A conditional standard for the customized fetal growth trajectory in twin pregnancy.

BACKGROUND: The difference in the birth weights between twins and singletons grows with advancing gestation. Although many fetal weight standards based on ultrasonographic measurements have been created for tracking fetal growth in twin pregnancies, their applicability to other groups is limited by the fact that they are population specific. OBJECTIVE: This study aimed to generate conditional centiles for growth assessment of twin fetuses and to compare them with other population-based growth standards for singleton and twin fetuses. STUDY DESIGN: This was a retrospective, longitudinal study of ultrasound-based estimated fetal weight data of normal twin fetuses delivered after 34 weeks of gestation. Linear mixed effects models that adjusted for maternal characteristics, fetal gender, and chorionicity were used to evaluate the relationship between estimated fetal weight and gestational age. The estimated fetal weight reference values were calculated using conditional centile based on the estimated fetal weight at an earlier gestational age. To compare our results with previous studies, fetal growth curves were generated using a formula we created that included maternal characteristics and the estimated fetal weight at 24 weeks of gestation in these studies. In a subgroup analysis of our low-risk twin babies born at full term, we calculated the number of fetuses who were reclassified as being in the bottom 10th percentile using each of the previous population-based standard. RESULTS: A total of 2644 ultrasounds with a median of 4 scans per fetus from 572 twin pregnancies were included in this analysis. In the cohort, 36% of the fetuses were monochorionic. Maternal age, body mass index, and the interaction between fetal gender and chorionicity were significantly associated with estimated fetal weight. The predicted growth curves matched the growth standard for twins. In our low-risk group, when the singleton standard was used, the incidence of estimated fetal weight <10th percentile was above 20% from gestational week 24 to 38, and this incidence varied when reclassified using other population-based twin standards. CONCLUSION: This conditional growth chart was specifically designed to assess fetal growth in twin pregnancies, but it is generalizable to other populations.

Ablative effect of the interstitial laser setting in the human placental model.

AIM: To assess the impact of laser power and time on interstitial ablation generated by neodymium-doped yttrium aluminium garnet (Nd:YAG) and diode laser in the human placental model. METHODS: The experiment was carried out in a simulation model of interstitial laser ablation on ex-vivo placental tissue. One-hundred and forty-four pieces of fresh placentae were interstitially ablated with Nd:YAG or diode laser at various power (15, 20, 25, 30 W)-time (5, 10, 15 s) combinations. The ablation tissues were evaluated using both sonographic and histopathologic measurements. RESULTS: Laser generator, power, and time significantly affected the ablation size (p < 0.001). The coagulation zone continuously increased with extending time at the power of 15, 20, and 25 W. When adjusting to the power of 30 W, increased time from 10 to 15 s did not induce the larger coagulation diameter. The maximal diameter was obtained at the laser power of 20 W for 15 s. The ablation from the diode laser was greater than that from Nd:YAG laser. The sonographic evaluation overestimated the ablation size by an average of 24%. CONCLUSION: Diode laser destroys greater tissue than Nd:YAG laser. Different power settings of interstitial laser ablation produce diverse patterns of correlation between laser time and coagulation size.

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

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

A 10-Year Retrospective Review of Prenatal Applications, Current Challenges and Future Prospects of Three-Dimensional Sonoangiography.

Realistic reconstruction of angioarchitecture within the morphological landmark with three-dimensional sonoangiography (three-dimensional power Doppler; 3D PD) may augment standard prenatal ultrasound and Doppler assessments. This study aimed to (a) present a technical overview, (b) determine additional advantages, (c) identify current challenges, and (d) predict trajectories of 3D PD for prenatal assessments. PubMed and Scopus databases for the last decade were searched. Although 307 publications addressed our objectives, their heterogeneity was too broad for statistical analyses. Important findings are therefore presented in descriptive format and supplemented with the authors' 3D PD images. Acquisition, analysis, and display techniques need to be personalized to improve the quality of flow-volume data. While 3D PD indices of the first-trimester placenta may improve the prediction of preeclampsia, research is needed to standardize the measurement protocol. In highly experienced hands, the unique 3D PD findings improve the diagnostic accuracy of placenta accreta spectrum. A lack of quality assurance is the central challenge to incorporating 3D PD in prenatal care. Machine learning may broaden clinical translations of prenatal 3D PD. Due to its operator dependency, 3D PD has low reproducibility. Until standardization and quality assurance protocols are established, its use as a stand-alone clinical or research tool cannot be recommended.

Morphology, intrafetal vascular pattern, and umbilical artery Doppler indices of acardiac twins.

