Table II.
Overall characteristics and outcomes.
| Characteristic or outcome | Number of studies | Number of women | Gonadotrophins mean (25th–75th percentile) or N (%) | Clomiphene citrate mean (25th–75th percentile) or N (%) | Letrozole mean (25th–75th percentile) or N (%) |
|---|---|---|---|---|---|
| Female age (in years) | 6 | 2273 | 31.9 (29.0–35.0) | 32.0 (29.0–35.0) | 32.2 (29.0–35.0) |
| Body mass index, BMI | 5 | 2161 | 24.9 (21.2–27.0) | 24.7 (21.1–26.6) | 27.3 (22.3–30.9) |
| Primary infertility (%) | 6 | 2273 | 714 (72%) | 695 (70%) | 180 (60%) |
| Number of cycles | 6 | 2381 | 2.5 (1.0–4.0) | 2.6 (1.0–4.0) | 3.2 (2.0–4.0) |
| Live birth (%) | 6 | 2357 | 287 (28%) | 222 (22%) | 56 (19%) |
| Multiple pregnancy (%) | 6 | 2357 | 47 (5%) | 22 (2%) | 9 (3%) |
| - Twin | 35 (74%) | 21 (95%) | 9 (100%) | ||
| - Triplet | 12 (26%) | 1 (5%) | 0 (0%) | ||
| Ongoing pregnancy (%) | 6 | 2357 | 299 (29%) | 233 (23%) | 60 (20%) |
| Clinical pregnancy (%) | 7 | 2411 | 326 (31%) | 268 (25%) | 67 (22%) |
| Miscarriage (%) | 7 | 2411 | 71 (7%) | 54 (5%) | 9 (3%) |
|
Cancellations,
per cycle (%) |
5 | 2163 | 231 (9%) | 204 (8%) | 35 (4%) |
| Number of follicles >14 mm, per cycle | 5 | 2163 | 2.2 (1–3) | 2.1 (1–3) | 2.0 (1–2) |