A model and scoring system to predict outcome of intrauterine pregnancies of uncertain viability

Temporal and external validation of the algorithm predicting first trimester outcome of a viable pregnancy

BACKGROUND

Symptoms like vaginal bleeding or abdominal pain in early pregnancy can create anxiety about potential miscarriage. Previous studies have demonstrated ultrasonographic variables at the first trimester transvaginal scan (TVS) which can assist in predicting outcomes by 12 weeks gestation.

AIM

To validate the miscarriage risk prediction model (MRP) in women who present with a viable intrauterine pregnancy (IUP) at the primary ultrasound.

MATERIALS AND METHODS

A multi-centre diagnostic study of 1490 patients was performed between 2011 and 2019 for retrospective external and 2017-2019 for prospective temporal validation. The reference standard was a viable pregnancy at 12 + 6 weeks. The MRP model is a multinomial logistic regression model based on maternal age, embryonic heart rate, logarithm (gestational sac volume/crown-rump length (CRL)) ratio, CRL and presence or absence of clots.

RESULTS

Temporal validation data from 290 viable IUPs were collected: 225 were viable at the end of the first trimester, 31 had miscarried and 34 were lost to follow-up. External validation data from 1203 viable IUPs were collected at two other ultrasound units: 1062 were viable, 69 had miscarried and 72 were lost to follow-up. Temporal validation with a cut-off of 0.1 demonstrated: area under the curve (AUC) of 0.8 (0.7-0.9), sensitivity 66.7%, specificity 83.9%, positive predictive value (PPV) 35.7%, negative predictive value (NPV) 94.9%, positive likelihood ration (LR+) 4.1 and negative LR (LR-) 0.4. External validation demonstrated: AUC 0.7 (0.7-0.8), sensitivity 44.9%, specificity 90.4%, PPV 23.3%, NPV 96.2%, LR+ 4.6 and LR- 0.6 (0.4-0.7).

CONCLUSION

The MRP model is not able to be used in real time for counselling, and management should be individualised.

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.

A Novel Approach to Predicting Early Pregnancy Outcomes Dynamically in a Prospective Cohort Using Repeated Ultrasound and Serum Biomarkers

This study aimed to develop a dynamic model for predicting outcome during the first trimester of pregnancy using baseline demographic data and serially collected blood samples and transvaginal sonographies. A prospective cohort of 203 unselected women with an assumed healthy pregnancy of < 8 weeks' gestation was followed fortnightly from 4-14 weeks' gestation until either miscarriage or confirmed first trimester viability. The main outcome was development of a model to predict outcome from gestational age-dependent hazard ratios using both baseline and updated serial data from each visit. Secondary outcomes were descriptions of risk factors for miscarriage. The results showed that 18% of the women experienced miscarriages. A fetal heart rate detected before 8 weeks' gestation indicated a 90% (95% CI 85-95%) chance of subsequent delivery. Maternal age (≥ 35 years), insufficient crown-rump-length (CRL) and mean gestational sac diameter (MSD) development, and presence of bleeding increased the risk of miscarriage. Serum biomarkers, including hCG, progesterone, and estradiol, were found to impact the risk of miscarriage with estradiol as the most important. The best model to predict miscarriage was a combination of maternal age, vaginal bleeding, CRL, and hCG. The second-best model was the sonography-absent model of maternal age, bleeding, hCG, and estradiol. This study suggests that combining maternal age, and evolving data from hCG, estradiol, CRL, and bleeding could be used to predict fetal outcome during the first trimester of pregnancy.Trial registration ClinicalTrials.gov identifier: NCT02761772.

A simple scoring system for the prediction of early pregnancy loss developed by following 13,977 infertile patients after in vitro fertilization

A retrospective study was conducted to investigate a convenient simple scoring system for the prediction of early pregnancy loss (EPL) based on simple demographics. A total of 13,977 women undergoing transvaginal ultrasound scans on Days 27-29 after in vitro fertilization-embryo transfer (IVF-ET) from June 2016 and December 2017 were included. The first trimester pregnancy outcome was recorded at 12 weeks of gestation. The areas under the curve of this scoring system were 0.884 (95% confidence interval (CI) 0.870-0.899) and 0.890 (95% CI 0.878-0.903) in the training set and test set, respectively. The score totals ranged from -8 to 14 points. A score of 5 points, which offered the highest predictive accuracy (94.01%) and corresponded to a 30% miscarriage risk, was chosen as the cutoff value, with a sensitivity of 62.84%, specificity of 98.79%, positive predictive value (PPV) of 88.87% and negative predictive value (NPV) of 94.54% for the prediction of EPL in the training set. In the test set, a score of 5 points had a sensitivity of 64.69%, specificity of 98.78%, PPV of 89.87% and NPV of 93.62%, and 93.91% of the cases were correctly predicted. Therefore, the simple scoring system using conventionally collected data can be conveniently used to predict EPL after ET. However, considering the limitations, its predictive value needs to be further verified in future clinical practice.

