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    Kurt Hecher

    In twin-to-twin transfusion syndrome (TTTS), genetically identical twins are exposed to different haemodynamic conditions during fetal life, which are considered to be the cause of prenatal and postnatal cardiovascular differences between... more
    In twin-to-twin transfusion syndrome (TTTS), genetically identical twins are exposed to different haemodynamic conditions during fetal life, which are considered to be the cause of prenatal and postnatal cardiovascular differences between the donor and the recipient. To assess intertwin differences on childhood cardiac outcome after intrauterine laser coagulation therapy (LC) of severe TTTS. Prospective, detailed, echocardiographic follow-up of 31 twin pairs aged 9.95±0.8 years (mean±SD) with severe TTTS treated by LC, and the comparison with reference values. Cardiac function was normal and did not show intertwin differences in twins without structural heart disease. Discordant birth weight or birth weight <3rd centile for gestational age had no influence on blood pressure and cardiac indices. Pulmonary stenosis was more common (5/62; 8.1%) than in the general population (prevalence 0.066%, relative risk 134.4, 95% CI 42.1 to 428.8, p<0.0001) and affected both donor and recip...
    Population-based pregnancy cohorts recruiting women before or at the moment of childbirth allow a longitudinal follow-up on children's health later in life. Important findings arising from pregnancy cohorts are discussed in the... more
    Population-based pregnancy cohorts recruiting women before or at the moment of childbirth allow a longitudinal follow-up on children's health later in life. Important findings arising from pregnancy cohorts are discussed in the present review. These insights have led to revised guidelines on how to minimize disease risks in children, e.g., in the context of chronic immune diseases including allergies and asthma. Moreover, insights from pregnancy cohorts also unveiled a collateral effect of pregnancy on maternal immunity, mirrored by an ameliorated course of certain autoimmune diseases, but also an increased risk of infection with influenza A virus. Future pregnancy cohort studies are still required to close gaps in knowledge on how parameters involved in the developmental origin of health or poor immunity observed in children later in life are operational. We discuss here features that should be covered by future pregnancy cohort studies. Expected insights from such studies will...
    Twin-twin transfusion syndrome complicates up to 15% of monochorionic pregnancies in the mid-trimester, and results in high perinatal mortality and morbidity if left untreated. Although some humoral factors play a role in the pathogenesis... more
    Twin-twin transfusion syndrome complicates up to 15% of monochorionic pregnancies in the mid-trimester, and results in high perinatal mortality and morbidity if left untreated. Although some humoral factors play a role in the pathogenesis of the disease, an unequal placental sharing and the presence of placental vascular anastomoses at the chorionic plate, allowing blood volume shifts between the twins, are the anatomic prerequisite for this complication unique to monochorionic twins. Within monochorionic pregnancies, it is possible to identify a subgroup of twin pairs at high risk of developing twin-twin transfusion syndrome or selective intrauterine growth restriction during the course of pregnancy as early as in the first or early second trimester. If progressive amniotic fluid discrepancy advances to moderate twin-twin transfusion syndrome, and finally reaches the stages of severe twin-twin transfusion syndrome, accurate classification of the clinical picture and diagnosis of th...
