List of databases and resources searched
| Electronic databases searched | Date of search |
| 1. Ovid multifile search (MEDLINE, EMBASE, PsycINFO) | 10 March 2017 |
| 2. POPline (via http://www.popline.org/), 1970–present | 10 March 2017 |
| 3. ProQuest multifile search | 10 April 2017 |
| 4. Applied Social Sciences Index Abstracts on ProQuest, 1987–current | 26 May 2017 |
| 5. Ovid MEDLINE 1948– and MEDLINE In-Process & Other Non-Indexed Citations to daily update | 26 July 2017 with monthly alert thereafter (cut-off date for included results 31 December 2017) |
| 6. Ovid EMBASE, 1980–2017 week 11 | 3 August 2017 with monthly alert thereafter (cut-off date for included results 31 December 2017) |
| 7. CINAHL Plus with Full Text/EBSCOhost to 2017 | 11 August 2017 with monthly alert thereafter (cut-off date for included results 31 December 2017) |
| 8. Ovid PsycINFO, 1972–March 2017 week 3 | 14 August 2017 with monthly alert thereafter (cut-off date for included results 31 December 2017) |
| 9. MIDIRS on Ovid, 1971–April 2017 | 18 August 2017 |
| 10. HMIC on Ovid, 1979 to date | 18 August 2017 |
| 11. Thomson Reuters Web of Science, 1900–2017 | 18 August 2017 |
| Grey literature sources | |
| 1. British Library Ethos (ethos.bl.uk) | |
| 2. Networked Digital Library of Theses and Dissertations (www.ndltd.org) | |
| 3. National Institute for Health and Care Excellence (https://www.nice.org.uk) | |
| 4. Trove - National Library of Australia (trove.nla.gov.au) | |
| 5. OpenGrey (http://www.opengrey.eu/) | |
| 6. Google | |
| 7. Google Scholar | |
| 8. Experts in the field | |
HMIC, Health Management Information Consortium; MIDIRS, Midwives Information & Resource Service.