Psychological impact of simple scoring system for predicting early pregnancy outcome in pregnancy of uncertain viability: randomized controlled trial

OBJECTIVE

To investigate whether psychological wellbeing of women with an intrauterine pregnancy of uncertain viability can be modified during the waiting period to final diagnosis, by offering predictive information regarding the likely outcome of the pregnancy (chance of ongoing viability).

METHODS

This was a single-center two-arm randomized controlled trial conducted over 18 months at a teaching hospital in London, UK. Consecutive eligible women attending the early pregnancy assessment unit with an interim ultrasound finding of intrauterine pregnancy of uncertain viability were recruited. All women were offered a follow-up ultrasound scan after 14 days. Participants were randomized to receive a prediction score for ongoing viability at 14 days or routine care (control). Anxiety, depression and worry symptoms were assessed using validated self-report questionnaires (hospital anxiety and depression scale (HADS), Penn state worry questionnaire (PSWQ)) prior to randomization and at two further timepoints during the waiting period preceding final diagnosis. The change in psychological scores over the study period was analyzed. The secondary outcome was the perceived value of the risk prediction tool reported by participants.

RESULTS

A total of 278 women participated in this study. After adjusting for baseline scores, no difference in anxiety, depression or worry scores was demonstrated between control and intervention groups at either timepoint. Subgroup analysis, first of women with high initial anxiety (HADS > 11) or worry (PSWQ ≥ 45), and second of women with a more favorable predicted prognosis (≥ 75% chance of ongoing viability), demonstrated no difference between intervention and control groups. Despite this, 76/110 (69.1% (95% CI, 60.5-78.4%)) women who provided feedback in the intervention group found it to be helpful and 97/110 (88.2% (95% CI, 81.0-93.7%)) reported that they would use the tool again.

CONCLUSION

Current prediction tools may be useful for healthcare professionals to guide management and optimize utilization of early pregnancy resources. However, in this study, implementation of an accurate tool did not result in an objective measurable benefit to patients in terms of reduction in anxiety, depression and worry symptoms experienced during the waiting period to final outcome compared with women who did not receive a prediction score. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Very early medical abortion: treatment with mifepristone and misoprostol before ultrasonographic visualisation of an intrauterine pregnancy

INTRODUCTION

Abortion providers may be reluctant to commence abortion before ultrasound evidence of intrauterine pregnancy (IUP) due to concerns of missed ectopic pregnancy. In 2017, very early medical abortion (VEMA) was introduced at an abortion service in Edinburgh, UK. Following ultrasound, patients without confirmed IUP, and without symptoms or risk factors for ectopic pregnancy, could commence treatment immediately after baseline serum-human chorionic gonadotrophin (hCG) measurement, and return for follow-up serum-hCG a week later to determine treatment success (≥80% decline from baseline). This study aimed to compare clinical outcomes between two pathways: (1) VEMA; and (2) standard-of-care delayed treatment where treatment is only commenced on IUP confirmation by serial serum-hCG monitoring and/or repeat ultrasound.

METHODS

A retrospective database review was conducted of VEMA eligible patients from July 2017 to December 2021. Study groups were determined by patient preference. Records were searched for abortion outcomes, duration of care, number of appointments (clinic visits, ultrasounds, serum-hCG) and clinical data entries.

RESULTS

Of 181 patients included, 77 (43%) chose VEMA and 104 (57%) chose delayed treatment. 11/181 (6.1%) were lost to follow-up. Cohort ectopic prevalence was 4.4% and was not statistically different between groups (2.6% vs 5.8%, VEMA vs delayed group, respectively, p=0.305), as with complete abortion rates (93.3% vs 97.6%, p=0.256). All VEMA group ectopics were detected on the seventh day (from initial visit) while time-to-diagnosis for delayed group ectopics ranged from 7 days to 3 weeks. VEMA patients had significantly reduced duration of care (12 vs 21 days, p<0.001), number of visits (2 vs 3, p<0.001), ultrasounds (1 vs 2, p<0.001) and data entries (6 vs 9, p<0.001).

CONCLUSIONS

VEMA is safe, effective and reduces the duration of care, number of appointments and clinical administrative time. It should be offered to medically eligible patients.

