ABSTRACT
Identification of small for gestational age Antenatal detection of babies with defective growth often falls short, missing up to 75% of babies at risk of being small for gestational age (SGA) before delivery.1 In low-risk pregnancies, the detection rate is worse (∼15%).2 Such poor performance takes a toll, as most instances of avoidable stillbirth and neonatal death are linked to failures in antenatal SGA detection.3,4
Current strategies to monitor growth involve symphysis-fundal height determination. However, only 16% of SGA infants are detected this way in low-risk populations.5 Consequently, most SGA births are full term.6 Thirdtrimester ultrasound (US) monitoring of fetal growth is done routinely in some countries, boosting detection rates to 40%– 80%.7,8 A recent well-designed prospective study comparing universal and selective (based on risk factors) third-trimester screening provides evidence that universal screening triples the detection rate of SGA and severe SGA.9 However, another observational study10 found that a contingent strategy based on selecting for third-trimester growth assessment the 50% of the population at highest risk as accrued by first-and secondtrimester screening yields similar performance as universal screening.
