Clinical implications of intra- and interobserver reproducibility of transvaginal sonographic measurement of gestational sac and crown-rump length at 6-9 weeks' gestation

Risk factors for missed abortion: retrospective analysis of a single institution's experience

OBJECTIVE

To explore the risk factors including the difference between mean gestational sac diameter and crown-rump length for missed abortion.

METHODS

Hospitalized patients with missed abortion and patients with continuing pregnancy to the second trimester from Chengdu Women's and Children's Central Hospital from June 2018 to June 2021 were retrospectively analyzed. The best cut-off value for age and difference between mean gestational sac diameter and crown-rump length (mGSD-CRL) were obtained by x-tile software. Univariate and multivariate logistic regression analysis were adopted to identify the possible risk factors for missed abortion.

RESULTS

Age, gravidity, parity, history of cesarean section, history of recurrent abortion (≥ 3 spontaneous abortions), history of ectopic pregnancy and overweight or obesity (BMI > 24 kg/m²) were related to missed abortion in univariate analysis. However, only age (≥ 30 vs < 30 years: OR = 1.683, 95%CI = 1.017-2.785, P = 0.043, power = 54.4%), BMI (> 24 vs ≤ 24 kg/m²: OR = 2.073, 95%CI = 1.056-4.068, P = 0.034, power = 81.3%) and mGSD-CRL (> 20.0vs ≤ 11.7 mm: OR = 2.960, 95% CI = 1.397-6.273, P = 0.005, power = 98.9%; 11.7 < mGSD-CRL ≤ 20.0vs > 20.0 mm: OR = 0.341, 95%CI = 0.172-0.676, P = 0.002, power = 84.8%) were identified as independent risk factors for missed abortion in multivariate analysis.

CONCLUSION

Patients with age ≥ 30 years, BMI > 24 kg/m² or mGSD-CRL > 20 mm had increasing risk for missed abortion, who should be more closely monitored and facilitated with necessary interventions at first trimester or even before conception to reduce the occurrence of missed abortion to have better clinical outcomes.

Automated prediction of early spontaneous miscarriage based on the analyzing ultrasonographic gestational sac imaging by the convolutional neural network: a case-control and cohort study

Background

It is challenging to predict the outcome of the pregnancy when fetal heart activity is detected in early pregnancy. However, an accurate prediction is of importance for obstetricians as it helps to provide appropriate consultancy and determine the frequency of ultrasound examinations. The purpose of this study was to investigate the role of the convolutional neural network (CNN) in the prediction of spontaneous miscarriage risk through the analysis of early ultrasound gestational sac images.

Methods

A total of 2196 ultrasound images from 1098 women with early singleton pregnancies of gestational age between 6 and 8 weeks were used for training a CNN for the prediction of the miscarriage in the retrospective study. The patients who had positive fetal cardiac activity on their first ultrasound but then experienced a miscarriage were enrolled. The control group was randomly selected in the same database from the fetuses confirmed to be normal during follow-up. Diagnostic performance of the algorithm was validated and tested in two separate test sets of 136 patients with 272 images, respectively. Performance in prediction of the miscarriage was compared between the CNN and the manual measurement of ultrasound characteristics in the prospective study.

Results

The accuracy of the predictive model was 80.32% and 78.1% in the retrospective and prospective study, respectively. The area under the receiver operating characteristic curve (AUC) for classification was 0.857 (95% confidence interval [CI], 0.793–0.922) in the retrospective study and 0.885 (95%CI, 0.846–0.925) in the prospective study, respectively. Correspondingly, the predictive power of the CNN was higher compared with manual ultrasound characteristics, for which the AUCs of the crown-rump length combined with fetal heart rate was 0.687 (95%CI, 0.587–0.775).

Conclusions

The CNN model showed high accuracy for predicting miscarriage through the analysis of early pregnancy ultrasound images and achieved better performance than that of manual measurement.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04936-0.

Sporadic miscarriage: evidence to provide effective care

The physical and psychological effect of miscarriage is commonly underappreciated. The journey from diagnosis of miscarriage, through clinical management, to supportive aftercare can be challenging for women, their partners, and caregivers. Diagnostic challenges can lead to delayed or ineffective care and increased anxiety. Inaccurate diagnosis of a miscarriage can result in the unintended termination of a wanted pregnancy. Uncertainty about the therapeutic effects of interventions can lead to suboptimal care, with variations across facilities and countries. For this Series paper, we have developed recommendations for practice from a literature review, appraisal of guidelines, and expert group discussions. The recommendations are grouped into three categories: (1) diagnosis of miscarriage, (2) prevention of miscarriage in women with early pregnancy bleeding, and (3) management of miscarriage. We recommend that every country reports annual aggregate miscarriage data, similarly to the reporting of stillbirth. Early pregnancy services need to focus on providing an effective ultrasound service, as it is central to the diagnosis of miscarriage, and be able to provide expectant management of miscarriage, medical management with mifepristone and misoprostol, and surgical management with manual vacuum aspiration. Women with the dual risk factors of early pregnancy bleeding and a history of previous miscarriage can be recommended vaginal micronised progesterone to improve the prospects of livebirth. We urge health-care funders and providers to invest in early pregnancy care, with specific focus on training for clinical nurse specialists and doctors to provide comprehensive miscarriage care within the setting of dedicated early pregnancy units.

Evaluating the Transvaginal Ultrasound Diagnostic Criteria for Abnormal First-Trimester Pregnancy With Follow-Up Into the Third Trimester and Validation of Results

OBJECTIVE

To evaluate the current ultrasound diagnostic criteria for non-viable pregnancy in the first trimester.

