Antenatal care implications of population-based trends in Down syndrome birth rates by rurality and antenatal care provider, Queensland, 1990-2004

Objective: To assess whether the rates of Down syndrome births in Queensland vary according to rurality (ie, whether the mother lives in a rural or urban area) and type of antenatal care provider, and to consider any implications for antenatal care. Design and setting: Population-based study of Down syndrome births in Queensland between 1990 and 2004, stratified by rurality and type of antenatal care provider (private obstetrician, public hospital or shared care). Results: Since 2000, there has been a large fall in maternal-age-adjusted rates of Down syndrome births among mothers living in urban areas (-14.3% per year; 95% CI, -22.7%, -5.0%) and among mothers receiving their antenatal care from private obstetricians (-27.5% per year; 95% CI, -37.6%, -15.8%). Similar decreases have not occurred among mothers living in rural areas (0.0%; 95% CI, -11.7%, 13.1%) or among mothers receiving antenatal care from public hospitals (+2.9%, 95% CI, -10.3%, 17.9%). Conclusion: Possible reasons for the observed trends include unequal access to antenatal screening; confusion about screening guidelines and protocols; late presentation for antenatal care; and differences in attitudes to screening and termination of pregnancy among expectant parents, such that they may choose not to have screening or not to act on a positive screening test result.