Mifepristone and misoprostol versus placebo and misoprostol for resolution of miscarriage in women diagnosed with missed miscarriage: the MifeMiso RCT

TRIAL DESIGN

A randomised, parallel-group, double-blind, placebo-controlled multicentre study with health economic and nested qualitative studies to determine if mifepristone (Mifegyne^®, Exelgyn, Paris, France) plus misoprostol is superior to misoprostol alone for the resolution of missed miscarriage.

METHODS

Women diagnosed with missed miscarriage in the first 14 weeks of pregnancy were randomly assigned (1 : 1 ratio) to receive 200 mg of oral mifepristone or matched placebo, followed by 800 μg of misoprostol 2 days later. A web-based randomisation system allocated the women to the two groups, with minimisation for age, body mass index, parity, gestational age, amount of bleeding and randomising centre. The primary outcome was failure to pass the gestational sac within 7 days after randomisation. The prespecified key secondary outcome was requirement for surgery to resolve the miscarriage. A within-trial cost-effectiveness study and a nested qualitative study were also conducted. Women who completed the trial protocol were purposively approached to take part in an interview to explore their satisfaction with and the acceptability of medical management of missed miscarriage.

RESULTS

A total of 711 women, from 28 hospitals in the UK, were randomised to receive either mifepristone plus misoprostol (357 women) or placebo plus misoprostol (354 women). The follow-up rate for the primary outcome was 98% (696 out of 711 women). The risk of failure to pass the gestational sac within 7 days was 17% (59 out of 348 women) in the mifepristone plus misoprostol group, compared with 24% (82 out of 348 women) in the placebo plus misoprostol group (risk ratio 0.73, 95% confidence interval 0.54 to 0.98; p = 0.04). Surgical intervention to resolve the miscarriage was needed in 17% (62 out of 355 women) in the mifepristone plus misoprostol group, compared with 25% (87 out of 353 women) in the placebo plus misoprostol group (risk ratio 0.70, 95% confidence interval 0.52 to 0.94; p = 0.02). There was no evidence of a difference in the incidence of adverse events between the two groups. A total of 42 women, 19 in the mifepristone plus misoprostol group and 23 in the placebo plus misoprostol group, took part in an interview. Women appeared to have a preference for active management of their miscarriage. Overall, when women experienced care that supported their psychological well-being throughout the care pathway, and information was delivered in a skilled and sensitive manner such that women felt informed and in control, they were more likely to express satisfaction with medical management. The use of mifepristone and misoprostol showed an absolute effect difference of 6.6% (95% confidence interval 0.7% to 12.5%). The average cost per woman was lower in the mifepristone plus misoprostol group, with a cost saving of £182 (95% confidence interval £26 to £338). Therefore, the use of mifepristone and misoprostol for the medical management of a missed miscarriage dominated the use of misoprostol alone.

LIMITATIONS

The results from this trial are not generalisable to women diagnosed with incomplete miscarriage and the study does not allow for a comparison with expectant or surgical management of miscarriage.

FUTURE WORK

Future work should use existing data to assess and rank the relative clinical effectiveness and safety profiles for all methods of management of miscarriage.

CONCLUSIONS

Our trial showed that pre-treatment with mifepristone followed by misoprostol resulted in a higher rate of resolution of missed miscarriage than misoprostol treatment alone. Women were largely satisfied with medical management of missed miscarriage and would choose it again. The mifepristone and misoprostol intervention was shown to be cost-effective in comparison to misoprostol alone.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN17405024.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 68. See the NIHR Journals Library website for further project information.

Progesterone to prevent miscarriage in women with early pregnancy bleeding: the PRISM RCT

BACKGROUND

Progesterone is essential for a healthy pregnancy. Several small trials have suggested that progesterone therapy may rescue a pregnancy in women with early pregnancy bleeding, which is a symptom that is strongly associated with miscarriage.

OBJECTIVES

(1) To assess the effects of vaginal micronised progesterone in women with vaginal bleeding in the first 12 weeks of pregnancy. (2) To evaluate the cost-effectiveness of progesterone in women with early pregnancy bleeding.

DESIGN

A multicentre, double-blind, placebo-controlled, randomised trial of progesterone in women with early pregnancy vaginal bleeding.

SETTING

A total of 48 hospitals in the UK.

PARTICIPANTS

Women aged 16-39 years with early pregnancy bleeding.

INTERVENTIONS

Women aged 16-39 years were randomly assigned to receive twice-daily vaginal suppositories containing either 400 mg of progesterone or a matched placebo from presentation to 16 weeks of gestation.

MAIN OUTCOME MEASURES

The primary outcome was live birth at ≥ 34 weeks. In addition, a within-trial cost-effectiveness analysis was conducted from an NHS and NHS/Personal Social Services perspective.

