Table 1.
Demographic, clinical and cycle characteristics of subjects included in this study. Values are expressed as median (interquartile range) unless otherwise stated
| Parameter | Value |
|---|---|
| Age (years) | 35 (33–37) |
| Body mass index (kg/m2) | 21.2 (19.7–23.0) |
| Type of subfertility | |
| Primary | 1726 (67.5 %) |
| Secondary | 830 (32.5 %) |
| Duration of subfertility (years) | 4 (3–6) |
| Cause of subfertility | |
| Male | 1324 (51.8 %) |
| Tubal | 472 (18.5 %) |
| Endometriosis | 237 (9.3 %) |
| Unexplained | 194 (7.6 %) |
| Others | 329 (12.9 %) |
| Smoking | |
| No | 2312 (90.5 %) |
| Yes | 217 (8.5 %) |
| Missing data | 27 (1.1 %) |
| Treatment protocol | |
| Long GnRH agonist | 2396 (93.7 %) |
| Short GnRH agonist | 3 (0.1 %) |
| GnRH antagonist | 156 (6.1 %) |
| No down-regulationa | 1 (<0.1 %) |
| Type of gonadotrophin used | |
| HMG | 1875 (73.3 %) |
| Recombinant FSH | 681 (26.7 %) |
| Total dose of FSH (IU) | 2025 (1650–2700) |
| Average daily dose of gonadotrophin (IU) | 183.3 (175.0–238.6) |
| Duration of stimulation (days) | 11 (10–12) |
| Peak serum oestradiol level (pmol/L) | 9471 (5757–14987) |
| Number of follicles reaching 16 mm | 6 (4–8) |
| Number of retrieved oocytes | 9 (5–13) |
| OSI in the first IVF cycle (oocytes per 1,000 IU) | 4.00 (2.05–6.67) |
| OSI in the second IVF cycle (oocytes per 1,000 IU)b | 2.67 (1.37–5.13) |
| Interval between first and second IVF cycles (years)b | 0.75 (0.48–1.56) |
aNo pituitary down-regulation was used in one subject with hypogonadotrophic hypogonadism
bApplicable to subjects who had a second IVF cycle subsequent to the index first cycle