METHODS

We conducted a retrospective chart review involving 3 tertiary care institutions. Consecutive first-trimester ultrasound reports between January 2013 and June 2016 were reviewed. All first-trimester ultrasound examinations performed to assess pregnancy viability with adequate imaging or clinical follow-up were included. Inclusion criteria based on follow-up were adequate imaging to document ongoing intrauterine pregnancy or clinical follow-up demonstrating viability or non-viability. Data on mean sac diameter (MSD), yolk sac presence/diameter, embryo presence/length, presence of a heartbeat, and heart rate were collected. This was followed by a retrospective validation review of another consecutive cohort.

RESULTS

Two hundred and forty-five examinations with a viable-pregnancy outcome and 301 examinations with a non-viable pregnancy outcome were reviewed. The main predictor of non-viable pregnancy was an MSD of ≥20 mm in the absence of a yolk sac (positive predictive value [PPV] 100%; 95% CI 93%-100%), embryo (PPV 100%; 95% CI 90%-100%), or heartbeat (PPV 100%; 95% CI 96%-100%]). Other predictors of non-viability were a measurable embryo without a yolk sac (PPV 100%; 95% CI 91%-100%), yolk sac diameter ≥8 mm (PPV 100%; 95% CI 91%-100%), and absence of heartbeat with an embryo ≥3 mm (PPV 100%; 95% CI 97%-100%). These findings were confirmed in a validation cohort of 45 viable and 53 non-viable pregnancies, with the exception of 1 case of viable pregnancy with no heartbeat and an embryo length 3.3 mm. Based on the median daily growth of 1.2 mm in the viable cohort, 21% of follow-up ultrasound examinations were performed too early for an MSD threshold of 20 mm and 55%, for an MSD threshold of 25 mm.

CONCLUSION

In our cohort, MSD ≥20 mm in the absence of yolk sac or an embryo with heartbeat always predicted a non-viable pregnancy.

Guideline No. 388-Determination of Gestational Age by Ultrasound

OBJECTIVE

To assist clinicians in assigning gestational age based on ultrasound biometry.

OUTCOMES

To determine whether ultrasound dating provides more accurate gestational age assessment than menstrual dating with or without the use of ultrasound. To provide maternity health care providers and researchers with evidence-based guidelines for the assignment of gestational age. To determine which ultrasound biometric parameters are superior when gestational age is uncertain. To determine whether ultrasound gestational age assessment is cost effective.

EVIDENCE

Published literature was retrieved through searches of PubMed or MEDLINE and The Cochrane Library in 2013 using appropriate controlled vocabulary and key words (gestational age, ultrasound biometry, ultrasound dating). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies written in English. There were no date restrictions. Searches were updated on a regular basis and incorporated in the guideline to July 31, 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Accurate assignment of gestational age may reduce post-dates labour induction and may improve obstetric care through allowing the optimal timing of necessary interventions and the avoidance of unnecessary ones. More accurate dating allows for optimal performance of prenatal screening tests for aneuploidy. A national algorithm for the assignment of gestational age may reduce practice variations across Canada for clinicians and researchers. Potential harms include the possible reassignment of dates when significant fetal pathology (such as fetal growth restriction or macrosomia) result in a discrepancy between ultrasound biometric and clinical gestational age. Such reassignment may lead to the omission of appropriate-or the performance of inappropriate-fetal interventions.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Ultrasound in Early Pregnancy: Viability, Unknown Locations, and Ectopic Pregnancies

Ultrasound is essential in the evaluation and management of pregnancies of unknown location. Differential diagnoses include early pregnancy loss, pregnancy of unknown location, and ectopic pregnancies. Both transabdominal and transvaginal routes should be available, in addition to physical examination, for complete evaluation. Diagnostic criteria for early pregnancy loss have expanded in recent years to ensure false positive results do not lead to inappropriate evacuation of desired pregnancies.

[Practices' evaluation of missed miscarriage diagnosis in gynecologic emergency service in Tours CHU]

INTRODUCTION

In the gynecology emergency departments, a pregnancy of uncertain viability is diagnosed in 29% of all first-trimester pregnancy medical consultations that require an ultrasound. The question of pregnancy viability is therefore common in our medical practice and comes along with human implications. In 2014, the French National College of Obstetricians and Gynecologists (CNGOF) promulgated clear guidelines regarding missed early miscarriage diagnosis and treatment. We wanted to evaluate our level of compliance with the diagnosis dimension of those guidelines and assess their optimization level since they were published.

MATERIALS AND METHODS

This retrospective and descriptive study is based on all missed early miscarriage that were taken care of within the gynecology emergency department at the CHU in Tours (France) over the course of three non-consecutive years. The year 2013 has been considered - before the guidelines were promulgated, 2015 - just after the guidelines were promulgated and lastly, 2018 in order to have the necessary distance for the interpretation. The following criteria was assessed for each year: the diagnostic ultrasound criteria; when relevant, the monitoring ultrasound deadlines; and the details regarding any patient management errors if errors were made. Secondarily, the uterine evacuation treatment procedures were examined.

RESULTS

The study population includes 297 women. The non-compliance with the guidelines affected 20% of the women in 2013, 12% in 2015 and 15% in 2018 (p = 0.25 when comparing the pre-guideline and post-guideline periods). An ultrasound performed too early is the most common error made each year even though its frequency has decreased (p = 0.03). The least experienced sonographers tend to be rather cautious, performing additional unnecessary examinations and scheduling excessive additional monitoring ultrasound deadlines. Only 13% of the medication-based therapies made uterine evacuation successful. If the initial use of prostaglandin substances was not successful, no additional dose of medication enabled any women patient to avoid surgery.