    Normal fetal growth depends on the genetically predetermined growth potential and its modulation by the health of the fetus, placenta and the mother. Fetuses that are small because of intrauterine growth restriction (IUGR) are at higher... more
    Normal fetal growth depends on the genetically predetermined growth potential and its modulation by the health of the fetus, placenta and the mother. Fetuses that are small because of intrauterine growth restriction (IUGR) are at higher risk for poor perinatal and long-term outcome than those who are appropriately grown. Of the many potential underlying processes that may result in IUGR,
    OBJECTIVE: Our purpose was to investigate arterial, venous, and intracardiac blood flow in growth-retarded fetuses and to relate the Doppler results to blood gases in umbilical venous blood obtained by cordocentesis.STUDY DESIGN: A... more
    OBJECTIVE: Our purpose was to investigate arterial, venous, and intracardiac blood flow in growth-retarded fetuses and to relate the Doppler results to blood gases in umbilical venous blood obtained by cordocentesis.STUDY DESIGN: A cross-sectional, pulsed-wave color Doppler ultrasonographic study of 23 severely growth-retarded fetuses undergoing cordocentesis and measurement of blood gases was performed. Blood velocity waveforms were recorded from the
    Endoscopic laser coagulation of the chorioangiopagus was successfully performed at 25 weeks' gestation in a pregnancy presenting with acute polyhydramnios due to twin transfusion syndrome. Under local anesthesia, a rigid fetoscope... more
    Endoscopic laser coagulation of the chorioangiopagus was successfully performed at 25 weeks' gestation in a pregnancy presenting with acute polyhydramnios due to twin transfusion syndrome. Under local anesthesia, a rigid fetoscope housed in a 2.7 mm diameter cannula was introduced transabdominally into the amniotic cavity and the communicating vessels were coagulated by Nd : YAG laser through a fiber that was passed down the side-arm of the cannula. There was rapid normalization of urine output in both fetuses and resolution of the oligo- and polyhydramnios in the donor and recipient twins, respectively. Furthermore, there was normalization in both fetal circulations, as assessed by Doppler velocimetry, and there was gradual resolution of the hydrops in the recipient. Two healthy babies were born 9 weeks after the procedure.
    To determine the alteration of blood flow velocity profile in the pulmonary arteries (PAs) of fetal sheep after tracheal occlusion (TO). Doppler ultrasound investigations of the PAs, the pulmonary trunk and the ductus arteriosus were... more
    To determine the alteration of blood flow velocity profile in the pulmonary arteries (PAs) of fetal sheep after tracheal occlusion (TO). Doppler ultrasound investigations of the PAs, the pulmonary trunk and the ductus arteriosus were performed weekly in nine ewes (gestational age 92-98 days, term 145 days) with singleton pregnancies after TO (n = 5) and in control fetuses (n = 4). Histological examinations with morphometry of pulmonary arterial vessels and of airways were performed in both groups. In the control group the experiments lasted 38 +/- 6 days (mean +/- SD), and in the TO group 25 +/- 7 days. Relative lung weight was significantly higher in the TO group compared with the control group (14.5 +/- 3.4% and 4.0 +/- 0.5% of body weight). There were no significant differences in the Doppler parameters (pulsatility index, resistance index, the systolic peak, the diastolic minimum, time averaged maximum velocity) between groups. When the Doppler values of PAs in TO and control fetuses were combined, no significant differences between the left and right PA could be detected. The external diameter of peripheral PAs was significantly higher in the TO group as compared to control group (105.7 +/- 2.5 microm vs. 96.9 +/- 1.3 microm). We found a threefold increase of fetal lung volume after TO without significant changes of blood flow velocity profiles in the PAs of fetal sheep.
