Ultrasound prediction of miscarriage
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Ultrasound prediction of miscarriage
Journal Club slides prepared by Dr Tommaso Bignardi(UOG Editor for Trainees)
UOG Journal Club: November 2011
Accuracy of first-trimester ultrasound in the diagnosis of early embryonic demise: a systematic reviewY. Jeve, R. Rana, A. Bhide, S. Thangaratinam
Limitations of current definitions of miscarriage using mean gestational sac diameter and crown–rump length measurements: a multicenter observational study
Y. Abdallah, A. Daemen, E. Kirk et al.Gestational sac and embryonic growth are not useful as criteria to define miscarriage: a multicenter observational study
Y. Abdallah, A. Daemen, S. Guha et al.Clinical implications of intra- and interobserver reproducibility of transvaginal sonographic measurements of
gestational sac and crown–rump length at 6–9 weeks gestationPexsters, J. Luts, D. Van Schoubroeck et al.
Volume 38, Issue 5, Date: November 2011, pages 489–515 (all articles)
Diagnosis of miscarriage on TVSDiagnosis of miscarriage on TVS
Royal College of Obstetricians and Gynaecologists(RCOG) 2006
• CRL ≥ 6mm with no visible cardiac activity
• MSD ≥ 20mm without a visible embryo or yolk sac
American College of Radiologists (ACR) 2000
• CRL > 5mm with no visible cardiac activity
• MSD > 16mm without a visible embryo or yolk sac
Society of Obstetricians and Gynaecologists of Canada (SOGC) 2005• CRL > 5mm with no visible cardiac activity
• MSD > 8mm without a visible yolk sac
• MSD > 16mm without a visible embryo
CRL, crown–rump lengthMSD, mean sac diameter
Current guidelines are based on weak or moderate level of evidence (small studies or opinion)
The current criteria used to diagnose miscarriage at ultrasound show variation
The accurate diagnosis of miscarriage is fundamental, as any error may be associated with
inadvertent termination of a viable pregnancy
Search of:1. MEDLINE (1951 to 2011)2. Embase (1980 to 2011) 3. Cochrane Library
720 citations reviewed, 23 met search criteria
Eight articles involving a total of 872 women were included
Accuracy of first-trimester ultrasound in the diagnosis of early embryonic demise: a systematic review
Jeve Y et al., UOG 2011
Jeve Y et al., UOG 2011 Nov
Results
Best criteriahave 95% CIrange of0.96 to 1.00
Conclusions• First systematic review of ultrasound diagnosis of miscarriage
• Studies are 15–20 years old, small numbers of miscarriage, reference standards were poor (method of miscarriage confirmation)
• Various cut-off values used (4–6mm for CRL, 13–25mm for MSD), making pooling of data impossible
• Best (most specific) criteria appeared to be MSD > 25mm with a missing embryo or MSD > 20mm with a missing yolk sac
• These criteria had a 95% CI of 0.96–1.00, therefore up to 4 out of 100
diagnoses of early fetal demise may be wrong
Jeve Y et al., UOG 2011 Nov
Conclusions
Limitations of current definitions of miscarriage using mean gestational sac diameter and crown–rump length measurements: a multicenter observational study
Abdallah Y et al., UOG 2011 (a)
Gestational sac and embryonic growth are not useful as criteria to define miscarriage: a multicenter observational study.
Abdallah Y et al., UOG 2011 (b)
Inclusion criteria:- Intrauterine pregnancy of uncertain viability (IPUV) at sonography- IPUV defined as an MSD < 20mm with no obvious yolk sac/embryo orCRL < 6mm with no fetal heart activity
Exclusion criteria:- women clinically unstable - women who subsequently underwent uterine evacuation
2D-transvaginal scans (6–12 MHz) at 0 and 7–14 days later
Multicenter observational study of 1060 women in four London hospitals
Abdallah Y et al., UOG 2011 (a)
Results: 1st scan cut-off values
1060 IPUV473 (44.6%) viable at 11–13-week scan587 (55.4%) non-viable at follow-up scans
Yolk sac - NOYolk sac - NOEmbryo - NOEmbryo - NO
MSD > 16mm FPR 4.4%MSD > 20mm FPR 0.5%MSD ≥ 21mm FPR 0%
Yolk sac - YESYolk sac - YESEmbryo - NOEmbryo - NO
MSD > 16mm FPR 2.6%MSD > 20mm FPR 0.4%MSD ≥ 21mm FPR 0%
1st scan
Yolk sac - YESYolk sac - YESEmbryo - YESEmbryo - YES
CRL > 4mm FPR 8.3%CRL > 5mm FPR 8.3%CRL ≥ 5.3mm FPR 0%
*FPR, false-positive rate for miscarriage at subsequent scans Abdallah Y et al., UOG 2011 (a)
Results: 2nd scan growth rate
1060 IPUVSubset of 359 patients where a gestational sac was seen on the second scan 7–14 days later
Significant overlap of MSD and CRL growth between viable and non-viable pregnancies
2nd scan
Failure to visualize a yolk sac or embryo on the follow-up scan was always associated with miscarriage
Abdallah Y et al., UOG 2011 (b)
Clinical implications of intra- and interobserver reproducibility of transvaginal sonographic measurement of gestational sac and crown–rump length at 6–9 weeks' gestation
Pexsters A et al., UOG 2011
Prospective cross-sectional study54 women at 6–9 weeks
• Observers blinded• CRL measured from the outer ends• Gestational sac measured in three planes• CRL and MSD measured twice by each observer
Pexsters A et al., UOG 2011
Results
• Based on 95% CI, for a given CRL of 6mm as measured by one observer, the second observer’s measurement may range from 5.4 to 6.7mm
• Similarly, given an MSD of 20mm as measured by one observer, the measurement for the second observer may range from 16.8 to 24.5mm
Summary• Data from these studies show that current definitions used to diagnose miscarriage are potentially unsafe
• Significant interobserver variability may be associated with a misdiagnosis of miscarriage
• Current national guidelines should be reviewed to avoid inadvertent termination of wanted pregnancy
• Large prospective studies with agreed reference standards are urgently required
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