Risk factors for cesarean section of the second twin after vaginal delivery of the first twin.

PURPOSE: To document risk factors for combined delivery, defined as unplanned cesarean section for the second twin after vaginal delivery of the first twin, particularly focusing on delivery interval between twins. METHODS: A multi-center cross-sectional study among a cohort of 5411 women with twin pregnancy experiencing vaginal delivery of the first twin in 2007-2016 at 191 tertiary referral hospitals in Japan was conducted. Primary outcome was the occurrence of combined delivery, and data were collected through the Japan Society of Obstetrics and Gynecology perinatal database. Risk factors for combined delivery were investigated using Poisson regression analysis. RESULTS: Combined delivery occurred in 235 women (5.1%) and was significantly associated with delivery interval (P < 0.001). Multivariate analysis showed women with ≥ 25 kg/m2 pre-pregnancy body mass index (BMI) and with birthweight < 1500 g of the second twin had significantly higher risk for combined delivery than women with 18.5-25 kg/m2 pre-pregnancy BMI and with birthweight ≥ 2500 g of the second twin (adjusted risk ratio (aRR) 1.72, 95% confidence interval (CI) 1.15-2.57, and aRR 2.06, 95% CI 1.14-3.72, respectively). Breech and transverse presentation of the second twin were also risk factors for combined delivery compared with cephalic presentation (aRR 3.60, 95% CI 2.67-4.85, and aRR 9.94, 95% CI 6.50-15.0, respectively). Although association of combined delivery with pre-pregnancy BMI was attenuated after adjustment by delivery interval, association with birthweight of the second twin was strengthened. CONCLUSION: Delivery interval was significantly associated with combined delivery and mediated the association between combined delivery and some other risk factors.

Clinical features of fetal hydrothorax associated with mucopolysaccharidosis-VII.

Mucopolysaccharidosis (MPS)-VII, called Sly disease, is a lysosomal storage disorder that can cause fetal hydrops, including fetal hydrothorax (FHT). We describe two fetal cases that received thoracoamniotic shunting for FHT, which was later found to be associated with MPS-VII by exome sequencing. Bilateral FHT accompanied by skin edema and ascites was found before 20 weeks of gestation in both cases. One fetus died in utero at 35 weeks of gestation, and the other survived with preterm delivery at 30 weeks of gestation. Both cases inherited compound pathogenic variants of GUSB from parents. Comparison with previously reported primary FHT cases revealed distinct clinical features in MPS-VII-associated FHT: early gestational age at diagnosis (<26 weeks), bilateral effusion, skin edema with ascites, and poor survival. A genetic analysis would be considered for FHT cases, with consideration of shunting when they show early-onset bilateral effusions with skin edema and ascites.

Ultrasound measurement of umbilical venous flow volume at the intra-abdominal portion in normal fetuses.

PURPOSE: Umbilical venous flow volume (UVFV) measured using ultrasound can be used to assess placental circulation in a fetus. UVFV measured at the intra-abdominal portion using half the maximum flow velocity of the umbilical vein (UV) has good reproducibility with low variance. However, reference values in previous reports were based on a small number of cases with a wide reference range. In the present study, we evaluated UVFV standard values measured at the intra-abdominal portion in normal Japanese fetuses. METHODS: Measurements were performed on normal pregnant women during routine ultrasound screening at around 20 or 30 weeks of gestation. The diameter and flow velocity of the UV were measured at the fetal abdomen point between the insertion of the UV and branches of the portal vein. UVFV (ml/min) was calculated as follows: (UV diameter [cm]/2)2 × maximum velocity [cm/s] × 0.5 × 3.14 × 60). RESULTS: A total of 278 pregnant women were included in the study. UVFV increased with gestational weeks, and UVFV per estimated fetal weight (EFW) slightly decreased with increasing gestational weeks. The 50th (10th-90th) percentiles of UVFV per EFW at 20, 25, and 30 weeks of gestation were 130 (105-165), 123 (94-147), and 104 (80-131) ml/min/kg, respectively. CONCLUSION: New UVFV reference values measured at the intra-abdominal portion of fetuses using large-scale samples were established. Future studies should assess fetuses under pathologic conditions using UVFV reference values.

A fetus with large mediastinal cystic lymphatic malformation managed with prenatal serial thoracocentesis and postnatal sclerotherapy.

