Table 2.
Quality assessment of studies on single embryo transfer versus double embryo transfer included in meta-analysis
| Target population described adequately | Sample size calculation | Adequate randomisation | Blinding | Intention to treat analysis performed | Two arms comparable at baseline | Follow-up >80% | |
|---|---|---|---|---|---|---|---|
| Published trials (details retrieved from published paper and response from authors) | |||||||
| Gerris et al, 199929 | Yes | No | Not stated in paper. Later confirmed as yes by author | Not stated in paper. Later confirmed as yes by author | Not stated in paper. Later confirmed as yes by author | Yes | Yes |
| Lukassen et al, 200527 | Yes | Yes | Yes | No | Yes | Yes | Yes |
| Martikainen et al, 200130 | Yes | No | Yes | Not stated in paper. Later confirmed as yes by author | Not stated in paper. Later confirmed as yes by author | Yes | Yes |
| Thurin et al, 200426 | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Van Montfoort et al, 200628 | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Unpublished trials (details retrieved from trial protocols and response from authors) | |||||||
| Thurin A, 20059 | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Davies M, 2003 | Yes | Yes | Yes | No | Results not previously analysed | Yes | Yes |
| Bhattacharya S, 200610 | Yes | Yes | Yes | Yes | Results not previously analysed | Yes | Yes |