CONCLUSION

The compliance with the guidelines regarding pregnancies of uncertain viability is not optimal. Partial improvements in our own patient care management have been made since the publication of the guidelines; however, the main risk at stake is to terminate the evolution of a normal pregnancy due to some remaining medical misjudgments. The introduction of quality scores for clinical ultrasound images would be an interesting topic to discuss.

Early pregnancy ultrasound measurements and prediction of first trimester pregnancy loss: A logistic model

Our objective was to prospectively validate the use of gestational sac (GS), yolk sac (YS) diameter, crown-rump length (CRL), and embryonal heart rate (HR) dimensions to identify early pregnancy loss. This was a prospective cohort study of first trimester pregnancies. GS and YS diameter, CRL, and HR measurements were serially obtained in singleton and twin pregnancies from 6 through 10 weeks' gestation. Non-parametric tests and logistic regression models were used for comparisons of distributions and testing of associations. A total of 252 patients were included, of which 199 were singleton pregnancies, 51 were twins, and 2 were triplets (304 total fetuses). Fifty-two patients had 61 losses. We built nomograms with the changes of the parameters evaluated in ongoing, as well as in pregnancy loss. In the pregnancies which failed, all the parameters showed significant changes, with different temporal onsets: GS and YS were the first to become abnormal, deviating from normality as early as 6 weeks' gestation (OR 0.01, 95% CI 0.0-0.09, and OR 3.36, 95% CI 1.53-7.34, respectively), followed by changes in HR, and CRL, which became evident at 7 and 8 weeks (OR 0.96, 95% CI 0.92-1.0, and OR 0.59, 95% CI 0.48-0.73, respectively). Our observations showed that, after 5 complete weeks' gestation, a small GS and a large YS reliably predicted pregnancy loss. The YS reliably identified the occurrence of a miscarriage at least 7 days prior its occurrence. CRL and HR became abnormal at a later time in pregnancy and closer to the event. These findings have important implications for patient counseling and care planning, as well as a potential bearing on cost effectiveness within early pregnancy care.

Utility of trans-vaginal ultrasound in diagnosis and follow-up of non-pregnant sexually active females with lower ureteric calculi

Objective

To assess the utility of trans-vaginal ultrasonography in evaluation of non-pregnant sexually active female patients with lower ureteric calculi.

Methods

A prospective study was done from January 2015 to December 2017 including non-pregnant sexually active females with suspected ureteric calculus. Trans-abdominal ultrasound was initially done in all patients. In those patients in whom trans-abdominal ultrasound was inconclusive or there was indirect evidence of lower ureteric calculus in form of ureteral dilation but no calculus was evident, trans-vaginal ultrasound was done. The patients with ureteric calculi detected on trans-vaginal ultrasound and kept on conservative management were also followed up with trans-vaginal ultrasound. Non-contrast computed tomography was done in patients with inconclusive trans-vaginal ultrasound.

Results

As per the study protocol, 156 out of the total 468 patients evaluated by trans-abdominal ultrasound were eligible for trans-vaginal ultrasound. Trans-vaginal ultrasound was done in 149 patients, as seven patients did not give consent. Seventy-nine patients were detected with a lower ureteric calculus on trans-vaginal ultrasound and 27 patients had gynecologic or other cause for their symptoms. Forty-three patients had an inconclusive trans-vaginal ultrasound of which 36 underwent non-contrast computed tomography, among them only one patient had a lower ureteric calculus. Stone free status could be easily demonstrated on follow-up trans-vaginal ultrasound.

Conclusion

Trans-vaginal ultrasound in addition to trans-abdominal ultrasound is a very useful tool in evaluation of sexually active females with suspected lower ureteric calculus.

How to measure size of tubal ectopic pregnancy on ultrasound

OBJECTIVE

To identify the preoperative ultrasound parameters for assessing the size of tubal ectopic pregnancy that correlate best with findings at surgery.

METHODS

This was a prospective study of all women attending our center who had a conclusive transvaginal ultrasound diagnosis of tubal ectopic pregnancy over a 10-month period. In each case, the total size of the ectopic pregnancy was measured by placing the calipers on the outer edges of the visible trophoblastic tissue. In ectopic pregnancies presenting with a well-defined gestational sac, the size of the celomic (chorionic) cavity was also measured using the inner borders of the trophoblastic ring as reference points. In women with signs of intra-abdominal bleeding, the size of the hematosalpinx and/or hemoperitoneum was measured. Surgeons were blinded to the ultrasound measurements and were asked to estimate the size of the ectopic pregnancy and the amount of hemoperitoneum intraoperatively.

RESULTS

A total of 105 women were diagnosed with a tubal ectopic pregnancy on ultrasound examination, of whom 71 (67.6%) were managed surgically. A significant (P < 0.01) positive correlation was found between all ultrasound measurements and the size of the tubal ectopic pregnancy as reported during surgery. In the absence of hematosalpinx, the mean total outer diameter of the ectopic pregnancy had the highest positive correlation with the size of the tubal ectopic pregnancy at surgery (r = 0.65, P < 0.001). In cases complicated by hematosalpinx, the mean diameter of the tube was the only variable that correlated significantly with the estimated size of the ectopic pregnancy at surgery (P < 0.001). There was a significant positive association between the amount of hemoperitoneum on ultrasound and the estimated volume of intraperitoneal blood at surgery (P < 0.001).