    This cross-sectional study investigated the circulatory profile of the donor and recipient fetuses in 20 pregnancies with twin-twin transfusion syndrome presenting with acute polyhydramnios at 17-27 (mean, 22) weeks' gestation.... more
    This cross-sectional study investigated the circulatory profile of the donor and recipient fetuses in 20 pregnancies with twin-twin transfusion syndrome presenting with acute polyhydramnios at 17-27 (mean, 22) weeks' gestation. Doppler investigations of the arterial vessels and ductus venosus, inferior vena cava, right hepatic vein, tricuspid and mitral ventricular inflow were performed in both fetuses. Mean values of most blood flow velocities on the venous side showed a significant decrease in both groups of fetuses, and a significant increase in mean values for indices describing waveform pulsatility was found in all three venous vessels in the group of recipients, whereas in the donor group this was only the case in the ductus venosus. Mean values of atrioventricular flow velocities showed a significant decrease in the donor group. The most significant findings on the arterial side were an increased mean umbilical artery pulsatility index and a decreased mean value for aortic blood flow velocity in both groups of fetuses. Five recipients and four donors had absence or reversal of blood flow during atrial contraction in the ductus venosus. All these fetuses showed pulsations in the umbilical vein. Tricuspid regurgitation was present in eight recipients. Absence or reversal of end-diastolic velocities in the umbilical artery was found in four donors.(ABSTRACT TRUNCATED AT 250 WORDS)
    This cross-sectional study establishes reference ranges with gestation for Doppler parameters of fetal venous and atrioventricular blood flow. Color flow Doppler was used to examine 143 normal singleton pregnancies at 20-40 weeks'... more
    This cross-sectional study establishes reference ranges with gestation for Doppler parameters of fetal venous and atrioventricular blood flow. Color flow Doppler was used to examine 143 normal singleton pregnancies at 20-40 weeks' gestation. Flow velocity waveforms were recorded from the ductus venosus, right hepatic vein and inferior vena cava. The waveforms are triphasic, reflecting ventricular systole, early diastole and atrial contraction. Peak velocities for these parameters were measured with pulsed Doppler and a new index, the peak velocity index for veins (PVIV), was calculated. Similarly, time-averaged maximum velocities for the whole cardiac cycle were measured and the pulsatility index for veins (PIV) was calculated. Flow velocity waveforms were also recorded at the level of the atrioventricular valves and the ratios of peak velocities at early diastolic filling (E) and atrial contraction (A) were calculated. Regression analysis was used to define the association of each measured and calculated Doppler parameter with gestational age. Blood flow velocities in the fetal veins and velocities and E/A ratios across the atrioventricular valves increased significantly with gestation, whereas PVIV and PIV decreased. Blood flow velocities were highest in the ductus venosus and lowest in the right hepatic vein, and PVIV and PIV were highest in the hepatic vein and lowest in the ductus venosus. In the ductus venosus, there was always forward flow throughout the heart cycle, whereas in the inferior vena cava and hepatic vein during atrial contraction, flow was away from or towards the heart or there was no flow. Pulsatility of flow velocity waveforms in the venous system is the consequence of changes in pressure difference between the venous system and the heart during the heart cycle. The finding that PVIV and PIV decrease with gestation is consistent with decreasing cardiac afterload and maturation of diastolic ventricular function.
    To assess the accuracy of magnetic resonance (MR) imaging in determining fetal lung volume (FLV) and to observe fetal lung development with B-mode ultrasonography (US) and MR imaging. Seven sheep fetuses between 92 and 141 gestational... more
    To assess the accuracy of magnetic resonance (MR) imaging in determining fetal lung volume (FLV) and to observe fetal lung development with B-mode ultrasonography (US) and MR imaging. Seven sheep fetuses between 92 and 141 gestational days (term, 145 days) with and without tracheal occlusion (controls) underwent serial MR imaging and US. FLV at MR imaging was measured with true fast imaging with steady-state precession in coronal and transverse planes. The combined cross-sectional left- and right-lung area was measured with US at three transverse levels. FLV was measured at autopsy. Statistical evaluations included linear regression analysis and calculation of the mean and 95% CI. No differences in FLV were observed on coronal or transverse MR images (r2 = 0.98; slope = 0.91; 95% CI: 0.82, 1.01). FLV at MR imaging at termination of the experiment was significantly related to FLV at autopsy (r2 = 0.96; slope = 1.27; 95% CI: 0.97, 1.57; n = 6). FLV at MR imaging increased more rapidly with gestational age in fetuses with tracheal occlusion (21.0 mL/d; 95% CI: 10.7, 31.3) than in controls (4.7 mL/d; 95% CI: 1.7, 7.7). Increase in left- and right-lung area at US was accelerated in fetuses with tracheal occlusion (1.60 cm2/d; 95% CI: 1.3, 1.9) compared with controls (0.38 cm2/d; 95% CI: 0.23, 0.53). Left- and right-lung area at US and FLV at MR imaging were significantly correlated (r2 = 0.82). FLV can be measured with moderate accuracy at MR imaging on both coronal and transverse images. MR imaging and B-mode US are useful tools for monitoring and quantifying tracheal occlusion-stimulated fetal lung growth in sheep fetuses.
