Vasa previa in singleton pregnancies: diagnosis and clinical management based on an international expert consensus.

BACKGROUND: There are limited data to guide the diagnosis and management of vasa previa. Currently, what is known is largely based on case reports or series and cohort studies. OBJECTIVE: This study aimed to systematically collect and classify expert opinions and achieve consensus on the diagnosis and clinical management of vasa previa using focus group discussions and a Delphi technique. STUDY DESIGN: A 4-round focus group discussion and a 3-round Delphi survey of an international panel of experts on vasa previa were conducted. Experts were selected on the basis of their publication record on vasa previa. First, we convened a focus group discussion panel of 20 experts and agreed on which issues were unresolved in the diagnosis and management of vasa previa. A 3-round anonymous electronic survey was then sent to the full expert panel. Survey questions were presented on the diagnosis and management of vasa previa, which the experts were asked to rate on a 5-point Likert scale (from "strongly disagree"=1 to "strongly agree"=5). Consensus was defined as a median score of 5. Following responses to each round, any statements that had median scores of ≤3 were deemed to have had no consensus and were excluded. Statements with a median score of 4 were revised and re-presented to the experts in the next round. Consensus and nonconsensus statements were then aggregated. RESULTS: A total of 68 international experts were invited to participate in the study, of which 57 participated. Experts were from 13 countries on 5 continents and have contributed to >80% of published cohort studies on vasa previa, as well as national and international society guidelines. Completion rates were 84%, 93%, and 91% for the first, second, and third rounds, respectively, and 71% completed all 3 rounds. The panel reached a consensus on 26 statements regarding the diagnosis and key points of management of vasa previa, including the following: (1) although there is no agreement on the distance between the fetal vessels and the cervical internal os to define vasa previa, the definition should not be limited to a 2-cm distance; (2) all pregnancies should be screened for vasa previa with routine examination for placental cord insertion and a color Doppler sweep of the region over the cervix at the second-trimester anatomy scan; (3) when a low-lying placenta or placenta previa is found in the second trimester, a transvaginal ultrasound with Doppler should be performed at approximately 32 weeks to rule out vasa previa; (4) outpatient management of asymptomatic patients without risk factors for preterm birth is reasonable; (5) asymptomatic patients with vasa previa should be delivered by scheduled cesarean delivery between 35 and 37 weeks of gestation; and (6) there was no agreement on routine hospitalization, avoidance of intercourse, or use of 3-dimensional ultrasound for diagnosis of vasa previa. CONCLUSION: Through focus group discussion and a Delphi process, an international expert panel reached consensus on the definition, screening, clinical management, and timing of delivery in vasa previa, which could inform the development of new clinical guidelines.

A learning curve for first trimester anatomy ultrasound in obese patients.

OBJECTIVES: A recent randomized controlled trial of first-trimester anatomy ultrasound in obese women found some advantages to using this technique in this population, but some aspects of feasibility were not clear, such as whether first-trimester ultrasound can be brought outside of a research setting. The learning curve for first-trimester anatomy has been described in the general population, but a learning curve has not been described for this technique in obese patients. This study sought to describe a learning curve for first-trimester anatomy ultrasounds in obese patients in an operator familiar with the basics of first-trimester imaging. DESIGN: This was a secondary analysis of the EASE-O pilot randomized controlled trial (NCT04639973), which recruited 128 women with a BMI≥35 kg/m2 and randomized them into two groups based on the timing of the first evaluation of fetal anatomy, to compare the completion rate of first- and second-trimester anatomy ultrasound. PARTICIPANTS: Pregnant women with a BMI≥35 kg/m2 Setting: January 2021 and February 2022 at maternal-fetal medicine clinics in Houston, Texas Methods: This secondary analysis evaluated data on the completion rate of first-trimester scans from the parent trial. Scans were grouped into bin sizes of 3, and prop_model for R version 4.2.0 for Windows was used to generate a learning curve across the first 60 scans. RESULTS: The parent study included 60 scans performed by one imager who had previously only done first-trimester scans in lean patients for limited anatomy. The probability of a complete scan increased over 60 scans from 0.38 to 0.69; 29 scans were required to reach the final probability, after which only marginal improvement followed. LIMITATIONS: The major limitation is the inclusion of only one operator for this curve. CONCLUSIONS: For an ultrasound operator with basic familiarity in first-trimester imaging, approximately 30 scans are needed to acquire a completion rate of 70% for detailed first trimester anatomy in women with BMI ≥35 kg/m2. This can be used in education and training programs focused on imaging in the first trimester.

Abnormal Shape and Size of the Cardiac Ventricles Are Associated with a Higher Risk of Neonatal Death in Fetuses with Isolated Left Congenital Diaphragmatic Hernia.