We report a very rare case of large fetal mediastinal cystic lymphatic malformation (cLM), formerly called lymphangioma, that was managed with prenatal serial thoracocentesis and postnatal sclerotherapy. A fetal pericardial effusion-like lesion gradually increased the size until it occupied more than half of the thoracic cavity. Thoracocentesis was performed three times, namely at 31 and 35 weeks of gestation, and also just before the delivery for decompression. The characteristic shape changes of the lesion were observed after thoracocentesis. A boy delivered by planned cesarian section at term required respiratory support after birth. Postnatal magnetic resonance imaging (MRI), which showed a large cystic lesion with septa and hemorrhage without solid components, led to the diagnosis of cLM. The fluid from the cyst continued to be drained. Neonatal sclerotherapy using OK-432 was effective and the infant recovered well. Fetal thoracocentesis may be useful for the diagnosis and management of a large mediastinal cLM.

Prevalence of common aneuploidy in twin pregnancies.

The incidence of chromosomal abnormalities in twin pregnancies is not well-studied. In this retrospective study, we investigated the frequency of chromosomal abnormalities in twin pregnancies and compared the incidence of chromosomal abnormalities in dichorionic diamniotic (DD) and monochorionic diamniotic (MD) twins. We used data from 57 clinical facilities across Japan. Twin pregnancies of more than 12 weeks of gestation managed between January 2016 and December 2018 were included in the study. A total of 2899 and 1908 cases of DD and MD twins, respectively, were reported, and the incidence of chromosomal abnormalities in one or both fetuses was 0.9% (25/2899) and 0.2% (4/1908) in each group (p = 0.004). In this study, the most common chromosomal abnormality was trisomy 21 (51.7% [15/29]), followed by trisomy 18 (13.8% [4/29]) and trisomy 13 (6.9% [2/29]). The incidence of trisomy 21 in MD twins was lower than that in DD twins (0.05% vs. 0.5%, p = 0.007). Trisomy 21 was less common in MD twins, even when compared with the expected incidence in singletons (0.05% vs. 0.3%, RR 0.15 [95% CI 0.04-0.68]). The risk of chromosomal abnormality decreases in twin pregnancies, especially in MD twins.

Long-term neurodevelopmental outcomes of the pump twin in twin reversed arterial perfusion sequence treated by radiofrequency ablation.

OBJECTIVES: To assess long-term neurodevelopmental outcomes in children after radiofrequency ablation (RFA) for twin reversed arterial perfusion (TRAP) sequence. METHODS: This cross-sectional study included children who underwent RFA for the TRAP sequence between 2012 and 2018. We assessed neurodevelopment in children using the Kinder Infant Development Scale, a validated questionnaire. The developmental quotient (DQ) assessed in nine subscales was calculated as the developmental age divided by the chronological age. Neurodevelopmental delay (NDD) was defined as a DQ of <70 points. RESULTS: In total, 38 children from 37 pregnancies underwent RFA for the TRAP sequence during the study period; 6 fetuses died in utero. We sent the questionnaire to the parents of the 32 surviving children and obtained answers for 27 (84%). The median age at the assessment was 2 years and 5 months old. The median total DQ was 111 (80-150). Most median DQs in the nine subscales were above 70. The incidence of NDD was 0% (0/27). There were no marked differences in DQ by chorionicity. CONCLUSIONS: Children who survived after RFA for TRAP sequence showed favorable long-term neurodevelopmental outcomes. Radiofrequency ablation seems to rarely affect fetal neurodevelopment. Pregnant women with TRAP sequence are encouraged to be treated by RFA.

Prenatally diagnosed lower urinary tract obstruction: A 15-year experience at two tertiary centers in Japan.

AIM: To examine the outcomes of prenatally diagnosed lower urinary tract obstruction (LUTO) with current management using vesicoamniotic shunting (VAS). METHODS: A retrospective study of prenatally diagnosed LUTO before 26 weeks of gestation at two tertiary centers in Japan between March 2002 and September 2017. LUTO was diagnosed by ultrasound demonstration of an enlarged fetal bladder associated with hydronephrosis and/or hydroureters. VAS was offered for fetuses with LUTO at ≤26 weeks of gestational age, in the presence of oligohydramnios or decreasing amniotic fluid and a favorable fetal urinary analysis. RESULTS: Among 87 fetuses with LUTO, 46 (53%) were terminated before 22 weeks of gestation. Eight cases (9%) underwent VAS and one underwent fetoscopic urethrotomy. The live birth rates in the VAS and expectant groups were 100% (8/8) and 56% (18/32), respectively (p = 0.034), and the survival rates at 6 months old with a normal renal function were 38% (3/8) and 16% (5/32), respectively (p = 0.608). The etiology varied with six cases of associated anomalies among 23 diagnosed cases. Among the nine cases of posterior urethral valve (PUV), only one fetus underwent VAS at 25 weeks of gestation, ultimately surviving with mild renal dysfunction. Among the other eight cases of PUV that were managed expectantly, two died, and only one of the six survivors showed a normal renal function. CONCLUSIONS: More than half of the prenatally diagnosed LUTO cases were terminated. VAS seemed effective for achieving a perinatal survival, regardless of etiology. The outcomes were poor in cases of expectantly managed PUV.