RESULTS

A total of 4153 women from 48 hospitals in the UK received either progesterone (n = 2079) or placebo (n = 2074). The follow-up rate for the primary outcome was 97.2% (4038 out of 4153 participants). The live birth rate was 75% (1513 out of 2025 participants) in the progesterone group and 72% (1459 out of 2013 participants) in the placebo group (relative rate 1.03, 95% confidence interval 1.00 to 1.07; p = 0.08). A significant subgroup effect (interaction test p = 0.007) was identified for prespecified subgroups by the number of previous miscarriages: none (74% in the progesterone group vs. 75% in the placebo group; relative rate 0.99, 95% confidence interval 0.95 to 1.04; p = 0.72); one or two (76% in the progesterone group vs. 72% in the placebo group; relative rate 1.05, 95% confidence interval 1.00 to 1.12; p = 0.07); and three or more (72% in the progesterone group vs. 57% in the placebo group; relative rate 1.28, 95% confidence interval 1.08 to 1.51; p = 0.004). A significant post hoc subgroup effect (interaction test p = 0.01) was identified in the subgroup of participants with early pregnancy bleeding and any number of previous miscarriage(s) (75% in the progesterone group vs. 70% in the placebo group; relative rate 1.09, 95% confidence interval 1.03 to 1.15; p = 0.003). There were no significant differences in the rate of adverse events between the groups. The results of the health economics analysis show that progesterone was more costly than placebo (£7655 vs. £7572), with a mean cost difference of £83 (adjusted mean difference £76, 95% confidence interval -£559 to £711) between the two arms. Thus, the incremental cost-effectiveness ratio of progesterone compared with placebo was estimated as £3305 per additional live birth at ≥ 34 weeks of gestation.

CONCLUSIONS

Progesterone therapy in the first trimester of pregnancy did not result in a significantly higher rate of live births among women with threatened miscarriage overall, but an important subgroup effect was identified. A conclusion on the cost-effectiveness of the PRISM trial would depend on the amount that society is willing to pay to increase the chances of an additional live birth at ≥ 34 weeks. For future work, we plan to conduct an individual participant data meta-analysis using all existing data sets.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN14163439, EudraCT 2014-002348-42 and Integrated Research Application System (IRAS) 158326.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 33. See the NIHR Journals Library website for further project information.

Terminology for describing normally sited and ectopic pregnancies on ultrasound: ESHRE recommendations for good practice

STUDY QUESTION

What recommendations can be provided to improve terminology for normal and ectopic pregnancy description on ultrasound?

SUMMARY ANSWER

The present ESHRE document provides 17 consensus recommendations on how to describe normally sited and different types of ectopic pregnancies on ultrasound.

WHAT IS KNOWN ALREADY

Current diagnostic criteria stipulate that each type of ectopic pregnancy can be defined by clear anatomical landmarks which facilitates reaching a correct diagnosis. However, a clear definition of normally sited pregnancies and a comprehensive classification of ectopic pregnancies are still lacking.

STUDY DESIGN SIZE DURATION

A working group of members of the ESHRE Special Interest Group in Implantation and Early Pregnancy (SIG-IEP) and selected experts in ultrasound was formed in order to write recommendations on the classification of ectopic pregnancies.

PARTICIPANTS/MATERIALS SETTING METHODS

The working group included nine members of different nationalities with internationally recognised experience in ultrasound and diagnosis of ectopic pregnancies on ultrasound. This document is developed according to the manual for development of ESHRE recommendations for good practice. The recommendations were discussed until consensus by the working group, supported by a survey among the members of the ESHRE SIG-IEP.

MAIN RESULTS AND THE ROLE OF CHANCE

A clear definition of normally sited pregnancy on ultrasound scan is important to avoid misdiagnosis of uterine ectopic pregnancies. A comprehensive classification of ectopic pregnancy must include definitions and descriptions of each type of ectopic pregnancy. Only a classification which provides descriptions and diagnostic criteria for all possible locations of ectopic pregnancy would be fit for use in routine clinical practice. The working group formulated 17 recommendations on the diagnosis of the different types of ectopic pregnancies on ultrasound. In addition, for each of the types of ectopic pregnancy, a schematic representation and examples on 2D and 3D ultrasound are provided.

LIMITATIONS REASONS FOR CAUTION

Owing to the limited evidence available, recommendations are mostly based on clinical and technical expertise.

WIDER IMPLICATIONS OF THE FINDINGS

This document is expected to have a significant impact on clinical practice in ultrasound for early pregnancy. The development of this terminology will help to reduce the risk of misdiagnosis and inappropriate treatment.

