Fetal Anatomy Scan Research Articles

Prenatal Care Clinician Preferences Among Patients With Spanish-Preferred Language.

To measure what patients with Spanish language preference and limited English proficiency value most when selecting a prenatal care clinician. A discrete choice experiment was administered at two large academic medical centers in Boston, Massachusetts. Participants were identified by electronic medical record, had preferred Spanish language and self-identified limited English proficiency, and either were pregnant with a completed fetal anatomy scan or had given birth within the past 12 months at the time of the study. The discrete choice experiment consisted of eight attributes to consider when selecting a prenatal care clinician: clinician Spanish proficiency, type of interpreter used, interpersonal dynamics (ie, making patients feel seen, heard, and cared for), cultural concordance, continuity of care, shared decision making, distance from home, and wait times for appointments. Descriptive statistics of demographic variables were calculated. Hierarchical Bayesian models were used to analyze discrete choice experiment data. The attributes that were most important to 166 participants when choosing their prenatal care clinician were interpersonal dynamics within the patient-clinician dyad and clinician Spanish language proficiency (average importance 21.4/100 and 20.8/100, respectively). Of lowest importance were wait time to receive an appointment and continuity of care (average importance 5.1 and 6.1, respectively). Although participants highly preferred that their clinician be "fluent or near fluent in Spanish," the second most preferred option was having a clinician with only basic Spanish proficiency rather than a more advanced level of Spanish proficiency with some misunderstandings. Our study demonstrates the importance of positive clinician-patient interpersonal dynamics and language-concordant care for patients with Spanish language preference in prenatal care. Promoting equitable patient-centered care for patients with limited English proficiency requires responding to preferences regarding clinician language proficiency and demonstrating attentiveness, empathy, and concern for prenatal care experiences.

Evaluation and Significance of Nonvisualization of the Cavum Septum Pellucidum on Prenatal Ultrasonography.

The identification of the cavum septum pellucidum (CSP) is an integral part of the routine second trimester fetal anatomy scan. The absence or nonvisualization of the CSP has significant clinical implications and requires further evaluation and counseling for the pregnant patient. The aim of this review is to review the importance of accurate sonographic identification of the CSP and the underlying pathologies that can be associated with nonvisualization of this structure. A literature review was performed with PubMed using key words including CSP, fetal anatomy ultrasound, and fetal anomalies. The absence of the CSP is associated with several central nervous system pathologies, all with a wide range of phenotypic outcomes, ranging from normal to very severe or lethal. Most obstetrician-gynecologists will have a patient in whom a CSP is not identified on fetal ultrasound. Thus, it is imperative to have a general understanding of this relatively common entity.

Evaluation and Significance of Nonvisualization of the Cavum Septum Pellucidum on Prenatal Ultrasonography

ABSTRACT Importance The identification of the cavum septum pellucidum (CSP) is an integral part of the routine second trimester fetal anatomy scan. The absence or nonvisualization of the CSP has significant clinical implications and requires further evaluation and counseling for the pregnant patient. Objective The aim of this review is to review the importance of accurate sonographic identification of the CSP and the underlying pathologies that can be associated with nonvisualization of this structure. Evidence Acquisition A literature review was performed with PubMed using key words including CSP, fetal anatomy ultrasound, and fetal anomalies. Results The absence of the CSP is associated with several central nervous system pathologies, all with a wide range of phenotypic outcomes, ranging from normal to very severe or lethal. Relevance Most obstetrician-gynecologists will have a patient in whom a CSP is not identified on fetal ultrasound. Thus, it is imperative to have a general understanding of this relatively common entity. Target Audience Obstetricians and gynecologists, family physicians Learning Objectives After completing this activity, the learner will be able to describe the CSP, the importance of accurate identification on ultrasonography, and the pitfalls to avoid/be aware of; explain the additional workup required in the setting of absent CSP including utility of antenatal ultrasound, fetal magnetic resonance imaging, and genetic counseling; and discuss the various pathologies that have an association with the absence of the CSP and patient counseling regarding the absence of the CSP.