CONCLUSIONS

The mean size of a hematosalpinx and the total outer mean diameter of an ectopic pregnancy on ultrasound correlate better with the surgical findings than does the size of the celomic cavity. Our findings show that the standard approach of measuring the size of an intrauterine pregnancy on ultrasound should be adapted to include these additional measurements in women diagnosed with a tubal ectopic pregnancy. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Measurement error of mean sac diameter and crown-rump length among pregnant women at Mulago hospital, Uganda

Background

Ultrasonography is essential in the prenatal diagnosis and care for the pregnant mothers. However, the measurements obtained often contain a small percentage of unavoidable error that may have serious clinical implications if substantial. We therefore evaluated the level of intra and inter-observer error in measuring mean sac diameter (MSD) and crown-rump length (CRL) in women between 6 and 10 weeks’ gestation at Mulago hospital.

Methods

This was a cross-sectional study conducted from January to March 2016. We enrolled 56 women with an intrauterine single viable embryo. The women were scanned using a transvaginal (TVS) technique by two observers who were blinded of each other’s measurements. Each observer measured the CRL twice and the MSD once for each woman. Intra-class correlation coefficients (ICCs), 95% limits of agreement (LOA) and technical error of measurement (TEM) were used for analysis.

Results

Intra-observer ICCs for CRL measurements were 0.995 and 0.993 while inter-observer ICCs were 0.988 for CRL and 0.955 for MSD measurements. Intra-observer 95% LOA for CRL were ± 2.04 mm and ± 1.66 mm. Inter-observer LOA were ± 2.35 mm for CRL and ± 4.87 mm for MSD. The intra-observer relative TEM for CRL were 4.62% and 3.70% whereas inter-observer relative TEM were 5.88% and 5.93% for CRL and MSD respectively.

Conclusions

Intra- and inter-observer error of CRL and MSD measurements among pregnant women at Mulago hospital were acceptable. This implies that at Mulago hospital, the error in pregnancy dating is within acceptable margins of ±3 days in first trimester, and the CRL and MSD cut offs of ≥7 mm and ≥ 25 mm respectively are fit for diagnosis of miscarriage on TVS. These findings should be extrapolated to the whole country with caution. Sonographers can achieve acceptable and comparable diagnostic accuracy levels of MSD and CLR measurements with proper training and adherence to practice guidelines.

Fetal biometry: Relevance in obstetrical practice

Ultrasound imaging in obstetrics and gynecology dates back to 1958 when The Lancet published the first article about the use of ultrasonography for fetal and gynecological assessments. It is now almost inconceivable, 60 years later, to think of effective performance in obstetrics and gynecology without the variety of ultrasound, for example, real time imaging, power and color Doppler, 3D/4D ultrasonography, etc. Such examinations facilitate the assessment of intrauterine fetal growth and development during pregnancy, provide alerts about the risk of pre-eclampsia and preterm birth, help identify anatomic reasons for infertility, diagnose ectopic pregnancies, uterine, ovary and tubal pathology. Ultrasonography is also used for diagnostic and treatment procedures during pregnancy or for the treatment of infertility. This article is an overview of the development of fetal ultrasound, the methodology and interpretation of ultrasound in the assessment of intrauterine fetal growth and fetal biometry standards both worldwide and in Lithuania.

Failed Intrauterine Pregnancy: What Is a Failed Pregnancy, What Is Not?

Pregnancy failure is defined as a lack of sonographic evidence of current or expected viability. Technologic advances in ultrasound imaging continue to redefine diagnostic criteria of pregnancy failure or success. When evaluating a pregnancy, the first step is an assessment of maternal risk factors for failure. Imaging clues such as an empty gestational sac measuring ≥25 mm or an embryo ≥7 mm without cardiac activity are reliable signs of pregnancy failure, whereas embryonic growth <1 mm/d is not. Combinations of sonographic findings can be used for a more accurate prediction of pregnancy success or failure.

Détermination de l'âge gestationnel par échographie

OBJECTIF

Aider les cliniciens à attribuer un âge gestationnel en fonction des résultats de la biométrie échographique.

ISSUES

Déterminer si la datation par échographie offre une évaluation plus précise de l'âge gestationnel que la datation en fonction des dernières règles avec ou sans recours à l'échographie. Offrir, aux praticiens et aux chercheurs du domaine des soins de maternité, des lignes directrices factuelles en matière d'attribution de l'âge gestationnel. Identifier les paramètres biométriques échographiques qui sont de fiabilité supérieure lorsque l'âge gestationnel est incertain. Déterminer la rentabilité de l'évaluation de l'âge gestationnel par échographie. RéSULTATS: La littérature publiée a été récupérée par l'intermédiaire de recherches menées dans PubMed ou MEDLINE et The Cochrane Library en 2013 au moyen d'un vocabulaire contrôlé et de mots clés appropriés (p. ex. « gestational age », « ultrasound biometry » et « ultrasound dating »). Les résultats ont été restreints aux analyses systématiques, aux essais comparatifs randomisés / essais cliniques comparatifs et aux études observationnelles rédigés en anglais. Aucune restriction n'a été appliquée en matière de dates. Les recherches ont été mises à jour de façon régulière et intégrées à la directive clinique jusqu'au 31 juillet 2013. La littérature grise (non publiée) a été identifiée par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales.

