ARE SOCIODEMOGRAPHIC FACTORS PREDICTIVE OF PRETERM BIRTH - A REAPPRAISAL OF THE 1958 BRITISH PERINATAL-MORTALITY SURVEY

Objective Reassessment of the predictive value of sociodemographic fac tors on preterm birth. Design Population-based case-control study. Set ting England, Wales and Scotland. Sample The study sample consisted of 5630 primiparous and 9538 multiparous women who were delivered during the first week of March 1958 in Britain. Multiple births were exclude d. Method Factors potentially predictive of preterm birth were assesse d for primiparous and multiparous women separately, using the split-sa mple cross-validation technique. Main outcome measure Preterm birth, d efined as birth occurring before 259 days of gestation. Results Preter m birth rates for primiparous and multiparous women were 54 and 53 per 1000 births, respectively. In primiparous women low maternal age (und er 20 years) was the only sociodemographic variable that was predictiv e of preterm birth (P = 0.01). However, only 10.7% of preterm birth am ong primiparous women was associated with low maternal age. In multipa rous women, using univariable analysis, employment status was statisti cally significantly associated with preterm birth. This association di sappeared when employment status was adjusted for by other variables i n the model. Social class was not predictive of preterm birth in eithe r primiparous or multiparous women. Conclusion From the results of thi s study it is concluded that sociodemographic factors do not have a su bstantial impact on the risk of preterm birth. It seems unlikely that preventative measures aimed at social-demographic adversity will reduc e preterm birth rates.