Prenatal cardiac findings and 22q11.2 deletion syndrome: Fetal detection and evaluation.

Clinical features of 22q11.2 microdeletion syndrome (22q11.2DS) are highly variable between affected individuals and frequently include a subset of conotruncal and aortic arch anomalies. Many are diagnosed with 22q11.2DS when they present as a fetus, newborn or infant with characteristic cardiac findings and subsequently undergo genetic testing. The presence of an aortic arch anomaly with characteristic intracardiac anomalies increases the likelihood that the patient has 22q11.2 DS, but those with an aortic arch anomaly and normal intracardiac anatomy are also at risk. It is particularly important to identify the fetus at risk for 22q11.2DS in order to prepare the expectant parents and plan postnatal care for optimal outcomes. Fetal anatomy scans now readily identify aortic arch anomalies (aberrant right subclavian artery, right sided aortic arch or double aortic arch) in the three-vessel tracheal view. Given the association of 22q11.2DS with aortic arch anomalies with and without intracardiac defects, this review highlights the importance of recognizing the fetus at risk for 22q11.2 deletion syndrome with an aortic arch anomaly and details current methods for genetic testing. To assist in the prenatal diagnosis of 22q11.2DS, this review summarizes the seminal features of 22q11.2DS, its prenatal presentation and current methods for genetic testing.

Current controversies in prenatal diagnosis: Noninvasive prenatal testing should replace other screening strategies for fetal trisomies 13, 18, 21.

This is a written summary of the oral debate presented at the International Society for Prenatal Diagnosis annual conference in Edinburgh in 2023. The topic under debate is whether noninvasive prenatal testing (NIPT) using cell-free fetal DNA should replace other screening strategies for the detection of fetal trisomies 13, 18, 21. There is no disagreement that NIPT is far more sensitive and has better positive predictive values for identifying trisomies 13, 18, and 21 than traditional screening approaches using biochemical markers and measurement of nuchal translucency. The major issue lies in the potential adverse consequences associated with abandoning traditional screening methods. The source of disagreement stems primarily from whether you consider the role of ultrasound in the context of screening to be strictly for nuchal translucency measurement or whether it should be combined with a fetal anatomy scan. The debate featured two experts who presented evidence in favor of each argument.

Vaginal Progesterone Is Associated with Intrahepatic Cholestasis of Pregnancy.

The frequency of intrahepatic cholestasis of pregnancy (ICP) peaks during the third trimester of pregnancy when plasma progesterone levels are the highest. Furthermore, twin pregnancies are characterized by higher progesterone levels than singletons and have a higher frequency of cholestasis. Therefore, we hypothesized that exogenous progestogens administered for reducing the risk of spontaneous preterm birth may increase the risk of cholestasis. Utilizing the large IBM MarketScan Commercial Claims and Encounters Database, we investigated the frequency of cholestasis in patients treated with vaginal progesterone or intramuscular 17α-hydroxyprogesterone caproate for the prevention of preterm birth. We identified 1,776,092 live-born singleton pregnancies between 2010 and 2014. We confirmed second and third trimester administration of progestogens by cross-referencing the dates of progesterone prescriptions with the dates of scheduled pregnancy events such as nuchal translucency scan, fetal anatomy scan, glucose challenge test, and Tdap vaccination. We excluded pregnancies with missing data regarding timing of scheduled pregnancy events or progesterone treatment prescribed only during the first trimester. Cholestasis of pregnancy was identified based on prescriptions for ursodeoxycholic acid. We used multivariable logistic regression to estimate adjusted (for maternal age) odds ratios for cholestasis in patients treated with vaginal progesterone, and in patients treated with 17α-hydroxyprogesterone caproate compared with those not treated with any type of progestogen (the reference group). The final cohort consisted of 870,599 pregnancies. Among patients treated with vaginal progesterone during the second and third trimester, the frequency of cholestasis was significantly higher than the reference group (0.75 vs. 0.23%, adjusted odds ratio [aOR]: 3.16, 95% confidence interval [CI]: 2.23-4.49). In contrast, there was no significant association between 17α-hydroxyprogesterone caproate and cholestasis (0.27%, aOR: 1.12, 95% CI: 0.58-2.16) CONCLUSION: Using a robust dataset, we observed that vaginal progesterone but not intramuscular 17α-hydroxyprogesterone caproate was associated with an increased risk for ICP. · Previous studies have been underpowered to detect potential association between progesterone and ICP.. · Vaginal progesterone was significantly associated with ICP.. · Intramuscular 17α-hydroxyprogesterone was not associated with ICP..

