Integrated and first trimester prenatal screening in California: program implementation and patient choice for follow-up services.

Objectives: The California Prenatal Screening Program serves over 350,000 women annually. This study examines utilization rates for the various screening options and patient choices regarding follow-up services.

Methods: The study tracked patients with first trimester positive results for Down syndrome to examine patient decisions regarding follow-up services and/or additional screening and to identify determinants of patient decisions.

Geographic distribution of autism in California: a retrospective birth cohort analysis.

Prenatal environmental exposures are among the risk factors being explored for associations with autism. We applied a new procedure combining multiple scan cluster detection tests to identify geographically defined areas of increased autism incidence. This procedure can serve as a first hypothesis-generating step aimed at localized environmental exposures, but would not be useful for assessing widely distributed exposures, such as household products, nor for exposures from nonpoint sources, such as traffic.

A procedure to characterize geographic distributions of rare disorders in cohorts.

Background: Individual point data can be analyzed against an entire cohort instead of only sampled controls to accurately picture the geographic distribution of populations at risk for low prevalence diseases. Analyzed as individual points, many smaller clusters with high relative risks (RR) and low empirical p values are indistinguishable from a random distribution. When points are aggregated into areal units, small clusters may result in a larger cluster with a low RR or be lost if divided into pieces included in units of larger populations that show no increased prevalence.