VALEURS

La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau 1). AVANTAGES, DéSAVANTAGES ET COûTS: L'attribution précise d'un âge gestationnel pourrait réduire l'incidence du déclenchement mené en raison d'une grossesse prolongée et améliorer les soins obstétricaux en nous permettant de planifier la chronologie des interventions nécessaires de façon optimale et d'éviter les interventions inutiles. Une datation plus précise permet l'optimisation de la tenue de tests prénataux de dépistage de l'aneuploïdie. Un algorithme national d'attribution de l'âge gestationnel pourrait atténuer les variations pancanadiennes en matière de pratique pour les cliniciens et les chercheurs. Parmi les désavantages potentiels, on trouve la réattribution possible des dates lorsqu'une pathologie fœtale importante (comme le retard de croissance intra-utérin ou la macrosomie) donne lieu à une divergence entre les résultats de la biométrie échographique et l'âge gestationnel clinique. Une telle réattribution pourrait mener à l'omission d'interventions fœtales justifiées ou à la tenue d'interventions fœtales injustifiées. DéCLARATIONS SOMMAIRES: RECOMMANDATIONS.

[Role of ultrasound in elective abortions]

Ultrasound plays a fundamental role in the management of elective abortions. Although it can improve the quality of post-abortion care, it must not be an obstacle to abortion access. We thus studied the role of ultrasound in pregnancy dating and possible alternatives and analyzed the literature to determine the role of ultrasound in post-abortion follow-up. During an ultrasound scan, the date of conception is estimated by measurement of the crown-rump length (CRL), defined by Robinson, or of the biparietal diameter (BPD), as defined by the French Center for Fetal Ultrasound (CFEF) after 11 weeks of gestation (Robinson and CFEF curves) (grade B). Updated curves have been developed in the INTERGROWTH study. In the context of abortion, the literature recommends the application of a safety margin of 5 days, especially when the CRL and/or BPD measurement indicates a term close to 14 weeks (that is equal or below 80 and 27mm, respectively) (best practice agreement). Accordingly, with the ultrasound measurement reliable to±5 days when its performance meets the relevant criteria, an abortion can take place when the CRL measurement is less than 90mm or the BPD less than 30mm (INTERGROWTH curves) (best practice agreement). While a dating ultrasound should be encouraged, its absence is not an obstacle to scheduling an abortion for women who report that they know the date of their last menstrual period and/or of the at-risk sexual relations and for whom a clinical examination by a healthcare professional is possible (best practice agreement). In cases of intrauterine pregnancy of uncertain viability or of a pregnancy of unknown location, without any particular symptoms, the patient must be able to have a transvaginal ultrasound to increase the precision of the diagnosis (grade B). Various reviews of the literature on post-abortion follow-up indicate that the routine use of ultrasound during instrumental abortions should be avoided (best practice agreement). If it becomes clear immediately after the procedure that the endometrial thickness exceeds 8mm, immediate reaspiration is necessary. Ultrasound examination of the endometrium several days after an instrumental elective abortion does not appear to be relevant (grade B). An analysis of the literature similarly shows that routine ultrasound scans after medical abortions should be avoided. If a transvaginal ultrasound is performed after a medical abortion, it should take place at least two weeks afterwards (best practice agreement). The only aim of an ultrasound examination during follow-up should be to determine whether a gestational sac is present (best practice agreement). Finally, if an ultrasound is performed at any point during pre- or post-abortion care, a report should be drafted, specifying any potential gynecologic abnormalities found, but its absence must not delay the scheduling of the abortion (best practice agreement).

Normal and Abnormal US Findings in Early First-Trimester Pregnancy: Review of the Society of Radiologists in Ultrasound 2012 Consensus Panel Recommendations

Since being introduced more than 30 years ago, endovaginal ultrasonography (US) and quantitative testing of serum levels of the beta subunit of human chorionic gonadotropin have become the standard means of establishing the presence of normal intrauterine pregnancy (IUP), failed IUP, and ectopic pregnancy. Appropriate use of these powerful tools requires clear, standardized interpretations based on conservative criteria to protect both the pregnancy and the mother. Since diagnoses are assigned earlier and available medical treatments for ectopic pregnancy and failed IUP are expanding, emphasis must carefully shift toward watchful waiting when the mother is clinically stable and a definitive location for the pregnancy cannot be established with US. To this end and to prevent inadvertent harm to early normal pregnancies, the Society of Radiologists in Ultrasound convened a consensus panel of radiologists, obstetricians, and emergency medicine physicians in 2012 with the goal of reviewing current literature and clinical practices and formulating modern criteria and terminology for the various first-trimester outcomes.

A prospective study to assess the clinical impact of interobserver reliability of sonographic measurements of fetal nuchal translucency and crown-rump length on combined first-trimester screening

OBJECTIVE:

To examine the interobserver variability for fetal biometric parameters and to focus on how this variability affects the combined first-trimester screening test results.

METHODS:

Sixty-four singleton pregnancies who were scheduled for combined first-trimester screening were investigated. Two experienced sonographers performed all examinations at the same visit. The risk calculations of screening were performed according to the each operator’s individual ultrasonographic fetal measurements. Interobserver variability in measurements of fetal nuchal translucency (NT) and crown-rump length (CRL) and the effect of this interobserver variability on the screening results were assessed.

RESULTS:

Interobserver reliabilities for NT and CRL were 0.687 and 0.945 (p<0.001), respectively. Interobserver reliability coefficients for trisomy 21 and trisomy 13/18 were 0.945 and 0.963 (p<0.001), respectively.

CONCLUSION:

Our study demonstrated quite high interobserver reliability for CRL measurement, while interobserver agreement for NT was lower. Despite this lower reliability and agreement for NT measurement, interobserver reliability for chromosomal abnormalities was quite high.

Defining safe criteria to diagnose miscarriage: prospective observational multicentre study

OBJECTIVES

To validate recent guidance changes by establishing the performance of cut-off values for embryo crown-rump length and mean gestational sac diameter to diagnose miscarriage with high levels of certainty. Secondary aims were to examine the influence of gestational age on interpretation of mean gestational sac diameter and crown-rump length values, determine the optimal intervals between scans and findings on repeat scans that definitively diagnose pregnancy failure.)

