FETAL GROWTH STANDARDS AND BIRTH WEIGHT REFERENCE TABLES THROUGHOUT EUROPE: WHICH ONES DO OBSTETRICIANS USE?

FETAL GROWTH STANDARDS AND BIRTH WEIGHT REFERENCE TABLES THROUGHOUT EUROPE: WHICH ONES DO OBSTETRICIANS USE? Class 15 Introdução à Medicina I / II 2010/2011 mimedturma15@googlegroups.com

SUMMARY • Introduction • Motivation • Aims • Methods • Expected results • Results • Conclusions • Discussion • Acknowledgments 2

INTRODUCTION WOMEN ARE MONITORED DURING PREGNANCY Estimation of fetal weight Prevent newborn complications and intrauterine death [Freire, Diacyr Magna Cabral et al. BrasGinecolObstet. 2010] Detect a normal or an abnormal fetal growth Predict some problems and diseases: • - Single umbilical artery (SUA) • - Renal failure • - Type 2 diabetes mellitus • - Metabolic syndrome • - Osteoporosis • - Dyslipidemia [C. N. Hales et al. Diabetologia. 2003] [C. N. Hales et al. Diabetologia. 2003] [Briana DD et al. Eur J Endocrinol. 2009] [Briana DD et al. Eur J Endocrinol. 2009] [Briana DD et al. Eur J Endocrinol. 2009] [Briana DD et al. Eur J Endocrinol. 2009] Gluckman PD and others. Effect of in uterus and early-life conditions on adult health and disease. The New England Journal Of Medicine 2008 3

INTRODUCTION WOMEN ARE MONITORED DURING PREGNANCY Use of different methods to measure parameters • - Palpation methods [Belete W., Gaym A. EthiopMed. J. 2008] • - Ultrasonography[Nardozza, Luciano Marcondes Machado, et al. Ver. Assoc. Med. Bras. 1992] Use of different formulas • - Shepard’s formula [Nardozza, Luciano Marcondes Machado, et al. Ver. Assoc. Med. Bras. 1992] • - Hadlock’s formulas [Nardozza, Luciano Marcondes Machado, et al. Ver. Assoc. Med. Bras. 1992] • - … Estimation of fetal weight 4

INTRODUCTION Fetal weight study Use of different fetal weight tables (relating gestation weekand fetal weight) Different Population Samples Figure 1. The Babson and Benda 1976 "fetal-infant growth graph“ – The fetal growth chart most commonly used in NICU’s (Neonatal Intensive Care Unit).

INTRODUCTION POPULATION REFERENCES AND/OR FETAL GROWTH STANDARDS • Population references are based on both low-risk and high-risk pregnancies and both normal and abnormal perinatal outcomes • Fetal growth standards are based on low-risk pregnancies with a normal outcome

INTRODUCTION HOWEVER, THERE ARE… Plenty of variables (population and ethnicity differences, gender, maternal factors, variations in fetal composition)[Gardosi J et al. Gynecol 6. 1995] Influence the outcome (different factors will lead to existence of populations with their particular characteristics) [David RJ, Collins et al. New England Journal of Medicine. 1997] In order to reach an adequate diagnosis, the chosen reference table must be adapted to the fetus’ characteristics [Romano-Zelekha O. et al. Prenat. Diagn. 2005]

INTRODUCTION Different tables – Different curves Different characteristics of the fetus Male/ Female; Firstborn/ Nonfirstborn; White/ Black mothers. B A Figure 3Distribution of birth weight on 3 different situations [1] A - Male/ Female; B - Nonfirstborn/ Firstborn; C - White/ Black mothers. Use of different curves C

MOTIVATION • It is important to monitor the fetal growth • It is important to adequate the fetal weight tables to the population • There are some studies about fetal weight tables used on some countries: • - Pakistan[Munim S. et al. J Obstet Gynaecol Res. 2010]; • - Turkey[Donma MM et al. Ultrasound Med Biol 2005]; • - Nigeria [Shittu AS et al. J Health Popul Nutr. 2007]; • - United States [Ananth CV et al. Paediatr Perinat Epidemiol 2007]; • - … BUT There are no studies about the tables used in Europe

SUMMARY • Introduction • Motivation • Aims • Methods • Expected results • Results • Conclusions • Discussion • Acknowledgments

AIMS • Assess which fetal growth standards or birth weight reference tables are used throughout 20 European countries; • Analize how fetal growth standards or birth weight reference tables are used throughout 20 European countries.

