CustOmized versus standard fundal-height measuREments for the detection of small-for-gestational age fetuses in low-risk women (CORE study): A randomized controlled trial.

Objective: To compare the proportion of small-for-gestational age (SGA) infants detected by routine care versus a growth assessment protocol using customized fundal-height charts in low-risk pregnancies of a developing country.

Methods: An open label randomized controlled trial was conducted at the Fatima Memorial Hospital (NUR International University, Pakistan). Low-risk pregnant women were randomly allocated to routine care (Mcdonald's rule for fundal height measurements followed by referral for scan with discrepancy of 3 cm from gestational age and a contingency third trimester scan) or the growth assessment protocol (GAP) developed by the Perinatal Institute (UK), which consists of the use of gestation-related optimal weight (GROW) customized charts, alongside management protocols for suspected SGA fetuses, audit tools and training. The primary prespecified outcome was the detection of SGA (defined as a birthweight <10th centile).

Results: Of the 2535 eligible women, 1884 (74%) were randomized (942 to standard care and 942 to GAP). After loss-to-follow-up, 1755 women were analyzed (874 in the standard measurement group and 881 in the GAP group). The detection rate of SGA infants was higher in the GAP group (83.2% [95% CI: 74.4%-89.9%] vs. 29% [95% CI: 20.4%-38.9%], P < 0.001), at the cost of an increased false positive rate (10.4% [95% CI: 8.3%-12.7%] vs. 1.4% [95% CI: 0.7%-2.5%], P < 0.001). The diagnostic odds ratio (positive likelihood ratio/negative likelihood ratio) was 42.6 (95% CI: 24.1-75.4) in the GAP group and 28.3 (95% CI:13.6-59.1) in the standard care group.

Conclusion: In low-risk pregnant women of a developing country, a growth assessment protocol based on customized fundal-height charts is superior to standard measurements for the antenatal detection of SGA in newborns.