DESIGN

Prospective multicentre observational trial.

SETTING

Seven hospital based early pregnancy assessment units in the United Kingdom.

PARTICIPANTS

2845 women with intrauterine pregnancies of unknown viability included if transvaginal ultrasonography showed an intrauterine pregnancy of uncertain viability. In three hospitals this was initially defined as an empty gestational sac <20 mm mean diameter with or without a visible yolk sac but no embryo, or an embryo with crown-rump length <6 mm with no heartbeat. Following amended guidance in December 2011 this definition changed to a gestational sac size <25 mm or embryo crown-rump length <7 mm. At one unit the definition was extended throughout to include a mean gestational sac diameter <30 mm or embryo crown-rump length <8 mm.

MAIN OUTCOME MEASURES

Mean gestational sac diameter, crown-rump length, and presence or absence of embryo heart activity at initial and repeat transvaginal ultrasonography around 7-14 days later. The final outcome was pregnancy viability at 11-14 weeks' gestation.

RESULTS

The following indicated a miscarriage at initial scan: mean gestational sac diameter ≥ 25 mm with an empty sac (364/364 specificity: 100%, 95% confidence interval 99.0% to 100%), embryo with crown-rump length ≥ 7 mm without visible embryo heart activity (110/110 specificity: 100%, 96.7% to 100%), mean gestational sac diameter ≥ 18 mm for gestational sacs without an embryo presenting after 70 days' gestation (907/907 specificity: 100%, 99.6% to 100%), embryo with crown-rump length ≥ 3 mm without visible heart activity presenting after 70 days' gestation (87/87 specificity: 100%, 95.8% to 100%). The following were indicative of miscarriage at a repeat scan: initial scan and repeat scan after seven days or more showing an embryo without visible heart activity (103/103 specificity: 100%, 96.5% to 100%), pregnancies without an embryo and mean gestational sac diameter <12 mm where the mean diameter has not doubled after 14 days or more (478/478 specificity: 100%, 99.2% to 100%), pregnancies without an embryo and mean gestational sac diameter ≥ 12 mm showing no embryo heartbeat after seven days or more (150/150 specificity: 100%, 97.6% to 100%).

CONCLUSIONS

Recently changed cut-off values of gestational sac and embryo size defining miscarriage are appropriate and not too conservative but do not take into account gestational age. Guidance on timing between scans and expected findings on repeat scans are still too liberal. Protocols for miscarriage diagnosis should be reviewed to account for this evidence to avoid misdiagnosis and the risk of terminating viable pregnancies.

True Reproducibility of UltraSound Techniques (TRUST): systematic review of reliability studies in obstetrics and gynecology

OBJECTIVES

To examine the quality of methods used and the accuracy of the interpretation of agreement in existing studies that examine the reliability of ultrasound measurements and judgments in obstetrics and gynecology.

METHODS

A systematic search of MEDLINE was performed on 25 March 2014, looking for studies that examined the reliability of ultrasound measurements and judgments in obstetrics and gynecology with evaluation of concordance (CCC) or intraclass (ICC) correlation coefficients or kappa as a main objective.

RESULTS

Seven hundred and thirty-three records were examined on the basis of their title and abstract, of which 141 full-text articles were examined completely for eligibility. We excluded 29 studies because they did not report CCC/ICC/kappa, leaving 112 studies that were included in our analysis. Two studies reported both ICC and kappa and were counted twice, therefore, the number used as the denominator in the analyses was 114. Only 16/114 (14.0%) studies were considered to be well designed (independent acquisition and blinded analysis) and to have interpreted the results properly. Most errors occurring in the studies are likely to overestimate the reliability of the method examined.

CONCLUSIONS

The vast majority of published studies examined had important flaws in design, interpretation and/or reporting. Such limitations are important to identify as they might create false confidence in the existing measurements and judgments, jeopardizing clinical practice and future research. Specific guidelines aimed at improving the quality of reproducibility studies that examine ultrasound methods should be encouraged.

Impact of new society of radiologists in ultrasound early first-trimester diagnostic criteria for nonviable pregnancy

OBJECTIVES

New early first-trimester diagnostic criteria for nonviable pregnancy recommended by the Society of Radiologists in Ultrasound via a multispecialty consensus panel extended the diagnostic size criteria of crown-rump length from 5 to 7 mm for embryos without a heartbeat and mean sac diameter from 16 to 25 mm for "empty" sacs. Our study assessed the potential impact of the new criteria on the number of additional follow-up sonograms these changes would engender.

METHODS

A retrospective study of all first-trimester sonograms in women with first trimester bleeding from 1999 to 2008 was conducted. Everyone included in the study had a visible gestational sac in the uterus. There were no pregnancies of unknown location or ectopic pregnancies included in this study cohort. Pregnancy of unknown location was used to describe cases in which there were no signs of pregnancy inside or outside the uterus on transvaginal sonography despite a positive pregnancy test result. A total of 1013 patients met the inclusion criteria.

RESULTS

Seven hundred fifty-two patients (74%) had identifiable embryos, and 261 (26%) did not. Of those with an identifiable embryo, 286 (38%) had no detectable embryonic cardiac activity. The breakdown of crown-rump lengths in this group was as follows: 100 measuring less than 5 mm, 36 measuring 5 to 7 mm, and 150 measuring 7 mm or greater. The breakdown of mean sac diameters in those without a visible embryo was as follows: 120 measuring less than 16 mm, 90 measuring 16 to 25 mm, and 51 measuring 25 mm or greater.

