Small-for-gestational age Portuguese babies: the effect of childhood social environment, growth and adult socioeconomic conditions.

OBJECTIVE

We aimed to estimate the extent to which differences in small-for-gestational age (SGA) according to maternal socioeconomic position (SEP) and anthropometrics are accounted for childhood background.

METHODS

Adult mothers of singletons (n=6893) recruited in 2005/2006 in Porto, Portugal self-reported data on socio-demographics. Grandparents' education and social class were used to characterise childhood social environment. Maternal education and marital status were used as adult SEP indicators. Height was categorised according to the 10th and 90th percentiles. The odds of SGA according to adult SEP and height were stratified by childhood conditions.

RESULTS

SGA (14.5%) was less likely in taller [vs. 10th-90th percentiles: 0.62 (95% confidence interval (CI): 0.46-0.83)], more educated [vs. low: 0.77 (0.65-0.90)] and in married women [vs. single: 0.64 (0.47-0.86)]. No association was found between childhood social conditions and SGA. The protection provided by maternal education was found in women from deprived childhood backgrounds but not in those with more advantage conditions. Shorter women were more likely to deliver SGA babies but the effect was stronger (pinteraction<0.001) in those from least deprived childhood conditions.

CONCLUSIONS

Sufficient increase in education seems to overcome disadvantage earlier in life. Other pathological processes might impact physical development beyond social influence, having long lasting effects on SGA.