Self-Administered Measurement of Symphysis-Fundus Heights

Abstract

If small-for-gestational-age (SGA) fetuses are identified antenatally, perinatal outcomes are likely to improve. The most widely used method of screening for SGA fetuses is for midwives to repeatedly measure symphysis-fundus (SF) height, but this is not an efficient practice. Deviant growth might be more efficiently identified if pregnant women themselves started making SF measurements earlier during pregnancy and made them more frequently. In order to determine whether pregnant women can reliably measure SF height, 40 healthy women with ultrasound-dated singleton pregnancies were asked to make 4 consecutive SF measurements each week, starting at 20 to 25 weeks' gestation and continuing up to the time of delivery. Self-administered measurements were compared with those made by midwives. Measurements were made using blank paper tape measures from the upper limit of the pubic bone to the highest point of the uterus—the fundus—in the direction of the fetus. Thirty-three pregnant women made self-administered SF measurements over a median period of 14 weeks. The SF curves constructed from these measurements had the same shape as population-based reference curves. Variance in self-administered measurements was, however, higher than for measurements made by midwives. Intra-individual variance of self-administered SF measurements was about 5 times higher than for midwives' open measurements. The degree of variance remained constant throughout pregnancy and was not a function of fetal size. The midwives performed a median of 6 SF measurements on each pregnant woman. Their blinded measurements were, on average, higher than the corresponding open SF measurements. Self-administered SF values tended to be higher than the corresponding measurements made by the midwives. These findings show that pregnant women are able to measure SF height by themselves, and that this practice makes it possible to follow fetal growth more closely, starting at a relatively early stage of pregnancy. Self-administered SF measurements have some potential to improve the early detection of intrauterine growth retardation.