Risk factors for small for gestational age

BACKGROUND: The purpose of the paper was to determine the risk factors for small-for-gestational-age (SGA) infants at full term, in Japan. METHODS: The study was conducted at four hospitals and clinics in the Tokyo metropolitan area. A retrospective review of 2972 mothers and their infants born from singleton pregnancies at any time during the years 2002 and 2003 was conducted. RESULTS: Of these women, 8.4% gave birth to SGA infants. The proportion of SGA infants was significantly higher among heavy smokers (>10 cigarettes/day; 13.7%, P < 0.01). The odds ratio (OR) for SGA decreased significantly in proportion to the pregnancy body mass index (OR, 0.89; 95% confidence interval CI]: 0.84-0.94, P < 0.001). The OR of SGA for stratified maternal weight gain was 1.79 (95%CI: 1.24-2.58, P 12 kg. CONCLUSION: The present study clearly confirms the detrimental effect of a low prepregnancy body mass index, low maternal weight gain and maternal smoking during pregnancy on the incidence of SGA infants.