STUDY FUNDING/COMPETING INTERESTS

The meetings of the working group were funded by ESHRE. T.T. declares speakers' fees from GE Healthcare. The other authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

DISCLAIMER

This Good Practice Recommendations (GPR) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and where relevant based on the scientific evidence available at the time of preparation. ESHRE's GPRs should be used for informational and educational purposes. They should not be interpreted as setting a standard of care or be deemed inclusive of all proper methods of care nor exclusive of other methods of care reasonably directed to obtaining the same results. They do not replace the need for application of clinical judgement to each individual presentation, nor variations based on locality and facility type. Furthermore, ESHRE's GPRs do not constitute or imply the endorsement, recommendation or favouring of any of the included technologies by ESHRE.

Mifepristone and misoprostol versus misoprostol alone for the management of missed miscarriage (MifeMiso): a randomised, double-blind, placebo-controlled trial

BACKGROUND

The anti-progesterone drug mifepristone and the prostaglandin misoprostol can be used to treat missed miscarriage. However, it is unclear whether a combination of mifepristone and misoprostol is more effective than administering misoprostol alone. We investigated whether treatment with mifepristone plus misoprostol would result in a higher rate of completion of missed miscarriage compared with misoprostol alone.

METHODS

MifeMiso was a multicentre, double-blind, placebo-controlled, randomised trial in 28 UK hospitals. Women were eligible for enrolment if they were aged 16 years and older, diagnosed with a missed miscarriage by pelvic ultrasound scan in the first 14 weeks of pregnancy, chose to have medical management of miscarriage, and were willing and able to give informed consent. Participants were randomly assigned (1:1) to a single dose of oral mifepristone 200 mg or an oral placebo tablet, both followed by a single dose of vaginal, oral, or sublingual misoprostol 800 μg 2 days later. Randomisation was managed via a secure web-based randomisation program, with minimisation to balance study group assignments according to maternal age (<30 years vs ≥30 years), body-mass index (<35 kg/m²vs ≥35 kg/m²), previous parity (nulliparous women vs parous women), gestational age (<70 days vs ≥70 days), amount of bleeding (Pictorial Blood Assessment Chart score; ≤2 vs ≥3), and randomising centre. Participants, clinicians, pharmacists, trial nurses, and midwives were masked to study group assignment throughout the trial. The primary outcome was failure to spontaneously pass the gestational sac within 7 days after random assignment. Primary analyses were done according to intention-to-treat principles. The trial is registered with the ISRCTN registry, ISRCTN17405024.

FINDINGS

Between Oct 3, 2017, and July 22, 2019, 2595 women were identified as being eligible for the MifeMiso trial. 711 women were randomly assigned to receive either mifepristone and misoprostol (357 women) or placebo and misoprostol (354 women). 696 (98%) of 711 women had available data for the primary outcome. 59 (17%) of 348 women in the mifepristone plus misoprostol group did not pass the gestational sac spontaneously within 7 days versus 82 (24%) of 348 women in the placebo plus misoprostol group (risk ratio [RR] 0·73, 95% CI 0·54-0·99; p=0·043). 62 (17%) of 355 women in the mifepristone plus misoprostol group required surgical intervention to complete the miscarriage versus 87 (25%) of 353 women in the placebo plus misoprostol group (0·71, 0·53-0·95; p=0·021). We found no difference in incidence of adverse events between the study groups.

INTERPRETATION

Treatment with mifepristone plus misoprostol was more effective than misoprostol alone in the management of missed miscarriage. Women with missed miscarriage should be offered mifepristone pretreatment before misoprostol to increase the chance of successful miscarriage management, while reducing the need for miscarriage surgery.

FUNDING

UK National Institute for Health Research Health Technology Assessment Programme.

Prediction of pregnancy loss by early first trimester ultrasound characteristics

BACKGROUND

Pregnancy loss prediction based on routinely measured ultrasound characteristics is generally aimed toward distinguishing nonviability. Physicians also use ultrasound indicators for patient counseling, and in some cases to decide upon the frequency of follow-up sonograms. To improve clinical utility, allocation of cut-points should be based on clinical data for multiple sonographic characteristics, be specific to gestational week, and be determined by methods that optimize prediction.

OBJECTIVES

To identify routinely measured features of the early first trimester ultrasound and the gestational age-specific cut-points that are most predictive of pregnancy loss.

MATERIALS AND METHODS

This was a secondary analysis of 617 pregnant women enrolled in the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial; all women had 1-2 previous pregnancy losses and no documented infertility. Each participant had a single ultrasound with a detectable fetal heartbeat between 6 weeks 0 days and 8 weeks 6 days. Cut-points for low fetal heart rate and small crown-rump length were separately defined for gestational weeks 6, 7, and 8 to optimize prediction. Identity and log-binomial regression models were used to estimate absolute and relative risks, respectively, and 95% confidence intervals between jointly categorized low fetal heart rate, small crown-rump length, and clinical pregnancy loss. Adjusted models accounted for gestational age at ultrasound in weeks. Missing data were addressed using multiple imputation.