BACKGROUND: Twin reversed arterial perfusion (TRAP) sequence consists of acardiac twin (A) paradoxically perfused by pump twin (P) through an umbilical artery (UA). We proposed characterization of acardiac twins with intrafetal vascular pattern (IVP), and assessed its correlation with morphology and UA Doppler indices. METHODS: We prospectively evaluated 21 cases of TRAP sequence. Morphology (acardia vs hemicardia) and IVP (simple vs complex) of acardiac twins were characterized with ultrasound and color Doppler. Twins weight ratio (A/P Wt) and UA Doppler indices of acardiac and pump twins including (1) difference of systolic/diastolic ratio (UA ∆S/D), (2) difference of resistance index (UA ∆RI), and (3) ratio of pulsatility index (UA PI A/P) were calculated. RESULTS: The median (min, max) gestational age at diagnosis was 18 (11, 27) weeks. Acardia (n = 14) were associated with simple IVP (n = 16) (P < .05). After exclusion of acardia with complex IVP (n = 1), the A/P Wt, UA ∆S/D, UA ∆RI, and UA PI A/P of acardia with simple IVP (n = 13), hemicardia with simple IVP (n = 3), and hemicardia with complex IVP (n = 4) were not significantly different (P > .05). CONCLUSIONS: Most of acardiac twins were acardia with simple IVP. Morphology and IVP of acardiac twins were not associated with UA Doppler indices.

Additional benefits of three-dimensional ultrasound for prenatal assessment of twins.

Three-dimensional ultrasound (3DUS) may provide additional information for prenatal assessment of twins. It may improve the diagnostic confidence of dating, nuchal translucency (NT) and chorionicity assignment in twin pregnancies. The "virtual 3DUS placentoscopy" can guide selective fetoscopic laser photocoagulation (SFLP) to treat twin-twin transfusion syndrome (TTTS). Volumetric assessment of the dysmorphic acardiac twin with the Virtual Organ Computer-aided Analysis (VOCAL) software is more accurate than the conventional ultrasound measurement. Twin anemia polycythemia (TAP) sequence and selective intrauterine growth restriction (sIUGR) may be clinically monitored with 3DUS placental volume (PV) and power Doppler vascular indices. Congenital anomalies are more common in twins. Evaluation of fetal anomalies with 3DUS could assist perinatal management. The 3DUS power Doppler can provide a better understanding of true and false umbilical cord knots, which are commonly found in monoamniotic (MA) twins. Single demise in monochorionic (MC) twin pregnancies can cause severe neurologic morbidity in the surviving co-twin. Prenatal prediction of brain injury in the surviving co-twin with unremarkable neurosonographic examination is difficult. The 3DUS power Doppler may aid in prenatal detection of subtle abnormal cerebral perfusion. Prenatal assessment of conjoined twins with 3DUS is important if emergency postnatal surgical separation is anticipated. There is no significant additional advantage in using real-time 3DUS to guide prenatal interventions. Assessment of the cervix and pelvic floor during twin pregnancies is enhanced with 3DUS. Due to lack of high-quality studies, routine prenatal 3DUS in twin pregnancies needs to be balanced with risks of excessive ultrasound exposure.

Comparison of Mannequin Training Satisfaction with a Conventional Box Trainer and a Low-Fidelity Fetoscopic Surgical Simulator for Selective Fetoscopic Laser Photocoagulation.

BACKGROUND: A low-fidelity fetoscopic surgical simulator (FSS) for training of selective fetoscopic laser photocoagulation (SFLP) was developed. OBJECTIVE: To evaluate and compare training satisfaction with an FSS and with a conventional box trainer (BT). METHODS: The BT consisted of a cleaned human placenta attached to the inside of a plastic storage box with a watertight lock cover and an ultrasound-transparent rubber skin. The FSS consisted of the replica of a monochorionic twin placenta attached to the inside of a spherically shaped, ultrasound-transparent phantom. Tap water was used as an ultrasound conduction agent. Evaluation of the mannequin trainings was conducted on 8 junior maternal-fetal medicine (MFM) attending physicians and 22 MFM fellows. Training satisfaction was scored from 0 to 10 on 8 different domains. RESULTS: The mean satisfaction score (±SD) with the FSS was higher than with the BT in all domains (p < 0.05). The fellows' training satisfaction with the BT was greater than that of the attending physicians in 4 domains: tactile feedback, demonstration of chorionic vessels, feedback on performance, and overall value as learning aid (p < 0.05). CONCLUSIONS: As evaluated by a small group of trainees, our FSS is superior to the BT in mannequin training of SFLP. However, the BT may be more useful for trainees with limited clinical experience.

Simulation-based fetal shunting training.

