Table 1 Input model parameters

Population

 Number of singleton pregnant women 15–49 years

111,752

111,003–113,134

Generated and calibrated using [1, 2]

 Down syndrome risk by maternal age

0.10 to 6.6%

[3]

 Voluntary induced abortion risk in Quebec

23% (90% in first trimester and 10% in second trimester)

[4]

 Spontaneous fetal loss risk, unaffected pregnancies

13.5%

[5]

 Spontaneous fetal loss risk, DS affected pregnancies

Week 10: 36%; week 12: 30%; week 14: 25%; week 16: 21%

[3, 6]

Uptake rates

 Current practice

50%

50–90%

[7]

 NIPT

90%

70–95%

[8, 9]

 Amniocentesis

90%

70–95%

[10, 11]

 Termination of pregnancy, DS confirmed

90%

50–100%

[10, 11]

Screening performances and outcomes

 Current screening practice

  Detection rate

85%

75–90%

[12]

  False positive

3.3%

2.5–5%

[7]

 NIPT

  Detection rate

99.9%

[13, 14]

  False positive rate

0.1%

 Failure rate of NIPT testing

2%

0–4%

[15]

 Fetal loss from amniocentesis

0.11%

0.05–1%

[16]

 Amniotic fluid leakage

1%

0.5–2%

[17]