    To investigate the effect of anemia on fetal venous, arterial, and intracardiac blood flows. Color flow Doppler was used to record flow-velocity waveforms from the atrioventricular valves, ductus venosus, right hepatic vein, inferior vena... more
    To investigate the effect of anemia on fetal venous, arterial, and intracardiac blood flows. Color flow Doppler was used to record flow-velocity waveforms from the atrioventricular valves, ductus venosus, right hepatic vein, inferior vena cava, middle cerebral artery, and descending thoracic aorta from 38 cases of red blood cell isoimmunized pregnancies. Immediately after the Doppler studies, funipuncture was performed and the fetal hemoglobin concentration was measured. Blood flow velocities in the thoracic aorta, middle cerebral artery, and the ductus venosus were increased compared to reference ranges established previously; however, a significant association with the degree of anemia was found only for the velocity in the thoracic aorta. Pulsatility indices in arteries and veins and the ratio of early to late atrioventricular inflow velocities were not significantly different from normal. Fetal anemia is associated with a hyperdynamic circulation in both arterial and venous vessels. Even in severe anemia, there is no evidence of congestive heart failure. Venous and intracardiac Doppler studies do not provide a clinically useful contribution in the management of red blood cell isoimmunization.
    In monozygotic twin pregnancies, there are placental vascular communications between the two fetuses. In 15 percent of such pregnancies there is an imbalance in net blood flow between the twins, resulting in the twin-twin transfusion... more
    In monozygotic twin pregnancies, there are placental vascular communications between the two fetuses. In 15 percent of such pregnancies there is an imbalance in net blood flow between the twins, resulting in the twin-twin transfusion syndrome. The recipient twin may have severe hydramnios during the second trimester of pregnancy, and there is a high risk of perinatal death and cerebral palsy in survivors. This condition can now be treated by endoscopic coagulation of the vascular anastomoses responsible for fetofetal transfusion with a neodymium:yttrium-aluminum-garnet (Nd: YAG) laser. We performed intrauterine surgery in 45 pregnant women carrying twins at 15 to 28 weeks of gestation (median, 21); in each case there was severe hydramnios in one fetus due to the twin-twin transfusion syndrome. With the use of local anesthesia and continuous ultrasound visualization, a rigid fetoscope 2 mm in diameter, housed in a 2.7-mm cannula, was introduced transabdominally into the amniotic cavity of the recipient twin. A systematic search was made for all vessels approaching or crossing the membrane between the twins, and these were coagulated with an Nd:YAG laser by means of a fiber in the side arm of the cannula. Coagulation of the communicating vessels was successful in all cases. The total number of fetuses who survived to delivery was 48 (53 percent), and the number of pregnancies with at least 1 survivor was 32 (71 percent). Among the live-born infants, the median gestational age at delivery was 35 weeks (range, 25 to 40), and the median birth weight was 2098 g (range, 550 to 4252). The median interval between the endoscopic laser procedure and delivery was 14 weeks (range, 0 to 21). All the survivors were developing normally at a median age of 12 months (range, 2 to 24). Our preliminary experience suggests that the twin-twin transfusion syndrome can be treated effectively by endoscopic laser coagulation of the communicating placental vessels.
