K. Harding et al., SCREENING FOR THE SMALL FETUS - A STUDY OF THE RELATIVE EFFICACIES OFULTRASOUND BIOMETRY AND SYMPHYSIOFUNDAL HEIGHT, Australian and New Zealand Journal of Obstetrics and Gynaecology, 35(2), 1995, pp. 160-164
In this study 3 different methods of screening for birth-weight <10th
percentile in pregnancy were evaluated both indivually and in combinat
ion; 1,135 women with singleton pregnancies were studied. Measurements
of symphysiofundal height by tape measure, and amniotic fluid index a
nd fetal abdominal circumference by ultrasound imaging, were made at 1
8, 24, 28, 34 and 38 weeks. At none of these gestational ages did amni
otic fluid index perform well as a screening test for birth-weight <10
th percentile. Combining the tests, using symphysiofundal height to se
lect a group at high risk who then had a fetal abdominal circumference
measurement, reduced the false positive rate but significantly decrea
sed the percentage of infants diagnosed. The results of this study con
firm that the most appropriate antenatal diagnostic test for birthweig
ht <10th percentile is ultrasound measurement of fetal abdominal circu
mference. Selecting pregnancies at risk by clinical measurement of sym
physiofundal height will provide a lower false positive rate than a po
licy of performing ultrasound on all pregnancies during the third trim
ester, but will also reduce the sensitivity.