INTRODUCTION: The objective of this study was to evaluate the association between fetal cardiac deformation analysis (CDA) and cardiac function with severe adverse perinatal outcomes in fetuses with isolated left congenital diaphragmatic hernia (CDH). METHODS: CDA in each ventricle (contractility, size, and shape), evaluated by speckle tracking and novel FetalHQ software, and markers of cardiac function (E/A ratios, pulmonary and aortic peak systolic velocities, and sigmoid annular valve diameters), were evaluated in fetuses with isolated left CDH. Two evaluations were performed: at referral (CDA and function) and within 3 weeks of delivery (CDA). Severe adverse neonatal outcomes were considered neonatal death (ND) or survival with CDH-associated pulmonary hypertension (CDH-PH). Differences and associations between CDA, cardiac function, and severe adverse outcomes were estimated. RESULTS: Fifty fetuses were included, and seventeen (34%) had severe adverse neonatal outcomes (11 ND and 6 survivors with CDH-PH). At first evaluation, the prevalence of a small left ventricle was 34% (17/50) with a higher prevalence among neonates presenting severe adverse outcomes (58.8 [10/17] vs. 21.2% [7/33]; p = 0.01; OR, 5.03 [1.4-19.1; p = 0.01]) and among those presenting with neonatal mortality (8/11 [72.7] vs. 9/39 [23.0%]; p = 0.03; OR, 8.9 [1.9-40.7; p = 0.005]). No differences in cardiac function or strain were noted between fetuses with or without severe adverse outcomes. Within 3 weeks of delivery, the prevalence of small left ventricle was higher (19/34; 55.8%) with a more globular shape (reduced transverse/longitudinal ratio). A globular right ventricle was significantly associated with ND or survival with CDH-PH (OR, 14.2 [1.5-138.3]; p = 0.02). CONCLUSION: Fetuses with isolated CDH at risk of perinatal death or survival with CDH-PH had a higher prevalence of a small left ventricle and abnormal shape of the right ventricle.

Completion of Fetal Anatomy Evaluations in Women With Body Mass Index ≥ 50 kg/m2.

OBJECTIVES: As maternal body mass index (BMI) increases, fetal anatomy ultrasound becomes more challenging, less sensitive, and less likely to be complete. We sought to report our experience of incomplete evaluation of anatomy in patients with BMI of 50 kg/m2 or greater. METHODS: This is a retrospective cohort of singleton gestations in mothers with BMI of 50 kg/m2 or greater, undergoing anatomy evaluations between 2017 and 2021 at 9 maternal-fetal-medicine sites in Houston, TX. Patient variables and scan results were collected throughout pregnancy to provide a longitudinal assessment of the primary outcome, completion rate (percent of all scans which optimally captured 24 American Institute of Ultrasound in Medicine-recommended images). Secondary outcomes included the rate of optimal capture of each individual structure. RESULTS: In total, 293 patients with BMI ≥50 kg/m2 were identified. Only 28% of initial scans were complete, but over the entire pregnancy, a complete anatomic evaluation was achieved in 76% of women, largely due to weekly ultrasounds done for antenatal testing later in pregnancy. Neither BMI, placental location, nor amniotic fluid volume affected completion rate. The most difficult views are the outflow tracts, 4-chamber view, and spine. CONCLUSIONS: One quarter of women with BMI of 50 kg/m2 or greater will not have a complete fetal anatomic evaluation by the end of pregnancy, since even basic fetal anatomic views are technically challenging to complete. Solutions deserve further attention, and may include first trimester imaging, transvaginal imaging, and optimization of ultrasound machine settings.

Does Prediction of Neonatal Mortality by the Observed/Expected Lung-To-Head Ratio Change during Pregnancy in Fetuses with Left Congenital Diaphragmatic Hernia?

INTRODUCTION: The aim of this study was to evaluate prediction of neonatal mortality in fetuses with isolated left congenital diaphragmatic hernia (CDH) when the observed/expected lung-to-head ratio (O/E LHR) was estimated at two different gestational time points during pregnancy. METHODS: Forty-four (44) fetuses with isolated left CDH were included. O/E LHR was estimated at the time of referral (first scan) and before delivery (last scan). The main outcome was neonatal death due to respiratory complications. RESULTS: There were 10/44 (22.7%) perinatal deaths. The areas under (AU) the ROC curves were: first scan, 0.76, best O/E LHR cut-off 35.5% with 76% sensitivity and 70% specificity; last scan, AU-ROC 0.79, best O/E LHR cut-off 35.2%, with 79.0% sensitivity and 80% specificity. Considering an O/E LHR cut-off ≤35% to define high-risk fetuses at any examination, prediction for perinatal mortality showed: 80% sensitivity, 73.5% specificity, 47.1% positive and 92.6% negative predictive values, and 3.02 (95% CI 1.59-5.73) positive and 0.27 (95% CI 0.08-0.96) negative likelihood ratios. Prediction was similar in the two evaluations as 16/21 (76.2%) of fetuses considered at risk had an O/E LHR ≤35% in the two examinations; in the remaining 5 cases, two were identified only in the first and three only in the last scan. CONCLUSION: The O/E LHR is a good predictor of perinatal death in fetuses with left isolated CDH. Approximately 80% of fetuses at risk of perinatal death can be identified with an O/E LHR ≤35%, and 90% of them will have similar O/E LHR values at the first and at the last ultrasound examinations prior to delivery. In general, 88.6% of all CDH fetuses have a similar severity classification based on the O/E LHR at the first diagnostic ultrasound or at the ultrasound examination prior to delivery.