RESULTS

A total of 64 women experienced a clinical pregnancy loss following the first ultrasound (10.4%), 7 were lost to follow-up (1.1%), and 546 women (88.5%) had a live birth. Low fetal heart rate and small crown-rump length (≤122, 123, and 158 bpm; ≤6.0, 8.5, and 10.9 mm for gestational weeks 6, 7, and 8, respectively) were independent predictors of clinical pregnancy loss, with greatest risks observed for pregnancies having both characteristics (relative risk, 2.08; 95% confidence interval, 1.24-2.91). The combination of low fetal heart rate and small crown-rump length was linked to a 16% (95% confidence interval, 9.1-23%) adjusted absolute increase in risk of subsequent loss, from 5.0% (95% confidence interval, 1.5-8.5%) to 21% (95% confidence interval, 15-27%). Abnormal yolk sac diameter or the presence of a subchorionic hemmhorage did not improve prediction of clinical pregnancy loss.

CONCLUSION

Identified cut-points can be used by physicians for patient counseling, and in some cases to decide upon the frequency of follow-up sonograms. The specified criteria should not be used to diagnose nonviability.

Coronavirus in pregnancy and delivery: rapid review

OBJECTIVES

There are limited case series reporting the impact on women affected by coronavirus during pregnancy. In women affected by severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), the case fatality rate appears higher in those affected in pregnancy compared with non-pregnant women. We conducted a rapid review to guide health policy and management of women affected by COVID-19 during pregnancy, which was used to develop the Royal College of Obstetricians and Gynaecologists' (RCOG) guidelines on COVID-19 infection in pregnancy.

METHODS

Searches were conducted in PubMed and MedRxiv to identify primary case reports, case series, observational studies and randomized controlled trials describing women affected by coronavirus in pregnancy. Data were extracted from relevant papers. This review has been used to develop guidelines with representatives of the Royal College of Paediatrics and Child Health (RCPCH) and RCOG who provided expert consensus on areas in which data were lacking.

RESULTS

From 9965 search results in PubMed and 600 in MedRxiv, 21 relevant studies, all of which were case reports or case series, were identified. From reports of 32 women to date affected by COVID-19 in pregnancy, delivering 30 babies (one set of twins, three ongoing pregnancies), seven (22%) were asymptomatic and two (6%) were admitted to the intensive care unit (ICU), one of whom remained on extracorporeal membrane oxygenation. No maternal deaths have been reported to date. Delivery was by Cesarean section in 27 cases and by vaginal delivery in two, and 15 (47%) delivered preterm. There was one stillbirth and one neonatal death. In 25 babies, no cases of vertical transmission were reported; 15 were reported as being tested with reverse transcription polymerase chain reaction after delivery. Case fatality rates for SARS and MERS were 15% and 27%, respectively. SARS was associated with miscarriage or intrauterine death in five cases, and fetal growth restriction was noted in two ongoing pregnancies affected by SARS in the third trimester.

CONCLUSIONS

Serious morbidity occurred in 2/32 women with COVID-19, both of whom required ICU care. Compared with SARS and MERS, COVID-19 appears less lethal, acknowledging the limited number of cases reported to date and that one woman remains in a critical condition. Preterm delivery affected 47% of women hospitalized with COVID-19, which may put considerable pressure on neonatal services if the UK's reasonable worst-case scenario of 80% of the population being affected is realized. Based on this review, RCOG, in consultation with RCPCH, developed guidance for delivery and neonatal care in pregnancies affected by COVID-19, which recommends that delivery mode be determined primarily by obstetric indication and recommends against routine separation of affected mothers and their babies. We hope that this review will be helpful for maternity and neonatal services planning their response to COVID-19. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

[Prognosis of pregnant women with vaginal bleeding during the first trimester: about 239 cases at the Kamenge University Hospital in Bujumbura]

The purpose of this study is to evaluate the post-discharge prognosis of pregnant women with vaginal bleeding during the first trimester, admitted to the Emergency Maternity at the Kamenge University Hospital (CHUK), according to patients age, amount of bleeding and ultrasound results. We conducted a retrospective descriptive and analytical study of 239 medical records of patients hospitalized over a period of six years from January 2012 to December 2017. In this study, the prognosis of pregnant women with first-trimester metrorrhagia hospitalized at the CHUK was bad; the majority of them (65.7%) had miscarriage. Amount of bleeding, maternal age below 20 years, or well above or equal to 35 years, were significant risk factors but much more ultrasound detection of trophoblastic detachment. It would be interesting to perform a prospective study to detect the causes of these metrorrhagias and to determine late pregnancy complications.

