Single pre-delivery symphysis-fundal height measurement as a predictor of birthweight and multiple pregnancy.

OBJECTIVE To compare the value of different pre-delivery maternal indices for predicting birthweight, and to examine the usefulness of a single pre-delivery symphysis-fundal height measurement for the detection of low birthweight and twin pregnancy or macrosomia. DESIGN Symphysis-fundal height measurements were gathered from 1509 women who had both a singleton delivery and available data of pre-delivery weight, height and mid-upper arm circumference, and from 73 women who had a twin delivery. SETTING A district hospital in rural Tanzania. RESULTS Symphysis-fundal height, pre-delivery weight and mid-upper arm circumference, respectively, explain 41%, 13% and 4% of the observed variation in birthweight. At a cut-off level of 30 cm for symphysis-fundal height, the detection rate for birthweight below 2500 g and 2000 g was 66% and 68%, respectively, and the false positive rate was 9% and 14%, respectively. At a cut-off level of 38 cm for symphysis-fundal height the detection rate for twin pregnancy or birthweight > or = 4000 g was 76%, and the false positive rate was 4%. CONCLUSION Symphysis-fundal height was a better predictor of birthweight than maternal height, pre-delivery weight or mid-upper arm circumference. It seems justified to investigate the value of a simple tricoloured symphysis-fundal height measuring tape for use in antenatal care in developing countries at village level.