Quincke versus Diamond-Tip Needles for Entry in Placental Laser Surgery for Twin-to-Twin Transfusion Syndrome.

INTRODUCTION: Chorioamniotic membrane separation (CAS), preterm prelabor rupture of membranes (PPROM), and preterm delivery (PTD) remain as major complications of fetoscopic laser photocoagulation (FLP) for twin-to-twin transfusion syndrome (TTTS). We sought to examine whether use of Quincke-tip needles for initial entry during FLP reduces the risk of these complications. METHODS: This is a secondary analysis of prospectively collected data from patients that had FLP for TTTS at a single tertiary care center (2011-2021). We excluded patients for whom direct trocar entry was used. Patients for whom a Quincke-tip needle was used were compared to those for whom a diamond-tip needle was used during Seldinger entry. Demographics, ultrasound findings and operative characteristics were compared between groups. Postoperative outcomes and complications (including CAS, PPROM, and PTD) were also compared. Multivariate logistic regression models were fit to assess independent risk factors for complications. RESULTS: 386 patients met inclusion criteria; Quincke-tip needles were used in 81 (21.0%) cases, while diamond-tip needles were used in 305 (79.0%). Rates of CAS (11.1 vs. 9.5%, p = 0.67) and PPROM (44.4 vs. 41.0%, p = 0.57) were similar between groups. Patients in the Quincke-tip group delivered 1.5 weeks earlier than those in the diamond-tip group (30.5 vs. 32.0 weeks, p = 0.01). However, these patients were more likely to be delivered for maternal (35.9 vs. 19.0%) and fetal (23.1 vs. 15.3%) indications (p < 0.01). In multivariate analysis, needle type was not identified as an independent risk factor for PPROM. However, Quincke-tip needle use was associated with PTD less than 32 weeks (aOR 1.74, 95% CI: 1.02-2.97, p = 0.043). CONCLUSION: Membrane complications following FLP were not associated with the needle type used for entry. Earlier delivery in the Quincke-tip group was likely attributable to higher rates of delivery for maternal and fetal indications, and not membrane complications. The needle chosen for entry is likely best determined by operator preference.

Semiquantitative Assessment of Amniotic Fluid Among Individuals With and Without Diabetes Mellitus.

OBJECTIVE: To compare the rate and severity of abnormal amniotic fluid volumes (oligohydramnios or polyhydramnios), as well as the distribution of amniotic fluid levels, in pregnancies with and without diabetes. METHODS: We performed a retrospective cohort study of singleton nonanomalous pregnancies receiving an ultrasound examination (USE) in the third trimester. Pregnancies were categorized into those with and without diabetes and subcategorized by diabetes type. The primary outcomes were oligohydramnios or polyhydramnios. Polyhydramnios was also examined by severity. The association between maternal diabetes status and oligohydramnios or polyhydramnios was assessed using logistic regression. In addition, we computed gestational age-specific amniotic fluid index (AFI) and deepest vertical pocket (DVP) centiles for pregnancies with and without diabetes. RESULTS: There were 60,226 USEs from 26,651 pregnancies that met inclusion criteria. There were 3992 (15.0%) pregnancies with diabetes and 22,659 (85.0%) without diabetes. Using AFI, the rate of polyhydramnios was 10.5 versus 3.8% (odds ratio [OR] 2.95; 95% confidence interval [CI] 2.62-3.32) for pregnancies with versus without diabetes, respectively; using DVP, the rate of polyhydramnios was 13.9 versus 5.4% (OR 2.84; 95% CI 2.56-3.15). Rates of oligohydramnios were also increased in pregnancies with diabetes (3.3 versus 2.6%; OR 1.26; 95% CI 1.04-1.52). The AFI and DVP were significantly higher in the cohort with diabetes between 28 and 36 weeks. CONCLUSION: Within our study population, pregnancies with diabetes had increased rates of oligohydramnios and polyhydramnios as well as increased gestational age-specific amniotic fluid volumes between 28 and 36 weeks. A higher prevalence of polyhydramnios was observed using DVP as compared to AFI; nevertheless, associations were similar using either method.

Weekly Differences in the Prevalence of a Short Cervix at 18+0 to 23+6 Weeks of Gestation in Pregnant Women with and without a History of Preterm Delivery.

