Maternal weight and weight gain during pregnancy--can the arm circumference be used as surrogate?

A survey among pregnant Nigerian women attending an antenatal clinic showed a strong correlation between the arm circumference and weight. The sensitivity and positive predictive value of mid-arm circumference less than 23 cm for first trimester weight of less than 45 kg was 85.7% and 54.5% respectively. In the second trimester, these values for mid-arm circumference of less than 24 cm and weight less than 50 kg were 55.6% and 32.3% respectively. The specificity was high, ranging up to 99.4%. The value of the screening was found to be higher amongst primigravidas. Mid-arm circumference was however found to be insensitive for monitoring of weight gain during pregnancy. Strips based on this principle may be useful as a screening tool especially for low cadre health workers to identify pregnant women considered nutritionally at risk.