OBJECTIVES: To develop a simulation model and assess the learning curve of fetal shunting. METHODS: Three staff and three trainees performed fetal shunting on a model using the fetal bladder stent. The model was evaluated according to various sources of validity evidence. The number of procedures to reach competency was determined by the learning curve-cumulative summation (LC-CUSUM) and CUSUM analysis. The learning and control phases were defined as the periods before and after passing the level of competency, respectively. RESULTS: The model was validated to be constructive in the educational process. A total of 600 procedures were carried out with an overall success rate of 94.2% and no significant difference between staff and trainees. The average number of procedures to reach competency was 47. Total procedural time decreased after passing the level of competency. Although the trainees required a longer procedural time in the learning phase than the staff did, there was no significant between-group difference in the control phase. CONCLUSIONS: Using this model, the estimated number of procedures to achieve competency was 47, as substantiated by the increased procedural success and reduced procedural time in the control phase. Training on this simulation model may improve technical performance.

Long-Term Assessment of a Prospective Cohort of Patients Undergoing Laparoscopic Sacrocolpopexy.

OBJECTIVE: To report long-term outcomes after laparoscopic sacrocolpopexy. METHODS: We conducted a prospective descriptive cohort study on 331 consecutive patients who underwent laparoscopic sacrocolpopexy for symptomatic prolapse (Pelvic Organ Prolapse Quantification [POP-Q] system stage 2 or greater) at one center, with minimum 1.5 years of follow-up by April 30, 2014. Primary outcome measures were Patient Global Impression of Change score and failure at the apex (C≥-1 cm; POP-Q stage 2 or greater). Secondary outcomes were anatomical failure in other compartments, duration of follow-up, occurrence and time point of complications, reinterventions, and functional outcomes by response to a standardized 24-question interview on prolapse and bladder, bowel, and sexual function. Assessment was by an experienced clinician not involved in patient management. RESULTS: The follow-up rate was 84.6% (280/331); 185 of 331 (55.9%) patients were both physically examined and interviewed, and 95 of 331 (25.7%) were interviewed only. The median age at interview was 72 years (interquartile range 13 years), with a follow-up period of 85.5 months (interquartile range 46 months). Approximately 83% (231/280) reported improvement; 5.7% (16/280) were unchanged, 5.7% (16/280) felt slightly worse, and 6.8% (17/280) reported clear deterioration. Anatomical failure at point-C was 8.6% (16/185); anterior (22.2%, 41/185) and posterior (28.6%, 53/185) prolapse were more common than apical prolapse. Of those with level-I anatomical cure, 10.1% (17/185) felt worse; half of them (9/17) because of prolapse in another compartment. The others had urinary problems (41.2%, 7/17), obstructive defecation (11.8%, 2/17), or dyspareunia (11.8%, 2/17). Conversely, the majority of patients with recurrence at the vault (62.5%, 10/16) self-reported to be improved. The reoperation rate was 17.8% (48/270), including 19 (7.0%) for graft-related complications and nine (3.3%) for prolapse. CONCLUSION: More than four out of five patients (82.5%) felt improved 86 months after laparoscopic sacrocolpopexy. Of those not improved, two thirds had recurrent prolapse; however, typically mid-vaginal. The other third reported urinary or bowel problems or dyspareunia. Reintervention for prolapse was 3.3%. The most common reasons for reoperation were graft-related complications (7.0%) and urinary incontinence (6.7%).

Advanced ultrasound for prenatal interventions.

Ultrasound is an integral part of prenatal interventions. Doppler studies and 3-dimensional ultrasound (3DUS) are frequently used to determine whether fetal surgery is required. The operator's experience remains crucial for reducing procedure-related morbidity. Real-time 3DUS (or 4DUS) can simultaneously display the needle tip in three orthogonal planes, providing reassurance that no fetal parts are in the path. In experienced hands, 4DUS guidance may not be more effective than B-mode, but its value for less-experienced operators remains to be determined. Recent developments in needle, shunt, and video endoscopic technologies may compliment the use of image-guided in utero procedures. Future developments of higher-dimensional transducers and image software may improve the utility of ultrasound for invasive obstetric interventions.

Time and temperature dependence of radiofrequency ablation in the human placenta.

