Ambulatory human chorionic gonadotrophin (hCG) testing: a verification of two hCG point of care devices

OBJECTIVES

Quantitative human chorionic gonadotropin (hCG) measurements are used to manage women classified with a pregnancy of unknown location (PUL). Two point of care testing (POCT) devices that quantify hCG are commercially available. We verified the i-STAT 1 (Abbott) and the AQT 90 FLEX (Radiometer) prior to use in PUL triage.

METHODS

Tests for precision, external quality assurance (EQA), correlation, hook effect and recovery were undertaken alongside a POCT usability assessment during this prospective multi-center verification.

RESULTS

Coefficients of variation ranged between 4.0 and 5.1 % for the three i-STAT 1 internal quality control (IQC) solutions and between 6.8 and 7.3 % for the two AQT IQC solutions. Symmetric differences in POCT EQA results when compared with laboratory and EQA stock values ranged between 3.2 and 24.5 % for the i-STAT 1 and between 3.3 and 36.9 % for the AQT. Correlation coefficients (i-STAT 1: 0.96, AQT: 0.99) and goodness of fit curves (i-STAT 1: 0.92, AQT: 0.99) were excellent when using suitable whole blood samples. An hCG hook effect was noted with the i-STAT 1 between 572,194 and 799,089 IU/L, lower than the hook effect noted with the AQT, which was between 799,089 and 1,619,309 IU/L. When hematocrit concentration was considered in sample types validated for use with each device, hCG recovery was 108 % with the i-STAT 1 and 98 % with the AQT. The i-STAT 1 scored lower on usability overall (90/130) than the AQT (121/130, p<0.001, Mann-Whitney).

CONCLUSIONS

Both hCG POCT devices were verified for use in clinical practice. Practical factors must also be considered when choosing which device to use in each unit.

Beta-human chorionic gonadotrophin point of care testing for the management of pregnancy of unknown location

RESEARCH QUESTION

Does a commercially available quantitative beta-human chorionic gonadotrophin (BHCG) point of care testing (POCT) device improve workflow management in early pregnancy by performing comparably to gold standard laboratory methods, and is the performance of a validated pregnancy of unknown location (PUL) triage strategy maintained using POCT BHCG results?

DESIGN

Women classified with a PUL between 2018 and 2021 at three early pregnancy units were included. The linear relationship of untreated whole-blood POCT and serum laboratory BHCG values was defined using coefficients and regression. Paired serial BHCG values were then incorporated into the validated M6 multinomial logistic regression model to stratify the PUL as at high risk or at low risk of clinical complications. The sensitivity and negative predictive value were assessed. The timings required for equivocal POCT and laboratory care pathways were compared.

RESULTS

A total of 462 PUL were included. The discrepancy between 571 laboratory and POCT BHCG values was -5.2% (-6.2 IU/l), with a correlation coefficient of 0.96. The 133 PUL with paired 0 and 48 h BHCG values were compared using the M6 model. The sensitivity for high-risk outcomes (96.2%) and negative predictive values (98.5%) was excellent for both. Sample receipt and laboratory processing took 135 min (421 timings), compared with 12 min (91 timings) when using POCT (P < 0.0001).

CONCLUSIONS

POCT BHCG values correlated well with laboratory testing measurements. The M6 model retained its performance when using POCT BHCG values. Using the model with POCT may improve workflow and patient care without compromising on effective PUL triage.

Using simple clinical and ultrasound variables to develop a model to predict first trimester pregnancy viability

INTRODUCTION

Early prediction of pregnancies destined to miscarry will allow couples to prepare for this common but often unexpected eventuality, and clinicians to allocate finite resources. We aimed to develop a prediction model combining clinical, demographic, and sonographic data as a clinical tool to aid counselling about first trimester pregnancy outcome.

MATERIAL AND METHODS

This is a prospective, observational cohort study conducted at Queen Charlotte's and Chelsea Hospital, UK from March 2014 to May 2019. Women with confirmed intrauterine pregnancies between 5 weeks and their dating scan (11-14 weeks) were recruited. Participants attended serial ultrasound scans in the first trimester and at each visit recorded symptoms of vaginal bleeding, pelvic pain, nausea and vomiting using validated scoring tools. Pregnancies were followed up until the dating scan (11-14 weeks). Univariate and multivariate analyses were performed to predict first trimester viability. A model was developed with multivariable logistic regression, variables limited by feature selection, and bootstrapping with multiple imputation was used for internal validation.

RESULTS

1403 women were recruited and after exclusions, data were available for 1105. 160 women (14.5 %) experienced first trimester miscarriage and 945 women (85.5 %) had viable pregnancies at 11-14 weeks' gestation. The average gestational age at the initial visit (calculated from the menstrual dates) was 7 + 1 weeks (+/-12.2 days). A multivariable logistic regression model was developed to predict first trimester viability and included the variables: mean gestational sac diameter, presence of fetal heart pulsations, difference in gestational age from last menstrual period and from mean sac diameter on ultrasonography, current folic acid usage and maternal age. The model demonstrated good performance (optimism-corrected area under curve (AUC) 0.84, 95 % CI 0.81-0.87; optimism-corrected calibration slope 0.969).

CONCLUSION

We have developed and internally validated a model to predict first trimester viability with good accuracy prior to the 11-14 week dating scan, which now needs to be externally validated prior to clinical use.

Time-effectiveness and convenience of transvaginal ultrasound probe disinfection using ultraviolet vs chlorine dioxide multistep wipe system: prospective survey study

OBJECTIVES

To compare the efficiency, ease of use and user satisfaction of two methods of transvaginal ultrasound probe high-level disinfection: ultraviolet-C radiation (UV-C) and a chlorine dioxide multistep wipe system.

METHODS

This was a prospective survey study. UV-C units were introduced into a busy early pregnancy assessment service and compared with a multiwipe system for disinfection. Before seeing each patient, healthcare professionals (HCPs) measured with a stopwatch the time taken to complete a cycle of disinfection using either UV-C or chlorine dioxide multistep wipes and responded to a quick-response (QR) code-linked survey. Additional essential tasks that could be completed before seeing the next patient during probe disinfection were also documented. Using another QR code-linked survey, data on ease of use, satisfaction with the system used and preferred system were collected. The ease of use and satisfaction with the system were rated on a 0 to 10 Likert scale (0 poor, 10 excellent). A free-text section for comments was then completed.

RESULTS

Disinfection using UV-C (n = 331) was 60% faster than the chlorine dioxide multiwipe system (n = 332) (101 vs 250 s; P < 0.0001). A greater number of tasks were completed during probe disinfection when using UV-C, saving a further 74 s per patient (P < 0.0001). The HCPs using UV-C (n = 71) reported greater ease of use (median Likert score, 10 vs 3; P < 0.0001) and satisfaction (median Likert score, 10 vs 2; P < 0.0001) compared with those using the multiwipe system (n = 43). HCPs reported that the chlorine dioxide system was time-consuming and environmentally unfriendly, while the UV-C system was efficient and easy to use. Overall, 98% of the HCPs preferred using the UV-C system.

CONCLUSIONS

UV-C technology is more time-efficient and allows more essential tasks to be completed during disinfection. For a 4-h ultrasound list of 15 patients, the use of UV-C would save 55 min 45 s. HCPs found UV-C preferable and easier to use. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Gradient boosted trees with individual explanations: An alternative to logistic regression for viability prediction in the first trimester of pregnancy

BACKGROUND

Clinical models to predict first trimester viability are traditionally based on multivariable logistic regression (LR) which is not directly interpretable for non-statistical experts like physicians. Furthermore, LR requires complete datasets and pre-established variables specifications. In this study, we leveraged the internal non-linearity, feature selection and missing values handling mechanisms of machine learning algorithms, along with a post-hoc interpretability strategy, as potential advantages over LR for clinical modeling.