    Objectives: Nuchal translucency measurement of 3 mm or more (≥95th centile for gestation age), hydrops fetalis or hygroma colli between the 11th and 14th weeks of gestation is associated with a higher risk of fetal Down syndrome and other... more
    Objectives: Nuchal translucency measurement of 3 mm or more (≥95th centile for gestation age), hydrops fetalis or hygroma colli between the 11th and 14th weeks of gestation is associated with a higher risk of fetal Down syndrome and other aneuploidies. So far, chromosome preparation of chorionic villi samplings (CVS) after short-term (or direct) culture is the only valid, reliable and rapid method of choice for the early detection of chromosomal aberrations. However, because of the placental mosaicisms detected after short-term culture, CVS has to be confirmed by a second method. Moreover, short-term villi preparation does not always provide a sufficient quantity and quality of metaphases to enable cytogenetic analysis. Unfortunately, a predicative cytogenetic result will be available only after long-term cultivation (usually after 1–2 weeks). An alternative rapid method, inexpensive and suitable for diagnosing autosomal trisomies, is the quantitative fluorescence polymerase reactio...
    Preeclampsia is a major cause of maternal and neonatal morbidity and mortality worldwide. Despite recent advances in screening, sensitive and specific biomarkers that help to identify pregnant women at risk of developing preeclampsia are... more
    Preeclampsia is a major cause of maternal and neonatal morbidity and mortality worldwide. Despite recent advances in screening, sensitive and specific biomarkers that help to identify pregnant women at risk of developing preeclampsia are lacking. One of the major mediators from healthy endothelium is nitric oxide; its production is regulated by asymmetric dimethylarginine (ADMA). ADMA has been shown to be elevated in cardiovascular and metabolic diseases; elevated ADMA levels are a prognostic marker for major cardiovascular events and mortality in patients with established cardiovascular disease and in the general population. Several studies have reported elevated ADMA levels in preeclampsia; some studies also suggested that ADMA is elevated in early stages of pregnancy in women who later develop preeclampsia. Moreover, ADMA has been associated with uterine artery flow disturbances. Its plasma concentration is regulated by dimethylarginine dimethylaminohydrolase (DDAH). Single nucleotide polymorphisms in the gene encoding for DDAH have been associated with the incidence of preeclampsia. Recently, diagnostic assays for ADMA, e.g. by ELISA, have become available, which render ADMA a possible biomarker to identify pregnant women at risk of developing preeclampsia.
    To assess the feasibility and outcome of fetoscopic laser coagulation in pregnancies with twin reversed arterial perfusion (TRAP) sequence. In a prospective multicenter study, percutaneous fetoscopic laser coagulation of placental... more
    To assess the feasibility and outcome of fetoscopic laser coagulation in pregnancies with twin reversed arterial perfusion (TRAP) sequence. In a prospective multicenter study, percutaneous fetoscopic laser coagulation of placental anastomoses (n = 18) or the umbilical cord of the acardiac twin (n = 42) was performed in 60 consecutive pregnancies at a median gestational age of 18.3 (range, 14.3-24.7) weeks under local or locoregional anesthesia. Vascular coagulation with arrest of blood flow was achieved in 82% (49/60) of cases by laser alone and in a further 15% (9/60) by laser coagulation in combination with bipolar forceps. The overall survival rate of the pump twin was 80% (48/60). Median gestational age at delivery was 37.4 (range, 23.7-41.4) weeks and the median interval between the procedure and delivery was 18.2 (range, 1.1-25.7) weeks. Median birth weight was 2720 (range, 540-3840) g. Preterm premature rupture of membranes before 34 weeks' gestation occurred in 18% (11/60) at a median of 62 (range, 1-102) days after the procedure. However, only two (3%) women delivered within 28 days of the procedure. Fetoscopic laser coagulation of placental vascular anastomoses or the umbilical cord of the acardiac twin is an effective treatment of TRAP sequence, with a survival rate of 80%, and 67% of pregnancies with surviving pump twins going beyond 36 weeks' gestation without further complications.