OBJECTIVE: The objective of the study is to compare radiofrequency (RF) effects on fresh placentae with varying levels of sustained time (Ts) and degrees of target temperature (°t). METHOD: A total of 108 pieces of fresh placentae were coagulated with a 2-cm RF needle at 60 W in an organ bath. The vertical and horizontal diameters (Vd, Hd) of tissue coagulation visualized by ultrasound were measured. The impacts of 12 different Ts-°t combinations on the ablation size ascertained on pathological examination (Vdp , Hdp ) were compared using 2-way ANOVA. The agreement between sonographic and pathological findings was assessed using Bland-Altman analysis. RESULTS: Considerable changes in the Vdp and Hdp were associated with increasing the Ts and °t. The impact of RF on tissue coagulation was greatest when the °t was set at 100°C, with further destruction as the Ts progressed to 7 minutes of exposure. The ablation size estimated by ultrasound exhibited an overestimation by an average of 5.65% and 21.02% for Vd and Hd, respectively. CONCLUSION: A prolonged Ts at a higher °t contributes to progressive placental tissue destruction by RF, with maximum destruction at 100°C for 7 minutes in an ex vivo nonperfused placenta. Tissue injury that is apparent on ultrasound may extend beyond pathological damage.

Model Surgical Training: Skills Acquisition in Fetoscopic Laser Photocoagulation of Monochorionic Diamniotic Twin Placenta Using Realistic Simulators.

Fetoscopic laser coagulation of arterio-venous anastomoses (AVA) in a monochorionic placenta is the standard of care for twin-twin transfusion syndrome (TTTS), but is technically challenging and can lead to significant complications. Acquiring and maintaining the necessary surgical skills require consistent practice, a critical caseload, and time. Training on realistic surgical simulators can potentially shorten this steep learning curve and enables several proceduralists to acquire procedure-specific skills simultaneously. Here we describe realistic simulators designed to allow the user familiarity with the equipment and specific steps required in the surgical treatment of TTTS, including fetoscopic handling, approaches to anterior and posterior placenta, recognition of anastomoses, and efficient coagulation of vessels. We describe the skills that are especially important in conducting placental laser coagulation that the surgeon can practice on the model and apply in a clinical case. These models can be adapted easily depending on the availability of materials and require standard fetoscopy equipment. Such training systems are complementary to traditional surgical apprenticeships and can be useful aids for fetal medicine units that provide this clinical service.

Undiagnosed Uterine Sarcomas Identified During Surgery for Presumed Leiomyoma at a National Tertiary Hospital in Thailand: A 10-Year Review.

OBJECTIVES: The aim of this study was to evaluate the rate, clinical characteristics, and survival outcomes of an undiagnosed uterine malignancy in patients who underwent surgical treatment for presumed leiomyomas. METHODS: Medical records of patients who underwent surgical treatment for presumed leiomyomas, from January 2004 to September 2013, were retrospectively reviewed, and the data were followed until September 2016. Demographic data, tumor characteristics, oncologic treatment, and response rate were analyzed by descriptive statistics. Kaplan-Meier method was used for survival analysis. This study includes follow-up data through December 31, 2016. RESULTS: A total of 11,258 medical records of presumed leiomyoma patients undergoing hysterectomy during the studied period were reviewed. Pathology of uterine sarcoma was found in 22 patients (0.2%), all of whom were included. Nineteen patients had leiomyosarcoma, and 3 had endometrial stromal sarcoma. Mean age of patients was 48.3 ± 6.9 years. All patients underwent total abdominal hysterectomy, with 20 patients undergoing concurrent bilateral salpingo-oophorectomy. Uterine sarcoma was classified as stage IB in 21 patients and stage IIIC in 1 patient. Fifteen patients were prescribed the following adjuvant treatment: chemotherapy in 13 patients and megestrol acetate in 2 patients. Thirteen patients had recurrent disease, and 3 patients died of their disease. The mean progression-free survival was 50.1 ± 41.3 months, and overall survival was 59.3 ± 43.0 months. CONCLUSIONS: One in 512 patients who underwent hysterectomy because of presumed uterine leiomyomas had inadvertent uterine sarcomas. Even with adjuvant therapy, treatment outcome was rather poor, with almost 60% recurrence rate and median progression-free survival and overall survival of less than 5 years.

Establishing Prenatal Surgery for Myelomeningocele in Asia: The Singapore Consensus.

OBJECTIVES: The Management of Myelomeningocele Study (MOMS Trial) has inspired many fetal therapy centers (FTCs) to offer open fetal surgery for myelomeningocele (MMC). This is an initial effort to create a candidate model that can be applicable to many parts of Asia. MATERIAL AND METHODS: A limited selection of specialists from 4 established FTCs in Thailand, Hong Kong, India, and Singapore met for a round table discussion. Experts from Children's Hospital of Philadelphia (CHOP) involved in the Trial moderated the session. The practice suggestions in this statement were from a targeted literature review and expert opinion. RESULTS: A high prevalence of MMC in Asia supports an effort to adopt the procedure, but only in established FTCs with good maternal and neonatal ancillary supports. The falling incidence of MMCs may affect case volume and maintenance of skill. A regional approach was recommended. Fetal benefits have to be weighed against maternal risks, with a consideration of recent outcome data from the endoscopic approach. Responsible FTCs need standardized diagnosis and management, with their long-term outcome data available for an audit. CONCLUSIONS: It is envisaged that the information presented by this multidisciplinary team would be useful for FTCs in Asia or elsewhere that plan to establish more advanced fetal care in the future.

