Serial plotting on customized fundal height charts results in doubling of the antenatal detection of small-for-gestational-age fetuses in nulliparous women

Abstract

Early detection of a small-for-gestational-age fetus (SGA) can potentially lower the risk of stillbirth, neonatal death, and other adverse outcomes. After identification of an SGA fetus, appropriate intervention can reduce the likelihood of perinatal morbidity, including fetal compromise during labor and cerebral palsy in childhood. The traditional guideline for SGA detection used in most obstetric units in Australia is that fundal height (FH) should be equal to gestational age. More than 10 years ago, a nonrandomized quasi-controlled study conducted in a primary health care setting reported that the use of serial plotting of the FH on customized charts increased the likelihood of detecting SGA nearly 2-fold compared with the traditional method. However, other studies have not confirmed these findings. This observational study investigated whether the introduction of serial plotting of the FH on customized charts at a teaching hospital in Australia would increase the antenatal detection rate of SGA among low-risk singleton nulliparous women when combined with a clinical practice guideline and regular audits. The SGA detection rate was compared with that of a historical control group comprising first-time mothers who had received traditional antenatal care and had delivered before this change in practice. In the intervention group, serial FH plotting on customized charts was used, together with a clinical practice guideline and regular audits to promote clinician adherence to the protocol. In the control group, FH was measured and documented during every antenatal visit, but no SGA guideline, serial plotting, or regular audits were used. Use of serial plotting nearly doubled the antenatal detection rate of SGA compared with the traditional approach for detection (intervention group: 50.6% 44⁄87 vs. control group: 24.8% 31⁄125); the odds ratio was 3.10, with a 95% confidence interval of 1.73 to 5.57 and P 0.001. These findings suggest that more clinicians should use serial FH plotting on a customized chart for primary screening and detection of SGA in nulliparous pregnant women at low risk for SGA rather than the traditional approach.