A new policy for prenatal screening and diagnosis of Down syndrome for pregnant women with advanced maternal age in a public hospital.
OBJECTIVE
Before April 2006, women with singleton pregnancy and advanced maternal age (AMA, 35 years and older) were offered either direct invasive tests or a variety of screening tests for Down syndrome (DS) with routine anomaly scan at 18-20 weeks. After April 2006, to reduce procedure-related fetal loss, invasive test was performed only for positive screening result or the presence of major fetal anomaly on ultrasound. We reviewed our 2-year experience after the policy change.


METHODS
Two-year data after policy change were compared to the 1-year historic control before policy change.


RESULTS
A total of 2257 eligible women were counselled in the 2 years after policy change. The uptake of screening was 96.7%. The overall detection rate for DS was 90% (18/20) at a false positive rate of 10.9%. The number of invasive tests performed to diagnose one case of DS was reduced 7-fold from 97 to 13.


CONCLUSIONS
The number of direct invasive tests was markedly reduced. With effective DS screening policy, it is possible to do away with direct invasive testing for the majority of women with AMA.
Lo
Tsz Kin
TK
Prenatal Diagnosis and Counseling Unit, Department of O&G, Kwong Wah Hospital, Kowloon West Cluster, HKSAR, China. a9401438@graduate.hku.hk
Lai
Fung King
FK
Leung
Wing Cheong
WC
Lau
Wai Lam
WL
Tang
Lawrence Chang Hung
LC
Chin
Robert Kien Howe
RK
D000328:Adult; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D006779:Hospitals, Public / Q000706:statistics & numerical data; D006801:Humans; D008403:Mass Screening / Q000706:statistics & numerical data*; D008423:Maternal Age; D017410:Practice Guidelines as Topic; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000706:statistics & numerical data*