METHODS 1. Study participants • Hospitals with more than 1500 births per year from the following European countries: No information was found about the number of births per year in each hospital from these countries. • Germany • Italy • Luxembourg • Netherlands • Norway • Portugal • Spain • Austria • Belgium • Czech Republic • Denmark • Finland • France • Sweden • Switzerland • Republic of Ireland • United Kingdom: England, Scotland, Wales and Northern Ireland

METHODS 1. Study participants Whythosecountries? • To represent a significant sample of European hospitals; • To have similarity to Portuguese hospitals. Why 1500 births per year? • To have a homogeneous sample of the population; • Hospitals with higher number of births are more specialized, offering therefore obstetric and neonatology services.

METHODS 1.1. SearchtheEuropeanHospitals Search on the National Statistic Site/National Health Service of each country No information was found All the information was found Send an e-mail to each country’s Statistic Center/National Health service asking the list of the hospitals with more than 1500 births Collect the Information

METHODS 1.1. SearchtheEuropeanHospitals Amongallthehospitalswithover1500 birthsineachcountry Representative sample If the country had less than 20 hospitals (with more than 1500 births) If the country had more than 20 hospitals (with more than 1500 births) 20 wererandomlychosenandcontacted Allwerecontacted

METHODS 1.2 InclusionandExclusioncriteria Exclusion Inclusion • The selected hospital closed or the department was moved to another hospital; • The hospital does not have both obstetric/gynecology and neonatology/pediatric department; • The hospital does not have any contact available. • European hospital; • ≥ 1500 births per year in the last national statistic available;

METHODS1.3 Samplesdefinition Population (hospitalswith more than 1500 births per yearfromtheselectedcountries) • 620 Intended sample 240 Surveyanswers • 44 19

METHODS 2. DATA COLLECTION METHODS 1. Contact the Obstetric’s Department of each hospital • An e-mail with a link of the site where the online survey could be answered was sent SURVEY

METHODS 2. Data collection methods If no answers are received within 2 weeks… If the hospital still does not reply… Attribute a missing value to the hospital 2. Re-send the e-mail If no answers are received within 1 week… 3. Call the hospital’s Obstetric Department asking an e-mail survey answer If no answers are received within 1 week… 4. Do the survey by phone 21

METHODS 3. Statisticalanalyses • IBM SPSS Statistics 19 (Statistical Data Analyses) was used to make a descriptive analysis of the results. • Microsoft Excel 2010 was used to build the graphics.

SUMMARY • Introduction • Motivation • Aims • Methods • Expectedresults • Results • Conclusions • Discussion • Acknowledgments 23

EXPECTED RESULTS • Havelowpercentageof responses fromtheEuropeanhospitals; • GetmanydifferenttypesoftablesusedthroughoutEurope; • Have a fewthat are more commonlyusedineveryselectedEuropeancountries; 24

RESULTS • 18% (n=44) obtained answers • 79% of those surveyed were physicians 87% (n=38) by e-mail 11% (n=5) byphone 2% (n=1) presentialy

