The heart after surviving twin-to-twin transfusion syndrome.

BACKGROUND: 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. OBJECTIVE: 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. STUDY DESIGN: 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. RESULTS: 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). CONCLUSION: 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.

Impact of Preoperative Cervical Length on Pregnancy Outcome in Twin-Twin Transfusion Syndrome.

OBJECTIVE: To evaluate the impact of preoperative cervical length on pregnancy outcome in monochorionic diamniotic twin pregnancies complicated by twin-twin transfusion syndrome that underwent laser surgery or cord occlusion. MATERIALS AND METHODS: Retrospective study of 330 patients stratified by preoperative cervical length (≥25 mm, 16-24 mm,≤15 mm). Maternal characteristics, operative data, and pregnancy outcomes were compared between the cervical length groups as well as between the subgroups of patients with a cervical length≤15 mm according to management (expectant vs. cerclage). RESULTS: A preoperative cervical length≥25 mm was observed in 82% (n=271) of cases, 16-24 mm in 9% (n=29), and≤15 mm in 9% (n=30). Patients with a preoperative cervical length≤15 mm showed shorter median procedure-to-delivery interval (5.5 weeks vs. 11.6 (16-24 mm) vs. 13.0 (≥25 mm); p<0.001); lower median gestational age at delivery (29.5 weeks vs. 34.3 (16-24 mm) vs. 33.4 (≥25 mm); p<0.001); higher rate of preterm delivery<32 weeks (78 vs. 20% (16-24 mm) vs. 31% (≥25 mm); p<0.001); and lower neonatal survival rate of at least one twin (70 vs. 88% (16-24 mm) vs. 93% (≥25 mm); p<0.001). Outcome of patients with a preoperative cervical length≤15 mm was similar regardless of management. CONCLUSION: Monochorionic diamniotic twin pregnancies complicated by twin-twin transfusion syndrome with a preoperative cervical length≤15 mm showed a higher rate of preterm delivery<32 weeks and lower neonatal survival. The role of a cervical cerclage remains unclear.

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

OBJECTIVE: To create prescriptive standards of cardiac morphometric and functional parameters in a cohort of uncomplicated monochorionic diamniotic (MCDA) twins. METHOD: 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. RESULTS: 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. CONCLUSION: 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.

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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Perinatal outcome after selective termination in dichorionic twins discordant for congenital anomalies.

INTRODUCTION: Our objective was to evaluate the perinatal outcome of selective termination of dichorionic twin pregnancies with discordant anomalies, according to gestational age at time of procedure. MATERIAL AND METHODS: Retrospective review of 147 dichorionic twin pregnancies referred to our Fetal Medicine Unit between 2003 and 2018 for selective termination. Gestational age at delivery, fetal loss, and overall and 28-day post-delivery survival rates, were evaluated according to gestational age at time of procedure. Selective termination procedure was defined as early, intermediate, and late when performed before 18 weeks, between 18 and 23 weeks, and after 23 weeks, respectively. Kruskal-Wallis and chi-squared test were used to compare groups. RESULTS: Overall survival at 28 days post-delivery, pregnancy loss, and preterm delivery before 32 weeks of gestation rates were 93.4%, 6.9%, and 15.5%, respectively. When stratified by gestational age at procedure, intermediate selective termination was associated with a lower survival rate than early and late procedures (86% vs. 96.9% and 100%, respectively; p = 0.035), and a nonsignificant trend for higher pregnancy loss (12% vs. 3.1%). Preterm delivery before 32 weeks of gestation occurred in 27% of late procedures, which was significantly higher than in early (9.5%) and intermediate (18.2%) procedures. CONCLUSIONS: Selective termination in dichorionic twin pregnancies with discordant fetal anomaly is associated with low pregnancy loss and preterm delivery rate, primarily when performed before 18 weeks. When legally possible, late procedures can be a good alternative, particularly in those cases diagnosed beyond the 18th week of gestation.

