population-based evaluation Adeeb Khalifeh, Stuart Weiner, Dhanya Mackeen, Andrew Gerson, Donnenfeld Alan Lankenau Medical Center, Obstericcs and Gynecology, Wynnewood, PA, Thomas Jefferson University, Obstetrics and Gynecology, Philadelphia, PA OBJECTIVE: To examine population-based trends in chorionic villus sampling (CVS) and amniocentesis utilization and advanced maternal age (AMA) as an indication for invasive prenatal diagnosis. STUDY DESIGN: This is a retrospective review of all pregnancies that have undergone invasive prenatal diagnostic testing, including CVS or amniocentesis, between June 2002 and December 2011 in the Mainline Health System Hospitals in Pennsylvania. Sequential screening was first offered to all patients in November 2006. We divided the study period into two groups representing two time periods: Group I from June 2002 to October 2006, and Group II from November 2006 to December 2011. Main outcome measures were trends in CVS and amniocentesis utilization and AMA as an indication for invasive testing. Chi square test was used for statistical analysis. A p value 0.05 was considered significant. RESULTS: There were 69,844 deliveries and 4,697 invasive procedures during the study period. Group I had 31,277 deliveries, compared with 38,567 in Group II (p NS). There were 2,755 procedures in Group I, and 2,758 in Group II (p 0.01), with a mean maternal age of 36 and 36.2 years, respectively (p NS). In Group I, there were 1,990 cases of amniocentesis versus 1,610 in Group II (p 0.01). There were also 765 cases of CVS in Group I, compared to 1,148 in Group II (p 0.01). Among the women in the study, 1,953 from Group I and 1,486 from Group II were referred for the sole indication of AMA (p 0.01). Group I had 172 abnormal results, while Group II had 245 (p NS). Among those, the number of fetuses of any trisomy was 92 (4.6%) and 102 (6.8%) for each group, respectively (p NS). CONCLUSION: There was a decrease in the incidence of invasive prenatal testing over the study period, as well as AMA as an indication for testing. There was a change in the pattern of invasive testing over time with a reduction in amniocentesis procedures and an increase in CVS uptake. This is likely due to the ability to obtain first trimester results with sequential screening.