Three-dimensional ultrasound for prenatal assessment of conjoined twins: additional advantages?

Conjoined twins are a rare, but serious, complication of monozygotic twins. Early prenatal diagnosis of conjoined twins is increasingly made with transvaginal ultrasound and color Doppler studies. Most prenatally diagnosed conjoined twins are terminated due to the high perinatal mortality, but advancement in pediatric surgery has allowed for successful postnatal separation in a small number of cases, and some parents may consider this option over termination of pregnancy. It is important to get a detailed prenatal ultrasound for the site and extent of fusion for an accurate categorization. Three-dimensional ultrasound (3DUS) provides images that can facilitate counselling for the parents. Additional information that impacts on diagnosis, prognostication, and perinatal management of conjoined twins could be obtained from selective use of 3DUS, particularly those with atypical fetal union. Most of the proposed additional benefits of 3DUS are based on case reports. Magnetic resonance imaging (MRI) has been increasingly used for the purpose of identifying intricate organ sharing. Because of the rarity of this condition, and the heterogeneity of fetal fusion, added benefits of either 3DUS or MRI for prenatal diagnosis and perinatal management of conjoined twins have not been demonstrated by well-conducted clinical trials. This article aims to review clinical application of various 3DUS display modes in prenatal assessment of conjoined twins, focusing on their potential additional benefits, risks and misuses. 3DUS may help detecting additional findings that are not possible with 2DUS, but, it has not been scientifically shown to improve the survival rate of the twins or reduce maternal morbidity.

In vivo evidence by magnetic resonance volumetry of a gestational age dependent response to tracheal occlusion for congenital diaphragmatic hernia.

OBJECTIVE: We aimed to assess in vivo changes in lung and liver volumes in fetuses with isolated congenital diaphragmatic hernia, either expectantly managed or treated in utero. METHOD: This is a secondary analysis of prospectively collected data at two fetal therapy centers. We used archived magnetic resonance images of fetuses taken ≥7 days apart, creating paired observations in 20 expectantly managed cases, 41 with a second magnetic resonance prior to balloon reversal and 64 after balloon removal. We measured observed to expected total fetal lung volume (O/E TFLV) and liver-to-thoracic volume ratio. We calculated changes in volume as compared with the initial measurement and its rate as a function of gestational age (GA) at occlusion. RESULTS: The liver-to-thoracic volume ratio did not change in either group. In expectantly managed fetuses, O/E TFLV did not increase with gestation. In fetuses undergoing tracheal occlusion, the measured increase in volume was 2.6 times larger with balloon in place as compared with that after its removal. GA at tracheal occlusion was an independent predictor of the O/E TFLV. The net rate seems to initially increase and plateau at a maximum of 1.5% per week by 35 to 45 days after occlusion. CONCLUSIONS: Tracheal occlusion induces a net increase in volume, its magnitude essentially dependent on the GA at occlusion.

Awareness of the benefits of folic acid and prevalence of the use of folic acid supplements to prevent neural tube defects among Thai women.

OBJECTIVE: To determine the level of knowledge about the usefulness of periconceptional folic acid supplementation among pregnant women. MATERIALS AND METHODS: An anonymous questionnaire was completed by selected subjects to assess folic acid awareness. The questionnaire was administered to pregnant women who were seeking antenatal care at King Chulalongkorn Memorial Hospital May to December 2005. The questions covered their knowledge and use of folic acid supplements, pregnancy intention, and demographic and socioeconomic characteristics. RESULTS: Out of 401 women surveyed, 76.1% of them reported that they had heard of folate. Of these, only 24.4% of the total subjects knew that folate was something important. Overall, 9.7% of the total women took folic acid during periconceptional period. The most common information sources on folate were the media. Logistic regression analysis showed that education of mother was the strongest predictor of having taken folic acid during the correct period. CONCLUSION: Although some pregnant women are aware of the need to take folic acid, the actual impact of the present recommendations is almost negligible. Information to specifically inform patients about the need to take folic acid to prevent neural tube defects by medias and healthcare personnel seem to improve the final intake of folic acid during the protective period.