METHODS

The dataset included 1154 patients with 2377 individual scans and was obtained from a prospective observational cohort study conducted at a hospital in London, UK, from March 2014 to May 2019. The data were split into a training (70%) and a test set (30%). Parsimonious and complete multivariable models were developed from two algorithms to predict first trimester viability at 11-14 weeks gestational age (GA): LR and light gradient boosted machine (LGBM). Missing values were handled by multiple imputation where appropriate. The SHapley Additive exPlanations (SHAP) framework was applied to derive individual explanations of the models.

RESULTS

The parsimonious LGBM model had similar discriminative and calibration performance as the parsimonious LR (AUC 0.885 vs 0.860; calibration slope: 1.19 vs 1.18). The complete models did not outperform the parsimonious models. LGBM was robust to the presence of missing values and did not require multiple imputation unlike LR. Decision path plots and feature importance analysis revealed different algorithm behaviors despite similar predictive performance. The main driving variable from the LR model was the pre-specified interaction between fetal heart presence and mean sac diameter. The crown-rump length variable and a proxy variable reflecting the difference in GA between expected and observed GA were the two most important variables of LGBM. Finally, while variable interactions must be specified upfront with LR, several interactions were ranked by the SHAP framework among the most important features learned automatically by the LGBM algorithm.

CONCLUSIONS

Gradient boosted algorithms performed similarly to carefully crafted LR models in terms of discrimination and calibration for first trimester viability prediction. By handling multi-collinearity, missing values, feature selection and variable interactions internally, the gradient boosted trees algorithm, combined with SHAP, offers a serious alternative to traditional LR models.

Ultrasound characteristics, serum biochemistry and outcome of ectopic pregnancies presenting during COVID-19 pandemic

OBJECTIVE

To describe and compare the characteristics of ectopic pregnancies (EPs) in the year prior to vs during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

This was a retrospective analysis of women diagnosed with an EP on transvaginal sonography conducted at a center in London, UK, providing early-pregnancy assessment, between 1 January 2019 and 31 December 2020. Women were identified via the Astraia ultrasound reporting system using coded and non-coded outcomes of EP or pregnancy outside the uterine cavity. Data related to predefined outcomes were collected using Astraia and Cerner electronic reporting systems. Main outcome measures included clinical, ultrasound and biochemical features of EP, in addition to reported complications and management.

RESULTS

There were 22 683 consultations over the 2-year period. Following consultation, a similar number and proportion of EPs were diagnosed in 2019 (141/12 657 (1%)) and 2020 (134/10 026 (1%)). Both cohorts were comparable in age, ethnicity, weight and method of conception. Gestational age at the first transvaginal sonography scan and at diagnosis were similar, and no difference in location, size or morphology of EP was found between the two cohorts. Serum human chorionic gonadotropin (hCG) levels at the time of EP diagnosis were higher in 2020 than in 2019 (1005 IU/L vs 665 IU/L; P = 0.03). The proportions of women according to type of final EP management were similar, but the rate of failed first-line management was higher during vs before the pandemic (16% vs 6%; P = 0.01). The rates of blood detected in the pelvis (hemoperitoneum) on ultrasound (23% vs 26%; P = 0.58) and of ruptured EP confirmed surgically (9% vs 3%; P = 0.07) were similar in 2019 vs 2020.

CONCLUSIONS

No difference was observed in the location, size, morphology or gestational age at the first ultrasound examination or at diagnosis of EP between women diagnosed before vs during the COVID-19 pandemic. Complication rates and final management strategy were also unchanged. However, hCG levels and the failure rate of first-line conservative management measures were higher during the pandemic. Our findings suggest that women continued to access appropriate care for EP during the COVID-19 pandemic, with no evidence of diagnostic delay or an increase in adverse outcome in our population. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Evaluating cut-off levels for progesterone, β human chorionic gonadotropin and β human chorionic gonadotropin ratio to exclude pregnancy viability in women with a pregnancy of unknown location: A prospective multicenter cohort study

INTRODUCTION

There is no global agreement on how to best determine pregnancy of unknown location viability and location using biomarkers. Measurements of progesterone and β human chorionic gonadotropin (βhCG) are still used in clinical practice to exclude the possibility of a viable intrauterine pregnancy (VIUP). We evaluate the predictive value of progesterone, βhCG, and βhCG ratio cut-off levels to exclude a VIUP in women with a pregnancy of unknown location.

MATERIAL AND METHODS

This was a secondary analysis of prospective multicenter study data of consecutive women with a pregnancy of unknown location between January 2015 and 2017 collected from dedicated early pregnancy assessment units of eight hospitals. Single progesterone and serial βhCG measurements were taken. Women were followed up until final pregnancy outcome between 11 and 14 weeks of gestation was confirmed using transvaginal ultrasonography: (1) VIUP, (2) non-viable intrauterine pregnancy or failed pregnancy of unknown location, and (3) ectopic pregnancy or persisting pregnancy of unknown location. The predictive value of cut-off levels for ruling out VIUP were evaluated across a range of values likely to be encountered clinically for progesterone, βhCG, and βhCG ratio.

RESULTS

Data from 2507 of 3272 (76.6%) women were suitable for analysis. All had data for βhCG levels, 2248 (89.7%) had progesterone levels, and 1809 (72.2%) had βhCG ratio. The likelihood of viability falls with the progesterone level. Although the median progesterone level associated with viability was 59 nmol/L, VIUP were identified with levels as low as 5 nmol/L. No single βhCG cut-off reliably ruled out the presence of viability with certainty, even when the level was more than 3000 IU/L, there were 39/358 (11%) women who had a VIUP. The probability of viability decreases with the βhCG ratio. Although the median βhCG ratio associated with viability was 2.26, VIUP were identified with ratios as low as 1.02. A progesterone level below 2 nmol/L and βhCG ratio below 0.87 were unlikely to be associated with viability but were not definitive when considering multiple imputation.

CONCLUSIONS

Cut-off levels for βhCG, βhCG ratio, and progesterone are not safe to be used clinically to exclude viability in early pregnancy. Although βhCG ratio and progesterone have slightly better performance in comparison, single βhCG used in this manner is highly unreliable.

External validation of models to predict the outcome of pregnancies of unknown location: a multicentre cohort study

Objective

To validate externally five approaches to predict ectopic pregnancy (EP) in pregnancies of unknown location (PUL): the M6P and M6NP risk models, the two‐step triage strategy (2ST, which incorporates M6P), the M4 risk model, and beta human chorionic gonadotropin ratio cut‐offs (BhCG‐RC).

Design

Secondary analysis of a prospective cohort study.

Setting

Eight UK early pregnancy assessment units.

Population

Women presenting with a PUL and BhCG >25 IU/l.

Methods

Women were managed using the 2ST protocol: PUL were classified as low risk of EP if presenting progesterone ≤2 nmol/l; the remaining cases returned 2 days later for triage based on M6P. EP risk ≥5% was used to classify PUL as high risk. Missing values were imputed, and predictions for the five approaches were calculated post hoc. We meta‐analysed centre‐specific results.