    The Bisulfite Sequencing Data Presentation and Compilation (BDPC) web interface for compilation and presentation of data from bisulfite sequencing DNA methylation studies has been improved by adding a new module. This module allows... more
    The Bisulfite Sequencing Data Presentation and Compilation (BDPC) web interface for compilation and presentation of data from bisulfite sequencing DNA methylation studies has been improved by adding a new module. This module allows visualization of the whole data set in form of a heatmap of DNA methylation levels and clustering and comparison of tissue methylation patterns. It can also be used for data not processed by BDPC. In addition, several functions of the existing BDPC compilation module have been improved.
    The aim of this study was to investigate prenatal and postnatal growth of twins with twin-twin transfusion syndrome (TTTS) after intrauterine laser coagulation. The weight and length of 54 sets of twins with severe TTTS surviving... more
    The aim of this study was to investigate prenatal and postnatal growth of twins with twin-twin transfusion syndrome (TTTS) after intrauterine laser coagulation. The weight and length of 54 sets of twins with severe TTTS surviving intrauterine laser coagulation at the intervention (median 20+4 weeks), at birth (median 34+3 weeks) and on the occasion of neurodevelopmental follow-up (median age 3 years 10 months) were investigated. All data were converted to Z scores, and groups were compared by two-tailed paired t test. At all time points, donors are significantly lighter than recipients (p<0.001). After laser treatment the weight Z score of donors until birth remains unchanged (p=0.76), whereas recipients lose weight significantly (p<0.01). Postnatally, both donors and recipients show catch-up growth. Intrauterine laser coagulation stops growth acceleration in recipients that leads to a decrease in intertwin discordance. After birth, significant catch-up growth was observed for the donor group (p<0.001).
    In monochorionic twin pregnancy in which one twin is a nonviable fetus, selective feticide may be considered. We aimed to occlude the umbilical cord with a bipolar forceps for doing so. This was a multicenter experience in 10 consecutive... more
    In monochorionic twin pregnancy in which one twin is a nonviable fetus, selective feticide may be considered. We aimed to occlude the umbilical cord with a bipolar forceps for doing so. This was a multicenter experience in 10 consecutive patients either with twin-to-twin transfusion syndrome and one fetus affected by a condition not compatible with normal extrauterine life or with acardiac twinning. There were no intraoperative problems, and the mean procedure time was 17.5 minutes. The flow was stopped in all 10 cases. Two cases were complicated by rupture of the fetal membranes within 2 days, and the pregnancies were terminated. The other 8 pregnancies resulted in the live birth of a healthy baby. The mean interval between procedure and birth was 15.1 weeks (range, 7-20 weeks). In one patient emergency cesarean delivery for abruptio placentae was done at 26 weeks, 7 weeks after the procedure. The other 7 patients were delivered beyond the 36th week of gestation. All 8 children are alive and well, with a mean follow-up of at least 1 year. Bipolar coagulation is a safe, effective, and simple procedure for cord coagulation that is feasible through a single port and can be performed solely under ultrasonographic guidance.
    The purpose of this study was to determine the value of ultrasound examination in the first trimester and at 16 weeks to predict fetal complications in monochorionic diamniotic (MCDA) twin pregnancies, defined as the occurrence of either... more
    The purpose of this study was to determine the value of ultrasound examination in the first trimester and at 16 weeks to predict fetal complications in monochorionic diamniotic (MCDA) twin pregnancies, defined as the occurrence of either twin-to-twin transfusion syndrome, severe discordant growth, or intrauterine death. We identified risk factors to predict a complicated fetal outcome in the first trimester and at 16 weeks in a prospective cohort of 202 twin pregnancies recruited during the first trimester in 2 centers of the EuroTwin2Twin project. Significant predictors in the first trimester were the difference in crown-rump length (odds ratio [OR], 11) and discordant amniotic fluid (OR, 10). At 16 weeks, significant predictors were the difference in abdominal circumference (OR, 29), discordant amniotic fluid (OR, 7), and discordant cord insertions (OR, 3). Risk assessment in the first trimester and at 16 weeks detected 29% and 48% of cases with a complicated fetal outcome, respectively, with a false-positive rate of 3% and 6%, respectively. Combined first-trimester and 16 week assessment identified 58% of fetal complications, with a false-positive rate of 8%. Of the MCDA twin pregnancies classified as high risk on the combined first trimester and 16 weeks assessment (n = 41), 73% had a complicated fetal outcome with a survival rate of only 69%. In contrast, of the pregnancies classified as low risk (n = 154), 86% had an uneventful fetal outcome with a survival rate of 95%.