Towards an explainable clinical decision support system for large-for-gestational-age births.

A myriad of maternal and neonatal complications can result from delivery of a large-for-gestational-age (LGA) infant. LGA birth rates have increased in many countries since the late 20th century, partially due to a rise in maternal body mass index, which is associated with LGA risk. The objective of the current study was to develop LGA prediction models for women with overweight and obesity for the purpose of clinical decision support in a clinical setting. Maternal characteristics, serum biomarkers and fetal anatomy scan measurements for 465 pregnant women with overweight and obesity before and at approximately 21 weeks gestation were obtained from the PEARS (Pregnancy Exercise and Nutrition with smart phone application support) study data. Random forest, support vector machine, adaptive boosting and extreme gradient boosting algorithms were applied with synthetic minority over-sampling technique to develop probabilistic prediction models. Two models were developed for use in different settings: a clinical setting for white women (AUC-ROC of 0.75); and a clinical setting for women of all ethnicity and regions (AUC-ROC of 0.57). Maternal age, mid upper arm circumference, white cell count at the first antenatal visit, fetal biometry and gestational age at fetal anatomy scan were found to be important predictors of LGA. Pobal HP deprivation index and fetal biometry centiles, which are population-specific, are also important. Moreover, we explained our models with Local Interpretable Model-agnostic Explanations (LIME) to improve explainability, which was proven effective by case studies. Our explainable models can effectively predict the probability of an LGA birth for women with overweight and obesity, and are anticipated to be useful to support clinical decision-making and for the development of early pregnancy intervention strategies to reduce pregnancy complications related to LGA.

Fetal anatomy scan with integrated nuchal translucency and combination of PAPP-A and fβhCG for prediction of aneuploidy.

Nuchal translucency (NT) is an important finding of early fetal anatomy scan because of the association with genetic and structural anomalies. Enlarged nuchal translucency can be easily detected even without measurement on fetal anatomy scan as a neck pathology. Because of demanding criteria for measurning NT in established prenatal aneuploidy screening we came with an idea of improvement and simplification with availabe methods. The aim of this study is to compare established screening methods with new model of screening composed of fetal anatomy scan with integrated nuchal translucency and combination of PAPP-A and fβhCG. A prospective one center study analyzed atotal of 351 pregnancies between January 2017 and December 2020. Sonographic measurement of NT and fetal anatomy scan (FAS) were performend with biochemical testing from blood sample in the first trimester. Combined screening and fetal anatomy scan was performed. Patients with a pathological screening or with structural defects underwent an invasive procedure. In patient with positive screenining who missed the first trimester invasive procedure, amniocentesis was performed. Fetuses were divided into two groups according to positive or negative karyotype and to calculate sensitivity and specificity of screening methods. From statistical methods regression analysis, significance p of individual predictor, sensitivity and specificity with graphic drawing of ROC charts were used. Data were analyzed using statistical tools of Microsoft Excel 365 and BESH stat. Four models for aneuploidy screening were tested. 1) Model of "Age at the time of diagnosis" was slightly significant predictor with insignificant odds ratio (P=0.04, OR=1). 2) Model of" First trimester biochemical screening" (age, free beta human chorionic gonadotropine - fβhCG and pregnancy associated plasmatic protein A -PAPP-A) were significant (P=0.0001; LR=21) with sensitivity of 87.5 % and specificity of 65.7 %. 3) Model of "First trimester combined test" (age of patients at the time of diagnosis, fβhCG, PAPP-A, NT) was significant (P=7.9 x10-14, LR=67, sensitivity 87 %, specificity 80 %). 4) Model of "Fetal anatomy scan with biochemistry" (structural abnormality finding with combination including age, fβhCG and PAPP-A) was significant (P=4.9x10-18, LR=87, sensitivity 95 %, specificity 80 %). Fetal anatomy scan combined with age, fβhCG and PAPP-A has the highest sensitivity and specificity for both, the detection of fetal aneuploidies and structural abnormalities. Our study shows that fetal anatomy scan is the best possible option for first trimester diagnostics (Tab. 4, Fig. 5, Ref. 16).

