Evaluation of First Trimester Contingent Test for Down ’ S Syndrome Screening

Abstract

Down's syndrome is the most common chromosomal disorder among children. There are various screening strategies to detect Down ' s syndrome antenatally, each having its own advantages and disadvantages. Much research is being carried out to improve the detection rate, lower the false positive rate and to make it more cost effective. The emphasis is on first trimester screening as it allows us to reassure the majority of patient's early on in pregnancy and allows the patient to take an early decision regarding continuation of pregnancy. The gold standard of first trimester screening is the 'combined test'. Combined test involves measurement of Nuchal Translucency (NT) in all cases, and is difficult to implement in a developing country like India. Our study on first trimester 'contingent screening' showed that NT was required in 22% cases only, and the overall detection rate and the false positive rate were comparable to combined screening. Furthermore, this screening strategy is cost effective and will be easier to implement in our country. The study is being continued to include larger number of patients to evaluate the outcome analysis data more accurately.