    Severe twin-twin transfusion can be treated by either serial amniocenteses with removal of large volumes of amniotic fluid or by endoscopic laser coagulation of the communicating vessels. We investigated the benefit of laser surgery in... more
    Severe twin-twin transfusion can be treated by either serial amniocenteses with removal of large volumes of amniotic fluid or by endoscopic laser coagulation of the communicating vessels. We investigated the benefit of laser surgery in comparison to serial amniocenteses in terms of pregnancy outcome. The data used in this comparative study were collected from 116 patients with severe twin-twin transfusion syndrome between 17 and 25 weeks' gestation. The patients were grouped according to the treatment center. The first group comprised 73 patients (median gestational age 20.7 weeks) treated in Hamburg by fetoscopic laser coagulation of the vascular placental anastomoses between January 1995 and May 1997. The second group comprised 43 patients (median gestational age 20.4 weeks), fulfilling identical diagnostic criteria and treated in Bonn by serial amniocenteses between 1992 and 1996. The overall fetal survival rate was not significantly different (61%, 89/146, vs 51%, 44/86; P =.239). There was a significantly higher proportion of pregnancies with >/=1 survivor in the laser-treated group (79%, 58/73, vs 60%, 26/43; P =.033). The number of cases with spontaneous intrauterine fetal death of both fetuses was significantly lower in the laser-treated group (3%, 2/73, vs 19%, 8/43; P =.003). The incidence of abnormal ultrasonographic findings in the brain was significantly lower among surviving neonates after laser surgery than after amniocenteses (6%, 5/89, vs 18%, 8/44; P =. 03). For pregnancies with >/=1 live-born baby, a significantly longer interval between first intervention and delivery (median 90 vs 72 days, P =.022) leading to a significantly higher gestational age at delivery (median 33.7 vs 30.7 weeks, P =.018) was observed for the laser-treated group. The birth weights of the donor fetuses were significantly higher in the laser-treated group (median 1750 vs 1145 g, P =.034), and a trend toward higher birth weight was also found for recipient fetuses (median 2000 vs 1560 g, P =.076). These findings indicate that endoscopic laser coagulation of placental vascular anastomoses offers a more effective alternative to serial amniocenteses as a treatment of severe second-trimester twin-twin transfusion syndrome.
    Our purpose was to investigate arterial, venous, and intracardiac blood flow in growth-retarded fetuses and to relate the Doppler results to blood gases in umbilical venous blood obtained by cordocentesis. A cross-sectional, pulsed-wave... more
    Our purpose was to investigate arterial, venous, and intracardiac blood flow in growth-retarded fetuses and to relate the Doppler results to blood gases in umbilical venous blood obtained by cordocentesis. A cross-sectional, pulsed-wave color Doppler ultrasonographic study of 23 severely growth-retarded fetuses undergoing cordocentesis and measurement of blood gases was performed. Blood velocity waveforms were recorded from the descending thoracic aorta, middle cerebral artery, inferior vena cava, ductus venosus, and atrioventricular valves. The Doppler studies demonstrated evidence of redistribution in the arterial system with increased impedance to flow in the aorta and decreased impedance in the cerebral circulation. The velocity of flow in the venous system and across the atrioventricular valves was decreased, whereas pulsatility of waveforms in the inferior vena cava and ductus venosus was increased. The mean umbilical venous blood PO2 and pH were decreased, and there were significant associations between blood gases and Doppler parameters in the thoracic aorta, middle cerebral artery, and ductus venosus. In severe intrauterine growth retardation the degree of fetal acidemia can be estimated from Doppler measurements of pulsatility in both the arterial system and the ductus venosus.