[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.

A Randomized Trial of Progesterone in Women with Bleeding in Early Pregnancy

BACKGROUND

Bleeding in early pregnancy is strongly associated with pregnancy loss. Progesterone is essential for the maintenance of pregnancy. Several small trials have suggested that progesterone therapy may improve pregnancy outcomes in women who have bleeding in early pregnancy.

METHODS

We conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate progesterone, as compared with placebo, in women with vaginal bleeding in early pregnancy. Women were randomly assigned to receive vaginal suppositories containing either 400 mg of progesterone or matching placebo twice daily, from the time at which they presented with bleeding through 16 weeks of gestation. The primary outcome was the birth of a live-born baby after at least 34 weeks of gestation. The primary analysis was performed in all participants for whom data on the primary outcome were available. A sensitivity analysis of the primary outcome that included all the participants was performed with the use of multiple imputation to account for missing data.

RESULTS

A total of 4153 women, recruited at 48 hospitals in the United Kingdom, were randomly assigned to receive progesterone (2079 women) or placebo (2074 women). The percentage of women with available data for the primary outcome was 97% (4038 of 4153 women). The incidence of live births after at least 34 weeks of gestation was 75% (1513 of 2025 women) in the progesterone group and 72% (1459 of 2013 women) in the placebo group (relative rate, 1.03; 95% confidence interval [CI], 1.00 to 1.07; P = 0.08). The sensitivity analysis, in which missing primary outcome data were imputed, resulted in a similar finding (relative rate, 1.03; 95% CI, 1.00 to 1.07; P = 0.08). The incidence of adverse events did not differ significantly between the groups.

CONCLUSIONS

Among women with bleeding in early pregnancy, progesterone therapy administered during the first trimester did not result in a significantly higher incidence of live births than placebo. (Funded by the United Kingdom National Institute for Health Research Health Technology Assessment program; PRISM Current Controlled Trials number, ISRCTN14163439.).

Efficacy and safety of very early medical termination of pregnancy: a cohort study

OBJECTIVE

To assess the efficacy and safety of medical termination of pregnancy (MTOP) when no intrauterine pregnancy (IUP) is confirmed on ultrasound.

DESIGN

Retrospective case-note review.

SETTING

Two gynaecological clinics in Vienna, Austria, and Gothenburg, Sweden.

POPULATION

All women with gestations of ≤49 days undergoing an MTOP during 2004-14 (Vienna) and 2012-15 (Gothenburg).

METHODS

Two study cohorts were created: women with and women without a confirmed IUP. An IUP was defined as the intrauterine location of a yolk sac or fetal structure visible by ultrasound. Women with an IUP were selected randomly and included in the IUP cohort.

MAIN OUTCOME MEASURES

Efficacy of MTOP, defined as no continuing pregnancy and with no need of surgery for incomplete TOP.

RESULTS

After excluding 11 women diagnosed with an extra-uterine or molar pregnancy, 2643 cases were included in the final analysis; 1120 (98.2%) had a successful TOP in the no-IUP group, compared with 1458 (97.1%) in the IUP group, with a risk difference of 1.09% (95% confidence interval, 95% CI, -0.14, 2.32%; P = 0.077). Significantly more women with confirmed IUP were diagnosed with incomplete TOP, and were treated with either surgery or additional medical treatment of misoprostol [64 (4.3%) versus 21 (1.8%); risk difference -2.42%; 95% CI -3.9, -1.1%; P < 0.001].

CONCLUSIONS

There was no difference between the groups in efficacy of MTOP, whereas early treatment resulted in significantly fewer interventions for incomplete TOP. The risk of ectopic pregnancy needs to be considered if treatment is initiated before an IUP is confirmed, but with structured clinical protocols the possibility of the early detection of an ectopic pregnancy in an asymptomatic phase may increase.

TWEETABLE ABSTRACT

MTOP before confirmed intrauterine pregnancy is as effective as at later gestation with less incomplete TOP.

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.

Prediction of subsequent miscarriage risk in women who present with a viable pregnancy at the first early pregnancy scan

OBJECTIVES

To generate and evaluate a new prediction model for miscarriage in women who present with a viable intrauterine pregnancy (IUP) at the primary early pregnancy scan and to compare this new model to a previously published model.

MATERIALS AND METHODS

Data were collected prospectively from women presenting to the early pregnancy unit with a viable IUP between November 2006 and January 2013. More than 30 historical, clinical and ultrasonographic variables were recorded on a standardised datasheet at the first visit. Women were followed until the final outcome was known at the end of the first trimester: viable IUP or miscarriage. A new multinomial logistic regression model was developed retrospectively on training cases and tested prospectively on test cases. The performance of the new prediction model was evaluated using receiver operating characteristic (ROC) curves and compared to a previously published model. After removing cases with missing values for the model of Oates, the area under the ROC curve (AUC) was also calculated for the new model and the Oates model.