OBJECTIVE: The study aimed to estimate weekly differences in the prevalence of a short cervix during the period of 18+0 to 23+6 weeks of gestation in pregnant women with and without a history of previous preterm delivery (PTD). DESIGN: An observational study was conducted. METHODS: Setting and participants: 20,002 pregnant women, 18,591 without a history of previous PTD (low risk) and 1,411 with at least one previous PTD (high risk), were evaluated at 18+0 to 23+6 weeks + days of gestation. Weekly differences in the prevalence of a short cervix (≤25 mm, ≤20 mm, and ≤15 mm) between women with and without previous PTD were estimated. RESULTS: High-risk women had a significantly higher prevalence of a short cervix, defined as either ≤25 mm (4.4% vs. 2.2%; p < 0.0001) or ≤20 mm (2.4% vs. 1.2%; p < 0.0001) but not for ≤15 mm (1.2% vs. 0.9%; p < 0.2) as compared to low-risk pregnant women. The odds ratio for a short cervix ≤25 mm in high-risk as compared to low-risk women was 2.0 (95% CI 1.54-2.61; p < 0.0001). Among low-risk women, those evaluated at 22 or 23 weeks of gestation had a significantly higher prevalence of a short cervix ≤25 mm (3.8% vs. 1.9%; p < 0.0001), ≤20 mm (2.4% vs. 0.98%; p < 0.0001), and ≤15 mm (1.6% vs. 0.7%; p < 0.0001) than low-risk women scanned between 18 and 21 weeks of gestation. Similar results were observed for high-risk women. LIMITATIONS: No gestational age at delivery was evaluated. CONCLUSION: There is higher prevalence of short cervix when pregnant women are evaluated at 22+0 to 23+6 than at 18+0 to 21+6 weeks of gestation.

Implementing a Universal Cervical Length Screening Program in a Large Hospital System: It Takes Some Time to Achieve Consistent Results.

OBJECTIVE: The aim of the study was to describe changes in the acceptance of transvaginal (TV) cervical length (CL) assessment and in the variance of CL measurements among operators, after implementation of universal TV-CL screening at 18+0 - to 23+6 weeks/days of gestation. DESIGN: Retrospective cohort. PARTICIPANTS/MATERIALS, SETTING, METHODS: This study was performed after universal TV-CL screening was implemented at the University of Texas Health Science Center in Houston, TX, USA, for all women undergoing an anatomy ultrasound (US) between 18 0/6 and 23 6/7 weeks/days of gestation. Pregnant women carrying singletons without prior history of preterm delivery who underwent anatomy US evaluation between September 2017 and March 2020 (30 months) were included. The complete study period was divided into five epochs of 6 months each. Changes in patient's acceptance for the TV scan, in CL distribution, in the prevalence of short cervix defined as ≤15, ≤20, or ≤25 mm, and in the performance of US operators across the five epochs were evaluated. Success rate was defined as the percentage of TV-CL measurements obtained in relation to the number of second-trimester anatomy scans. RESULTS: A total of 22,207 low-risk pregnant women evaluated by 36 trained sonographers (operators) were analyzed. Overall, the acceptance for TV-CL measurement was 82.3% (18,289/22,207), increasing from 76.7% in the first epoch to 82.8% (p < 0.0001) in the last epoch. The mean CL did not significantly change from 38.6 mm in the first epoch to 38.5 mm in the last epoch (p = 0.7); however, the standard deviation decreased from 7.9 mm in the first epoch to 7.04 mm in the last epoch (p = <0.01). The prevalence of a short cervix ≤25 mm was 2.2% (n = 399/18,289), ≤20 mm was 1.2% (224/18,289), and ≤15 mm was 0.9% (162/18,289). This prevalence varied only for CL ≤25 mm from 3.02% (88/2,907) in the first epoch to 1.77% (64/3,615) in the last epoch (p = 0.0009). There was a variation in CL measurements among operators (mean 3.3 mm). Sonographers with less than 1 year of experience had a lower success rate for completing TV-CL examinations than more experienced sonographers (80.8% vs. 85.8%; p < 0.03). In general, 77% (27/35) of operators had a success rate ≥80% for completing TV-CL scans. LIMITATIONS: Characteristics of individuals who accepted versus those who declined TV-CL were not compared; CL values were not correlated with clinical outcomes. CONCLUSIONS: During the first 6 months after implementation of a universal CL screening program, there was greater variation in CL measurements, lower acceptance for TV US, and a higher number of women diagnosed with a CL ≤25 mm, as compared to subsequent epochs. After the first 6 months, these metrics improved and remained stable. Most operators improved their performance over time; however, there were a few with a low success rate for TV-CL and others who systematically over- or underestimate CL measurements.

Methods for Monitoring Risk of Hypoxic Damage in Fetal and Neonatal Brains: A Review.