Chromosome microarray analysis should be offered to all invasive prenatal diagnostic testing following a normal rapid aneuploidy test result.

Chromosomal microarray analysis (CMA) has now replaced karyotyping in the analysis of prenatal cases with a fetal structural anomaly, whereas in those pregnancies undergoing invasive prenatal diagnosis with a normal fetal ultrasound, conventional karyotyping is still performed. The aims of this study were to establish the diagnostic yield of CMA in prenatal diagnosis, and to provide new data that might contribute to reconsider current practices. We reviewed 2905 prenatal samples with a normal rapid aneuploidy detection test referred for evaluation by CMA testing. Our study revealed pathogenic and reported susceptibility copy number variants associated with syndromic disorders in 4.8% (n = 138/2905) of cases, being 2.8% (n = 81/2905) the estimated added diagnostic value of CMA over karyotyping. Clinically significant CMA abnormality was detected in 5.4% (107/1975) of the fetuses with ultrasound anomalies and in 1.4% (5/345) of those considered as low-risk pregnancies. Our series shows that in prenatal samples, CMA increases 2-fold the diagnostic yield achieved by conventional karyotyping.

Characterizing cardiac dysfunction in fetuses with left congenital diaphragmatic hernia.

OBJECTIVE: To evaluate cardiac function by conventional echocardiography and tissue Doppler imaging in fetuses with left congenital diaphragmatic hernia (CDH). METHODS: Conventional echocardiography (myocardial performance index, ventricular filling velocities, and E/A ratios) and tissue Doppler imaging (annular myocardial peak velocities, E/E' and E'/A' ratios) in mitral, septal, and tricuspid annulus were evaluated in a cohort of 31 left-sided CDH fetuses and compared with 75 controls matched for gestational age 2:1. RESULTS: In comparison to controls, CDH fetuses had prolonged isovolumetric time periods (isovolumetric contraction time 35 ms vs 28 ms, P < .001), with higher myocardial performance index (0.49 vs 0.42, P < .001) and tricuspid E/A ratios (0.77 vs 0.72, P = .033). Longitudinal function assessed by tissue Doppler showed signs of impaired relaxation (mitral lateral A' 8.0 vs 10.1 cm/s, P < .001 and an increased mitral lateral E'/A' ratio 0.93 vs 0.78, P < .001) in the CDH fetuses as compared with controls, with preserved systolic function. CONCLUSION: Left CDH fetuses show echocardiographic signs of diastolic dysfunction, probably secondary to fetal heart compression, maintaining a preserved systolic function.

Gender-Specific Antenatal Growth Reference Charts in Monochorionic Twins.

OBJECTIVE: To create antenatal gender-specific reference growth charts in uncomplicated monochorionic diamniotic twins. MATERIALS AND METHODS: This is a prospective longitudinal study in which uncomplicated monochorionic (MC) twin pregnancies were included from 23 + 4 weeks of gestation onwards. Estimated fetal weight (EFW) and biometric parameters (biparietal diameter, head circumference, abdominal circumference, and femur length) were evaluated in both fetuses every 2 weeks using standardized methodology. Maternal and fetal complications were excluded. Charts were fitted for each biometric parameter and EFW in relation to gestational age and fetal gender using multilevel mixed models. RESULTS: The final analysis included a total of 456 ultrasound examinations in 62 MC twins, with a mean of 7 scans per pregnancy (range 5-8). The mean as well as 5th and 95th percentiles of each biometric parameter and EFW were adjusted in relation to gender and gestational age between 24 and 37 weeks of gestation. Male fetuses have higher reference values than females, and the disparity is larger in the upper centiles of the distribution. DISCUSSION: We provide gender-specific reference growth charts for MC twins. We suggest that these charts will improve prenatal MC twin assessment and surveillance, with a more accurate classification of normal or growth-restricted fetuses adjusted per sex.

Differential Changes in Myocardial Performance Index and Its Time Intervals in Donors and Recipients of Twin-to-Twin Transfusion Syndrome before and after Laser Therapy.