Main outcome measures

Discrimination, calibration and clinical utility (decision curve analysis) for predicting EP.

Results

Of 2899 eligible women, the primary analysis excluded 297 (10%) women who were lost to follow up. The area under the ROC curve for EP was 0.89 (95% CI 0.86–0.91) for M6P, 0.88 (0.86–0.90) for 2ST, 0.86 (0.83–0.88) for M6NP and 0.82 (0.78–0.85) for M4. Sensitivities for EP were 96% (M6P), 94% (2ST), 92% (N6NP), 80% (M4) and 58% (BhCG‐RC); false‐positive rates were 35%, 33%, 39%, 24% and 13%. M6P and 2ST had the best clinical utility and good overall calibration, with modest variability between centres.

Conclusions

2ST and M6P performed best for prediction and triage in PUL.

Tweetable abstract

The M6 model, as part of a two‐step triage strategy, is the best approach to characterise and triage PULs.

The M6 model, as part of a two‐step triage strategy, is the best approach to characterise and triage PULs.

The potential use of urinary hCG measurements in the management of pregnancies of unknown location

Multiple measurements of serum human chorionic gonadotropin (hCG) are used to predict the final pregnancy outcome for women with a pregnancy of unknown location (PUL) and monitor the management of ectopic pregnancy (EP). Urine-based testing would be more convenient and economical. This prospective cohort study involving 80 women assessed the degree of correlation between serum and urine hCG levels and whether urine hCG levels have the potential to impact clinical decision making in the management of women with a PUL. Paired urine and serum hCG measurements differed quite widely but were well correlated and the degree of correlation improved after creatinine correction. Although serial serum hCG measurements appear to be better for the overall prediction of pregnancy outcome in PUL (AUC 0.77-0.94 compared to corrected urine AUC 0.69-0.84), serial urine hCG measurements may have a role in identifying subtypes of low-risk PUL (AUC 0.83-0.84).

Natural history of pregnancy-related enhanced myometrial vascularity following miscarriage

OBJECTIVES

Our primary aim was to report the incidence of enhanced myometrial vascularity (EMV) in consecutive women attending our early pregnancy assessment unit, following first-trimester miscarriage. We aimed further to evaluate the clinical presentation and complications associated with expectant and surgical management of EMV in these women.

METHODS

This was a prospective cohort study conducted in a London teaching hospital between June 2015 and June 2018, including consecutive patients with an observation of EMV on transvaginal ultrasonography following first-trimester miscarriage. The diagnosis was made following the subjective identification of EMV using color Doppler ultrasonography and a peak systolic velocity (PSV) ≥ 20 cm/s within the collection of vessels. Women were followed up with repeat scans every 14 days. Management was expectant unless intervention was indicated because of excessive or prolonged bleeding, persistent presence of retained tissue in the endometrial cavity or patient choice. The final clinical outcome was recorded. Time to resolution of EMV was defined as the interval from detection of EMV until resolution.

RESULTS

During the study period, there were 2627 first-trimester fetal losses in the department and, of these, 40 patients were diagnosed with EMV, hence the incidence of EMV following miscarriage was 1.52%. All cases were associated with ultrasound evidence of retained products of conception (RPOC) at presentation (mean dimensions, 22 × 20 × 20 mm). Thirty-one patients opted initially for expectant management, of which 18 had successful resolution without intervention, five were lost to follow-up and eight subsequently had surgical evacuation due to patient choice. No expectantly managed case required emergency intervention. Nine patients chose surgical evacuation as primary treatment. No significant correlation was seen between PSV within the EMV at presentation and blood loss at surgery. Median PSV was 47 (range, 20-148) cm/s. The estimated blood loss in all cases managed surgically ranged from 20-300 mL. Presence of RPOC was confirmed in all specimens that were sent for analysis following surgery. For cases successfully managed expectantly, the mean time to resolution was 48 (range, 21-84) days. In the nine cases managed surgically from the beginning, the mean time to resolution of EMV was 10.6 (range, 3-29) days.

CONCLUSIONS

This study suggests that EMV is an uncommon finding following miscarriage and is associated with the presence of RPOC. Expectant management was a safe option in our cohort, with minimal bleeding, although it was associated with protracted time to resolution. In patients who opted for surgery, the maximum blood loss was 300 mL and no patient required blood transfusion or embolization. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

First-trimester intrauterine hematoma and pregnancy complications

OBJECTIVE

To assess whether sonographic diagnosis of intrauterine hematoma (IUH) in the first trimester of pregnancy is associated with first-trimester miscarriage and antenatal, delivery and neonatal complications.

METHODS

This was a prospective observational cohort study of women with an intrauterine singleton pregnancy between 5 and 14 weeks' gestation recruited at Queen Charlotte's and Chelsea Hospital, London, UK, between March 2014 and March 2016. Participants underwent serial ultrasound examinations in the first trimester, and the presence, location, size and persistence of any IUH was evaluated. First-trimester miscarriage was defined as pregnancy loss before 14 weeks' gestation. Clinical symptoms, including pelvic pain and vaginal bleeding, were recorded at each visit using validated symptom scores. Antenatal, delivery and neonatal outcomes were obtained from hospital records. Logistic regression analysis and the chi-square test were used to assess the association between the presence and features of IUH and the incidence of adverse pregnancy outcome. Odds ratios (OR) were first adjusted for maternal age (aOR) and then further adjusted for the presence of vaginal bleeding or pelvic pain in the first trimester.

RESULTS

Of 1003 women recruited to the study, 946 were included in the final analysis and of these, 268 (28.3%) were diagnosed with an IUH in the first trimester. The presence of IUH was associated with the incidence of preterm birth (aOR, 1.94 (95% CI, 1.07-3.52)), but no other individual or overall antenatal, delivery or neonatal complications. No association was found between the presence of IUH in the first trimester and first-trimester miscarriage (aOR, 0.81 (95% CI, 0.44-1.50)). These findings were independent of the absolute size of the hematoma and the presence of vaginal bleeding or pelvic pain in the first trimester. When IUH was present in the first trimester, there was no association between its size, content or position in relation to the gestational sac and overall antenatal, delivery and neonatal complications. Diagnosis of a retroplacental IUH was associated with an increased risk of overall antenatal complications (P = 0.04).

CONCLUSIONS

Our findings demonstrate that there is no association between the presence of IUH in the first trimester and first-trimester miscarriage. However, an association with preterm birth, independently of the presence of symptoms of pelvic pain and/or vaginal bleeding, is evident. Women diagnosed with IUH in the first trimester should be counseled about their increased risk of preterm birth and possibly be offered increased surveillance during the course of their pregnancy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Triaging women with pregnancy of unknown location using two-step protocol including M6 model: clinical implementation study

OBJECTIVE

The M6 risk-prediction model was published as part of a two-step protocol using an initial progesterone level of ≤ 2 nmol/L to identify probable failing pregnancies (Step 1) followed by the M6 model (Step 2). The M6 model has been shown to have good triage performance for stratifying women with a pregnancy of unknown location (PUL) as being at low or high risk of harboring an ectopic pregnancy (EP). This study validated the triage performance of the two-step protocol in clinical practice by evaluating the number of protocol-related adverse events and how effectively patients were triaged.

