Final draft perinatal institute

Obstetric Ultrasound for Evaluation of Fetal Growth 22nd June 2014 Lorraine Walsh Aims • • • • • • Rationale Scanning protocol, HC, AC, FL Accuracy of measurements Audit Factors affecting quality of ultrasound Implications for workforce Rationale Not done routinely Biometric tests (measuring fetal size) are designed to predict fetal size at a point in gestation If performed periodically can indicate growth but not fetal well being Biophysical tests (Doppler / liquor assessment) can predict fetal well being but not growth Why we assess growth? “Fetal growth restriction is the single largest category of conditions associated with stillbirth and is found in the majority of the cases previously considered unexplained” Using Classification of stillbirth by relevant condition at death (ReCoDe) Gardosi et al 2005 Importance of Good Scanning • Unexplained perinatal death may be regarded as unavoidable • However death after IUGR raises possibility of being avoided with better recognition, investigation and management • Affect management of future pregnancies Past obstetric history of a SGA baby- at least a twofold risk increase of a subsequent SGA baby RCOG Green-top Guideline 31 2013/14 Role of Ultrasound in diagnosis of IUGR Three important criteria needed; Accurate gestational age Estimated fetal weight – ( HC, AC and FL or AC and FL Charts-Hadlock et al 1985) A weight percentile calculated from the estimated weight and gestational age (CGC) Third Trimester growth scan          Fetal heart Presentation and fetal lie HC / AC / FL Estimated fetal weight Placenta Liquor volume (SDVP/AFI) Doppler Fetal movements and FBM Report MEASUREMENTS HC , AC AND FL BPD “BPD should not be used in routine clinical practice for the estimation of gestational age or the appropriateness of fetal size in later pregnancy” Loughna et al 2009 INTERGROWTH-21st • The International Fetal and Newborn Growth Consortium for the 21st Century • Large scale population based multicentre observational project of fetal and newborn growth across countries • Serial fetal growth scans every +/- 1week from 14 to 42 weeks • BPD OFD HC (ellipse) APAD TAD AC ( ellipse) FL • ( Head measurements made at trans thalamic section BPD – outer to outer) Accuracy of Ultrasound • “Ultrasound fetal weight estimation is currently the most accurate method available in clinical practice for the obese and non-obese pregnant women • Despite this, errors in weight estimation of ± 20% are possible and must be borne in mind when decisions regarding obstetric management are formulated” Farrell et al 2002 West Midlands Regional Ultrasound Workforce Report 2013 • • • • • • Shortage of sonographers Aging workforce Increasing demands day working Affecting training of future staff Increased birth-rate Young Population and Increasing Birth-rate SGA fetus should be examined closely  Structural abnormalities may not develop until later pregnancy • Craniospinal abnormalities • Intestinal obstruction/atresia • Urinary tract abnormalities • Skeletal abnormalities  Chromosomal abnormalities “The recognition of IUGR in late pregnancy must always trigger a re-evaluation of the apparent normality of the foetus” Bricker et al 2009 Why don’t we scan all babies? Sensitivity • The ability to identify those subjects who have the disease • High sensitivity means that the test ‘catches’ as many people with the condition as possible • It is measured as the proportion of those with the condition, who have a positive test result Specificity • The ability to identify those subjects who not have the disease • High specificity means the test has as few false positives as possible RCOG Green Top Guideline No 31 US to assess growth Low risk population • Sensitivity varies from 0-10% • Specificity 66-99% US to assess growth High risk population Fetal AC ˂ 10th Centile • Sensitivity ranging 72.9 94.5% • Specificity 50.6-83.6% EFW˂ 10th Centile • Sensitivity ranging 33.3 – 89.2% • Specificity 52.7 – 90.7% How can we improve Accuracy of Ultrasound • Audit US to confirm best practise:  Standardisation of measurements  Quality of sections used for measurements  Accuracy of ultrasound in EFW • Quality of Equipment  Use all pre and post processing facilities  Application specialist Summary • • • • • • Rationale Scanning protocol, HC, AC, FL Accuracy of measurements Audit Factors affecting quality of ultrasound Implications for workforce Conclusion “With well designed modern equipment, standardised methods and well trained, experienced and conscientious sonographers, it may be possible to eliminate systematic error and reduce random errors to less than 5% for EFW” Dudley 2013 References • • • • • • Benacerraf, B (2013) The use of obstetrical ultrasound in the obese gravida Seminars in Perinatology, 37(5), pp.345-7 Birmingham Fetal Growth Audit West Midlands Perinatal Institute, 