CONCLUSIONS

When diagnosing a failed pregnancy, there can be no room for error. Only 126 of 1013 early pregnancies threatening to abort (12%) fell into the more conservative zones defined by the new compared to the former size criteria (crown-rump length, 5-7 mm; mean sac diameter, 16-25 mm). Therefore, the potential impact of the new guidelines on follow-up sonograms does not appear inordinate.

Rationalising the change in defining non-viability in the first trimester

Introduction: With the publication of four papers in late 2011, international cut-offs for definitions of non-viability in the first trimester of pregnancy were challenged. These definitions were inconsistent across different international guidelines. For example, a gestational sac with absent yolk sac or embryo and a mean diameter of ≥ 16 mm would be classified as a miscarriage in the USA, whereas the same sac would have to measure ≥ 20 mm in the UK or Australia to meet this definition. Likewise, an embryo with no detectable heartbeat and a CRL of ≥ 5 mm would also meet criteria for missed miscarriage in the USA, compared to a CRL ≥ 6 mm in the UK or Australia. Methods: Later in 2011 and then in 2012, guidelines across the three countries were updated and are now consistent, defining an empty gestational sac with a mean diameter of > 25 mm as a non-viable pregnancy and/or an embryo with CRL > 7 mm and no detectable heartbeat. In this paper we explore the rationale that led to these changes in order to potentially avoid wrongly diagnosing miscarriage at the decision boundary measurements and in turn avoiding inadvertent termination of potentially viable pregnancies. Conclusion: Although reducing women's anxiety and making a definitive diagnosis as early as possible is desirable, the need for absolute certainty is paramount before diagnosis of the death of an early pregnancy is made.

When is a pregnancy nonviable and what criteria should be used to define miscarriage?

In 2011, the first systematic review of the evidence behind the diagnostic criteria for miscarriage was published. It states, "findings were limited by the small number and poor quality of the studies," and concluded that further studies were, "urgently required before setting future standards for the accurate diagnosis of early embryonic demise." This implies that data used to define criteria to diagnose miscarriage are unreliable. The 2011 Irish Health Service executive review into miscarriage misdiagnosis highlighted this issue. In parallel to these publications a multicenter prospective study was published examining cut-off values for mean sac diameter (MSD) and embryo size to define miscarriage. The authors also published evidence on expected findings when ultrasonography is repeated at an interval. This led to guidance on diagnostic criteria for miscarriage in the UK changing. These new criteria state miscarriage be considered only when: an empty gestation sac has an MSD of ≥ 25 mm (with no obvious yolk sac), or embryonic crown rump length ≥ 7 mm (the latter without evidence of fetal heart activity). If in doubt, repeating scans at an interval is emphasized. It is axiomatic that decisions about embryonic viability must not be open to doubt. So it is surprising how little evidence exists to support previous guidance. Any clinician working in this area knows of women being wrongly informed that their pregnancy has failed. This cannot be acceptable and guidance in this area must be "failsafe."

Impact of ovulation and implantation timing on first-trimester crown-rump length and gestational age

OBJECTIVE

To determine the impact of ovulation and implantation timing on first-trimester crown-rump length (CRL) and the derived gestational age (GA).

METHOD

One hundred and forty-three women who were trying to conceive were recruited prospectively. The timing of ovulation and implantation and the ovulation to implantation (O-I) interval were established in 101 pregnancies using home urinary tests for luteinizing hormone and human chorionic gonadotropin. In 71 ongoing pregnancies, GA determined by measurement of fetal CRL at 10-14 weeks' gestation was compared with GA based on ovulation and implantation day. First-trimester growth was determined by serial ultrasound scans at 6-7, 8-9 and 10-14 weeks.

RESULTS

The median ovulation and implantation days were 16 and 27, respectively, with an O-I interval of 11 days. GA estimated from CRL at 10-14 weeks was on average 1.3 days greater than that derived from ovulation timing. CRL Z-score was inversely related to O-I interval (ρ= -0.431, P=0.0009). There was no significant relationship between CRL growth rate and the difference between observed CRL and expected CRL based on GA from last menstrual period (ρ=0.224, P=0.08).

CONCLUSIONS

Early implantation leads to a larger CRL and late implantation to a smaller CRL at 10-14 weeks, independent of CRL growth rate. Implantation timing is a major determinant of fetal size at 10-14 weeks and largely explains the variation in estimates of GA in the first trimester derived from embryonic or fetal CRL.

Cytogenetic and morphological analysis of early products of conception following hystero-embryoscopy from couples with recurrent pregnancy loss

OBJECTIVE

Our knowledge about miscarriages mainly concerns pregnancies of at least 8 weeks' gestation. Information about the morphology and the genetic determinants of early aborted embryos remains limited. In addition, it is known that aneuploidies account for less than half of recurrent spontaneous abortions. We hypothesized that (recurrent) early pregnancy losses might have other genetic causes.

METHOD

Products of conception from 51 couples with at least one previous miscarriage were collected by hystero-embryoscopy. The extracted DNA was analyzed by low resolution array comparative genomic hybridization and high resolution single nucleotide polymorphism arrays to detect aneuploidies, polyploidies, submicroscopic copy number variants or copy neutral loss of heterozygosity.

RESULTS

Chromosomal aberrations were identified in 65.6% (21/32) of miscarriages and in 89% (8/9) of anembryonic cases. Interestingly, 4/11 chromosomally euploid embryos contained regions of loss of heterozygosity >5 Mb, suggesting the miscarriages might be due to an underlying lethal recessive disease.