METHODS

This was a prospective multicenter interventional study of 3272 women with a PUL, carried out between January 2015 and January 2017 in four district general hospitals and four university teaching hospitals in the UK. The final pregnancy outcome was defined as: a failed PUL (FPUL), an intrauterine pregnancy (IUP) or an EP (including persistent PUL (PPUL)). FPUL and IUP were grouped as low-risk and EP/PPUL as high-risk PUL. Serum progesterone and human chorionic gonadotropin (hCG) levels were measured at presentation in all patients. If the initial progesterone level was ≤ 2 nmol/L, patients were discharged and were asked to have a follow-up urine pregnancy test in 2 weeks to confirm a negative result. If the progesterone level was > 2 nmol/L or a measurement had not been taken, hCG level was measured again at 48 h and results were entered into the M6 model. Patients were managed according to the outcome predicted by the protocol. Those classified as 'low risk, probable FPUL' were advised to perform a urine pregnancy test in 2 weeks and those classified as 'low risk, probable IUP' were invited for a scan a week later. When a woman with a PUL was classified as high risk (i.e. risk of EP ≥ 5%) she was reviewed clinically within 48 h. One center used a progesterone cut-off of ≤ 10 nmol/L and its data were analyzed separately. If the recommended management protocol was not adhered to, this was recorded as a protocol deviation and classified as: unscheduled visit for clinician reason, unscheduled visit for patient reason or incorrect timing of blood test or ultrasound scan. The classifications outlined in the UK Good Clinical Practice (GCP) guidelines were used to evaluate the incidence of adverse events. Data were analyzed using descriptive statistics.

RESULTS

Of the 3272 women with a PUL, 2625 were included in the final analysis (317 met the exclusion criteria or were lost to follow-up, while 330 were evaluated using a progesterone cut-off of ≤ 10 nmol/L). Initial progesterone results were available for 2392 (91.1%) patients. In Step 1, 407 (15.5%) patients were classified as low risk (progesterone ≤ 2 nmol/L), of whom seven (1.7%) were ultimately diagnosed with an EP. In 279 of the remaining 2218 women with a PUL, the M6 model was not applied owing to protocol deviation or because the outcome was already known (usually on the basis of an ultrasound scan) before a second hCG reading was taken; of these patients, 30 were diagnosed with an EP. In Step 2, 1038 women with a PUL were classified as low risk, of whom eight (0.8%) had a final outcome of EP. Of 901 women classified as high risk at Step 2, 275 (30.5%) had an EP. Therefore, 275/320 (85.9%) EPs were correctly classified as high risk. Overall, 1445/2625 PUL (55.0%) were classified as low risk, of which 15 (1.0%) were EP. None of these cases resulted in a ruptured EP or significant clinical harm. Sixty-two women participating in the study had an adverse event, but no woman had a serious adverse event as defined in the UK GCP guidelines.

CONCLUSIONS

This study has shown that the two-step protocol incorporating the M6 model effectively triaged the majority of women with a PUL as being at low risk of an EP, minimizing the follow-up required for these patients after just two visits. There were few misclassified EPs and none of these women came to significant clinical harm or suffered a serious adverse clinical event. The two-step protocol incorporating the M6 model is an effective and clinically safe way of rationalizing the management of women with a PUL. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Early-pregnancy events and subsequent antenatal, delivery and neonatal outcomes: prospective cohort study

OBJECTIVE

To assess prospectively the association between pelvic pain, vaginal bleeding, and nausea and vomiting occurring in the first trimester of pregnancy and the incidence of later adverse pregnancy outcomes.

METHODS

This was a prospective observational cohort study of consecutive women with confirmed intrauterine singleton pregnancy between 5 and 14 weeks' gestation recruited at Queen Charlotte's & Chelsea Hospital, London, UK, from March 2014 to March 2016. Serial ultrasound scans were performed in the first trimester. Participants completed validated symptom scores for vaginal bleeding, pelvic pain, and nausea and vomiting. The key symptom of interest was any pelvic pain and/or vaginal bleeding during the first trimester. Pregnancies were followed up until the final outcome was known. Antenatal, delivery and neonatal outcomes were obtained from hospital records. Logistic regression analysis was used to assess the association between first-trimester symptoms and pregnancy complications by calculating adjusted odds ratios (aOR) with correction for maternal age.

RESULTS

Of 1003 women recruited, 847 pregnancies were included in the final analysis following exclusion of cases due to first-trimester miscarriage (n = 99), termination of pregnancy (n = 20), loss to follow-up (n = 32) or withdrawal from the study (n = 5). Adverse antenatal complications were observed in 166/645 (26%) women with pelvic pain and/or vaginal bleeding in the first trimester (aOR = 1.79; 95% CI, 1.17-2.76) and in 30/181 (17%) women with no symptoms. Neonatal complications were observed in 66/634 (10%) women with and 11/176 (6%) without pelvic pain and/or vaginal bleeding (aOR = 1.73; 95% CI, 0.89-3.36). Delivery complications were observed in 402/615 (65%) women with and 110/174 (63%) without pelvic pain and/or vaginal bleeding during the first trimester (aOR = 1.16; 95% CI, 0.81-1.65). For 18 of 20 individual antenatal complications evaluated, incidence was higher among women with pelvic pain and/or vaginal bleeding, despite the overall incidences being low. Nausea and vomiting in pregnancy showed little association with adverse pregnancy outcomes.

CONCLUSIONS

Our study suggests that there is an increased incidence of antenatal complications in women experiencing pelvic pain and/or vaginal bleeding in the first trimester. This should be considered when advising women attending early-pregnancy units. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Validation of a virtual reality simulator for the use of transvaginal ultrasonography in gynaecology and early pregnancy

Introduction

The objective was to validate a virtual reality simulation ultrasound model as a tool for training in the use of transvaginal ultrasonography in gynaecology and early pregnancy.

Methods

Three separate groups consisting of novice and intermediate level residents as well as expert ultrasound examiners were recruited to the study. All were asked to answer a questionnaire regarding demographic data and ultrasound experience. They subsequently completed two modules: basic gynaecology and early pregnancy, followed by corresponding assessments using a high-fidelity simulator (Scantrainer; Medaphor™, Cardiff, UK). Finally, the expert group completed an additional questionnaire about various elements of the simulator using a 5-point Likert scale.

Results

Each group consisted of eight participants. Overall, the participants agreed that simulation played a role in training (Novices: 75% (n = 6); Intermediates: 100% (n = 8); Experts: 75% (n = 6)). For the degree of realism of the target objects in the gynaecology and early pregnancy module environments compared to a real-patient environment, the simulator was rated satisfactory or very satisfactory by 88% (n = 7) and 75% (n = 6) of experts, respectively. All experts rated the overall usefulness of the content of the simulator for learning fundamental ultrasound technical skills compared to current training methods to be at least satisfactory. When reviewing the assessment scores, experts scored higher than non-experts in gynaecology (P = 0.002) and early pregnancy modules (P = 0.03).

Discussion

Face, content and construct validity were demonstrated by the virtual reality ultrasound simulator, suggesting it may be an effective method for training ultrasound skills in gynaecology and early pregnancy to non-expert residents.

Can risk factors, clinical history and symptoms be used to predict risk of ectopic pregnancy in women attending an early pregnancy assessment unit?

OBJECTIVE

To examine whether risk factors and symptoms may be used to predict the likelihood of ectopic pregnancy (EP) in women attending early pregnancy assessment units in the UK.

METHODS

This was an observational cohort study of pregnant women under 12 weeks' gestation who were recruited from three London university hospitals between August 2012 and April 2013. One hospital continued recruitment between January and June 2015. A standardized information sheet incorporating patient demographics, medical history and symptoms was completed by patients and confirmed by examining clinicians. The outcome measure was final pregnancy location.

