Table 1.
Characteristics of randomised and non-randomised studies included in the review
| Author | Country | Study design | Study duration | Population | Average age of participants (years) | Sample size |
| Randomised | ||||||
| Alexander et al 13 | Nigeria | RCT | 1.4 years | Pregnant women | 28 | 324 |
| McCracken et al 15 | Guatemala | RCT | 2 years | Women | 53 | 120 |
| Quinn et al 16 | Ghana | RCT | 5 months | Pregnant women (non-smoking and primary cooks) | 24 | 44 |
| Non-randomised | ||||||
| Alexander et al 12 | Bolivia | Before and after | 1.2 years | Women (non-smoking) | 52 | 28 |
| Clark et al 14 | Nicaragua | Before and after | 2 years | Women (non-smoking and primary cooks) | 35 | 74 |
RCT, randomised controlled trial.