前言：唐氏症患者發展遲緩及諸多先天性的健康缺損，帶來的經濟負擔相當龐大。而現今篩檢策略有多種，其中包括最新的胎兒母血游離DNA篩檢，準確度比起現有的篩檢方式精確，但價格也昂貴許多。世界各國已開始探討如何選擇唐氏症篩檢策略，本研究則是欲探討台灣的唐氏症篩檢成本效果分析。
研究目的：本研究利用成本效果分析方法，評估台灣不同種的唐氏症篩檢策略。
研究方法：本研究樣本為台灣地區2016年孕婦人數共210,267人，35歲以上共57151人，34歲以下則為153,116人。研究設計以決策樹模型對35歲以上孕婦進行以下六種篩檢策略的成本效果分析: 羊膜穿刺術、第一孕期唐氏症篩檢（first trimester screening, FTS）、第二孕期唐氏症篩檢(second trimester screening, STS)、應變式第一孕期篩檢、應變式第二孕期篩檢及全面cfDNA篩檢；34歲以下孕婦則扣掉羊膜穿刺術，進行其他五種策略的成本效果分析。效果參數來自國外文獻查證，成本的參數則使用各地衛生局的醫療機構自費項目。另外考慮參數的不確定性，藉由蒙地卡羅模擬，進行機率性敏感度分析。結果呈現為不同篩檢策略下之增加成本效果比(incremental cost-effectiveness ratio, ICER)、成本效果接受曲線(acceptability curve)。最大願付價格(willingness to pay, WTP)參考文獻設定為新台幣一千萬元。
研究結果： 若WTP閾值為新台幣一千萬元，35歲以上孕婦以羊膜穿刺術比起成本最低的第二孕期唐氏症篩檢其增加成本效果比為690萬元新台幣；但若WTP閾值小於五百萬元，則以FTS相對於STS的增加成本效果比等於871,610為最低。而34歲以下孕婦若WTP閾值為新台幣一千萬元，FTS比起成本最低的STS其增加成本效果比為4,981,156元。至於cfDNA篩檢因價格過於昂貴，無法成為優勢策略。但若以醫源性流產的效果來看，應變式第二孕期唐氏症篩檢具成本效果。
結論：若WTP閾值為新台幣一千萬元，本研究結果顯示34歲以下孕婦接受第一孕期唐氏症篩檢、35歲以上孕婦接受羊膜穿刺，在診斷唐氏症的結果上是最具成本效果的策略，而全面cfDNA篩檢則不具有成本效果。但若是考量到醫源性流產的結果，則不論產婦的年齡為35歲上下，皆以包含cfDNA的應變式第二孕期唐氏症篩檢為優勢策略。

This study is a decision tree model analyzing 6 Down screening strategies in pregnant women older than 35 years old and 5 strategies in those younger than 34 years old in Taiwan. The 6 strategies include amniocentesis, first trimester screening, second trimester screening, contingent first trimester screening, contingent second trimester screening and cfDNA screening. The 5 strategies for pregnancies younger than 34 years old are the remaining except amniocentesis. The target population was all pregnant women of Taiwan in 2016. Comparing the 6 strategies for pregnancies above 35 years old, amniocentesis had an incremental cost-effectiveness ratio lower than maximum willingness-to-pay and had highest probability of being cost-effective in acceptability curve. In pregnancies under 34 years old, first trimester screening is the most cost-effective strategy. Universal cfDNA screening is hard to be cost-effective due to its high cost. Nevertheless, contingent second trimester screening might be most cost-effective in terms of the outcome of procedure related fetal loss.

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