Defining safe criteria to diagnose miscarriage: prospective observational multicentre study

Abstract

ObjeCtivesTo validate recent guidance changes by establishing the performance of cut-off values for embryo crownrump 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.) DesignProspective 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 MeasuresMean 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. resultsThe 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%). COnClusiOnsRecently 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 avo...

First‐trimester intrauterine hematoma and pregnancy complications

“…First-trimester miscarriage was defined as pregnancy loss before 14 weeks' gestation, and was diagnosed using the criteria outlined by Abdallah et al 21 and Preisler et al 22 . Late pregnancy outcome measures were defined as antenatal, delivery and neonatal complications.…”

A Yolk Sac Larger Than 5 mm Suggests an Abnormal Fetal Karyotype, Whereas an Absent Embryo Indicates a Normal Fetal Karyotype

“…A diagnosis of miscarriage before 12 weeks' gestation has been referred to in several reports. [14][15][16][17][18] The diagnostic criteria of early miscarriage in this study were as follows: (1) fetal cardiac activity was confirmed once, but could not be observed anymore 2 weeks later; (2) an embryo with a crown-rump length of 7 mm or greater without visible cardiac activity; (3) a mean gestational sac diameter of 25 mm or greater with an empty sac; and (4) Pregnancies without an embryo and a mean gestational sac diameter of less than 12 mm that had not doubled after 2 weeks and pregnancies without an embryo and a mean gestational sac diameter of 12 mm or greater that had shown no cardiac activity after 1 or 2 weeks.…”

“…Abnormal US findings are highly predictive in the diagnosis of early miscarriage. [14][15][16][17][18] Considering cost-effectiveness, 8 workload, and examinations without insurance in Japan, fetal karyotyping is usually not performed. Therefore, it is clinically useful to predict the presence or absence of an abnormal fetal karyotype with reference to US findings when fetal karyotyping is not performed out.…”

Diagnosing a miscarriage

“…5 Given these recent shifts in criteria to define something so important, it is timely that in this issue Preisler and colleagues (doi:10.1136/bmj.h4579) present a large prospective multicentre study to inform about when it is safe to make the call that a pregnancy has failed. 6 Over two and a half years the team recruited 2558 women across seven early pregnancy units in the United Kingdom. 6 They included women in whom it was unclear at the first ultrasound scan whether the pregnancy was ongoing, and plans were made for repeat scanning.…”

“…6 Over two and a half years the team recruited 2558 women across seven early pregnancy units in the United Kingdom. 6 They included women in whom it was unclear at the first ultrasound scan whether the pregnancy was ongoing, and plans were made for repeat scanning. By the follow-up scans performed at 11 to 14 weeks' gestation, about half of the pregnancies appeared healthy and the remainder had definitely miscarried.…”