    The purpose of this study was to document pregnancy and neonatal outcome of monochorionic diamniotic twin pregnancies. This observational study describes a prospective series included in the first trimester in 2 centers of the... more
    The purpose of this study was to document pregnancy and neonatal outcome of monochorionic diamniotic twin pregnancies. This observational study describes a prospective series included in the first trimester in 2 centers of the Eurotwin2twin project. Of the 202 included twin pairs, 172 (85%) resulted in 2 survivors, 15 (7.5%) in 1 survivor, and 15 (7.5%) in no survivors. The mortality was 45 of 404 (11%), and 36 of 45 (80%) were fetal losses of 24 weeks or less, 5 of 45 (11%) between 24 weeks and birth, and 4 of 45 (9%) were neonatal deaths. Twin-to-twin transfusion syndrome (TTTS) occurred in 18 of 202 (9%). The mortality of TTTS was 20 of 36 (55%), which accounted for 20 of 45 (44%) of all losses. Severe discordant growth without TTTS occurred in 29 of 202 (14%). Its mortality was 5 of 58 (9%), which accounted for 5 of 45 (11%) of all losses. Major discordant congenital anomalies occurred in 12 of 202 (6%). Of the 178 pairs that continued after 24 weeks, 10 (6%) had severe hemoglobin differences at birth. After 32 weeks, the prospective risk of intrauterine demise was 2 in 161 pregnancies (1.2%; 95% confidence interval, 0.3-4.6). Of the monochorionic twins recruited in the first trimester, 85% resulted in the survival of both twins, and 92.5% resulted in the survival of at least 1 twin. Most losses were at 24 weeks or less, and TTTS was the most important cause of death. After 32 weeks, the risk of intrauterine demise appears to be small.
    The purpose of this study was to examine the clinical and placental characteristics of monochorionic diamniotic twin pregnancies with early-onset discordant growth diagnosed at 20 weeks, late-onset discordant growth diagnosed at 26 weeks... more
    The purpose of this study was to examine the clinical and placental characteristics of monochorionic diamniotic twin pregnancies with early-onset discordant growth diagnosed at 20 weeks, late-onset discordant growth diagnosed at 26 weeks or later, and concordant growth. We studied a prospective cohort that underwent an ultrasound scan in the first trimester, at 16, 20, and 26 weeks. We excluded pregnancies complicated by twin-to-twin transfusion syndrome, miscarriage, fetal death less than 16 weeks, or severe congenital anomalies. Placental sharing and angioarchitecture were assessed by injection of each cord vessel with dyed barium sulphate. The 2 territories were delineated on an X-ray angiogram. The diameter of each intertwin anastomosis was measured on a digital photograph. We included 178 twin pairs. Early onset discordant growth, late-onset discordant growth, and concordant growth occurred in 15, 13, and 150 pregnancies, respectively. Twin pairs with early-onset discordant growth had lower survival rates and were delivered at an earlier gestational age than pairs with late-onset discordant and concordant growth. The degree of birthweight discordance was similar in early- and late-onset discordant growth. Severe intertwin hemoglobin differences at the time of birth occurred in 0%, 38%, and 3% of pairs with early-onset discordant growth, late-onset discordant growth, and concordant growth, respectively. The placentas of pairs with early-onset discordant growth were more unequally shared and had larger arterioarterial anastomoses and a larger total anastomotic diameter as compared with placentas of pairs with late onset-discordant or concordant growth. Unequal placental sharing appears to be involved in the etiology of early-onset discordant growth, whereas a late intertwin transfusion imbalance may be involved in some cases with late-onset discordant growth.

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