THE PLUNKET-NATIONAL-CHILD-HEALTH-STUDY - BIRTH-DEFECTS AND SOCIODEMOGRAPHIC FACTORS

Aims. The Plunket National Child Health Study was set up to examine th e health experience of a representative sample of New Zealand children . This paper examines the association of birth defects with the sociod emographic variables of maternal age and education, parity, socioecono mic group, region of domicile and marital status; infant's ethnic grou p and sex. The effect of maternal smoking on the prevalence of birth d efects was also examined. The paper compares the prevalence of birth d efects in infants alive at 6 weeks with the reported prevalence at bir th as described in various other publications. Methods. A cohort of 42 86 children born in New Zealand during 1990-1 were enrolled in the stu dy. The presence of birth defects in the study population was determin ed by clinical examination and review of hospital or midwife referrals . All described defects were reviewed and coded according to the ICD-9 . Results. The overall prevalence of birth defects in the study was 4. 3%. There was a significant association between socioeconomic status a nd the incidence of birth defect but no other significant sociodemogra phic variations. Cigarette smoking had no statistically significant ef fect on the rate of birth defects. There was a marked difference betwe en the rates for certain defects in the Plunket study when compared to Health Department notifications. Conclusions. Because of the differen ces between the current study and official Health Department notificat ions we suggest that criteria for congenital anomaly notification are clarified, and that a second notification takes place at six weeks of age.