Validity of Johnson' formula for estimation of fetal weight among sudanese patients .


Research type: Research Paper

Authors: Fadl, Abdel Magid Mustafa Abbdalla .

Abstract: This is a descriptive study conducted in El Gadarif Teaching Hospital in the period from August 1996 to February 1997. The aim of this study was to test the validity of Johnson's formula for estimation of fetal weight among Sudanese patients while in labour in order to reduce the perinantal mortality rate which was noticed to be significantly high in this hospital. The study covered 960 patients while labouring for whom their heights and weights were recorded. Gestational age was determined, symphyseal fundal height was measured and the station of the head was recorded. Their all actual birth weights were recorded against their estimated birth weights by Johnson's respectively. From this study it was found that Johnson's gives unreliably high predicting birth weight towards higher symphyseal fundal heights with a sensitivity of 31.3 percent and specificity of 93.2 percent regarding birth weight greater than or equal 3.5 kg. This study came to a conclusion that Johnson's formula has no place in large hospitals with the advanced ultrasound technology but rural areas with poor facilities (such as El Gadarif State) may get benefits from the formula providing that all those who are interested, should be well acquainted with the techniques of abdominal examination and other relevant procedures, otherwise it becomes unreliable. The study recommended further standardization and evaluation of such formulas and to be in easy froms like growth charts rather than calculations, just like that in the suggestion.