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

National register data are of value in studies on miscarriage-Validation of the healthcare register data in Finland

INTRODUCTION

Despite the high prevalence of miscarriages, they are not systematically registered and few epidemiological studies have been done. As Finnish health registries are comprehensive and widely used in research, we validated the Finnish register data concerning diagnostics and treatment of miscarriage, and treatment-related adverse events.

MATERIAL AND METHODS

We conducted a validation study regarding miscarriage-related codes of diagnoses and surgical procedures in a Finnish National Hospital Discharge Registry (NHDR) by comparing the information from the NHDR with that of the hospital records. We selected a random sample of 4 months during 1998-2016 from three hospitals, comprising 687 women aged 15-49 experiencing a first miscarriage during follow-up. Women with diagnoses unrelated to miscarriage, or proven to be other than miscarriage, were excluded. The final sample consisted of 643 women with confirmed miscarriage, which was used for analyses regarding the diagnosis, treatment and adverse events of miscarriage treatment.

RESULTS

The majority of miscarriages registered in the NHDR were confirmed by the hospital records (positive predictive value [PPV] = 93.6% [95% confidence interval [CI] 91.8%-95.4%]). Different types of miscarriage were also reliably identified; spontaneous abortion with PPV = 85.6% (95% CI 80.9%-89.2%), missed abortion with PPV = 92.7% (95% CI 88.8%-95.3%) and blighted ovum with PPV = 91.1% (95% CI 84.3%-95.1%). The PPV of surgical treatment (62.2% [95% CI 55.7%-68.3%]) was lower than the PPV of non-surgical treatment (93.3% [95% CI 90.5%-95.3%]). The diagnoses regarding adverse events of miscarriage treatment could be reliably identified. The PPV for clinical infections was 76.0% (95% CI 56.6%-88.5%) and for retained products of conception or/and vaginal bleeding 96.8% (95% CI 83.8%-99.4%).

CONCLUSIONS

The coverage of the NHDR was good concerning identification of miscarriages, different types of miscarriages and non-surgical treatment. Nevertheless, there is a need for clearly defined procedural codes concerning to medical treatment of miscarriage. The register-based data are reliable and practicable for both clinical evaluation and research concerning miscarriage.

Predictors of complete miscarriage after expectant management or misoprostol treatment of non-viable early pregnancy in women with vaginal bleeding

Purpose

To identify predictors of complete miscarriage after expectant management or misoprostol treatment of non-viable early pregnancy in women with vaginal bleeding.

Methods

This was a planned secondary analysis of data from a published randomized controlled trial comparing expectant management with vaginal single dose of 800 µg misoprostol treatment of women with embryonic or anembryonic miscarriage. Predefined variables—serum-progesterone, serum-β-human chorionic gonadotropin, parity, previous vaginal deliveries, gestational age, clinical symptoms (bleeding and pain), mean diameter and shape of the gestational sac, crown-rump-length, type of miscarriage, and presence of blood flow in the intervillous space—were tested as predictors of treatment success (no gestational sac in the uterine cavity and maximum anterior–posterior intracavitary diameter was ≤ 15 mm as measured with transvaginal ultrasound on a sagittal view) in univariable and multivariable logistic regression.

Results

Variables from 174 women (83 expectant management versus 91 misoprostol) were analyzed for prediction of complete miscarriage at ≤ 17 days. In patients managed expectantly, the rate of complete miscarriage was 62.7% (32/51) in embryonic miscarriages versus 37.5% (12/32) in anembryonic miscarriages (P = 0.02). In multivariable logistic regression, the likelihood of success increased with increasing gestational age, increasing crown-rump-length and decreasing gestational sac diameter. Misoprostol treatment was successful in 80.0% (73/91). No variable predicted success of misoprostol treatment.

Conclusions

Complete miscarriage after expectant management is significantly more likely in embryonic miscarriage than in anembryonic miscarriage. Gestational age, crown-rump-length, and gestational sac diameter are independent predictors of success of expectant management. Predictors of treatment success may help counselling women with early miscarriage.

[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.

Misoprostol treatment vs expectant management in women with early non-viable pregnancy and vaginal bleeding: a pragmatic randomized controlled trial

OBJECTIVE

To compare vaginal misoprostol treatment with expectant management in early non-viable pregnancy with vaginal bleeding with regard to complete evacuation of the uterine cavity within 10 days after randomization.

METHODS

This was a parallel randomized controlled, open-label trial conducted in Skåne University Hospital, Sweden. Patients with anembryonic pregnancy or early fetal demise (crown-rump length ≤ 33 mm) and vaginal bleeding were randomly allocated to either expectant management or treatment with a single dose of 800 μg misoprostol administered vaginally. Patients were evaluated clinically and by ultrasound until complete evacuation of the uterus was achieved (no gestational sac in the uterine cavity and maximum anteroposterior diameter of the intracavitary contents < 15 mm as measured by transvaginal ultrasound on midsagittal view). Follow-up visits were planned at 10, 17, 24 and 31 days. Dilatation and evacuation (D&E) was recommended if miscarriage was not complete within 31 days, but was performed earlier at patient's request, or if there was excessive bleeding as judged clinically. Analysis was by intention to treat. The main outcome measure was number of patients with complete miscarriage without D&E ≤ 10 days.

RESULTS

Ninety-four patients were randomized to misoprostol treatment and 95 to expectant management. After exclusion of three patients and withdrawal of consent by two patients in the expectant management group, 90 women were included in this group. Miscarriage was complete ≤ 10 days in 62/94 (66%) of the patients in the misoprostol group and in 39/90 (43%) of those in the group managed expectantly (risk difference (RD) = 23%; 95% CI, 8-37%). At 31 days, the corresponding figures were 81/94 (86%) and 55/90 (61%) (RD = 25%; 95% CI, 12-38%). Two patients from each group underwent emergency D&E because of excessive bleeding and one of these in each group received blood transfusion. The number of patients undergoing D&E at their own request was higher in the expectantly managed group, 15/90 (17%) vs 3/94 (3%) in the misoprostol group (RD = 14%; 95% CI, 4-23%), as was the number of patients making out-of-protocol visits, 50/90 (56%) vs 27/94 (29%) (RD = 27%; 95% CI, 12-40%). Compared with the expectant management group, more patients in the misoprostol group experienced pain (71/77 (92%) vs 91/91 (100%); RD = 8%; 95% CI, 1-17%) and used painkillers (59/77 (77%) vs 85/91 (93%); RD = 17%; 95% CI, 5-29%). No major side effect was reported in any group.

CONCLUSIONS

In women with early non-viable pregnancy and vaginal bleeding, misoprostol treatment is more effective than is expectant management for complete evacuation of the uterus. Both methods are safe but misoprostol treatment is associated with more pain than is expectant management. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

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

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

Diagnostic Methods of Ectopic Pregnancy and Early Pregnancy Loss: a Review of the Literature

This review article presents recent evidence on early pregnancy loss and ectopic pregnancy. In the light of recent evidence, the β-hCG discriminatory zone may be extended in clinically stable cases without evidence of bleeding. A possible cut-off is 4300 mIU/ml, which corresponds to when a sonographer should detect an intrauterine pregnancy. Embryonic demise can be confirmed when a transvaginal ultrasound finding shows no heartbeat in an embryo of more than 7 mm CRL, no embryo in a gestational sac having a mean sac diameter of more than 25 mm, or no appearance of an embryo within 7-10 days after the primary examination. These are considered definitive signs of embryonic demise. Suggestive signs of embryonic demise require closer monitoring of the pregnancy.

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.

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

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

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

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

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

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.