Fetal, perinatal, and neonatal asphyxia are vital health issues for the most vulnerable groups in human beings, including fetuses, newborns, and infants. Severe reduction in oxygen and blood supply to the fetal brain can cause hypoxic-ischemic encephalopathy (HIE), leading to long-term neurological disorders, including mental impairment and cerebral palsy. Such neurological disorders are major healthcare concerns. Therefore, there has been a continuous effort to develop clinically useful diagnostic tools for accurately and quantitatively measuring and monitoring blood and oxygen supply to the fetal and neonatal brain to avoid severe consequences of asphyxia HIE and neonatal encephalopathy. Major diagnostic technologies used for this purpose include fetal heart rate monitoring, fetus scalp blood sampling, ultrasound imaging, magnetic resonance imaging, X-ray computed tomography, and nuclear medicine. In addition, given the limitations and shortcomings of traditional diagnostic methods, emerging technologies such as near-infrared spectroscopy and photoacoustic imaging have also been introduced as stand-alone or complementary solutions to address this critical gap in fetal and neonatal care. This review provides a thorough overview of the traditional and emerging technologies for monitoring fetal and neonatal brain oxygenation status and describes their clinical utility, performance, advantages, and disadvantages.

Personalized assessment of cervical length improves prediction of spontaneous preterm birth: a standard and a percentile calculator.

BACKGROUND: A sonographic short cervix (length <25 mm during midgestation) is the most powerful predictor of preterm birth. Current clinical practice assumes that the same cervical length cutoff value should apply to all women when screening for spontaneous preterm birth, yet this approach may be suboptimal. OBJECTIVE: This study aimed to (1) create a customized cervical length standard that considers relevant maternal characteristics and gestational age at sonographic examination and (2) assess whether the customization of cervical length evaluation improves the prediction of spontaneous preterm birth. STUDY DESIGN: This retrospective analysis comprises a cohort of 7826 pregnant women enrolled in a longitudinal protocol between January 2006 and April 2017 at the Detroit Medical Center. Study participants met the following inclusion criteria: singleton pregnancy, ≥1 transvaginal sonographic measurements of the cervix, delivery after 20 weeks of gestation, and available relevant demographics and obstetrical history information. Data from women without a history of preterm birth or cervical surgery who delivered at term without progesterone treatment (N=5188) were used to create a customized standard of cervical length. The prediction of the primary outcome, spontaneous preterm birth at <37 weeks of gestation, was assessed in a subset of pregnancies (N=7336) that excluded cases with induced labor before 37 weeks of gestation. Area under the receiver operating characteristic curve and sensitivity at a fixed false-positive rate were calculated for screening at 20 to 23 6/7, 24 to 27 6/7, 28 to 31 6/7, and 32 to 35 6/7 weeks of gestation in asymptomatic patients. Survival analysis was used to determine which method is better at predicting imminent delivery among symptomatic women. RESULTS: The median cervical length remained fundamentally unchanged until 20 weeks of gestation and subsequently decreased nonlinearly with advancing gestational age among women who delivered at term. The effects of parity and maternal weight and height on the cervical length were dependent on the gestational age at ultrasound examination (interaction, P<.05 for all). Parous women had a longer cervix than nulliparous women, and the difference increased with advancing gestation after adjusting for maternal weight and height. Similarly, maternal weight was nonlinearly associated with a longer cervix, and the effect was greater later in gestation. The sensitivity at a 10% false-positive rate for prediction of spontaneous preterm birth at <37 weeks of gestation by a short cervix ranged from 29% to 40% throughout pregnancy, yet it increased to 50%, 50%, 53%, and 54% at 20 to 23 6/7, 24 to 27 6/7, 28 to 31 6/7, and 32 to 35 6/7 weeks of gestation, respectively, for a low, customized percentile (McNemar test, P<.001 for all). When a cervical length <25 mm was compared to the customized screening at 20 to 23 6/7 weeks of gestation by using a customized percentile cutoff value that ensured the same negative likelihood ratio for both screening methods, the customized approach had a significantly higher (about double) positive likelihood ratio in predicting spontaneous preterm birth at <33, <34, <35, <36, and <37 weeks of gestation. Among symptomatic women, the difference in survival between women with a customized cervical length percentile of ≥10th and those with a customized cervical length percentile of <10th was greater than the difference in survival between women with a cervical length ≥25 mm and those with a cervical length <25 mm. CONCLUSION: Compared to the use of a cervical length <25 mm, a customized cervical length assessment (1) identifies more women at risk of spontaneous preterm birth and (2) improves the distinction between patients at risk for impending preterm birth in those who have an episode of preterm labor.

Novel Speckle Tracking Analysis Showed Excellent Reproducibility for Size and Shape of the Fetal Heart and Good Reproducibility for Strain and Fractional Shortening.

