Small-for-gestational-age term birth: the contribution of socio-economic, behavioural and biological factors to recurrence.

This paper follows a previous study comparing women who had repeatedly given birth to small-for-gestational-age (SGA) term infants ('repeater' mothers) with multiparous women who had had only one such infant ('non-repeater' mothers). The present investigation involves the individual matching of each woman in the above groups with a control mother whose offspring were all term non-SGA infants. The study was based on all Western Australian Caucasian women giving birth to singletons and the study population comprised 594 repeater cases with 594 matched controls and 935 non-repeater cases with 935 matched controls. Conditional logistic regression analyses indicated that demographic and paternal factors were significant predictors for recurrent SGA term birth whereas obstetric conditions, particularly preeclampsia, were important for the prediction of isolated SGA term birth. Maternal smoking, low maternal birthweight and lack of higher educational qualifications were associated with both types of SGA birth. After multivariable analyses, a strong and significant association remained between having a first infant as a teenager and recurrent SGA term birth. The tendency to repeat SGA term birth appears to be associated with social, economic and behavioural disadvantage and is unlikely to be ameliorated without fundamental changes in society.