RESULTS

There were 1320 eligible patients included in the analysis, with a total of 72 EPs (rate of 6%). Pelvic pain and diarrhea > three times in the previous 24 h were independent symptoms that increased the risk of EP, with relative risks of 2.4 (95% CI, 1.4-4.0; P = 0.002) and 2.2 (95% CI, 1.08-4.5; P = 0.03), respectively. The only other independent marker of risk of EP was duration of vaginal bleeding; the risk of EP increased by 20% (95% CI, 14%-27%) for every 1-day increment in duration (P < 0.001). A logistic regression model incorporating these factors demonstrated an area under the receiver-operating characteristics curve of 0.73 (95% CI, 0.67-0.79). The prevalence of EP was low when there was no pelvic pain, no diarrhea and the duration of bleeding was ≤ 3 days, with an EP rate of 2% (6/391). In the presence of a single risk factor, the EP rate increased to 5% (29/631) when only pelvic pain was present, 8% (1/12) when only diarrhea > three times in the previous 24 h was reported and 9% (9/103) when there was only vaginal bleeding with a duration > 3 days. Women with pelvic pain and vaginal bleeding of any severity for > 3 days had a high EP rate of 16% (23/146). In the nine women who also reported diarrhea > three times in the previous 24 h, two had EP.

CONCLUSIONS

Only the presence of pelvic pain, diarrhea > three times in the previous 24 h and duration of bleeding were symptoms that significantly increased the risk for EP in women attending early pregnancy assessment units. Risk factors and symptoms alone could not be used to predict reliably an EP. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Managing pregnancy of unknown location based on initial serum progesterone and serial serum hCG levels: development and validation of a two-step triage protocol

OBJECTIVES

A uniform rationalized management protocol for pregnancies of unknown location (PUL) is lacking. We developed a two-step triage protocol to select PUL at high risk of ectopic pregnancy (EP), based on serum progesterone level at presentation (step 1) and the serum human chorionic gonadotropin (hCG) ratio, defined as the ratio of hCG at 48 h to hCG at presentation (step 2).

METHODS

This was a cohort study of 2753 PUL (301 EP), involving a secondary analysis of prospectively and consecutively collected PUL data from two London-based university teaching hospitals. Using a chronological split we used 1449 PUL for development and 1304 for validation. We aimed to assign PUL as low risk with high confidence (high negative predictive value (NPV)) while classifying most EP as high risk (high sensitivity). The first triage step assigned PUL as low risk using a threshold of serum progesterone at presentation. The remaining PUL were triaged using a novel logistic regression risk model based on hCG ratio and initial serum progesterone (second step), defining low risk as an estimated EP risk of < 5%.

RESULTS

On validation, initial serum progesterone ≤ 2 nmol/L (step 1) classified 16.1% PUL as low risk. Second-step classification with the risk model selected an additional 46.0% of all PUL as low risk. Overall, the two-step protocol classified 62.1% of PUL as low risk, with an NPV of 98.6% and a sensitivity of 92.0%. When the risk model was used in isolation (i.e. without the first step), 60.5% of PUL were classified as low risk with 99.1% NPV and 94.9% sensitivity.

CONCLUSION

PUL can be classified efficiently into being either high or low risk for complications using a two-step protocol involving initial progesterone and hCG levels and the hCG ratio. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Evaluating the risk of ovarian cancer before surgery using the ADNEX model: a multicentre external validation study

BACKGROUND

The International Ovarian Tumour Analysis (IOTA) group have developed the ADNEX (The Assessment of Different NEoplasias in the adneXa) model to predict the risk that an ovarian mass is benign, borderline, stage I, stages II-IV or metastatic. We aimed to externally validate the ADNEX model in the hands of examiners with varied training and experience.

METHODS

This was a multicentre cross-sectional cohort study for diagnostic accuracy. Patients were recruited from three cancer centres in Europe. Patients who underwent transvaginal ultrasonography and had a histological diagnosis of surgically removed tissue were included. The diagnostic performance of the ADNEX model with and without the use of CA125 as a predictor was calculated.

RESULTS

Data from 610 women were analysed. The overall prevalence of malignancy was 30%. The area under the receiver operator curve (AUC) for the ADNEX diagnostic performance to differentiate between benign and malignant masses was 0.937 (95% CI: 0.915-0.954) when CA125 was included, and 0.925 (95% CI: 0.902-0.943) when CA125 was excluded. The calibration plots suggest good correspondence between the total predicted risk of malignancy and the observed proportion of malignancies. The model showed good discrimination between the different subtypes.

CONCLUSIONS

The performance of the ADNEX model retains its performance on external validation in the hands of ultrasound examiners with varied training and experience.

The clinical performance of the M4 decision support model to triage women with a pregnancy of unknown location as at low or high risk of complications

STUDY QUESTION

What are the adverse outcomes associated with using the M4 model in everyday clinical practice for women with pregnancy of unknown location (PUL)?

SUMMARY ANSWER

There were 17/835 (2.0%) adverse events and no serious adverse events associated with the performance of the M4 model in clinical practice.

WHAT IS KNOWN ALREADY

The M4 model has previously been shown to stratify women classified as a PUL as at low or high risk of complications with a good level of test performance. The triage performance of the M4 model is better than single measurements of serum progesterone or the hCG ratio (serum hCG at 48 h/hCG at presentation).

STUDY DESIGN, SIZE, DURATION

A prospective multi-centre cohort study of 1022 women with a PUL carried out between August 2012 and December 2013 across 2 university teaching hospitals and 1 district general hospital.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All women presenting with a PUL to the early pregnancy units of the three hospitals were recruited. The final outcome for PUL was either a failed PUL (FPUL), intrauterine pregnancy (IUP) or ectopic pregnancy (EP) (including persistent PUL (PPUL)), with EP and PPUL considered high-risk PUL. Their hCG results at 0 and 48 h were entered into the M4 model algorithm. If the risk of EP was ≥5%, the PUL was predicted to be high-risk and the participant was asked to re-attend 48 h later for a repeat hCG and transvaginal ultrasound scan by a senior clinician. If the PUL was classified as 'low risk, likely failed PUL', the participant was asked to perform a urinary pregnancy test 2 weeks later. If the PUL was classified as 'low risk, likely intrauterine', the participant was scheduled for a repeat scan in 1 week. Deviations from the management protocol were recorded as either an 'unscheduled visit (participant reason)', 'unscheduled visit (clinician reason)' or 'differences in timing (blood test/ultrasound)'. Adverse events were assessed using definitions outlined in the UK Good Clinical Practice Guidelines' document.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 835 (82%) women classified as a PUL were managed according to the M4 model (9 met the exclusion criteria, 69 were lost to follow-up, 109 had no hCG result at 48 h). Of these, 443 (53%) had a final outcome of FPUL, 298 (36%) an IUP and 94 (11%) an EP. The M4 model predicted 70% (585/835) PUL as low risk, of which 568 (97%) were confirmed as FPUL or IUP. Of the 17 EP and PPUL misclassified as low risk, 5 had expectant management, 7 medical management with methotrexate and 5 surgical intervention.Nineteen PUL had an unscheduled visit (participant reason), 38 PUL had an unscheduled visit (clinician reason) and 68 PUL had deviations from protocol due to a difference in timing (blood test/ultrasound).Adverse events were reported in 26 PUL and 1 participant had a serious adverse event. A total of 17/26 (65%) adverse events were misclassifications of a high risk PUL as low risk by the M4 model, while 5/26 (19%) adverse events were related to incorrect clinical decisions. Four of the 26 adverse events (15%) were secondary to unscheduled admissions for pain/bleeding. The serious adverse event was due to an incorrect clinical decision.