OBJECTIVE: To evaluate left myocardial performance index (MPI) and time intervals in fetuses with twin-to-twin transfusion syndrome (TTTS) before and after laser surgery. METHODS: Fifty-one fetal pairs with TTTS and 47 uncomplicated monochorionic twin pairs were included. Left ventricular isovolumetric contraction time (ICT), ejection time (ET), and isovolumetric relaxation time (IRT) were measured using conventional Doppler. RESULTS: Recipients showed prolonged ICT (46 ± 12 vs. 31 ± 8 vs. 30 ± 5 ms; p < 0.001) and IRT (51 ± 9 vs. 43 ± 8 vs. 43 ± 5 ms; p < 0.001) and higher MPI (0.57 ± 0.12 vs. 0.47 ± 0.09 vs. 0.44 ± 0.05; p < 0.001) than donors and controls. Donors showed shorter ET than recipients and controls (157 ± 12 vs. 169 ± 10 vs. 168 ± 10 ms; p < 0.001) and higher MPI than controls (0.47 ± 0.09 vs. 0.44 ± 0.05; p = 0.006). Preoperative MPI changes were observed in all TTTS stages. Time intervals partially improved after surgery. CONCLUSION: Donor and recipient twins had higher MPI due to different changes in the time intervals, possibly reflecting the state of hypovolemia in the donor and hypervolemia and pressure overload in the recipient.

Accuracy of Fetal Echocardiography in the Differential Diagnosis between Truncus Arteriosus and Pulmonary Atresia with Ventricular Septal Defect.

OBJECTIVES: To report on the accuracy of fetal echocardiography in the distinction between truncus arteriosus communis (CAT) and pulmonary atresia with ventricular septal defect (PA-VSD) and to describe the association with extracardiac and chromosomal anomalies. METHODS: This was a retrospective study on 31 fetuses with a single arterial trunk overriding a VSD with a nonidentifiable right ventricle outflow tract with anterograde flow. Data on the type of cardiac defect, gestational age, characteristics of the arterial trunk valve, presence of additional vascular, chromosomal and extracardiac abnormalities and postnatal outcome were obtained. Misdiagnosed cases were reevaluated by four-dimensional spatiotemporal image correlation (4D-STIC) echocardiography. RESULTS: The overall diagnostic accuracy was 81% and increased to 93.5% with 4D-STIC. Chromosomal and extracardiac anomalies were detected in 40 and 27%, respectively. In the PA-VSD group, patent ductus arteriosus and major aortopulmonary collateral arteries (MAPCAs) were present in 70 and 50% of the cases, respectively, coexisting in 1 of 5 cases. MAPCAs were significantly associated with a right aortic arch and with a 22q11 microdeletion in 50% of cases. CONCLUSIONS: A prenatal distinction between CAT and PA-VSD can currently be achieved in most cases. MAPCAs should be actively searched for when PA-VSD is suspected, as they are associated with a higher risk of 22q11 microdeletion and potentially complicate postnatal treatment.

Longitudinal annular displacement by M-mode (MAPSE and TAPSE) in twin-to-twin transfusion syndrome before and after laser surgery.

OBJECTIVE: To evaluate mitral and tricuspid annular plane systolic excursion (MAPSE and TAPSE) in fetuses with twin-to-twin transfusion syndrome (TTTS) before and after laser therapy. METHODS: A prospective study in 24 fetal pairs with TTTS evaluated 24 h before and within 48 h after fetoscopy and 13 gestational age-matched normal monochorionic fetal pairs. MAPSE and TAPSE were measured in an apical or basal four-chamber view by placing the M-mode cursor at the lateral valve ring. RESULTS: Mean preoperative MAPSE (controls 3.6 ± 1.3 mm vs. donors 2.7 ± 0.8 mm vs. recipients 2.8 mm ± 0.9; P < 0.001) and TAPSE (controls 4.4 ± 1.5 mm vs. donors 3.3 ± 1 mm vs. recipients 3.6 ± 1.1 mm; P < 0.001) values were significantly reduced in both TTTS fetuses. When subdividing according to TTTS stages, changes were significant in both stage I-II and III-IV subgroups, although differences were more pronounced in the latter. All observations remained unchanged 48 h post-fetoscopy. CONCLUSION: Both recipient and donor fetuses had decreased global longitudinal motion, even in early TTTS stages.

