Dose-response associations of maternal height and weight with small for gestational age: a meta-analysis.

BACKGROUND/OBJECTIVES: Small for gestational age (SGA) may be associated with increased rates of mortality and morbidity not only during the infantile period but also in later life. This study was performed to determine the dose-response relationships of maternal height and weight with risk of SGA.

SUBJECTS/METHODS: Dose-response meta-analyses were performed to summarize adjusted relative risks of SGA per 1-cm in maternal height and 1-kg increase in weight (linear model) and for varying levels relative to 160 cm in height and 55 kg in weight (nonlinear model). The adjustments for potential confounders were made using the Hamling method. Eight databases, including PubMed (MEDLINE), were searched. Study quality was assessed using the Newcastle-Ottawa scale (NOS).

RESULTS: Totals of 117,114 and 13,049 subjects were extracted from high-quality studies (e.g., NOS score ≥ 8) to evaluate maternal height (n = 7) and weight (n = 3), respectively. Corresponding to P for nonlinearity (P < 0.05), the dose-response relationships were nonlinear rather than linear. The nonlinear model showed that maternal height and weight were significantly and inversely associated with the risk of SGA, regardless of the levels below or above their means (i.e., 160 cm or 55 kg, respectively).

CONCLUSIONS: SGA risk may be reduced by increasing maternal height and weight.