Bimodal Ultrasound Simulator Training in Obstetrics

Ultrasound is a vital diagnostic tool in obstetrics that requires a minimum skill level to understand and operate. This study aimed to evaluate the effects of bimodal simulator training (reading theoretical knowledge and obtaining images in a simulator during 1-2 sessions) on medical trainee’s (1) knowledge of fetal anatomy and (2) ability to manipulate the ultrasound to obtain proper images for fetal biometry and anatomy scans.

Prenatal Biochemical and Ultrasound Markers in COVID-19 Pregnant Patients: A Prospective Case-Control Study.

This prospective observational study aimed to evaluate whether women with SARS-CoV-2 infection during the first trimester of pregnancy are at higher risk of noninvasive prenatal screening test alterations and/or of congenital fetal anomalies at the second-trimester fetal anatomy scan. Maternal symptoms were secondly investigated. The study was carried out on 12-week pregnant women admitted for noninvasive prenatal testing (16 April and 22 June 2020). The cohort had seromolecular tests for SARS-CoV-2, after which they were divided into a positive case group and a negative control group. Both groups had 20-week ultrasound screening. Seventeen out of the 164 women tested positive for SARS-CoV-2 (10.3%). There were no significant differences in mean nuchal translucency thickness or biochemical markers (pregnancy-associated plasma protein A, alpha-fetoprotein, human chorionic gonadotropin, unconjugated estriol) between cases and controls (p = 0.77, 0.63, 0.30, 0.40, 0.28) or in the fetal incidence of structural anomalies at the second-trimester fetal anatomy scan (p = 0.21). No pneumonia or hospital admission due to COVID-19-related symptoms were observed. Asymptomatic or mildly symptomatic SARS-CoV-2 infection during the first trimester of pregnancy did not predispose affected women to more fetal anomalies than unaffected women. COVID-19 had a favorable maternal course at the beginning of pregnancy in our healthy cohort.

Integration of nuchal translucency screening into the first-trimester fetal anatomy scan: the time has come.

Integration of nuchal translucency screening into the first-trimester fetal anatomy scan: the time has come.

