5. Reduced visits/goal‐oriented visits vs standard ANC: Preterm birth.
| Study ID | Reduced visits | Standard care | Cluster number and ICC |
| Individual randomisation | |||
| England 1996 | 98/1361 | 82/1396 | |
| USA 1995 | 17/227 | 7/174 | |
| USA 1996 | 73/1165 | 63/1163 | |
| USA 1997 | 5/43 | 2/38 | |
| Cluster randomisation | |||
| WHO 2001 | 910/11534 | 852/11040 | 53 clinics. ICC 0.002 from WHO 2001 (Piaggio 2001) study |
| Zimbabwe 1996 | 945/9394 | 705/6138 | 7 clinics. ICC 0.002 from WHO 2001 (Piaggio 2001) study |
| Zimbabwe 2007 | 599/5058 | 588/4930 | 23 clinics. ICC 0.002 from WHO 2001 (Piaggio 2001) study |