Characteristics of the included studies
| Characteristic | N (%) |
| Research area | |
| Obstetrics | 32 (38) |
| Reproductive medicine | 28 (34) |
| Oncology | 5 (6) |
| (Uro)gynaecology | 18 (22) |
| Tested intervention | |
| Drugs | 20 (24) |
| Surgery | 20 (24) |
| Infertility treatments | 20 (24) |
| Obstetrical treatments | 12 (15) |
| Gynaecological treatments | 2 (2.4) |
| Diagnostic strategy | 6 (7.2) |
| Tested intervention | |
| Existing intervention | 69 (83) |
| New intervention | 14 (17) |
| Tested intervention | |
| Only available in the study | 17 (20) |
| Available outside the study | 66 (80) |
| Blinding | 18 (22) |
| No blinding | 65 (78) |
| Number of arms | |
| 2 | 77 (93) |
| >2 | 6 (7) |
| Pilot study | 17 (20) |
| No pilot study | 66 (80) |
| Recruiting centres | |
| Only Dutch centres | 70 (84) |
| Including foreign centres | 13 (16) |
| Funding | 68 (82) |
| No funding | 15 (18) |