A NEW METHOD FOR EVALUATION OF FETAL GROWTH FROM SIZE AT BIRTH

Abstract

A new method for evaluation of weight(BW) in relation to length (BL) (leanness/fatness) in the newborn infant is presented using standard deviation score for BW (BWSDS) and for BL (BLSDS) normalized for sex, gestational age (GA) in a linear regression model, based on all Swedish “healthy” singletons 1986 (n=79,976). Result: A continuous variable called LEANSDS was found with intercepts, regr. coeff. =0 .715, SD=0.699 and r=0.72 irrespective of sex and GA (34-43 weeks). It was tested on the 1985 years cohort with good fit. A chart is constructed which simplify visual evaluation. Using -2SD as cut off lines about 1/3 of the infants light for date (LFD) are also lean but 2/3 of the lean infants are not LFD. In stillborn infants the proportion of lean not LFD infants is increased 13 times, in early neonatal deaths 2.6 times. Other methods based on GA dependent regression of BW on BL or ponderal indices are more complex. Conclusion: A continous LEANSDS variable which can be added for further processing unlike percentiles will together with BWSDS and BLSDS improve evaluation of for example intrauterine growth retardation from size at birth in proportionally small (extreme stunting) and in lean (extreme wastage).