Effects of changes in prenatal aneuploidy screening policies in an integrated health care system.
OBJECTIVE
To estimate changes in rates of prenatal testing for aneuploidy over a 5-year period in a large integrated health care system.


METHODS
Data from the Kaiser Permanente Northern California cytogenetics laboratory and Regional Prenatal Screening Program were used to estimate rates of prenatal aneuploidy screening and diagnostic testing in females of all ages during 2006-2010. We estimated the number of chromosome abnormalities detected and the proportion of abnormal cytogenetic results. Dichotomous variables were compared using χ tests. Rates of use and aneuploidy detection rates were compared for trend using a linear repeated-measures model.


RESULTS
Annual deliveries decreased during this period, from 36,276 to 34,314, whereas births to women aged 35 years or older increased from 21.8% to 22.7% (P=.004). The rate of aneuploidy screening decreased minimally from 76.1% to 75.4% (P=.04). Among women 35 years or older, the rate of screening increased from 53.1% in 2006 to 63.7% in 2010 (P<.001), whereas the percentage having diagnostic testing decreased from 40.9% to 26.8% (P<.001). Among women younger than 35 years old, the rate of screening decreased from 82.5% in 2006 to 78.9% in 2010 and the rate of diagnostic testing decreased from 4.1% to 2.8% (P<.001). Abnormal diagnostic test results increased from 5.9% to 8.2% (P<.001); the number of chromosome abnormalities identified overall was 7.2 per 1,000 births in 2006 and 6.7 per 1,000 births in 2010 (P=.43).


CONCLUSIONS
Offering comprehensive aneuploidy testing options to all pregnant women in an integrated health care system resulted in lower use and higher yield of diagnostic testing.


METHODS
II.
Department of Obstetrics and Gynecology, Stanford University School of Medicine/Lucile Packard Children's Hospital, Stanford, the Department of Obstetrics, Gynecology and Reproductive Sciences, the Department of Medicine, and the Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, and the Prenatal Genetic Screening Program, Kaiser Permanente Northern California, Oakland, California.
Mary E
ME
Norton
Sanae
S
Nakagawa
Carol
C
Norem
Steven E
SE
Gregorich
Miriam
M
Kuppermann
D000328:Adult; D000782:Aneuploidy; D019033:Delivery of Health Care, Integrated; D005260:Female; D006801:Humans; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods* / Q000592:standards*; D014481:United States