SYMPHYSIS-FUNDUS HEIGHT - CONSTRUCTION OF A NEW SWEDISH REFERENCE CURVE, BASED ON ULTRASONICALLY DATED PREGNANCIES

Repeated measurements of the symphysis-fundus (SF) distance is general ly regarded as an acceptable screening instrument for antenatal detect ion of intrauterine growth retardation (IUGR). In the present investig ation an SF curve is constructed, based on measurements from 1650 Swed ish women with ultrasound dated pregnancies. The SF measurements were included in a cross-sectional stratified manner; only one measurement from each woman was used and the same number of measurements (n=75) wa s used for each gestational week from 20 through 41. A regression anal ysis by a polynomial equation of third degree was applied on the means and standard deviations of the SF measurements in each week respectiv ely to construct a graph of fundal height. This SF curve was compared with the SF curve in common use in Sweden (constructed by Westin); in the new curve the mean measurement was about one cm higher up to 37 ge stational weeks, after which time the curves almost coincided. Neither did the mean SF height differ between smokers and non-smokers nor bet ween nulliparous and parous women. The mean SF difference between the heaviest women (greater than or equal to 79 kg) and the lightest (grea ter than or equal to 53 kg) was about two cm throughout pregnancy. The validity of the constructed SF curve as a screening instrument for IU GR needs to be investigated in a different study.