Comparison Between Body Mass Index and Mid Upper Arm Circumference for Classifying Nutritional Status of Pregnant Women: a Prospective Cohort Study

Background: BMI is used to assess nutritional status of pregnant women however weight gain during pregnancy confounds the nutritional status later in pregnancy. Unlike weight, MUAC does not undergo significant change as the pregnancy advances. We aim to compare the changes in BMI and MUAC in pregnant women over various trimesters to assess whether change in MUAC is less compared to weight.Methods: In this prospective observations study, BMI and MUAC measurements were taken of 300 pregnant women during different trimesters. Chi-square tests were conducted to assess associations between socio-demographic indicators and nutritional status. Correlation coefficients were calculated between BMI and MUAC over three trimesters. ANOVA tests were conducted on BMI and MUAC to assess their respective mean differences over three trimesters.Results: Mean difference of 0.43 cm (3.2%) was noted in MUAC compared to 5.32 kg/m2 (23.14%) in BMI from first to third trimester. No significant differences were observed in mean MUACs between first and second (p=0.326) and second and third trimesters (p=0.143) but, it was significantly different between first and third trimesters (p=0.003). Significant differences were observed in mean BMIs between first and second (p=0.05), second and third (p<0.001) and first and third trimesters (p<0.001). Correlation between BMI and MUAC were positive and significant in all three trimesters.Conclusions: Positive correlations were found between BMI and MUAC. Less change was observed in MUAC than BMI over three trimesters. MUAC seems to be a reliable tool for assessing nutritional status of antenatal women.