1. Optimal information size calculations: Chemoprevention versus placebo.
| Outcome | Assumed risk | Source | Clinically important relative reduction | Sample size required1,2 |
| Maternal mortality | 350/100,000 | Analysis 1.1 | 25% | 125228 |
| Severe anaemia | 150/1000 | Analysis 1.2 | 25% | 2540 |
| Anaemia | 650/1000 | Analysis 1.3 | 25% | 284 |
| Malaria | 170/1000 | Analysis 1.5 | 25% | 2194 |
| Parasitaemia | 290/1000 | Analysis 1.6 | 25% | 1124 |
| Spontaneous abortions | 32/1000 | Analysis 1.9 | 25% | 13348 |
| Still births | 33/1000 | Analysis 1.10 | 25% | 12932 |
| Neonatal deaths | 37/1000 | Analysis 1.12 | 25% | 11492 |
| Preterm birth | 160/1000 | Analysis 1.13 | 25% | 2356 |
| Low birthweight | 150/1000 | Analysis 1.14 | 25% | 2540 |
| Placental parasitaemia | 300/1000 | Analysis 1.18 | 25% | 1074 |
1 All calculations are based on: 2‐sided tests, with a ratio of 1:1, power of 0.8, and confidence level of 0.05. 2 All calculations were performed using: http://www.sealedenvelope.com/power/binary‐superiority