Women ’ s Perception of BMI and Knowledge of Weight Gain in Pregnancy Guidelines

1. Women’s Perception of BMI and Knowledge of Weight Gain in Pregnancy Guidelines Emma Jeffs1, Joanna Gullam2, Benjamin Sharp3, Helen Paterson1 1 Department of Women’s and Children’s Health, Dunedin School of Medicine, University of Otago, New Zealand. 2 Department of Obstetrics and Gynaecology, Christchurch School of Medicine, University of Otago, New Zealand. 3 Department of Obstetrics and Gynaecology, Christchurch Women’s Hospital, New Zealand Contact: emma.jeffs@cdhb.govt.nz Background Results continued • Measured vs. perceived BMI • 2% (n=7) of participants identified themselves as underweight, 70% (n=285) as normal weight, 26% (107) as overweight and 2% (n=8) as obese • Obese women were most likely to incorrectly identify their BMI with 12 perceiving themselves as normal weight, 50 as overweight and only 8 as obese (p<0.0001) • Knowledge of weight gain in pregnancy guidelines • Overweight and obese individuals today are more likely to consider themselves to be of normal weight than overweight and obese individuals 20 years ago[1], and individuals of all BMI groups are more likely to identify increased body size as normal[2], indicating an upward shift in the social norms of body weight • Women of childbearing age are particularly susceptible to misperception of own their body weight, with estimates suggesting nearly 25% of overweight women underestimate their own weight[3] • Individuals who underestimate their weight are more likely to have a decreased perception of health risk related to their body size and are consequently less likely to desire weight change and to participate in healthy behaviours, such as physical activity[2] • To assess the perceptions women in early pregnancy have of their own BMI and their knowledge of appropriate weight gain guidelines for pregnancy • A cross sectional survey of 411 pregnant women attending a nuchal translucency scan at 11 to 13+6 weeks gestation in community radiology units in Christchurch was carried out over a three month period in 2011 • Women completed a questionnaire to establish basic demographics including parity, whether they had been weighed during this pregnancy and a question asking them to identify their BMI status (underweight, normal weight, overweight or obese) • Participants were asked what the appropriate weight gain for themselves during their pregnancy would be. Options included the 2009 Institute of Medicine (IOM) weight gain in pregnancy guidelines and the answers ‘I should not gain any weight’ and ‘it does not matter how much weight I gain’ • Participants had their height and weight measured using calibrated equipment and their BMI calculated • Statistical significance was calculated using a Chi Squared Test Objective Methods • 24% (n=35) of underweight / normal weight women identified the recommended weight gain in pregnancy as did 44.7% (n=42) of overweight participants and 27.9% (n=17) of obese participants • Appropriate weight gain in pregnancy was overestimated by 72% (n=44) of obese women • Overweight and obese participants were significantly more likely to overestimate recommended weight gain for pregnancy compared to underweight / normal weight participants (p<0.0001) Results • Participants’ age ranged from 17-50 years (mean 31) • 50%of women were multiparous • 53% of women had a university qualification • Ethnicity; 75% New Zealand European, 5% Asian, 4.5%, Maori and 15.5% ‘other’ • 60% of women had been weighed during this pregnancy Conclusion Women incorrectly identify their BMI and are not having their BMI’s calculated by their maternity carers. The majority of women are not aware of the amount of weight the IOM guidelines recommend gaining during pregnancy. Obese women were more likely to overestimate appropriate weight gain during pregnancy and to incorrectly identify their BMI. References 3 Rahman, M. and A. Berenson, Self-perception of weight and its association with weight-related behaviours in young, reproductive age women. Obstetrics and Gynecology, 2010. 116(6): p. 1274-1280. 1 Burke, M., F. Heiland, and C. Nadler, From "overweight" to "about right": evidence of a generational shift in body weight norms. Obesity, 2010. 18: p. 1226-1234. 2 Post, R., et al., The influence of physician acknowledgement of patients' weight status on patient perceptions of overweight and obesity in the united states. Archives of Internal Medicine, 2011. 171(4): p. 316-321.