Feasibility of 4D-Spatio Temporal Image Correlation (STIC) in the Comprehensive Assessment of the Fetal Heart Using FetalHQ®.

Fetal Heart Quantification (FetalHQ®) is a novel speckle tracking software that permits the study of global and regional ventricular shape and function from a 2D four-chamber-view loop. The 4D-Spatio Temporal Image Correlation (STIC) modality enables the offline analysis of optimized and perfectly aligned cardiac planes. We aimed to evaluate the feasibility and reproducibility of 4D-STIC speckle tracking echocardiography (STE) using FetalHQ® and to compare it to 2D STE. We conducted a prospective study including 31 low-risk singleton pregnancies between 20 and 40 weeks of gestation. Four-chamber view volumes and 2D clips were acquired with an apex pointing at 45° and with a frame rate higher than 60 Hz. Morphometric and functional echocardiography was performed by FetalHQ®. Intra- and interobserver reproducibility were evaluated by the intraclass correlation coefficient (ICC). Our results showed excellent reproducibility (ICC > 0.900) for morphometric evaluation (biventricular area, longitudinal and transverse diameters). Reproducibility was also good (ICC > 0.800) for functional evaluation (biventricular strain, Fractional Area Change, left ventricle volumes, ejection fraction and cardiac output). On the contrary, the study of the sphericity index and shortening fraction of the different ventricular segments showed lower reproducibility (ICC < 0.800). To conclude, 4D-STIC is feasible, reproducible and comparable to 2D echocardiography for the assessment of cardiac morphometry and function.

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.

Congenital heart block related to maternal autoantibodies: descriptive analysis of a series of 18 cases from a single center.

The objective of this study was to describe the clinical and immunological characteristics of maternal autoimmune-mediated fetal congenital heart block (CHB) in a cohort of pregnant women from an autoimmune disease pregnancy clinic. This is a retrospective observational study of all women presenting with CHB in our autoimmune disease pregnancy clinic from January 1997 to December 2014. In addition, perinatal outcome is also described. Fourteen patients accounting for 18 fetuses with CHB were identified. The median age was 32.5 years (range, 22-40). Seven (50 %) patients had Sjögren's syndrome, and the remaining seven were asymptomatic carriers of autoantibodies. All patients had anti-Ro/SSA antibodies, and 11/13 (85 %) had anti-La/SSB antibodies. The median gestational age at the time of CHB was 22 weeks (range 18-28). Complete third degree CHB was detected in 12 (67 %). Seven cases of CHB were treated with dexamethasone, two with ritodrine, and one with the association of dexamethasone, ritodrine, and terbutaline. In 9 (50 %) cases that presented with, or developed, very poor prognosis factors, such as a ventricular rate below 50-55 bpm and/or the presence of fetal hydrops, parents opted for the termination of pregnancy, after dedicated counseling. Finally, there were nine newborns (seven males [78 %]) with median age at delivery of 37 weeks (range, 32-39). A definitive epicardial pacemaker was placed in six newborns, four of them within 2 weeks of life. CHB is a severe complication related to maternal anti-Ro/SSA and anti-La/SSB antibodies. Our results confirm previous data showing that therapy is ineffective, and most of the surviving patients will require neonatal pacemaker.

Cardiac function monitoring of fetuses with growth restriction.