It is about time. The advantage of transabdominal cervical length screening

Purpose Sonographic cervical length (CL) measurement has become a standard practice for identifying women at increased risk for preterm birth. We aimed to assess the time needed for CL measurement during fetal anatomy scan using either transabdominal or transvaginal ultrasound, and to provide a predictive value of the transabdominal CL measurements for reassuring transvaginal CL measurements of more than 25 mm. Methods In a prospective study we measured CL transabdominally, and transvaginally in all the anatomy scans performed at 18–25 weeks’ gestation, from January 2017 until January 2018. CL and the duration of the examination were compared between the two approaches. Adjustments were made for, body mass index, previous cesarean sections and parity. Results Four hundred sixty-eight patients participated in the study. The time needed for the transabdominal CL measurement was significantly lower compare with the transvaginal CL measurement (0.46 ± 0.3 min versus 6.9 ± 1.38 min, p < 0.001). The CL measured transabdominally was significantly shorter than the CL measured transvaginally (36.7 ± 6.7 mm versus 41.9 ± 7.3 mm, respectively p < 0.001). All women with transabdominal CL measurements above 36 mm (64.2% of patients) had a transvaginal CL of more than 25 mm. Conclusion Transvaginal measurement of CL is a time-consuming procedure that prolong fetal anomaly scan by 25%. Transabdominal CL measurement of 36 mm is reassuring CL above 25 mm. Transabdominal ultrasound should be used as an initial tool for CL screening. Transvaginal measurements of CL should be reserved for high-risk women, for women with difficulties in demonstrating the cervix abdominally, and for women with transabdominal measurements of less than 36 mm.

VP04.03: Assessment of maternal anxiety among women undergoing an early comprehensive fetal anatomy scan

VP04.03: Assessment of maternal anxiety among women undergoing an early comprehensive fetal anatomy scan

Quality-improvement program for ultrasound-based fetal anatomy screening using large-scale clinical audit.

ABSTRACTObjectiveA large‐scale audit and peer review of ultrasound images may improve sonographer performance, but is rarely performed consistently as it is time‐consuming and expensive. The aim of this study was to perform a large‐scale audit of routine fetal anatomy scans to assess if a full clinical audit cycle can improve clinical image‐acquisition standards.MethodsA large‐scale, clinical, retrospective audit was conducted of ultrasound images obtained during all routine anomaly scans performed from 18 + 0 to 22 + 6 weeks' gestation at a UK hospital during 2013 (Cycle 1), to build a baseline understanding of the performance of sonographers. Targeted actions were undertaken in response to the findings with the aim of improving departmental performance. A second full‐year audit was then performed of fetal anatomy ultrasound images obtained during the following year (Cycle 2). An independent pool of experienced sonographers used an online tool to assess all scans in terms of two parameters: scan completeness (i.e. were all images archived?) and image quality using objective scoring (i.e. were images of high quality?). Both were assessed in each audit at the departmental level and at the individual sonographer level. A random sample of 10% of scans was used to assess interobserver reproducibility.ResultsIn Cycle 1 of the audit, 103 501 ultrasound images from 6257 anomaly examinations performed by 22 sonographers were assessed; in Cycle 2, 153 557 images from 6406 scans performed by 25 sonographers were evaluated. The analysis was performed including the images obtained by the 20 sonographers who participated in both cycles. Departmental median scan completeness improved from 72% in the first year to 78% at the second assessment (P < 0.001); median image‐quality score for all fetal views improved from 0.83 to 0.86 (P < 0.001). The improvement was greatest for those sonographers who performed poorest in the first audit; with regards to scan completeness, the poorest performing 15% of sonographers in Cycle 1 improved by more than 30 percentage points, and with regards to image quality, the poorest performing 11% in Cycle 1 showed a more than 10% improvement. Interobserver repeatability of scan completeness and image‐quality scores across different fetal views were similar to those in the published literature.ConclusionsA clinical audit and a set of targeted actions helped improve sonographer scan‐acquisition completeness and scan quality. Such adherence to recommended clinical acquisition standards may increase the likelihood of correct measurement and thereby fetal growth assessment, and should allow better detection of abnormalities. As such a large‐scale audit is time consuming, further advantages would be achieved if this process could be automated. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

A Survey Assessment of Maternal Understanding of the Midtrimester Anatomy Scan [32D

