When is birthweight at term abnormally low?: a systematic review and meta-analysis of the association and predictive ability of current birthweight standards for neonatal outcomes

BackgroundIntrauterine growth restriction is a cause of neonatal morbidity and mortality. A variety of definitions of low birthweight are used in clinical practice, with a lack of consensus regarding which definitions best predict adverse outcomes.ObjectivesTo evaluate the relationship between birthweight standards and neonatal outcome in term-born infants (at ≥ 37 weeks of gestation).Search strategyMEDLINE (1966–January 2011), EMBASE (1980–January 2011), and the Cochrane Library (2011:1) and MEDION were included in our search.Selection criteriaStudies comprising live term-born infants (gestation ≥ 37 completed weeks), with weight or other anthropometric measurements recorded at birth along with neonatal outcomes.Data collection and analysisData were extracted to populate 2 × 2 tables relating birthweight standard with outcome, and meta-analysis was performed where possible