prediction of early pregnancy outcomes

Narendra MalhotraJaideep Malhotra

Neharika Malhotra BoraRishabh Bora

Keshav Malhotrawww.malhotrahospitals.com

Outline of this PresentationUltrasound diagnosis of early pregnancy failure

Definition/TerminologiesSonographic criteriaGuidelines for diagnosis

IssuesCurrent Recommendations

Safe cut off levelFollow up

Definite signs of Early Pregnancy Failure

• Absence of cardiac activity in an embryo-Embryonic demise

• Absence of yolk sac/embryo in a large GS-Blighted ovum

FAILED PREGNANCY

Definite signs of Early Pregnancy Failure

What is the descriminatory size for safe diagnosis?

Mean Sac diameterCRL

Definite signs of Early Pregnancy Failure

What is the descriminatory size for safe diagnosis?

TAS TVSGestational sac(MSD)

> 20mm with out YS > 8mm without YS

> 25mm without cardiac activity

>16mm without embryo cardiac activity

Nyberg, 1986 Threatened Abortion: Sonographic distinction of normal and abnormal pregnancy

Definite signs of Early Pregnancy Failure

What is the descriminatory size for safe diagnosis?

TAS TVSEmbryo(CRL)

> 8mm1 > 4mm 2 > 5mm 1,3

1 Pennell, 1991 Prospective comparison of vaginal and abdominal sonography in normal early pregnancy

2 Levi, 1990TVS: Demonstration of cardiac activity in embryos of less than 5mm in CRL

3 Brown, 1990Diagnosis of early embryonic demise by TVS

GUIDELINES FOR DIAGNOSISOF EARLY PREGNANCY FAILURE

Royal College of Obstetricians and Gynaecologists(RCOG) 2006

• CRL ≥ 6mm with no visible cardiac activity

• MSD ≥ 20mm without a visible embryo or yolk sac

Society of Obstetricians and Gynaecologists of Canada (SOGC) 2005

• CRL > 5mm with no visible cardiac activity, >9mm(TAS)

• MSD > 8mm without a visible yolk sac, 20mm (TAS)

• MSD > 16mm without a visible embryo, (25mm (TAS)

LEVEL 11-2 a

AIUM, 2007• CRL > 5mm (TVS) with no visible cardiac activity

American College of Radiologists (ACR) 2000

• CRL > 5mm with no visible cardiac activity

• MSD > 16mm without a visible embryo or yolk sac

GUIDELINES FOR DIAGNOSISOF EARLY PREGNANCY FAILURE

Practice in the Philippines

• CRL > 5mm with no visible cardiac activity

• MSD > 18mm without a visible embryo or yolk sac

Australian Society for Ulltrasound in Medicine (ASUM)

• CRL > 6mm with no visible cardiac activity

• MSD > 20mm without a visible embryo or yolk sac

Hongkong College of Obstetricians and Gynaecologists(HKCOG) 2004

• CRL > 5mm (TVS), >9mm (TAS) with no visible cardiac activity

• MSD ≥ 20mm without a visible embryo or yolk sac

OB-GYN USG for practicing Clinician 2nd Ed

FOGSI GUIDELINES A FEW YEARS BACK MSD >20without YS/E :CRL >6mm without cardiac activityIFUMB/ICMU and ICOG

Author Type of Study Study Pop (n) Exam Sonographic criteria used

Nyberg (1986) Cohort, Retrospective

168 TAS No embryo, MSD >25mm, No yolk sac, MSD > 20mm

Nyberg (1987) Cohort Prospective

83 TAS No embryo, MSD >25mm, No yolk sac, MSD > 20mm

Scott (1987) CohortProspective

102 TAS Empty GS > 26mm

Levi (1988) CohortProspective

55 TVS No YS and MSD > 8mmNo embryo, cardiac > 16mm

Levi (1990) Cohort retrospective

71 TVS No cardiac activity, CRL < 5mm

Best criteriahave 95% CIrange of0.96 to 1.00

Best criteria:An empty gestational sac > 25mmMissing yolk sac with gestational sac > 20mm:

Specificity 1, 95% CI range of 0.96 to 1.00***Up to 4 in every 100 diagnosis may be false positive

Inclusion criteria:- Intrauterine pregnancy of uncertain viability (IPUV) at sonographyIPUV defined as an MSD < 20mm with no obvious yolk sac/embryo orCRL < 6mm with no fetal heart activity

2D-transvaginal scans (6–12 MHz) at 0 and 7–14 days later

MSD 16mm: FPR (viable pregnancy): 4.4%

MSD 20mm: FPR is 0.5%

MSD 21mm: vFPR is 0

CRL 4mm and 5mm: FPR= 8.3%CRL 5.3mm: FPR=0

** There are still a number of cases at or around the critical decision boundaries(descriminatory level) used to define miscarriage.

** There is a need to increase the cut off level to a safer level.

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

• 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

RECOMMENDATIONS

Empty GS = an MSD of 25 mm with out yolk sac or embryo

Embryonic demise= A CRL of 7mm with no cardiac activity

Wait for 7-10 days before a repeat scan if results arebelow the descriminatory level.

SUMMARY The current criteria used to diagnose miscarriage at ultrasound show variation.

Current guidelines are based on weak or moderate level of evidence (small studies or opinion).

Diagnosis of Early Pregnancy Failure

The descriminatory size of 5mm for CRL and 20mm for GS may be unsafe cut off levels and may result to inadvertent termination of pregnancy.

SUMMARY

A new cut off level of MSD of 25mm empty sac and CRL of 7mm without cardiac activity to make a diagnosis of pregnancy level is being considered

Diagnosis of Early Pregnancy Failure

National guidelines should be reviewed, a diagnosis of pregnancy failure should have no chance of error (100% specificity).