INTRODUCTION: Few studies have examined patients' understanding of prenatal ultrasounds (US). Our primary aim was to describe women's understanding of abnormalities detectable by midtrimester fetal anatomy scan. Our secondary aim was to determine if differences in the results varied with maternal demographics to identify subgroups who may benefit from additional counseling. METHODS: This was a cross-sectional survey of English-speaking patients presenting for a midtrimester fetal anatomy scan at a tertiary care teaching hospital. Patients were recruited prior to their US and if consent was obtained they completed a pre-US survey. The survey obtained demographic information and assessed knowledge of US detectable anatomic abnormalities by seven questions. Comparison between groups was performed by Wilcoxon rank sum test, Spearman rank correlation, and bivariate linear regression as appropriate. RESULTS: 123 participants were recruited, 117 consented, and 116 completed surveys. A median of 43% [Interquartile Range 14-71%] of questions were answered correctly. Number of correct responses was found to correlate inversely with income <$50,000/year (P<0.0001), education less than Bachelor’s Degree (P<0.0001), age (P=0.001), and African American race (P<0.0001) in bivariate analyses. CONCLUSION: Patients with lower income, less education, younger age, and African American race have less knowledge about fetal anomalies detected via a midtrimester ultrasound. These data suggest that these women may benefit from additional counseling regarding the function of ultrasound as a medical test with the purpose of detecting fetal anomalies early in pregnancy.

1034: Abdominal vs. vaginal approach for the mid-trimester cervical length screening

Cervical length (CL) of less than 25mm is a risk factor for preterm birth. Recent studies have suggested the use of a routine cervical length (CL) measurement, to identify women at risk for preterm birth. In this study, we compared between transabdominal and transvaginal CL measurement in order to establish practical recommendations for CL screening following routine mid-trimester anatomy scan. CL measurements were performed at 20-24 weeks' gestation, from January 2017 until April 2018, immediately after fetal anatomy scan. CL measurements were obtained transabdominally before (full bladder), and transvaginally after (empty bladder) voiding. The differences in CL and duration of transabdominal and transvaginal measurements were compared between the groups and adjustment was made for maternal age (MA), and body mass index (BMI). 468 women carrying a singleton pregnancy gave their informed consent to participate in the study. The overall duration for the fetal anatomy scan was 27±5.3minutes. The duration of CL measured transabdominally was significantly shorter than the duration of CL measured transvaginally (6.9±1.38min vs. 0.46±0.3min, P<0.001). Difficulty in demonstrating the cervix transabdominally has been noted in 39 women (8.3%). The CL measured transvaginally was significantly longer than the CL measured transabdominally (42±7.5mm vs 37.34±6.8mm, p<0.001). The differences between the groups were unrelated to maternal age or BMI. All women whom transabdominal measurements of CL were above 35mm (66% of patients) had transvaginal CL above 25mm (98.2% of patient) (Fig 1). Transvaginal measurement of CL is associated with discomfort and embarrassment. Additionally, the transvaginal measurement is a time-consuming procedure with a significant prolongation of fetal anatomy scan compared with the transabdominal approach. Therefore, transabdominal measurement of CL should be offered as an initial tool for cervical length screening. Transvaginal measurements of CL should be reserved for high-risk women (who had preterm delivery in the past), when there are difficulties in demonstrating the cervix abdominally, and for women with transabdominal measurements of less than 35mm.

Impact of prenatal diagnosis on the management and early outcome of critical duct-dependent cardiac lesions.