Risk Profiling of the Solomon Technique versus Selective Technique of Fetoscopic Laser Surgery for Twin-Twin Transfusion Syndrome.

We evaluated the outcomes and adverse events after fetoscopic laser surgery (FLS) for twin-twin transfusion syndrome (TTTS) using the Solomon technique in comparison to the selective technique. A retrospective analysis of a single-center consecutive cohort of FLS-treated TTTS using the selective (January 2010 to July 2014) and Solomon (August 2014 to December 2017) techniques was performed. Among 395 cases, 227 underwent selective coagulation and 168 underwent the Solomon technique. The incidence rates of recurrent TTTS (Solomon vs. selective: 0% vs. .9%, p = .510) and twin anemia-polycythemia sequence (.6% vs. .4%, p = .670) were very low in both groups. The incidence rates of placental abruption (Solomon vs. selective: 10.7% vs. 3.5%, p = .007) and preterm premature rupture of the membranes (pPROM) with subsequent delivery before 32 weeks (20.2% vs. 7.1%, p < .001) were higher in the Solomon group. The median birth recipient weight was significantly smaller in the Solomon group (1790 g vs. 1933 g, p = .049). The rate of survival of at least one twin was significantly higher in the Solomon group (98.2% vs. 93.8%, p = .046). The Solomon technique and total laser energy were significant risk factors for pPROM (odds ratio: 2.64, 1.07, 95% CI [1.32, 5.28], [1.01, 1.13], p = .006, p = .014, respectively). These findings suggest that the Solomon technique led to superior survival outcomes but increased risks of placental abruption, pPROM and fetal growth impairment. Total laser energy was associated with the occurrence of pPROM. Close attention to adverse events is required for perinatal management after FLS to treat TTTS using the Solomon technique.

Ultrasound measurement of fetal arterial pulse pressure using phased-tracking methods: A phantom study and clinical experience with antenatal corticosteroid therapy.

AIM: This study aimed to compare the accuracy of fetal pulse pressure estimated with a vascular simulator with that obtained by a manometer (reference) and evaluate the pulse pressure in normal human fetuses and fetuses whose mothers received corticosteroids. METHODS: Fetal pulse pressure was estimated as the product of blood flow velocity and pulse wave velocity, based on the water hammer equation. Ultrasonic raw radiofrequency signals for blood flow velocity were captured from the fetal descending aortas at the diaphragm level, and pulse wave velocity was simultaneously measured from different directions using the phased-tracking method. First, the precision and accuracy of pulse pressure in the estimated method were verified by a circulatory phantom simulator, which reproduced fetal blood flow using a pulsating pump. Then, the pulse pressure of 98 normal human fetuses after 17 weeks of gestation and the fetal pulse pressure in 21 mothers who received antenatal corticosteroids for fetal maturation were measured. RESULTS: A significant correlation between the estimated pulse pressure values and the actual values was found in the phantom simulation (r = 0.99, P < 0.01). The estimated pulse pressure was significantly correlated with gestational age in normal fetuses (r = 0.74, P < 0.01). In steroid-treated pregnant women, fetal pulse pressure was observed to increase significantly on the second day of administration (P < 0.01). CONCLUSION: A noninvasive and accurate estimation model of fetal pulse pressure could be established using phased-tracking method, and this method has the potential to improve the assessment of human fetal hemodynamics.

Reliability and characteristics of ultrasound measurement of fetal umbilical venous blood flow volume according to the site of measurement.

PURPOSE: This study aimed at assessing the reliability and characteristics of fetal umbilical venous blood flow volume (UVFV) measurement using ultrasound. METHODS: We conducted a prospective study at our center from November 2017 to July 2019. We performed transabdominal ultrasound examinations at 18-34 weeks' gestation in uncomplicated singleton pregnancies. UVFV was calculated using vessel diameter (D) and maximum flow velocity (V) as follows: (D/2)2 × π × V × 0.5 × 60 (Q, mL/min). Two examiners measured each value three times in the free-loop (FL) and intra-abdominal (IA) portions of the umbilical vein. Intra-rater and inter-rater reliability was evaluated by intraclass correlation coefficient (ICC) and a Bland-Altman plot. RESULTS: Two hundred and eight cases were measured by two examiners. The rate of complete measurement at FL and IA was not significantly different (88.5% vs. 79.3%, respectively; p = 0.113). The intra-rater reliability of D and V was high at FL and IA. Regarding inter-rater reliability, the ICC of D, V, and Q was 0.973, 0.582, and 0.963 at FL, and 0.994, 0.912, and 0.989 at IA, respectively. A Bland-Altman plot showed that D and V had greater standard deviation at FL than IA. Regarding Q, the standard deviation at FL was also larger than at IA, and measurement variance at FL increased as the measured value increased, but that at IA did not. CONCLUSION: UVFV measurement showed high intra-rater and inter-rater reliability at FL and IA, but the variance of measurements at FL became large as the measured value increased. Properties of different measurement sites should be considered when evaluating UVFV.

