic diamniotic compared to dichorionic pregnancies.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

234: Incidence of adverse pregnancy outcomes based on mode of conception in monochorionic diamniotic twins

To compare the incidence of monochorionic diamniotic (MCDA) twin-specific complications in spontaneous versus assisted reproductive technology (ART)-conceived MCDA twin pregnancies. This was a retrospective cohort study of all MCDA pregnancies followed at a maternal fetal medicine center between January 1, 2012 and July 15, 2017. Exclusion criteria were structural anomalies, chromosomal abnormalities, or intrauterine fetal demise prior to 16 weeks. MCDA twin pregnancies were divided into two groups: spontaneous or conceived by ART. The primary outcome was development of twin-to-twin transfusion syndrome (TTTS), twin anemia polycythemia sequence (TAPS), or selective intrauterine growth restriction (sIUGR). The student t-test and the chi(2) test were used to compare categorical variables and means. Inter-correlations between variables (namely MCDA complications) were investigated by Spearman rank correlation. Ninety-one MCDA twin pregnancies met inclusion criteria. Of these pregnancies, 64 (70.3%) were conceived spontaneously and 27 (29.6%) were conceived by ART. Maternal age was significantly higher in the ART group (p < 0.001) and body mass index was significantly lower (p < 0.01). Women who had conceived by ART were more likely to identify as white (47% versus 21%, p<0.05) and carry a medical comorbidity unrelated to a MCDA pregnancy, namely thyroid and autoimmune disease (p<0.05). Overall, 9.9% of all MCDA twins developed TTTS: 12.5% versus 3.7%, from the spontaneous versus ART group respectively (r = -0.13, p = 0.72). Seven pregnancies (7.7%) were complicated by TAPS: 9.3% spontaneous conceptions versus 3.7% ART conceptions (r=-0.09, p=0.19). Thirty (33%) pregnancies developed sIUGR: 34% versus 29.6% (r=-0.03, p=0.10). MCDA pregnancies conceived by ART were more likely to undergo a caesarean section (p<0.05) with no difference in gestational age of delivery (mean 34 weeks, p=0.34). Conception via fertility treatment does not appear to increase the incidence of MCDA-specific pregnancy complications.

Twin-Twin Transfusion Syndrome and Maternal Symptomatology-An Exploratory Analysis of Patient Experiences When Reporting Complaints.

Objective:The aim of this study was to assess patient experiences when reporting symptoms of twin–twin transfusion syndrome (TTTS) to their health-care providers.Methodology:The study utilized an online, retrospective survey of women, over the age of 18, who were living in the United States at the time of their pregnancy and had completed a TTTS pregnancy.Results:Three hundred sixty-seven cases were included for analysis. Nearly half of the respondents (45.2%) reported experiencing maternal symptoms prior to TTTS diagnosis. The average number of symptoms experienced was 2.85. The average gestational week of symptom onset was 18.2. A total of 76.2% of respondents experiencing symptoms shared these concerns with their health-care provider; however, slightly more than half (51.2%) believed that the provider dismissed their complaints.Conclusions:Results suggest a disconnect between patients’ reporting TTTS symptoms and health-care providers responding attentively, as perceived by the patient. It would be advantageous for health-care providers to inform women pregnant with a monochorionic–diamniotic pregnancy to immediately report the presence of any symptom described in the present research, which may be associated with any number of twin pregnancy–related complications.