Association between small for gestational age and intrauterine fetal death: Comparing a customized South Korean growth standard versus a population-based fetal growth chart

Objective: To determine if a customized growth standard developed for an ethnically homogeneous South Korean population is better at identifying (SGA) fetuses at risk for intra-uterine fetal death (IUFD), compared with a current population based-growth standard.Study design: A retrospective cohort study comparing the identification of SGA fetuses at risk for IUFD using a customized versus a population based-chart. The association between a SGA infant defined as a birth weight <10th percentile using the South Korean population chart versus the customized chart and IUFD were compared. Intrauterine fetal death was defined as fetal demise occurring after 20 weeks gestation. Statistical analyses including OR, 95% confidence interval (CI), and screening accuracy using each chart were performed.Results: The customized singleton chart identified 11 (8.2%) of the SGA pregnancies detected by the population chart and classified 15 additional fetuses as SGA. Those identified as SGA using the customized chart had an OR for IUFD that was approximately 15 times as high as those identified using the population chart. The customized chart also showed a higher sensitivity and specificity for identifying SGA pregnancies at risk for IUFD.Conclusion: In this ethnically homogenous population, the customized growth chart showed improved discrimination in identifying SGA pregnancies at risk for fetal death than the population-based growth chart.