OBJECTIVE: To describe the time sequence of changes in cardiac function in intrauterine growth restriction. STUDY DESIGN: This was a prospective longitudinal study on 22 singleton pregnancies with growth-restricted fetuses. Pulsatility indices of fetal arterial and venous Doppler waveforms, systolic peak velocity in the aorta and pulmonary artery, right and left ventricular shortening fraction and atrioventricular flow E/A ratio were assessed at each monitoring session. Logistic regression was used for modeling the probability of abnormality of a variable in relation to the time interval before delivery. Trends over time were analyzed by Mann-Withney U-test. RESULTS: Umbilical artery pulsatility index was the first variable to become abnormal, followed by the middle cerebral artery, right diastolic indices (right E/A, ductus venosus), right systolic indices and, finally, both diastolic and systolic left cardiac indices. CONCLUSION: We have found an earlier and more pronounced right than left and diastolic than systolic fetal cardiac function deterioration in growth restricted fetuses monitored longitudinally.

First-trimester screening for Down syndrome with ductus venosus Doppler studies in addition to nuchal translucency and serum markers.

OBJECTIVE: To estimate the improvement in screening efficiency when fetal ductus venosus Doppler studies are added to existing first-trimester Down syndrome screening protocols. METHODS: Statistical modelling was used with parameters derived from prospective ductus venosus studies and from the published literature. The pulsatility index for veins (PIV), was determined in the fetal ductus venosus for 3706 unaffected and 25 Down syndrome pregnancies at 10-14 weeks' gestation. Concurrent nuchal translucency measurement and maternal serum pregnancy associated plasma protein A and free-beta human chorionic gonadotrophin were also measured. RESULTS: The median PIV in Down syndrome was 1.70 times higher than in unaffected pregnancies (95% confidence interval 1.36-2.12). PIV levels followed an approximately log Gaussian distribution with log(10) standard deviations of 0.193 and 0.076 in Down syndrome and unaffected pregnancies. There were no statistically significant correlations between PIV and the other markers. Modelling predicts that for a fixed 5% false-positive rate, the addition of PIV to nuchal translucency alone will increase the detection rate from 76 to 85%, and combined with serum markers, from 88 to 92%. For a fixed 85% detection rate, the false-positive rate reduced from 15 to 4.8% and from 3.2 to 1.2% respectively. CONCLUSION: Ductus venosus Doppler studies can substantially improve Down syndrome screening efficiency.

Ultrasonographic diagnosis of Jarcho-Levin syndrome at 20 weeks' gestation in a fetus without previous family history.

Jarcho-Levin syndrome (JLS; spondylothoracic dysplasia) is a congenital disease characterized by multiple vertebral and rib malformations, causing a short trunk dwarfism commonly leading to respiratory insufficiency and death during the first years of life. We describe a case diagnosed during the second trimester routine ultrasound scan for screening of fetal anomalies without a previous family history. The fetus had a severe disorganization of the spine and ribs, skeletal kyphosis, with several hemivertebrae and a small thorax. All of the findings at postmortem examination confirmed the ultrasound features and were consistent with the JLS. To the best of our knowledge there is only one case reported in the literature of a prenatal diagnosis of the syndrome in a family with low risk for the condition.

Individual placental territories after selective laser photocoagulation of communicating vessels in twin-twin transfusion syndrome.

