Embase (Embase.com)
Steps	Text words and subject headings	Sets of search
1	'cell‐free dna'	Index test
2	'cell free dna'
3	cfdna
4	ffdna
5	cffdna
6	'free foetal dna'
7	'free fetal dna'
8	nipd
9	nipt
10	'non invasive'
11	noninvasive
12	'non‐invasive'
13	genetic NEXT/1 (diagnos* or screen* or test* or detect*)
14	'genetic screening'/exp
15	'genetic testing'/exp
16	'sequence analysis dna'/exp
17	antenatal NEXT/1 (diagnos* or screen* or test* or detect*)
18	prenatal NEXT/1 (diagnos* or screen* or test* or detect*)
19	pre?natal NEXT/1 (diagnos* or screen* or test* or detect*)
20	'prenatal diagnosis'/exp
21	1 OR 2 OR 3 OR 4 OR 5 OR 6 OR 7 OR 8 OR 9 OR 10 OR 11 OR 12 OR 13 OR 14 OR 15 OR 16 OR 17 OR 18 OR 18 OR 19 OR 20
22	antenatal	Patient description
23	prenatal
24	pre?natal
25	maternal
26	foetus
27	fetus
28	foetal
29	fetal
30	pregnanc*
31	pregnant
32	'pregnancy'/exp
33	'pregnancy complications'/exp
34	'pregnant woman'/exp
35	'pregnant women'/exp
36	22 OR 23 OR 24 OR 25 OR 26 OR 27 OR 28 OR 29 OR 30 OR 31 OR 32 OR 33 OR 34 OR 35
37	trisom*	Target condition
38	aneuploid*
39	down* NEXT/1 syndrome
40	'aneuploid'/exp
41	'aneuploidy'/exp
42	'trisomy'/exp
43	'downs syndrome'/exp
44	'down syndrome'/exp
45	'chromosome disorders'
46	37 OR 38 OR 39 OR 40 OR 41 OR 42 OR 43 OR 44 OR 45
47	21 and 36 and 46	Final combined set