Severe fetal growth restriction (FGR) is a leading cause of adverse perinatal morbidity and mortality; however, in Victoria, 35% of severely growth‐restricted infants are undelivered by 40 weeks gestation.
We aimed to identify factors associated with failure to deliver severely growth‐restricted fetuses by 40 weeks gestation.
We conducted a retrospective case‐control study of term singletons born <3rd centile for gestation at a single tertiary centre (2010–2017). Infants with a planned delivery for FGR between 37.0–39.6 weeks gestation (‘planned birth’ group; n = 187) were compared with those undelivered by 40.0 weeks (‘undelivered’ group; n = 233). Variables assessed included the presence of risk factors for FGR, model of care, symphyseal‐fundal height measurements and third trimester ultrasounds. Results An equivalent proportion of women were ‘high‐risk’ for FGR on history (31.3% vs 38.0%, P = 0.187) in the planned and undelivered groups. Women booked under low‐risk models (shared care and midwifery‐led care) were significantly more likely to be in the undelivered group compared to those booked under traditional collaborative models (79.8% vs 37.4%, P < 0.001). Women in the undelivered group were less likely to have received a third trimester ultrasound (93.0% vs 40.3%, P < 0.001); however, they were more likely to have had a reassuring ultrasound with an estimation of fetal weight or abdominal circumference >10th centile (78.7% vs 16.1%, P < 0.001). Conclusions Failure to deliver the severely growth‐restricted fetus before 40.0 weeks is more likely to occur in the following situations: (i) failure to receive an indicated third trimester ultrasound; (ii) the presence of falsely reassuring third trimester ultrasound scan; and (iii) booking under a low‐risk rather than traditional collaborative models of care.