The objective of this study was to compare the preoperative management and outcome of neonates with duct-dependent critical CHD with fetal versus postnatal diagnosis. Patients referred with CHD to our centre from January 1, 2009 to December 31, 2010 were enrolled prospectively. Live births with a critical form of CHD, a gestational age ⩾36 weeks and a weight ⩾2 kg at birth, and the intention-to-treat were included in this sub-study. Excluded were neonates with lethal non-cardiac and/or genetic anomalies. In total, 129, 63 fetal and 66 postnatal, cases met the study inclusion criteria. All had received appropriate antenatal care, including a routine fetal anatomy scan. Both cohorts were comparable in weight, gestational age, and APGAR scores at birth. Unlike the postnatal cases, there were no deaths (0/63 versus 5/66; p=0.06) and no cardiac arrests (0/63 versus 9/63; p=0.003) before surgery or catheter intervention in those cases with a prenatal diagnosis of critical CHD. Moreover, newborns with fetal diagnoses were admitted earlier (median 0 (range 0-3) versus 2 (0-25) days; p<0.001) and were less likely to require preoperative ventilation (19/63 versus 31/61, p=0.03) and vasoactive medication (4/63 versus 15/61, p=0.006) than the postnatal cases. Prenatal diagnosis of critical CHD in this study was associated with significantly shorter time intervals from birth to neonatal admission and the absence of life-threatening or fatal preoperative cardiac events. Increased efforts should be made to improve rates of prenatal diagnosis.

First trimester fetal anatomy scan and identification of major anomalies: A cross sectional study

First trimester fetal anatomy scan and identification of major anomalies: A cross sectional study

Screening the second-trimester fetal heart in women with an increased body mass index using three-dimensional volume sweep.

To determine the percentage of fetal cardiac anatomy as detailed in the International Society of Ultrasound in Obstetrics and Gynecology Practice Guidelines on sonographic screening examination of the fetal heart, which can be visualised in women with a body mass index (BMI) >30 kg/m2 using three-dimensional (3D) volume sweeps. 3D volumes of the fetal heart were taken prospectively in 40 fetuses during routine second-trimester fetal anatomy scan. Scans and 3D volume sweeps were performed by two experienced sonographers and two experienced raters interpreted the 3D data. 3D volume acquisitions and post-processing analysis were performed according to the techniques described by Weissmann-Brenner et al. The two raters were able to detect an average of 12.9 and 14.1 of the 16 parameters in the 40 patients. Agreement between raters for the 16 parameters had an average of 80%. Five parameters (stomach, situs, heart occupies a third of thoracic area, majority of heart in the left chest and cardiac axis) were detected by both raters on all patients. The range of agreement was between 40% and 100%. The three-vessel view and bifurcation had agreement <60%. Consistent identification of all views of the fetal heart was not achieved using the simple method described in women with a BMI > 30 kg/m2.

P21.09: Incorporation of vasa previa screening into a routine anomaly scan

Vasa previa (VP) has a reported fetal mortality of 60% if not recognised before attempt at vaginal delivery. Prenatal detection by ultrasound is possible in nearly all cases, but can be notoriously difficult unless there is a high index of suspicion. We report our experience in detection of VP using a structured protocol as part of the routine fetal anomaly scan at 20-22 weeks. Patients attending anomaly screening at a single centre over a 5 year period (2012-2016) underwent assessment for VP using a structured protocol as a part of a routine fetal anatomy scan. Suspected cases of VP were then re-scanned by a specialist sonographer and subsequently followed up. The diagnosis of VP was assigned by documentation of fetal vessels beneath the membranes, within 20 mm of the internal cervical os. 24690 anatomy scans were performed during the study period and 56 of these were identified as potential VP at the 20 -22 week anomaly scan. Of these, 20 were confirmed by the ultrasound specialist at 28 weeks or later. In five patients the only risk factor was a velamentous insertion. All 20 patients had planned Caesarean delivery but one patient bled at 35 weeks before planned delivery and this fetus died. Another patient experienced bleeding and an emergency Caesarean delivery at 31 weeks 3 days, and this baby lived. The remaining 18 had Caesarean delivery as planned. Placental histology was available in 11 cases. No case of VP was unexpectedly found at delivery during the study period (100% detection). The incidence of vasa previa in this unselected population is 1:1234. Use of a specific protocol as part of routine screening, permits high detection rate (100%), resulting in a low (5%) fetal mortality. We suggest that assessment for VP should be incorporated into routine fetal anatomy screening at 20-22 weeks using a structured protocol similar to one presented here.