Radiofrequency Ablation with an Internally Cooled Electrode for Twin Reversed Arterial Perfusion Sequence.

OBJECTIVE: The study aims to evaluate the efficacy of radiofrequency ablation (RFA) with an internally cooled electrode for twin reversed arterial perfusion (TRAP) sequence. METHODS: From April 2008 through December 2014, we retrospectively reviewed all patients who underwent RFA with an internally cooled electrode for TRAP sequence at 3 tertiary referral centers in Japan. RESULTS: Twenty-five monochorionic diamniotic twin pregnancies underwent RFA with an internally cooled electrode for TRAP sequence at 16-27 weeks of gestation. In all cases, umbilical cord blood flow cessation in the acardiac twin was confirmed by ultrasonography with color Doppler. There were 2 cases of procedure-related complications: 1 case of unintentional septostomy and 1 case of anemia in a pump twin. Fetal demise of the pump twin occurred in 3 (12%) cases. Twenty-two (88%) of 25 pump twins were delivered alive. The median gestational age at delivery was 36 + 3 weeks (range 25 + 2-40 + 5 weeks). There were 14 cases (64%) of premature deliveries before 37 weeks and 5 (23%) before 32 weeks. CONCLUSION: RFA with an internally cooled electrode is a feasible and effective procedure for the treatment of TRAP sequence.

Measurement of internal diameter changes and pulse wave velocity in fetal descending aorta using the ultrasonic phased-tracking method in normal and growth-restricted fetuses.

Phased tracking (PT) is an ultrasound-based technique that enables precise measurement of a target velocity. The aims of this study were to use PT to evaluate arterial pulse waveform, pulse wave velocity and fetal pulse pressure in normal and growth-restricted fetuses. One hundred fetuses with normal development and 15 fetuses with growth restriction were analyzed. Ultrasonic raw radiofrequency signals were captured from a direction perpendicular to the vascular axis at the fetal diaphragmatic level for the difference in internal dimensions (DID), or simultaneously from different directions for the pulse wave velocity. Pulsatile movement of the proximal and distal intima of the vessels was analyzed using PT. The fetal DID exhibited no significant changes in growth-restricted fetuses. Pulse wave velocity (3.8 ± 0.32 m/s vs. 2.2 ± 0.069 m/s, p < 0.001) and estimated pulse pressure (6.9 ± 0.90 kPa vs. 2.5 ± 0.18 kPa, p < 0.001) were significantly elevated in growth-restricted fetuses. Assessment of DID and pulse wave velocity of the descending aorta using PT is a feasible, non-invasive approach to evaluation of fetal hemodynamics.

Assessing Fetal Cardiac Function by Measuring Myocardial Radial Velocity Using the Phased-Tracking Method.

OBJECTIVE: This study aimed to assess the cardiac function of healthy and pathological fetuses by measuring radial velocity using phased tracking (PT). Based on phase differences, PT allows the displacement of a specified point to be detected with improved spatial and temporal resolution. METHODS: PT was used to assess cardiac radial velocity in the basal free wall of the left and right ventricles in 134 healthy fetuses, 10 second-trimester intrauterine growth-restricted (IUGR) fetuses, and 10 recipient twins with twin-to-twin transfusion syndrome (TTTS). Maximum velocities were measured in systole and early diastole. RESULTS: Maximum radial velocity was successfully measured in 126 healthy fetuses (94%) at gestational ages of 16-40 weeks. Systolic and early diastolic maximum velocities increased with gestational age in both ventricles. As compared with controls, IUGR fetuses had significantly lower early diastolic maximum velocities in the right ventricle, and recipient twins with TTTS had significantly lower systolic and early diastolic maximum velocities in both ventricles. CONCLUSIONS: PT demonstrated right ventricular diastolic dysfunction in second-trimester IUGR fetuses as well as systolic and diastolic dysfunctions in both ventricles in recipient twins with TTTS. PT could be useful for evaluating fetal cardiac radial function.