LIMITATIONS, REASONS FOR CAUTION

A limitation of the study was that 69/1022 (7%) of PUL were lost to follow-up. A 48 h hCG level was missing for 109/1022 (11%) participants.

WIDER IMPLICATIONS OF THE FINDINGS

The low number of adverse events (2.0%) suggests that expectant management of PUL using the M4 prediction model is safe. The model is an effective way of triaging women with a PUL as being at high- and low-risk of complications and rationalizing follow-up. The multi-centre design of the study is more likely to make the performance of the M4 model generalizable in other populations.

STUDY FUNDING/COMPETING INTERESTS

None.

TRIAL REGISTRATION NUMBER

Not applicable.

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.

Accuracy of ultrasonography performed by examiners with varied training and experience in predicting specific pathology of adnexal masses

OBJECTIVES

To assess the diagnostic performance of subjective assessment by Level II ultrasound examiners in predicting the specific histology of adnexal masses.

METHODS

The women included in this prospective multicenter cross-sectional study were older than 16 years of age and had at least one adnexal mass. They underwent transvaginal sonography (TVS) performed by Level II examiners, all of whom were familiar with the International Ovarian Tumor Analysis (IOTA) group definitions of ultrasound features of ovarian masses. The final outcome was histology. Specific diagnoses were categorized into 16 groups. Agreement between subjective assessment and final histology was measured using unweighted kappa coefficients. Sensitivities and specificities were obtained for subjective assessment.

RESULTS

Of the 1279 women who underwent TVS, 313 were included in the final analysis. Overall agreement (16 × 16 table) between subjective assessment and histology was moderate, with a Cohen's kappa coefficient of 0.59 (95% CI, 0.53-0.65). The specificity of subjective assessment ranged between 91% and 100% for all histological subgroups. Highest sensitivities were achieved in the diagnosis of simple cysts (100% (95% CI, 61-100%)), hydrosalpinges (100% (95% CI, 34-100%)), mature teratomas (88% (95% CI, 74-96%)), endometriomas (75% (95% CI, 61-85%)), ovarian fibromas (88% (95% CI, 47-100%)), tubo-ovarian abscesses (88% (95% CI, 47-100%)) and serous cystadenocarcinomas (82% (95% CI, 66-93%)). Serous cystadenomas were misdiagnosed most commonly (40.5%). The sensitivity of subjective assessment in diagnosing adnexal torsion was 54% (95% CI, 25-81%); the 17 confirmed and/or suspected cases of adnexal torsion were not included in the 313 cases examined and analyzed for diagnostic performance.

CONCLUSION

Overall, subjective assessment by Level II examiners was good for the detection of simple cysts, endometriomas, mature teratomas, hydrosalpinges, fibroma, tubo-ovarian abscess and serous cystadenocarcinomas.

The characteristic ultrasound features of specific types of ovarian pathology (review)

Characterizing ovarian masses enables patients with malignancy to be appropriately triaged for treatment by subspecialist gynecological oncologists, which has been shown to optimize care and improve survival. Furthermore, correctly classifying benign masses facilitates the selection of patients with ovarian pathology that may either not require intervention, or be suitable for minimal access surgery if intervention is required. However, predicting whether a mass is benign or malignant is not the only clinically relevant information that we need to know before deciding on appropriate treatment. Knowing the specific histology of a mass is becoming of increasing importance as management options become more tailored to the individual patient. For example predicting a mucinous borderline tumor gives the opportunity for fertility sparing surgery, and will highlight the need for further gastrointestinal assessment. For benign disease, predicting the presence of an endometrioma and possible deeply infiltrating endometriosis is important when considering both who should perform and the extent of surgery. An examiner’s subjective assessment of the morphological and vascular features of a mass using ultrasonography has been shown to be highly effective for predicting whether a mass is benign or malignant. Many masses also have features that enable a reliable diagnosis of the specific pathology of a particular mass to be made. In this narrative review we aim to describe the typical morphological features seen on ultrasound of different adnexal masses and illustrate these by showing representative ultrasound images.

Predicting successful vaginal birth after Cesarean section using a model based on Cesarean scar features examined by transvaginal sonography

OBJECTIVE

To develop a model to predict the success of a trial of vaginal birth after Cesarean section (VBAC) based on sonographic measurements of Cesarean section (CS) scar features, demographic variables and previous obstetric history.

METHODS

We used transvaginal sonography (TVS) to examine the CS scar of 320 consecutive pregnant women. TVS was carried out at 11-13, 19-21 and 34-36 weeks' gestation and prospective measurements of the scar were recorded at each visit according to a defined protocol. A logistic regression model to predict success of VBAC was developed for those patients with a visible scar on ultrasound and only one previous CS. The model was evaluated using bootstrap validation.

RESULTS

There were 131 women with one previous CS and a visible scar, of whom 10 underwent CS prior to labor and were excluded from analysis. Successful VBAC was achieved in 74/121 (61%) of the remaining cases. The prediction model developed was based on patient age, previous history of VBAC, residual myometrial thickness (RMT) and the change in RMT from the first to the second trimester (ΔRMT). The internally validated area under the receiver-operating characteristics curve was 0.62 when measurements of RMT and ΔRMT were excluded, but 0.94 when scar information was incorporated into the model.

CONCLUSION

Ultrasound measurements of CS scar, namely RMT and the change in RMT from the first to the second trimester of pregnancy, when incorporated into a mathematical model, can predict accurately a successful trial of labor in patients with one previous CS.

Changes in Cesarean section scar dimensions during pregnancy: a prospective longitudinal study

OBJECTIVES

To describe changes in Cesarean section (CS) scars longitudinally throughout pregnancy, and to relate initial scar measurements, demographic variables and obstetric variables to subsequent changes in scar features and to final pregnancy outcome.

METHODS

In this prospective observational study we used transvaginal sonography (TVS) to examine the CS scar of 320 consecutive pregnant women at 11-13, 19-21 and 32-34 weeks' gestation. For scars visible on TVS, the hypoechoic part was measured in three dimensions and the residual myometrial thickness (RMT) was also measured. Analyses were carried out using one-way repeated measures ANOVA and mixed modeling. The incidence of subsequent scar rupture was recorded.

RESULTS

The CS scar was visible in 284/320 cases (89%). Concerning length and depth of the hypoechoic part of the scar and RMT, the larger the initial scar measurement, the larger the decrease observed during pregnancy. For the hypoechoic part of the scar, the width increased on average by 1.8 mm per trimester, while the depth and length decreased by 1.8 and 1.9 mm, respectively (false discovery rate P < 0.0001). Mean RMT in the first trimester was 5.2 mm and on average decreased by 1.1 mm per trimester. Two cases (0.62%) of uterine scar rupture were confirmed following a trial of vaginal delivery; these had a mean RMT of 0.5 mm at second scan and an average decrease of 2.6 mm over the course of pregnancy.

CONCLUSION

This study establishes reference data and confirms that the dimensions of CS scars change throughout pregnancy. Scar rupture was associated with a smaller RMT and greater decrease in RMT during pregnancy. There is the potential to test absolute values and observed changes in CS scar measurements as predictors of uterine scar rupture and outcome in trials of vaginal birth after Cesarean section.