INTRODUCTION: This study aimed to evaluate reproducibility and agreement of fetal cardiac shape and deformation using FetalHQ. METHODS: Fifty normal fetuses at 20-38 weeks of gestation were evaluated. Two operators independently selected an optimal cardiac cycle using FetalHQ®™software for speckle tracking analysis. Intra- and interobserver correlation coefficient and limits of agreement for cardiac shape and deformation were estimated. RESULTS: Global cardiac markers: high correlation (r = 0.98) and agreement (mean difference, standard deviation [MD, SD] 5.07, 75.8) for ventricular area; moderate correlation (r = 0.78) and agreement (MD, SD: 0.016, 0.08) for global sphericity index (SI) and for left ventricle (LV) global strain (r = 0.65; MD, SD: -4.48, 11.9); and low but still significant correlation (r = 0.58) and agreement (MD, SD: -3.77, 12.27) for right ventricle (RV) global strain. For individual ventricular parameters: high correlation for LV ([median r; range] 0.98; 0.93-0.99) and RV (r = 0.98; 0.97-1.0) SI, and for LV (r = 0.92: 0.56-0.99) and RV (r = 0.96; 0.67-0.99) end diastolic diameters; moderate correlation for LV fractional shortening (r = 0.53; 0.87-0.98); and no significant correlation for RV fractional shortening (r = 0.36; 0.32-0.97). Inter- and intraobserver correlation and agreement were similar for all evaluated parameters. CONCLUSION: Speckle tracking analysis of the fetal heart provides reliable estimations of global and LV shape and deformation. Low correlation in the RV can be related to anatomical structures such as the moderator band.

Preoperative Cervical Length Predicts the Risk of Delivery within One Week after Pleuroamniotic Shunt in Fetuses with Severe Hydrothorax.

OBJECTIVE: The objective of this study was to assess the predictive performance of preoperative cervical length (CL) for delivery within 1 week after pleuroamniotic shunting (PAS) in fetuses with severe hydrothorax. METHODS: A prospective cohort of fetuses with severe hydrothorax referred to our fetal surgery center in Querétaro, Mexico from January 2012 to July 2020. Severe fetal hydrothorax was diagnosed as an accumulation of fluid within the fetal pleural space accompanied with severe bilateral lung compression, mediastinal shift, polyhydramnios, and/or hydrops. Transvaginal CL was measured immediately before PAS, and a short cervix was defined as that <25 mm. The interval from fetal intervention to delivery, prevalence of preterm prelabor rupture of membranes (PPROMs), and associations with delivery within the first week after PAS according to a short or a normal CL, were evaluated. RESULTS: Thirty-five pregnancies with severe fetal hydrothorax treated with PAS were evaluated. Median gestational age at PAS was (weeks + days) 31+2 (range, 26+0-36+1). Two (5.7%) and 7 (20.0%) cases delivered within the first 24 h and 1 week after PAS, respectively. Ten (28.6%) women had a short cervix before PAS, while 25 (71.4%) had normal preoperative CL. Women with a short cervix showed lower mean interval between fetal intervention and delivery (2.4 vs. 5.5 weeks, p = 0.01), and higher prevalence of PPROM (50 vs. 12%, p = 0.01), as compared to women with a nonshort cervix. Preoperative short cervix was associated with significantly higher risk of delivery within the first 24 h (20.0 vs. 0%, respectively, p < 0.05) and 1 week after PAS (50.0 vs. 8.0%, respectively, p < 0.01) compared with pregnancies with normal preoperative CL. CONCLUSION: In pregnancies with severe fetal hydrothorax candidates for pleuroamniotic shunt, identification of a short cervix before fetal intervention can predict delivery within 1 week after the surgical procedure.

Functional Connectome of the Fetal Brain.

Large-scale functional connectome formation and reorganization is apparent in the second trimester of pregnancy, making it a crucial and vulnerable time window in connectome development. Here we identified which architectural principles of functional connectome organization are initiated before birth, and contrast those with topological characteristics observed in the mature adult brain. A sample of 105 pregnant women participated in human fetal resting-state fMRI studies (fetal gestational age between 20 and 40 weeks). Connectome analysis was used to analyze weighted network characteristics of fetal macroscale brain wiring. We identified efficient network attributes, common functional modules, and high overlap between the fetal and adult brain network. Our results indicate that key features of the functional connectome are present in the second and third trimesters of pregnancy. Understanding the organizational principles of fetal connectome organization may bring opportunities to develop markers for early detection of alterations of brain function.SIGNIFICANCE STATEMENT The fetal to neonatal period is well known as a critical stage in brain development. Rapid neurodevelopmental processes establish key functional neural circuits of the human brain. Prenatal risk factors may interfere with early trajectories of connectome formation and thereby shape future health outcomes. Recent advances in MRI have made it possible to examine fetal brain functional connectivity. In this study, we evaluate the network topography of normative functional network development during connectome genesis in utero Understanding the developmental trajectory of brain connectivity provides a basis for understanding how the prenatal period shapes future brain function and disease dysfunction.

Fortnightly surveillance of monochorionic diamniotic twins for twin to twin transfusion syndrome: Compliance and effectiveness.

