RESUMEN
AIM: Small-for-gestational-age (SGA) status has negative health consequences in neonates and later life. Low socioeconomic status (SES) is a reported risk factor for adverse birth outcomes, such as SGA and preterm birth (PTB). The present study investigated whether maternal SES is associated with adverse outcomes in Japanese pregnant women. METHODS: Retrospective data were collected for 1970 Japanese women with singleton pregnancies who delivered between January 2007 and December 2011 at a single center: low SES group (n = 197); and controls (n = 1773). Low SES was defined according to the criteria of the Japanese pregnant-childbirth hospitalization support policy system. RESULTS: The low SES group included a significantly higher proportion of young women, women with single marital status, greater parity, pre-pregnancy smoking and a lack of regular employment (P < 0.001, respectively). The crude odds ratio (OR) for the association between low maternal SES and SGA was 1.80 (95% confidence interval [CI] 1.15-2.82, P = 0.010). After adjustment for baseline maternal age, parity, body mass index, smoking and gestational weight gain, the adjusted OR for the association between low maternal SES and SGA was 1.92 (95% CI 1.17-3.17, P = 0.010). No significant association was found between maternal SES and PTB. CONCLUSION: The present results suggest that low maternal SES is associated with SGA births in the Japanese population. Mitigation of low maternal SES could be urgent public health to prevent disadvantage birth outcome.