The relationship between body mass index and mid-arm circumference in a pregnant population

Abstract

Our objective was to correlate body mass index (BMI) with mid-arm circumference (MAC) and also to ascertain whether maternal BMI could be calculated from MAC at booking. We approached all Caucasian women who met the inclusion criteria attending the University College Hospital, London between 1 April 1996 and 30 June 1997 and the Rotunda Hospital, Dublin, Ireland between 15 April 2003 and 19 May 2004. A total of 2,912 women agreed to participate in the research. The participants’ maternal height and weight were measured. Their BMI was calculated using the formula: BMI = weight (kg) ÷ height (m²). The MAC was measured in cm. Statistical analysis was performed using SPSS for Windows version 11 with p < 0.05 as significant. We found that BMI is directly correlated with MAC (r = 0.836) and estimates of BMI may be calculated from the simple equation BMI = MAC ± 2. Alternatively, a MAC of ≥ 27 cm allowed for a detection rate for overweight patients of 75%, with a false positive rate of 15%.

Keywords::

• Body mass index
• mid-arm circumference
• obesity

Acknowledgements

This project would not have been possible without the participation and enthusiasm of the women who agreed to participate. We would like to thank them for their participation. In addition, we would like to thank ‘The Friends of the Rotunda’ for their fundraising and financial support.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.