OBJECTIVES: To determine the compliance and effectiveness of fortnightly ultrasound surveillance for detection of twin-twin transfusion syndrome (TTTS) in monochorionic diamniotic (MCDA) twin gestations. METHODS: This is a retrospective study of ultrasound surveillance of MCDA twins for TTTS. Our surveillance protocol requires fortnightly ultrasounds starting at 16 weeks of gestational age (GA) continuing until delivery. Compliance was assessed by determining the GA of surveillance initiation and time between ultrasounds. GA and Quintero Stage at diagnosis were evaluated to determine whether TTTS was detected prior to advanced disease (Quintero Stage III +) or fetal demise. RESULTS: Of 442 women, 264 (59.7%) initiated surveillance after 16 weeks; follow-up ultrasounds were late in 17.4% of cases. TTTS was diagnosed in 43 (9.7%) women at a median GA of 19.7 [17.4, 23.9] weeks. Of 25/43 (58.1%) cases diagnosed during protocol compliance, 12 had advanced disease and two had fetal demise. A similar proportion of diagnoses (n = 18), made while non-compliant, exhibited advanced disease (11/18, 61.1%, P = .40). Thirteen diagnoses occurred during periods of increased ultrasound frequency due to abnormalities (ie, fluid/estimated fetal weight discrepancies or Doppler abnormalities). CONCLUSIONS: In this population, fortnightly ultrasound compliance was suboptimal. Advanced disease and fetal demise occurred during protocol compliance.

Dual-Imaging Modality Approach to Evaluate Cerebral Hemodynamics in Growth-Restricted Fetuses: Oxygenation and Perfusion.

OBJECTIVE: To evaluate a dual-imaging modality approach to obtain a combined estimation of venous blood oxygenation (SνO2) using susceptibility-weighted magnetic resonance imaging (SWI-MRI), and blood perfusion using power Dopp-ler ultrasound (PDU) and fractional moving blood volume (FMBV) in the brain of normal growth and growth-restricted fetuses. METHODS: Normal growth (n = 33) and growth-restricted fetuses (n = 10) from singleton pregnancies between 20 and 40 weeks of gestation were evaluated. MRI was performed and SνO2 was calculated using SWI-MRI data obtained in the straight section of the superior sagittal sinus. Blood perfusion was estimated using PDU and FMBV from the frontal lobe in a mid-sagittal plane of the fetal brain. The association between fetal brain SνO2 and FMBV, and the distribution of SνO2 and FMBV values across gestation were calculated for both groups. RESULTS: In growth-restricted fetuses, the brain SνO2 values were similar, and the FMBV values were higher across gestation as compared to normal growth fetuses. There was a significantly positive association between SνO2 and FMBV values (slope = 0.38 ± 0.12; r = 0.7; p = 0.02) in growth-restricted fetuses. In normal growth fetuses, SνO2 showed a mild decreasing trend (slope = -0.7 ± 0.4; p = 0.1), whereas FMBV showed a mild increasing trend (slope = 0.2 ± 0.2; p = 0.2) with advancing gestation, and a mild but significant negative association (slope = -0.78 ± 0.3; r = -0.4; p = 0.04) between these two estimates. CONCLUSION: Combined MRI (SWI) and ultrasound (FMBV) techniques showed a significant association between cerebral blood oxygenation and blood perfusion in normal growth and growth-restricted fetuses. This dual-imaging approach could contribute to the early detection of fetal "brain sparing" and brain oxygen saturation changes in high-risk pregnancies.

Quantitative susceptibility mapping in the human fetus to measure blood oxygenation in the superior sagittal sinus.

OBJECTIVES: To present the feasibility of performing quantitative susceptibility mapping (QSM) in the human fetus to evaluate the oxygenation (SvO2) of cerebral venous blood in vivo. METHODS: Susceptibility weighted imaging (SWI) data were acquired from healthy pregnant subjects (n = 21, median = 31.3 weeks, interquartile range = 8.8 weeks). The susceptibility maps were generated from the SWI-phase images using a modified QSM processing pipeline, optimised for fetal applications. The processing pipeline is as follows: (1) mild high-pass filtering followed by quadratic fitting of the phase images to eliminate background phase variations; (2) manual creation of a fetal brain mask that includes the superior sagittal sinus (SSS); (3) inverse filtering of the resultant masked phase images using a truncated k-space approach with geometric constraint. Further, the magnetic susceptibility, ∆χv and corresponding putative SvO2 of the SSS were quantified from the generated susceptibility maps. Systematic error in the measured SvO2 due to the modified pipeline was also studied through simulations. RESULTS: Simulations showed that the systematic error in SvO2 when using a mask that includes a minimum of 5 voxels around the SSS and five slices remains < 3% for different orientations of the vessel relative to the main magnetic field. The average ∆χv in the SSS quantified across all gestations was 0.42 ± 0.03 ppm. Based on ∆χv, the average putative SvO2 in the SSS across all fetuses was 67% ± 7%, which is in good agreement with published studies. CONCLUSIONS: This in vivo study demonstrates the feasibility of using QSM in the human fetal brain to estimate ∆χv and SvO2. KEY POINTS: • A modified quantitative susceptibility mapping (QSM) processing pipeline is tested and presented for the human fetus. • QSM is feasible in the human fetus for measuring magnetic susceptibility and oxygenation of venous blood in vivo. • Blood magnetic susceptibility values from MR susceptometry and QSM agree with each other in the human fetus.

