Population attributable fractions of perinatal outcomes for nulliparous women associated with overweight and obesity, 1990–2014

Kate Cheney, Rachel Farber, Alexandra L Barratt, Kevin McGeechan, Bradley de Vries, Robert Ogle and Kirsten I Black
Med J Aust 2018; 208 (3): 119-125. || doi: 10.5694/mja17.00344


Objective: To examine the prevalence across 25 years of overweight and obesity among nulliparous Australian women during early pregnancy; to estimate the proportions of adverse perinatal outcomes attributable to overweight and obesity in this population.

Design: Cohort study; retrospective analysis of electronic maternity data.

Setting, participants: 42 582 nulliparous women with singleton pregnancies giving birth at the Royal Prince Alfred Hospital, an urban teaching hospital in Sydney, January 1990 – December 2014.

Main outcome measures: Maternal body mass index (BMI), socio-demographic characteristics, and selected maternal, birth and neonatal outcomes; the proportion of adverse perinatal outcomes that could be averted by reducing the prevalence of overweight and obesity in women prior to first pregnancies (population attributable fraction, PAF).

Results: The prevalence of overweight among nulliparous pregnant women increased from 12.7% (1990–1994) to 16.4% (2010–2014); the prevalence of obesity rose from 4.8% to 7.3% in the same period, while the proportion with normal range BMIs fell from 73.5% to 68.2%. The PAFs for key adverse maternal and neonatal outcomes increased across the study period; during 2010–2014, 23.8% of pre-eclampsia, 23.4% of fetal macrosomia, and 17.0% of gestational diabetes were attributable to overweight and obesity. Were overweight and obese women to have moved down one BMI category during 2010–2014, 19% of pre-eclampsia, 15.9% of macrosomia, 14.2% of gestational diabetes, 8.5% of caesarean deliveries, 7.1% of low for gestational age birthweight, 6.8% of post partum haemorrhage, 6.5% of admissions to special care nursery, 5.8% of prematurity, and 3.8% of fetal abnormality could have been averted.

Conclusions: Over the past 25 years, the proportions of adverse perinatal outcomes attributable to overweight and obesity have risen with the increasing prevalence of maternal overweight and obesity. A substantial proportion of these outcomes might be averted with obesity prevention strategies that reduce pre-pregnancy maternal weight.

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  • Kate Cheney1
  • Rachel Farber2
  • Alexandra L Barratt2
  • Kevin McGeechan2
  • Bradley de Vries1,3
  • Robert Ogle1
  • Kirsten I Black1,3

  • 1 Royal Prince Alfred Hospital, Sydney, NSW
  • 2 Sydney School of Public Health, University of Sydney, Sydney, NSW
  • 3 University of Sydney, Sydney, NSW

Competing interests:

No relevant disclosures.