RESULTS 1. Percentage of answers in each country Norway (n=14) 7% Finland (n=14) 7% Scotland (n=12) 25% England (n=20) 15% Sweden (n=20) 40% Northern Ireland (n=5) Republic of Ireland (n=19) 16% Denmark (n=18) 28% Wales (n=9) Czech Republic (n=17) 12% Belgium (n=11) Luxembourg (n=2) France (n=20) Austria (n=14) 21% Switzerland (n=5) 40% Portugal (n=20) 60% No answers (0%) Spain (n=20) 5% At leat one answer (5 to 60%)

p = 0,059* Xbirths = 2722 Births in 2010 *Chi-square RESULTS 2. RELATION BETWEEN “NUMBER OF BIRTHS” AND “NUMBER OF TABLES USED”

RESULTS 3. FREQUENCIES

RESULTS 4. TABLES/GROWTH STANDARDS MOST COMMONLY USED Yudkin 1 Jeanty 1 Fenton 1 Hadlock 10 Doubilet 1 2 Lubchenco 1 National 10 Local 1 1 3 1 Other 4 Yudkin 1

RESULTS 4. TABLES/GROWTH STANDARDS MOST COMMONLY USED • Marsal K, Persson P-H, Larsen T, Lilja H, Selbing A, Sultan B, Intrauterine growth curves based on ultrasonocally estimated foetal weights. Acta Pædiatr 1996; 85: 843-848 • Lähde: Pihkala J, Hakala T, Voutilainen P, Raivio K. Uudet suomalaiset sikiön kasvukäyrät. Duodecim 1989:105;1540-6 • Persson P-H, Weldner B-M: Intra-uterine weight curves obtained by ultrasound. Acta Obstet Gynecol Scand 1986; 65: 169-173 • Chitty et al (1994) Abdominal Circumference Charts • Gjessing HK, Grøttum and Eik-Nes 2007 • British Medical Ultrasound Society (BMUS) reference charts (Chitty charts)

RESULTS 5. VARIABLES ASSESSED FOR CHOOSING A TABLE/GROWTH STANDARD Mother’s weight 4 Ethnicity 4 Mother’s parity 3 Mother’s smoking status 1 Other 3 • Size of the fetus; • Height; • Paternal and maternal biotype. • For this statistic, only the hospitals which answered “yes” to the question “Do you use different fetal growth standards/reference tables in order to adjust for any fetal/maternal variables?” were analysed.

RESULTS 6. REASONS FOR USING THE TABLE/GROWTH STANDARD

CONCLUSIONS • The majority of the surveyed regularly use fetal growth standards/reference tables (and those are the same for all the obstetricians in the department); • The fetal growth standards/reference tables most commonly used throughout Europe are Hadlock and National Curves (specific for each country); • Although some hospitals use more than one table, there is no observed association between the number of births and the number of different tables used;

CONCLUSIONS • The majority of the surveyed agree that the fetal growth standards/reference tables should be appropriate to the population (and they also believe they use the most apropriate one). • However, a high percentage does not adjust the table/standard to the fetal/maternal characteristics

DISCUSSION • Germany, Italy and Netherlands are relevant countries. However, no information was found about the number of births per hospital and thus they are not included in the study; • France and Belgium are relevant countries that were contacted but that did not answered; • The high percentage of responses from Portugal comparing to other countries may affect the final results; • Some answers were obtained by phone/presentially and ideally they all should had been obtained by e-mail;

DISCUSSION • Although the majority of the hospitals consider important to adequate the standard/table to the population, most of them do not adjust it to the fetal/maternal characteristics. Thus, we think that it is important to achieve a higher awareness about the importance of this adjustment; • Regarding to the question about the main fetal growth standard/reference table used, some selected the option ‘National’ and specified a curve that is not country-specific, although it is probably used throughout all the hospitals in the country.

ACKNOWLEDGMENTS 41 41 • Prof. Mário Dinis Ribeiro • Dr. Ricardo Santos • Francisco Ribeiro Mourão • Prof. Dr. Altamiro da Costa Pereira • Engineer Jorge Jácome • CIDES • National Health Services/National Statistic Centers

FETAL GROWTH STANDARDS AND BIRTH WEIGHT REFERENCE TABLES THROUGHOUT EUROPE: WHICH ONES DO OBSTETRICIANS USE?