CONCLUSION

Hystero-embryoscopic biopsy followed by array comparative genomic hybridization is a valuable diagnostic tool for early and recurrent miscarriages. Genome-wide high resolution single nucleotide polymorphism microarray analysis of a larger group of miscarriages could provide more insight into the genetic causes of recurrent spontaneous abortion.

Limitations of current definitions of miscarriage using mean gestational sac diameter and crown-rump length measurements: a multicenter observational study

OBJECTIVES

There is significant variation in cut-off values for mean gestational sac diameter (MSD) and embryo crown-rump length (CRL) used to define miscarriage, values suggested in the literature ranging from 13 to 25 mm for MSD and from 3 to 8 mm for CRL. We aimed to define the false-positive rate (FPR) for the diagnosis of miscarriage associated with different CRL and MSD measurements with or without a yolk sac in a large study population of patients attending early pregnancy clinics. We also aimed to define cut-off values for CRL and MSD that, on the basis of a single measurement, can definitively diagnose a miscarriage and so exclude possible inadvertent termination of pregnancy.

METHODS

This was an observational cross-sectional study. Data were collected prospectively according to a predefined protocol. Intrauterine pregnancy of uncertain viability (IPUV) was defined as an empty gestational sac or sac with a yolk sac but no embryo seen with MSD < 20 or < 30 mm or an embryo with an absent heartbeat and CRL < 6 mm or < 8 mm. We recruited to the study 1060 consecutive women with IPUV. The endpoint was presence or absence of a viable pregnancy at the time of first-trimester screening ultrasonography between 11 and 14 weeks. The sensitivity, specificity, positive and negative predictive values were calculated for potential cut-off values to define miscarriage from MSD 8 to 30 mm with or without a yolk sac and from CRL 3 to 8 mm.

RESULTS

Of the 1060 women with a diagnosis of IPUV, 473 remained viable and 587 were non-viable by the time of the 11-14-week scan. In the absence of both embryo and yolk sac, the FPR for miscarriage was 4.4% when an MSD cut-off of 16 mm was used and 0.5% for a cut-off of 20 mm. There were no false-positive test results for miscarriage when a cut-off of MSD ≥ 21 mm was used. If a yolk sac was present but an embryo was not, the FPR for miscarriage was 2.6% for an MSD cut-off of 16 mm and 0.4% for a cut-off of 20 mm, with no false-positive results when a cut-off of MSD ≥ 21 mm was used. When an embryo was visible with an absent heartbeat, using a CRL cut-off of 4 mm the FPR for miscarriage was 8.3%, and for a CRL cut-off of 5 mm it was also 8.3%. There were no false-positive results using a CRL cut-off of ≥ 5.3 mm.

CONCLUSIONS

These data show that some current definitions used to diagnose miscarriage are potentially unsafe. Current national guidelines should be reviewed to avoid inadvertent termination of wanted pregnancies. An MSD cut-off of > 25 mm and a CRL cut-off of > 7 mm could be introduced to minimize the risk of a false-positive diagnosis of miscarriage.

Gestational sac and embryonic growth are not useful as criteria to define miscarriage: a multicenter observational study

OBJECTIVES

We studied changes in mean gestational sac diameter (MSD) and embryonic crown-rump length (CRL) in intrauterine pregnancies of uncertain viability (IPUVs). We aimed to establish cut-off values for MSD and CRL growth that could be definitively associated with either viability or miscarriage, and to establish the relationship between growth in MSD and appearance of embryonic structures in the gestational sac.

METHODS

One thousand and sixty consecutive IPUVs were recruited prospectively from four London University hospitals: 462 with no yolk sac or embryo, 419 with a yolk sac but no embryo, and 179 with an embryo but no heartbeat visible. IPUV was defined as an empty gestational sac with or without a yolk sac but no embryo seen with MSD < 20 or < 30 mm (depending on center) or an embryo with no heartbeat and CRL < 6 mm or < 8 mm (depending on center). Scans were repeated 7-14 days later. The endpoint was viability at first-trimester screening ultrasonography between 11 and 14 weeks. Change in MSD and CRL between the first and second scans of each pregnancy was compared with respect to viability and appearance of embryonic structures using the two-sample t-test.

RESULTS

The study included 359 pregnancies in which a gestational sac with or without embryo was identified at the follow-up scan 7-14 days later. Of these, 192 were viable and 167 non-viable at the 11-14-week scan. MSD growth was significantly higher in viable than non-viable pregnancies (mean 1.003 vs. 0.503 mm/day; P < 0.001, 95% CI of difference 0.403-0.596). A difference in CRL growth was found between the two groups (mean 0.673 vs. 0.148 mm/day; P < 0.001, 95% CI of difference 0.345-0.703). MSD growth of 0.6 mm/day was associated with a specificity for diagnosing miscarriage of 90.1%, a sensitivity of 61.7% and 19 false-positive test results. A cut-off of CRL growth rate of 0.2 mm/day gave a sensitivity of 76.3% and there were no false-positive test results for miscarriage. On repeat scan the failure of either a yolk sac or embryo to be visualized was always associated with miscarriage.

CONCLUSION

There is an overlap in MSD growth rates between viable and non-viable IPUV. No cut-off exists for MSD growth below which a viable pregnancy could be safely excluded. A cut-off value for CRL growth of 0.2 mm/day was always associated with miscarriage. These data suggest that criteria to diagnose miscarriage based on growth in MSD and CRL are potentially unsafe. However, finding an empty gestational sac on two scans more than 7 days apart is highly likely to indicate miscarriage, irrespective of growth.