Severe smallness as predictor of adverse perinatal outcome in suspected late small-for-gestational-age fetuses: systematic review and meta-analysis

Objective To investigate the performance of severe smallness in the prediction of adverse perinatal outcome among fetuses with suspected late-onset small-for-gestational age (SGA). Methods A systematic search was performed to identify relevant studies in PubMed, Web of Science and Scopus. Late-onset SGA was defined as estimated fetal weight (EFW) or abdominal circumference (AC) < 10(th) percentile diagnosed at or after 32 weeks' gestation, while severe SGA was defined as EFW or AC < 3(rd) percentile or < 2 SD. Random-effects modeling was used to generate hierarchical summary receiver-operating-characteristics (HSROC) curves. The performance of severe SGA (as a presumptive diagnosis) in predicting adverse perinatal outcome among singleton pregnancies with suspected late-onset SGA was expressed as area under the HSROC curve (AUC), sensitivity, specificity and positive/negative likelihood ratios. The association between suspected severe SGA and adverse perinatal outcome was also assessed by random-effects modeling using the Mantel-Haenszel method and presented as odds ratio (OR). The non-exposed group was defined as non-severe SGA (EFW >= 3(rd) centile). Results Twelve cohort studies were included in this systematic review and meta-analysis. The studies included a total of 3639 fetuses with suspected late-onset SGA, of which 1246 had suspected severe SGA. Significant associations were found between suspected severe SGA and composite adverse perinatal outcome (OR, 1.97 (95% CI, 1.33-2.92)), neonatal intensive care unit admission (OR, 2.87 (95% CI, 1.84-4.47)) and perinatal death (OR, 4.26 (95% CI, 1.07-16.93)). However, summary ROC curves showed limited performance of suspected severe SGA in predicting perinatal outcomes, with AUCs of 60.9%, 66.9%, 53.6%, 57.2%, 54.6% and 64.9% for composite adverse perinatal outcome, neonatal intensive care unit admission, neonatal acidosis, Cesarean section for intrapartum fetal compromise, low Apgar score and perinatal death, respectively. Conclusion Although suspected severe SGA was associated with a higher risk of perinatal complications, it performed poorly as a standalone parameter in predicting adverse perinatal outcome. (c) 2022 International Society of Ultrasound in Obstetrics and Gynecology.