Symphysis-fundus measurement in prediction of fetal growth disturbances.

Graphic supervision of pregnancy by symphysisfundus (SF) tape measurement was introduced in an area of north Stockholm in 1972. Subsequently a considerable and persistent drop in perinatal mortality was seen. SF-tape measurements reflect the fetal growth and correlate well with fetal crown-rump length. Over a 2-year period SF-growth data were collected for all infants admitted to the neonatal unit in the area. In all, 812 singletons were studied. Maternal smoking habits in the first trimester were recorded. A group of 283 normal neonates served as controls. A highly significant statistical difference was found on comparing the mean birth weights of infants associated with high, "normal", and low and/or static SF-curves from 34 weeks of gestation and onwards. The sensitivity in detecting LGA infants by high SF-curves was 74%, with a specificity of 84%. The proportion of mothers with uncertain expected dates of confinement (EDC) was high among those having "normal" SF-curves, yet giving birth to SGA infants. After correction for gestational age, the SF-curves adjusted for dates were in most cases low and/or static during the weeks prior to delivery. The sensitivity and specificity would thereby have increased to 95% and 93%, respectively, in detecting SGA infants had their dates been certain. Maternal smoking showed an overall incidence of 37% in the first trimester. No increase in incidence was seen among mothers to preterm infants. There was as could be expected a highly increased ratio of smoking mothers to infants with birth weight less than -1 S.D., regardless of gestational age. SF-tape measurement is recommended as a graphic method of supervising pregnancy for the detection of accelerated and retarded fetal growth. Early and correct determination of gestational age, however, is a prerequisite.