2007 Available at: http://www.pi.nhs.uk/ultrasound/Birmingham_FGR_Audit Summary.pdf Bricker, L., Mahsud-Dornan, S., Dornan, J C., (2009 ) Detection of foetal growth restriction using third trimester ultrasound Best Practice & Research Clinical Obstetrics & Gynaecology, 23(6), December 2009, Pp 833-844, (http://www.sciencedirect.com/science/article/pii/S1521693409001047) Chitty LS, Altman DG, Henderson A, Campbell S (1994) Charts of fetal size: Abdominal measurements Br J Obstet Gynaecol 101 (2),pp.125– 31 Dudley, N J 2013 A review of ultrasound fetal weight estimation in the early prediction of low birthweight Ultrasound ,21(4) pp181-186 Dudley N J and Chapman, S (2002) The importance of quality management in fetal measurement Ultrasound in Obstetrics & Gynaecology ,2002; 19 (2): pp190–196 References • • • • • Farrell, T., Holmes, R and Stone, P (2002) The effect of body mass index on three methods of fetal weight estimation (2002) BJOG: An International Journal of Obstetrics & Gynaecology,109(6), pages 651–657, June 2002 Fetal Growth Assessment & Implementation of customised charts available online at http://www.perinatal.nhs.uk/growth/index_growth.htm Francis, A., Tonks, A and Gardosi J (2011) Accuracy Of Ultrasound Estimation Of Fetal Weight At Term Archives of Disease in Childhood Fetal and Neonatal Edition, Available at: http://fn.bmj.com/content/96/Suppl_1/Fa61.1.abstract Gakidou et al Global, regional, and national prevalence of overweight and obesity in children and adults during 1980—2013: a systematic analysis for the Global Burden of Disease Study 2013 The Lancet 2014 available at: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)604608/fulltext Gardosi, J, Madurasinghe, V., Williams, M., Malik, A and Francis, A (2013) Maternal and fetal risk factors for stillbirth : population based study BMJ, Vol.346 Available at: http://www.bmj.com/content/346/bmj.f108 References • • • • • Gardosi J, Kady SM, McGeown P, Francis A, Tonks A (2005) “Classification of stillbirth by relevant condition at death (ReCoDe): population based cohort study” BMJ 331(7525): pp1113-7 Gardosi, J (2009) Intrauterine growth restriction: new standards for assessing adverse outcome Best Practice Research Clinical Obstetrics and Gynaecology 23(6),pp741-9 Hadlock, F P., Harrist, R B., Sharman, R S., Deter, R L., & Park, S K (1985) Estimation of fetal weight with the use of head, body, and femur measurements—a prospective study American journal of obstetrics and gynecology, 151(3) pp.333-337 Hargreaves, K., Cameron, M., Edwards, H., Gray,R., and Deane K ( 2011) Is the use of symphysis-fundal height measurement and ultrasound examination effective in detecting small or large fetuses? Journal of Obstetrics and Gynaecology, 31(5) pp.380-383 Health Education West Midlands (2014) West Midlands Regional Ultrasound Workforce Report 2013-2018 Available at: wm.hee.nhs.uk/wp /Enc.-9-Sonography-Workforce-Shortages.pdf References • • • • • Loughna P, Chitty L, Evans T and Chudleigh T (2008) Fetal size and dating: charts recommended for clinical obstetric practice Ultrasound , 17(3) pp.160-166 National Institute for Clinical Excellence (2002 ) Principles for Best Practice in Clinical Audit Radcliffe Medical Press available at http://www.nice.org.uk/media/796/23/BestPracticeClinicalAudit.pdf/ Paladini, D ( 2009) Sonography in obese and overweight pregnant women: clinical, medicolegal and technical issues Ultrasound in Obstetrics and Gynaecology, 33(6) pp720-729 RCOG Green-top Guideline No 31 February 2013 “Small-for-GestationalAge Fetus, Investigation and Management.” Sarris, I., Ioannou, C., Chamberlain, P., Ohuma, E., Roseman, E., Hoch, l., Altman, D.G., and Papageorghiou A T (2012) Intra- and interobserver variability in fetal ultrasound measurements Ultrasound Obstet Gynecol , 39 (3): pp 266–273 References • • • Sarris, I., Ioannou, C., Dighe, M., Mitidieri, A., Oberto, M., Qingqing, W., Shah, J., Sohoni, S., Al Zidjali, W., Hoch, L., Altman, D G., Papageorghiou, A T and for the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st) (2011), Standardization of fetal ultrasound biometry measurements: improving the quality and consistency of measurements Ultrasound Obstet Gynecol, 38: 681–687 doi: 10.1002/uog.8997 The Nursing and Midwifery Council (2008) The code: Standards of conduct, performance and ethics for nurses and midwives Available at: http://www.nmc-uk.org/Publications/Standards/The-code/Provide-a-highstandard-of-practice-and-care-at-all-timesWest Midlands Regional Ultrasound Group (2003) West Midlands obstetric ultrasound biometry audit Available at: http://www.pi.nhs.uk/ultrasound/standards/RUG%20standards%20report%2 0summary.pdf ... relevant condition at death (ReCoDe) Gardosi et al 2005 Importance of Good Scanning • Unexplained perinatal death may be regarded as unavoidable • However death after IUGR raises possibility of