1. Intervention and quality summary.
| Study | Delivery type | IUC | Inadequate randomization and allocation concealment | No blinding | Loss to follow‐up > 20% | Quality of evidencea |
| Immediate versus early insertion (10 minutes to 48 hours) | ||||||
| Dahlke 2011 | Vaginal | LNG‐IUS | _ | ‐1 | _ | Moderate |
| Ahuja 2014b | Vaginal | CuT 380A | _ | ‐1 | Unclear | Moderate |
| Singh 2014b | Vaginal or cesarean | CuT 380A | ‐1 | Unclear | Unclear | Low |
| Immediate versus standard insertion (weeks) | ||||||
| Chen 2010 | Vaginal | LNG‐IUS (6 to 8 weeks) | _ | _ | _ | High |
| Dahlke 2011 | Vaginal | LNG‐IUS (> 6 weeks) | _ | ‐1 | _ | Moderate |
| Whitaker 2014 | Cesarean | LNG‐IUS (4 to 8 weeks) | _ | _ | ‐1 | Moderate |
| Lester 2015 | Cesarean | CuT 380A (6 weeks) | _ | ‐1 | _ | Moderate |
| Ogburn 2013b | Vaginal or cesarean | CuT 380A (4 to 12 weeks) | ‐1 | Unclear | Unclear | Low |
| Immediate insertion: IUC types, modifications, or insertion techniques | ||||||
| Thiery 1980 | Unclear | Multiload 250 versus CuT 200 | ‐1 | Unclear | _ | Moderate |
| WHO 1980 | Vaginal | Copper 7 versus Lippes Loop D vs Nova‐T‐PP | _ | ‐1 | _ | Moderate |
| Van Kets 1987 | Unclear | Nova‐T‐PP vs Nova T | ‐1 | Unclear | _ | Moderate |
| Lavin 1983 | Unclear | Progestasert vs CuT 200 | _ | Unclear | ‐1 | Moderate |
| Apelo 1985 | Vaginal | IPCS‐52 vs CuT 200 | _ | Unclear | ‐1 | Moderate |
| Cole 1984 | Vaginal |
_ |
Unclear | ‐1 | Moderate | |
| Kisnisci 1985 | Unclear | Delta Loop vs Delta T | _ | Unclear | _ | Moderate |
| Xu 1996 | Vaginal | CuT 380A: hand vs ring‐forceps insertion | _ | _ | _ | High |
aRCTs considered high quality initially, then downgraded for (1) no information on randomization sequence generation or allocation concealment, or one was clearly inadequate; (2) no blinding; (3) losses > 20%; (4) information missing for both blinding and losses. Follow‐up time not shown as all studies met criteria. bNo full report; sources included conference abstracts and clinical trial listings.