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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
Author(s) -
Malin GL,
Morris RK,
Riley R,
Teune MJ,
Khan KS
Publication year - 2014
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/1471-0528.12517
Subject(s) - medicine , odds ratio , meta analysis , anthropometry , birth weight , pediatrics , gestation , likelihood ratios in diagnostic testing , obstetrics , low birth weight , gestational age , cochrane library , pregnancy , genetics , biology
Background Intrauterine 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. Objectives To evaluate the relationship between birthweight standards and neonatal outcome in term‐born infants (at ≥ 37 weeks of gestation). Search strategy MEDLINE (1966– J anuary 2011), EMBASE (1980– J anuary 2011), and the C ochrane L ibrary (2011:1) and MEDION were included in our search. Selection criteria Studies 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 analysis Data were extracted to populate 2 × 2 tables relating birthweight standard with outcome, and meta‐analysis was performed where possible. Main results Twenty‐nine studies including 21 034 114 neonates were selected. Absolute birthweight was strongly associated with mortality, with birthweight < 1.5 kg giving the largest association ( OR 48.6, 95% CI 28.62–82.53). When using centile charts, regardless of threshold, the summary odds ratios were significant but closer to 1 than when using absolute birthweight. For all tests, summary predictive ability comprised high specificity and positive likelihood ratio for neonatal death, but low sensitivity and a negative likelihood ratio close to 1. Author's conclusions Absolute birthweight is a prognostic factor for neonatal mortality. The indirect evidence suggests that centile charts or other definitions of low birthweight are not as strongly associated with mortality as the absolute birthweight. Further research is required to improve predictive accuracy.