RESULTS

A total of 1115 consecutive first-trimester women presented to the early pregnancy unit. Eight hundred and sixty-two women with a viable IUP at the first scan whose outcome was known at the end of the first trimester were included in the final analysis. Five hundred and sixty-six women were included in the training set and 296 in the test set. 92.1% were viable and 7.9% had miscarried at the end of the first trimester. The most significant independent prognostic variables for the logistic regression model were as follows: maternal age, embryonic heart rate (EHR), logarithm [gestational sac (GS) volume/crown-rump length (CRL)], CRL and the presence or absence of clots per vagina (PV) at presentation. The performance of the new model compared with the Oates model gave an AUC of 0.870 vs 0.847 for the training set and 0.783 vs 0.744 for the test set. After removing cases with missing values for the model of Oates 2013, the performance of the new model compared to the Oates model gave an AUC of 0.887 vs 0.861 for the training set and 0.816 vs 0.734 for the test set (P-value <0.04).

CONCLUSIONS

We have developed a new prediction model which indicates the likelihood of miscarriage. In women who present with a viable IUP at the primary scan, advancing maternal age in the presence of clots PV increases the probability of subsequent miscarriage. Whereas, in women with a higher EHR in the presence of an increased GS volume/CRL ratio, the likelihood of subsequent miscarriage is reduced. This new model outperforms the previously published model developed in our unit.

Termination of pregnancy at very early gestation without visible yolk sac on ultrasound

INTRODUCTION

Requests for termination of pregnancy (TOP) at very early gestation (≤6 weeks) can prove challenging for abortion services as the ultrasound feature usually accepted as definitive evidence of an intrauterine pregnancy (IUP), the presence of a yolk sac within a gestational sac, may not yet be evident. In 2011 the Edinburgh TOP service introduced a protocol permitting women to proceed to treatment without further investigations provided that ultrasound showed the features of an eccentrically placed gestational sac (≥3 mm) with a decidual reaction, and there were no signs, symptoms or risk factors for ectopic pregnancy.

METHODS

A retrospective audit was conducted of outcomes of women presenting for TOP at ≤6 weeks' gestation over a 2-year period using the hospital computerised database.

RESULTS

A total of 1155 women presented for TOP with an ultrasound gestational age of ≤6 weeks. Of these, 1030 (89%) had ultrasound evidence of a yolk sac. Eighty-seven women (7.5%) had an eccentrically placed gestational sac with a decidual reaction. All 87 women fulfilled our criteria to proceed to medical TOP, and 66 did so. In the remaining 21 cases, further investigations were performed before they proceeded to medical TOP. Two (0.17%) medical TOPs failed, both in women whose initial ultrasound had shown a yolk sac.

CONCLUSION

Women with ultrasound features consistent with a very early IUP (≥3 mm eccentrically placed gestational sac with a decidual reaction) and without signs, symptoms or risk factors for ectopic pregnancy can proceed directly to medical TOP without the need for delay for further ultrasonography.

Do women with pain and bleeding in early pregnancy require a vaginal speculum examination as part of their assessment?

AIMS

To investigate whether a vaginal speculum examination (VSE) prior to a transvaginal scan (TVS) alters the diagnosis or management of women who complain of bleeding in early pregnancy.

METHODS

A prospective study. Women were asked to describe their bleeding as heavy, moderate or light and to consent to VSE prior to TVS. TVS was performed to obtain a final diagnosis of pregnancy outcome.

RESULTS

221 consecutive women were included in the study. In 14.5% (n = 32) complaining of heavy bleeding, blood was seen in all but two VSE and 84% (n = 27) had a miscarriage diagnosed by TVS. Products of conception were removed in 18.8% (n = 6), but this did not alter the subsequent immediate management of any cases. 65.2% (n = 144) of women complained of light bleeding, blood was seen on VSE in 53% (n = 77). Of these women, 25% (n = 19) of those where blood was seen had a miscarriage, compared to 6% (n = 4) of women where blood was not seen. A cervical ectropion was visualised in 11.7% (n = 26) and 2.3% (n = 5) had a cervical polyp. No other clinically significant pathology was detected.

CONCLUSION

The amount of bleeding reported by women in early pregnancy relates well with VSE findings. Performing a VSE did not alter the subsequent management of these patients. This study demonstrates that routine objective assessment of blood by a clinician performing VSE prior to a TVS is unnecessary.

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."

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.