Table 3 Description and Examples of the Normalization Process of the Free-text Eligibility Criteria

1- Remove redundancy among inclusion and exclusion criteria

IC: no contraindication to low weight molecular heparin

EC: any contraindication to low weight molecular heparin

EC: any contraindication to low weight molecular heparin

2- Identify individual criteria (e.g. split a single complex criterion into multiple simple criteria)

IC: renal artery imaging dated less than 1 year confirming the existence of two normal-sized kidneys > 90 mm and showing no renal artery stenosis

IC: renal artery imaging dated less than 1 year;

IC: kidney size > 90 mm;

IC: no renal artery stenosis

3- Reformulate criteria (e.g. negate and switch from inclusion to exclusion)

IC: no renal artery stenosis

EC: renal artery stenosis

(Negation removed)

4- Recognition of individual medical concepts:

EC: known pregnancy or no effective contraception for women of childbearing age or breastfeeding

- Pregnancy

- Effective contraception

- Age

- Breastfeeding

5- Remove semantic ambiguity (based on knowledge sources or human expertise)

- Female contraception

- Oral contraception

- Intrauterine device

- Diaphragm

- Spermicide

- Impossible follow-up

- No translation

6- Translating medical concepts from local languages to English

EC: Grossesse connue ou absence de contraception efficace pour les femmes en âge de procréer ou allaitement.

EC: Known pregnancy or no effective contraception for women of childbearing age or breastfeeding