Diagnostic Accuracy of Neonatal Assessment for Gestational Age Determination: A Systematic Review.

ABSTRACT

CONTEXT An estimated 15 million neonates are born preterm annually. However, in low- and middle-income countries, the dating of pregnancy is frequently unreliable or unknown. OBJECTIVE: To conduct a systematic literature review and meta-analysis to determine the diagnostic accuracy of neonatal assessments to estimate gestational age (GA). DATA SOURCES PubMed, Embase, Cochrane, Web of Science, POPLINE, and World Health Organization library databases. STUDY SELECTION Studies of live-born infants in which researchers compared neonatal signs or assessments for GA estimation with a reference standard. DATA EXTRACTION Two independent reviewers extracted data on study population, design, bias, reference standard, test methods, accuracy, agreement, validity, correlation, and interrater reliability. RESULTS: Four thousand nine hundred and fifty-six studies were screened and 78 included. We identified 18 newborn assessments for GA estimation (ranging 4 to 23 signs). Compared with ultrasound, the Dubowitz score dated 95% of pregnancies within ±2.6 weeks (n = 7 studies), while the Ballard score overestimated GA (0.4 weeks) and dated pregnancies within ±3.8 weeks (n = 9). Compared with last menstrual period, the Dubowitz score dated 95% of pregnancies within ± 2.9 weeks (n = 6 studies) and the Ballard score, ±4.2 weeks (n = 5). Assessments with fewer signs tended to be less accurate. A few studies showed a tendency for newborn assessments to overestimate GA in preterm infants and underestimate GA in growth-restricted infants. LIMITATIONS: Poor study quality and few studies with early ultrasound-based reference. CONCLUSIONS: Efforts in low- and middle-income countries should focus on improving dating in pregnancy through ultrasound and improving validity in growth-restricted populations. Where ultrasound is not possible, increased efforts are needed to develop simpler yet specific approaches for newborn assessment through new combinations of existing parameters, new signs, or technology.