OBJECTIVE: Intrauterine fetal death of one or both twins after laser therapy (selective photocoagulation of communicating vessels) may occur, in part, from insufficient individual placental mass. The objective of this study was to assess the percentage of individual placental mass (individual placental territory) that is associated with fetal survival in twin-twin transfusion syndrome after selective photocoagulation of communicating vessels. STUDY DESIGN: Placentas from 72 patients with selective photocoagulation of communicating vessels-treated twin-twin transfusion syndrome without intrauterine fetal death and from 61 monochorionic pregnancies without twin-twin transfusion syndrome (control subjects) were assessed. The placentas were weighed fresh (total placental mass) and cut along the vascular equator, which yielded the individual placental mass and the individual placental territory. Patency of anastomoses was ruled out with air-injection. The individual fetoplacental ratio was obtained by dividing birth weight by the corresponding individual placental mass. RESULTS: The 5th percentile individual placental territory that was associated with fetal survival was 27% in control subjects and 18% in cases with twin-twin transfusion syndrome, with a minimum of 10% to 14%, respectively. There were no differences in total placental mass, individual placental mass, individual placental territory, or individual fetoplacental ratio between pregnancies with twin-twin transfusion syndrome and control subjects. However, corrected for gestational age, the birth weight of recipient and donor twins were significantly smaller than control subjects. The individual placental territory of donors was statistically smaller than that of recipients. Individual placental territories were not different within control subjects. CONCLUSION: Fetal survival typically is associated with at least 18% of individual placental territory after selective photocoagulation of communicating vessels for twin-twin transfusion syndrome, but it can occur with as little as 10% to 14% individual placental territory. Decreased birth weight of the donor twin could result from relative decreased percentage of individual placental territory or from the loss of nutrients to the recipient twin. Decreased birth weight of the recipient twin could result from partial deprivation of functional placental tissue after surgery. Our findings may contribute to the understanding of normal and pathologic monochorionic twin gestations, in the counseling of patients, and potentially to the improvement of surgical treatment of twin-twin transfusion syndrome.

Ductus venosus assessment at the time of nuchal translucency measurement in the detection of fetal aneuploidy.

OBJECTIVE: To assess the potential value of ductus venosus Doppler studies in the detection of fetal aneuploidy on measurement of nuchal translucency. METHODS: The pulsatility index for veins (PIV) and the lowest velocity during atrial contraction (A-wave) were determined in the fetal ductus venosus in 3382 consecutive pregnancies at 10 to 14 weeks and studied from December 1996 to December 2001. Nuchal translucency was also measured. The population studied included 1664 pregnancies at high risk and 1718 at low risk for fetal aneuploidy. RESULTS: In relation to the prenatal detection of trisomy 21, the ductus venosus PIV was increased in 75% (36/48), the A-wave was decreased in 58% (28/48), and nuchal translucency was enlarged in 81% (39/48) of the trisomy 21 fetuses [71% (22/31) when nuchal translucency referrals were excluded]. The corresponding figures for trisomies 18 and 13 were 71, 58 and 83%, respectively, being 33, 33 and 33% for other unbalanced anomalies. CONCLUSION: There is a high proportion of fetuses with trisomies 21, 18 and 13 (around 75%) in which the ductus venosus PIV is increased (above the 95th percentile) at 10 to 14 weeks, this proportion being similar to that observed for increased nuchal translucency measurement.

Transcervical chorionic villus sampling in multiple pregnancies using a biopsy forceps.

OBJECTIVE: The aim of this study was to assess the effectiveness and safety of chorionic villus sampling (CVS) performed in multiple pregnancies by means of a transcervical biopsy forceps. METHODS: The study included CVS performed from January 1990 to March 2000 in our Unit. The results were analysed in two consecutive periods, period A (1990-1994) and period B (1995-2000), in an attempt to assess the effect of increasing experience. RESULTS: Seventy-five samplings were performed in 39 multiple pregnancies, 38 twin sets and one triplet. A cytogenetic report was obtained in 73% of cases in period A and in 98% in period B. An abnormal karyotype was observed in 11 samples. The need for subsequent amniocentesis decreased from 38% in period A to 10% in period B. The spontaneous fetal loss rate in chromosomally and structurally normal fetuses before the 20th week decreased from 8.7% in period A to 3.3% in period B. The fetal loss rate after the 20th week was 3.3% in period B and none in period A. It must be noted that in three out of the four cases of fetal loss an amniocentesis was needed after CVS. CONCLUSION: Our results suggest that effectiveness and safety improved with increasing experience. Transcervical chorionic villus sampling allows an earlier prenatal genetic diagnosis in multiple pregnancies and this may be particularly relevant for a safer selective termination when chosen by parents if one of the fetuses has an abnormal karyotype.