Does the presence of a Caesarean section scar affect implantation site and early pregnancy outcome in women attending an early pregnancy assessment unit?

STUDY QUESTION

Are there any differences in the location and distance to the internal cervical ostium of the implantation site of the intrauterine gestation sacs, early pregnancy symptoms and pregnancy outcome at 12 weeks gestation between women with and without a previous Caesarean section (CS)?

SUMMARY ANSWER

The presence of a CS scar affects the site of implantation, and the distance between implantation site and the scar is related to the risk of spontaneous abortion. WHAT IS KNOWN ALREADY?: Little is known about the impact of a CS scar on implantation other than the risk of Caesarean scar pregnancy (CSP). Furthermore, there is a paucity of information on how the proximity of implantation to the scar impacts on pregnancy outcome in the first trimester.

STUDY DESIGN, SIZE, AND DURATION

A prospective cohort study conducted over 15 months in the early pregnancy unit of a London Teaching Hospital. Three hundred and eighty women underwent a transvaginal scan at 6-11 weeks of gestation. A total of 170 women had undergone ≥1 CS, and 210 women had no history of CS.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The 380 women were recruited as consecutive non-selected cases. The relationship between the implanted sac and the CS scar was assessed by quantifiable measures and by subjective impression. Logistic regression analysis was used to determine the influence of the presence of a CS scar on pregnancy outcome. The final outcome of the study was the viability of the pregnancy at 12 weeks.

MAIN RESULTS AND THE ROLE OF CHANCE

Implantation was most frequently posterior (53%) in the CS group and fundal in the non-CS group (42%). Gestation sac implantation was 8.7 mm lower in the CS group (95% confidence interval (CI) 6.7-10.7, P < 0.0001). Presenting complaints differed in women with and without a previous CS (P = 0.0009). More frequent vaginal bleeding [73 versus 55%, difference -18, 95% CI (-27 to -8%] yet no clearly increased spontaneous abortion rates were noted in the CS group compared with the non-CS group (adjusted odds ratio = 1.1, 95% CI 0.6-1.9, P = 0.74). Subjective impression showed that in eight cases the implantation site crossed the scar, seven of which resulted in spontaneous abortion, while the remaining case survived to term complicated by placenta praevia and post-partum haemorrhage. The subjective impression of the examiner was supported by the measurements of distance between implantation site and CS scar.

LIMITATIONS, REASONS FOR CAUTION

A weakness of the study is the lack of a reference technique to verify the location of implantation.

WIDER IMPLICATIONS OF THE FINDINGS

This study adds further support to the hypothesis that the presence of a CS on the uterus impacts on the implantation site of a future pregnancy. The possibility that the CS scar has an impact on the risk of spontaneous abortion should be further studied. Caution must be exercised when implantation occurs near to, and crosses, a CS scar as this is not always associated with the diagnosis of CSP. A potential limitation of the study is that we did not examine scar dimensions and morphology.

A multicenter prospective external validation of the diagnostic performance of IOTA simple descriptors and rules to characterize ovarian masses

OBJECTIVES

To evaluate the diagnostic performance of the IOTA (International Ovarian Tumor Analysis group) (clinically oriented three-step strategy for preoperative characterization of ovarian masses when ultrasonography is performed by examiners with different background training and experience.

METHODS

A 27-month prospective multicenter cross-sectional study was performed. 36 level II ultrasound examiners contributed in three UK hospitals. Transvaginal ultrasonography was performed using a standardized approach. Step one uses simple descriptors (SD), step two ultrasound simple rules (SR) and step three subjective assessment of ultrasound images (SA) by examiners. The final outcome was findings at surgery and the histological diagnosis of surgically removed masses.

RESULTS

1165 women with adnexal masses underwent transvaginal ultrasonography, 301 had surgery. Prevalence of malignancy was 31% (n=92). SD were able to classify 46% of the masses into benign or malignant (step one), with a sensitivity of 93% and specificity of 97%. Applying SD followed by SR to residual unclassified masses by SD enabled 89% of all masses (n=268) to be classified with a sensitivity 95% of and specificity of 95%. SA was then used to evaluate the rest of the masses. Compared to the risk of malignancy index (RMI), the sensitivity and specificity for the three-step (SD+SR+SA) strategy were 93% (95% CI: 86-97%) and 92% (95% CI: 87-95%) vs. 72% (95% CI: 62-80%) and 95% (95% CI: 91-97%) for RMI, respectively.

CONCLUSION

The IOTA three-step strategy shows good test performance on external validation in the hands of ultrasonography examiners with different background training and experience. This performance is considerably better than the RMI.

Visibility and measurement of cesarean section scars in pregnancy: a reproducibility study

OBJECTIVES

To evaluate the visibility of cesarean section (CS) scars by transvaginal sonography (TVS) in pregnant women, to apply a standardized approach for measuring CS scars and to test its reproducibility throughout the course of pregnancy.

METHODS

In this observational cohort study, 320 consecutive pregnant women with a previous cesarean delivery were examined to assess scar visibility by two independent examiners. TVS was carried out at 11-13, 19-21 and 34-36 weeks' gestation. A scar was defined as visible when an area of hypoechogenicity representing myometrial discontinuity at the anterior wall of the lower uterine segment was identified. In a subset of patients (n = 111), visible scars were measured by two independent examiners in three dimensions: scar width, depth and length as well as the residual myometrial thickness (RMT). Descriptive analysis was used to assess scar visibility, and the intraclass correlation coefficient (ICC) was calculated to show the strength of absolute agreement between two examiners for scar measurements. For RMT, a cut-off of 2.4 mm was used and measurement agreement was assessed using Cohen's kappa coefficient.

RESULTS

The scar was visible in 284/320 cases (88.8%). Visible scars were significantly associated with anteverted uteri (P < 0.0001). Both examiners had 100% agreement on scar visibility at 12 and 20 weeks' gestation, while agreement was 96% at 34 weeks. The intra- and interobserver agreements for scar measurements were generally good (ICC 0.86 and 0.89, respectively). The kappa coefficient for the RMT was 0.27 in the first trimester, compared with 0.51 and 0.72 in the second and third trimesters, respectively.

CONCLUSION

CS scars remain visible in the majority of women throughout pregnancy. They can be reproducibly measured in three dimensions when assessed by TVS in all trimesters of pregnancy. The agreement between two observers for CS scar measurement can be considered good for the first trimester, compared with relatively moderate agreement for the second and third trimesters.

Does the presence of a cesarean section scar influence the site of placental implantation and subsequent migration in future pregnancies: a prospective case-control study

OBJECTIVES

To describe placental location in the first trimester of pregnancy and subsequent placental migration in women with and without a history of previous cesarean delivery.

METHODS

In this prospective case-control study, placental location was defined according to five anatomical sites in relation to the endometrial cavity. Placental localization was carried out by transabdominal ultrasound between 11 and 14 weeks' gestation. We recruited 738 women who had undergone one or more previous cesarean sections (CS) and 1856 patients without previous cesarean delivery. Comparative analysis was performed of placental location between the two groups, and to assess placental migration of those classified as being low lying at 20 and 32 weeks' gestation.

RESULTS

There were significant differences in placental location between the two groups. In the CS group there were significantly more posterior and fewer fundal placentae than in the control group (47.2 vs 31.5% and 4.7 vs 15.5%, respectively). The number of previous cesarean deliveries did not have a significant effect on placental location. There was no significant difference in the incidence of anterior low-lying placenta between groups (1.5 vs 0.9%). Placental migration of the low-lying subtypes was similar in both groups (62 vs 64%).