A Non-Lethal Osteogenesis Imperfecta Type II Mutation.

BACKGROUND: We discuss the ethical decision points in a case report that describes a novel COL1A1 mutation associated to Osteogenesis Imperfecta type II, but with a non-lethal outcome. CASE: A 33-year-old female underwent a 21-week ultrasound that revealed short bowed femurs and humeri with old fractures and bowed tibias and fibulas. Amniotic fluid testing revealed a novel COL1A1 mutation (c.1840G>A; p.Gly614Arg). OI Type II diagnosis was made. A previously reported mutation of the same gene but different locus (c.1840G>C; p.Gly614Arg) led to a lethal form of OI type II. The newborn was delivered via a cesarean delivery and intravenous bisphosphonates (Zaledronic acid) was administered every 3 months. Currently the infant is 22 months old, is growing, with mild bilateral conductive hearing loss. CONCLUSION: The unexpected clinical outcome should serve as a reminder that phenotypic variability can occur with genetic mutations. Our case shows that the diagnosis of the type of OI should be based not only on clinical findings and genetic investigations but also on the clinical course over time.

Familial Hydrocephalus and Dysgenesis of the Corpus Callosum Associated with Xp22.33 Duplication and Stenosis of the Aqueduct of Sylvius with X-Linked Recessive Inheritance Pattern.

INTRODUCTION: X-linked recessive mutations predominantly affect male fetuses with milder or no abnormalities in female siblings. Most reports show only one affected member in the family. We are reporting a family affected with hydrocephalus, stenosis of the aqueduct of Sylvius, dysgenesis of the corpus callosum, and Xp22.33 microduplication. CASE PRESENTATION: Eighteen-year-old patient was evaluated for her 2 pregnancies; the first was a male fetus with severe hydrocephalus and the second a female fetus with mild hydrocephalus. Postnatal MRI evaluation of the male neonate revealed stenosis of the aqueduct of Sylvius, dysgenesis of the corpus callosum, and severe hydrocephalus requiring ventriculoperitoneal shunt. Postnatal MRI evaluation of the female neonate revealed mild hydrocephalus, stenosis of the aqueduct of Sylvius, and mild dysgenesis of the corpus callosum. The female baby did not require surgical intervention. Genetic testing of the mother and the 2 children revealed a 439 Kb duplication of Xp22.33. DISCUSSION: This family demonstrates typical X-linked recessive heritability. X-inactivation is a compensatory mechanism that explains the mild symptoms of the female child and the severe symptoms of the male child. This familial case shows the importance of prenatal testing and genetic counseling and testing, including karyotype and chromosomal microarray.

Quantitative Flow Imaging in Human Umbilical Vessels In Utero Using Nongated 2D Phase Contrast MRI.

BACKGROUND: Volumetric assessment of afferent blood flow rate provides a measure of global organ perfusion. Phase-contrast magnetic resonance imaging (PCMRI) is a reliable tool for volumetric flow quantification, but given the challenges with motion and lack of physiologic gating signal, such studies, in vivo on the human placenta, are scant. PURPOSE: To evaluate and apply a nongated (ng) PCMRI technique for quantifying blood flow rates in utero in umbilical vessels. STUDY TYPE: Prospective study design. STUDY POPULATION: Twenty-four pregnant women with median gestational age (GA) 30 4/7 weeks and interquartile range (IQR) 8 1/7 weeks. FIELD STRENGTH/SEQUENCE: All scans were performed on a 3.0T Siemens Verio system using the ng-PCMRI technique. ASSESSMENT: The GA-dependent increase in umbilical vein (UV) and arterial (UA) flow was compared to previously published values. Systematic error to be expected from ng-PCMRI, in the context of pulsatile UA flow and partial voluming, was studied through Monte-Carlo simulations, as a function of resolution and number of averages. STATISTICAL TESTS: Correlation between the UA and UV was evaluated using a generalized linear model. RESULTS: Simulations showed that ng-PCMRI measurement variance reduced by increasing the number of averages. For vessels on the order of 2 voxels in radius, partial voluming led to 10% underestimation in the flow. In fetuses, the average flow rates in UAs and UV were measured to be 203 ± 80 ml/min and 232 ± 92 ml/min and the normalized average flow rates were 140 ± 59 ml/min/kg and 155 ± 57 ml/min/kg, respectively. Excellent correlation was found between the total arterial flow vs. corresponding venous flow, with a slope of 1.08 (P = 0.036). DATA CONCLUSION: Ng-PCMRI can provide accurate volumetric flow measurements in utero in the human umbilical vessels. Care needs to be taken to ensure sufficiently high-resolution data are acquired to minimize partial voluming-related errors. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2017.