  • 1. NCD Risk Factor Collaboration. Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19.2 million participants. Lancet 2016; 387: 1377-1396.
  • 2. Ng M, Fleming T, Robinson M, 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. Lancet 2014; 384: 766-781.
  • 3. Ma RCW, Schmidt MI, Tam WH, et al. Clinical management of pregnancy in the obese mother: before conception, during pregnancy, and postpartum. Lancet Diabetes Endocrinol 2016; 4: 1037-1049.
  • 4. McIntyre HD, Gibbons KS, Flenady VJ, Callaway LK. Overweight and obesity in Australian mothers: epidemic or endemic? Med J Aust 2012; 196: 184-188. <MJA full text>
  • 5. Godfrey KM, Reynolds RM, Prescott SL, et al. Influence of maternal obesity on the long-term health of offspring. Lancet Diabetes Endocrinol 2017; 5: 53-64.
  • 6. World Health Organization. Consideration of the evidence on childhood obesity for the Commission on Ending Childhood Obesity: report of the ad hoc working group on science and evidence for ending childhood obesity, Geneva: WHO, 2016. (viewed June 2017).
  • 7. Flegal KM, Panagiotou OA, Graubard BI. Estimating population attributable fractions to quantify the health burden of obesity. Ann Epidemiol 2015; 25: 201-207.
  • 8. Oteng-Ntim E, Kopeika J, Seed P, et al. Impact of obesity on pregnancy outcome in different ethnic groups: calculating population attributable fractions. PLoS One 2013; 8: e53749.
  • 9. MacInnis N, Woolcott CG, McDonald S, Kuhle S. Population attributable risk fractions of maternal overweight and obesity for adverse perinatal outcomes. Sci Rep 2016; 6: 22895.
  • 10. New South Wales Ministry of Health. NSW mothers and babies 2014. Sydney: NSW Ministry of Health, 2016. (viewed Nov 2017).
  • 11. Rasmussen KM, Yaktine AL (ed). Weight gain during pregnancy: reexamining the guidelines. Washington (DC): National Academies Press, 2009. (viewed Nov 2017).
  • 12. Australian Bureau of Statistics. 2033.0.55.001. Census of Population and Housing: Socio-Economic Indexes for Areas (SEIFA), Australia, 2011 (tab, Past & future releases). Mar 2013. (viewed Nov 2017).
  • 13. Australian Bureau of Statistics. 1269.0. Standard Australian Classification of Countries (SACC), 2016. June 2016. (viewed Nov 2017).
  • 14. Hoffman L, Nolan C, Wilson JD, et al. Gestational diabetes mellitus — management guidelines. Med J Aust 1998; 169: 93-97. <MJA full text>
  • 15. Lowe SA, Brown MA, Dekker GA, et al. Guidelines for the management of hypertensive disorders of pregnancy 2008. Aust N Z J Obstet Gynaecol 2009; 49: 242-246.
  • 16. Perinatal Society of Australia and New Zealand. Perinatal mortality classifications. In: PSANZ Perinatal Mortality Group, Clinical practice guideline for perinatal mortality. Second edition, version 2.2. (viewed Nov 2017).
  • 17. WHO: recommended definitions, terminology and format for statistical tables related to the perinatal period and use of a new certificate for cause of perinatal deaths. Modifications recommended by FIGO as amended October 14, 1976. Acta Obstet Gynecol Scand 1977; 56: 247-253.
  • 18. Villar J, Papageorghiou AT, Pang R, et al. The likeness of fetal growth and newborn size across non-isolated populations in the INTERGROWTH-21 Project: the Fetal Growth Longitudinal Study and Newborn Cross-Sectional Study. Lancet Diabetes Endocrinol 2014; 2: 781-892.
  • 19. Rockhill B, Newman B, Weinberg C. Use and misuse of population attributable fractions. Am J Public Health 1998; 88: 15-19.
  • 20. Levin ML. The occurrence of lung cancer in man. Acta Unio Int Contra Cancrum 1953; 9: 531-541.
  • 21. Gaudet L, Ferraro ZM, Wen SW, Walker M. Maternal obesity and occurrence of fetal macrosomia: a systematic review and meta-analysis. Biomed Res Int 2014; 2014: 640291.
  • 22. WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 2004; 363: 157-163.
  • 23. Brownfoot F, Davey MA, Kornman L. Routine weighing to reduce excessive antenatal weight gain: a randomised controlled trial. BJOG 2016; 123: 254-261.
  • 24. Allen-Walker V, Woodside J, Holmes V, et al. Routine weighing of women during pregnancy — is it time to change current practice? BJOG 2016; 123: 871-874.
  • 25. Australian Health Ministers’ Advisory Council. Clinical practice guidelines: antenatal care — module 1. Canberra: Australian Government Department of Health and Ageing, 2012.$File/ANC_Guidelines_Mod1_v32.pdf (viewed Nov 2017).
  • 26. Dodd J, Turnbull D, McPhee A, et al. Limiting weight gain in overweight and obese women during pregnancy to improve health outcomes: the LIMIT randomised controlled trial. BMC Pregnancy Childbirth 2011; 11: 79.
  • 27. Poston L, Bell R, Croker H, et al. Effect of a behavioural intervention in obese pregnant women (the UPBEAT study): a multicentre, randomised controlled trial. Lancet Diabetes Endocrinol 2015; 3: 767-777.
  • 28. Frayne DJ, Verbiest S, Chelmow D, et al. Health care system measures to advance preconception wellness: consensus recommendations of the Clinical Workgroup of the National Preconception Health and Health Care Initiative. Obstet Gynecol 2016; 127: 863-872.
  • 29. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists. Management of obesity in pregnancy: College statement C-Obs 49. Updated Mar 2017.,-Management-of-(C-Obs-49) (viewed July 2017).
  • 30. Talley N. National Health Summit on Obesity calls for Australia to take action to stem the pandemic. Med J Aust 2017; 206: 106-107. <MJA full text>


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