FM027 Detecting slow growth by serial fundal height measurement reduces stillbirth risk

Objective: Standardised measurement of fundal height (SFH) improves the identification of small for gestational age (SGA) fetuses in low risk pregnancy1,2. We investigated the association of stillbirth risk with slow growth determined by serial SFH regardless of fetal size. 

Methods: The study cohort consisted of singleton pregnancies with at least two third trimester SFHs.  From the last two measurements, we calculated the projected optimal weight range (POWR)3 to determine whether the fetus had slow growth. The Figure illustrates a chart with plotted serial SFH measurements and an alert for slow growth.    

Results: This low risk cohort consisted of 222,335 deliveries including 372 stillbirths (1.20). The last two SFH measurements were done at an average of 34+2 and 37+5 weeks and indicated slow growth in 16.8% of pregnancies, without being SGA (<10th centile) in 77.1% of cases. Fetuses with slow SFH growth but no ultrasound scan had a significantly increased stillbirth risk: RR 4.27, CI 2.70-6.76. The risk was lower but still significant when slow SFH growth was followed by ultrasound scan: RR 1.67, CI 1.19-2.36. These fetuses were delivered at an average of 39+3 weeks, 5 days earlier than fetuses that did not have a scan following slow SFH growth (40+1 weeks). 

Conclusion: Digital assessment of serial SFH provides an additional parameter for fetal growth surveillance and can reduce stillbirth risk. Pregnancies with slow fundal height growth regardless of fetal size are at increased risk and require urgent referral for further investigation. 1. Butler E, Hugh O, Gardosi J. Evaluating the Growth Assessment Protocol for stillbirth prevention: progress and challenges. J Perinat Med 2022;50:737–47. https://doi.org/10.1515/jpm-2022-0209 

2. Ahmed F, Hanook S, Ismail F, Shah F, Arsalan M, et al. Customized vs standard fundal-height measurements for the detection of small-for-gestational age fetuses in low-risk women: RCT. Int J Gynecol Obstet 2024. https://doi.org/10.1002/ijgo.16107 

3. Perinatal Institute. Fetal growth rate calculator. 2022. https://www.perinatal.org.uk/growthrate