CONCLUSION

The presence of CS scars in the uterus are associated with an increase in the number of posterior placentae and a reduced number that implant in the fundus of the cavity. Migration of a low-lying placenta is independent of the presence of a CS scar in the uterus.

Do pocket-sized ultrasound machines have the potential to be used as a tool to triage patients in obstetrics and gynecology?

OBJECTIVES

To evaluate the performance and potential impact on patient management of a pocket-sized ultrasound machine (PUM) in comparison to high-specification ultrasound machines (HSUM).

METHODS

This was an observational cohort study with 204 unselected patients in three categories: 1) women with pain and bleeding in early pregnancy (101 patients); 2) women presenting for routine obstetric ultrasound assessment (53 patients); 3) women with possible gynecological pathology (50 patients). Scans were carried out transabdominally using a PUM. A second operator repeated the examination transvaginally and/or transabdominally, depending on the clinical indication, using an HSUM. The operators were blind to each other's findings.

RESULTS

In the early pregnancy group, there was good to very good agreement between the PUM and HSUM for identifying the presence or absence of an embryo, gestational sac, fetal heart motion, pregnancy location and final diagnostic outcome (kappa coefficients, 0.844, 0.843, 0.729, 0.785 and 0.812, respectively; P < 0.0001). In the obstetric ultrasound group there was good to very good agreement for fetal presentation, placental location and placental position (kappa coefficients, 0.924, 0.924 and 0.647, respectively; P < 0.0001). In the gynecological pathology group, there was very good agreement for final diagnosis and type of ovarian mass (low risk or complex) (kappa coefficients, 0.846 and 0.930, respectively; P < 0.0001). For the measured continuous variables, there was close agreement for crown-rump length, mean sac diameter, femur length and mean diameter of an ovarian mass, but not for endometrial thickness. Neither patient demographics (age, body mass index, ethnicity) nor operator experience and familiarity with a PUM had an impact on agreement between the two machines. If a PUM had been the only equipment available for an initial assessment, only two cases would have led to a suboptimal patient management plan.

CONCLUSION

The findings and final diagnosis in the three study groups were similar for both a PUM used transabdominally and an HSUM used transvaginally and/or transabdominally.

Ultrasound assessment of the peri-implantation uterus: a review

Emerging evidence suggests that early embryo implantation is a more active maternal process than hitherto appreciated, involving active encapsulation of the implanting blastocyst by maternal decidual cells and coordinated changes in the underlying inner myometrium, known as the junctional zone. These concepts raise the possibility that early ultrasound markers predictive of adverse pregnancy outcome could be identified. In this review we assess the role of ultrasound in predicting the likelihood of different pregnancy outcomes and highlight potential novel markers that could be tested.

Standardized approach for imaging and measuring Cesarean section scars using ultrasonography

Incomplete healing of the scar is a recognized sequel of Cesarean section (CS) and may be associated with complications in later pregnancies. These complications can include scar pregnancy, a morbidly adherent placenta, scar dehiscence or rupture. To date there is uncertainty relating to the factors that lead to poor scar healing and how to recognize it. In recent years, there has been an increase in studies using ultrasound that describe scars as deficient, or poorly, incompletely or inadequately healed with few data to associate the morphology of the scar with the functional integrity of the lower segment of the uterus. There have been multiple attempts to describe CS scars using ultrasonography. Different terminology, methods and results have been reported, yet there is still no consensus regarding the prevalence, clinical significance or most appropriate method to describe the appearances of these scars. Developing a test that can predict the likelihood of women having problems associated with a CS scar is becoming increasingly important. On the other hand, understanding whether the ultrasound appearances of the scar can tell us anything about its integrity is not well supported by the research evidence. In this article we present an overview of ultrasound-based definitions and methods used to describe CS scars. We also present information relating to the performance of alternative techniques used to evaluate CS scars. Having examined the current evidence we suggest a standardized approach to describe CS scars using ultrasound so that future studies can be meaningfully compared.

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.

A randomized trial of mifepristone (10 mg) and levonorgestrel for emergency contraception

OBJECTIVE

To compare the efficacy, patient acceptability and adverse effects of low-dose mifepristone (10 mg) with the levonorgestrel regimen (2 doses of 750 microg given 12 hours apart) for emergency contraception.

METHODS

This randomized controlled trial compared mifepristone (10 mg) to levonorgestrel (2 doses of 750 microg given 12 hours apart) in the context of emergency contraception within 120 hours of unprotected intercourse. The primary outcome measure was unintended pregnancy. Secondary outcomes included adverse effects experienced by women, acceptability of the method of emergency contraception used, and the timing of the first menstrual cycle after treatment.

RESULTS

The total number of women recruited was 2,065. The crude pregnancy rates were 1.3% and 2.0% for mifepristone and levonorgestrel (P = .46), with 77% and 64% of expected pregnancies prevented, respectively. Women receiving mifepristone were more likely to have a delayed onset of the subsequent menstrual cycle after treatment (P < .001), whereas those having levonorgestrel were more likely to have an early onset of the subsequent menstrual cycle (P < .001). Acceptability levels were high for both methods, with 94% of women receiving mifepristone and 91% receiving levonorgestrel expressing satisfaction. There was no difference in adverse effects (nausea, vomiting, breast tenderness, abdominal pain, lethargy, headache, hot flushes, and dizziness) experienced by women in the 2 groups.

CONCLUSION

This study suggests that a small dose of mifepristone is not less effective than levonorgestrel for emergency contraception. Both regimens were highly acceptable to women.

A randomised study comparing a low dose of mifepristone and the Yuzpe regimen for emergency contraception

OBJECTIVE

To compare 100 mg mifepristone with the standard Yuzpe regimen for emergency contraception.

DESIGN

Randomised controlled trial.

SETTING

Family Planning Clinic, Aberdeen.

SAMPLE

One thousand women seeking emergency contraception within 72 hours after an episode of unprotected sexual intercourse.

METHODS

Women were randomised to receive either 100 mg (half tablet) of mifepristone as a single dose or the Yuzpe regimen (two tablets each with 50 microg ethinyloestradiol and 0.25 mg levonorgestrel, to be repeated 12 hours later).

OUTCOME MEASURES

Crude pregnancy rates, proportion of pregnancies prevented, side effects and patient acceptability.

RESULTS

The crude pregnancy rates (95% CI) for the Yuzpe regimen and mifepristone were 3.6% (2.3-5.7) and 0.6% (0.2-1.8), respectively, with a significant difference between the two groups (RR 6.04; 95% CI 1.75-20.75). Mifepristone prevented 92% of pregnancies and the Yuzpe regimen preventing 56%. An increasing coitus to treatment interval was associated with contraceptive failure in the Yuzpe group (P = 0.03) with no association seen with mifepristone. Following administration of mifepristone 24.5% and 13.1% given the Yuzpe regimen had a delayed period (RR 2.14; 95% CI 1.46-3.15). Overall, mifepristone was better tolerated than the Yuzpe regimen with significantly fewer side effects. More women were satisfied (P < 0.0001) with mifepristone as an emergency contraceptive and would recommend it to a friend (P = 0.02).

CONCLUSION

Mifepristone administered in a 100 mg dose is a highly effective post-coital contraceptive with high patient acceptability and fewer side effects compared with the standard Yuzpe regimen. Delay in the onset of menstruation did not decrease patient acceptability.