Table 1. Characteristics of the cohort (n = 3131).
| Variables | n (%) |
| Treatment Period | |
| 2009 | 1553(49.6%) |
| 2010 | 1578(50.4%) |
| Age (year) | |
| mean±SD | 31±3.90 |
| ≤28 | 924(29.51%) |
| (28,31] | 942(30.09%) |
| (31,33] | 493(15.75%) |
| (33,35] | 346(11.05%) |
| (35,38] | 286(9.13%) |
| >38 | 140(4.47%) |
| Duration of infertility (year) | |
| mean±SD | 5.12±3.56 |
| Body mass index (kg/m2) | |
| mean±SD | 21.47±2.78 |
| Insemination method | |
| IVF | 2343(74.83%) |
| ICSI | 608(19.42%) |
| 50%IVF+50%ICSI | 180(5.75%) |
| Protocol | |
| Long GnRH agonist protocol | 2901(92.65%) |
| Short GnRH agonist protocol | 171(5.46%) |
| GnRH antagonist protocol | 59(1.88%) |
| Infertility Type | |
| Primary infertility | 1532(48.93%) |
| Secondary infertility | 1599(51.07%) |
| Diagnosis of infertility | |
| Tubal factor | 1638(52.29%) |
| Male factor | 463(14.8%) |
| Endometriosis | 85(2.72%) |
| Ovarian factor | 80(2.56%) |
| Unexplained | 160(5.11%) |
| Other reasons | 703(22.47%) |
| Number of oocytes retrieved | |
| median(IQR) | 11.9(7–16) |
| ≤6 | 589(18.81%) |
| 7–14 | 1542(49.25%) |
| 15–20 | 785(25.07%) |
| ≥21 | 215(6.87%) |
| Total number of embryos | |
| median(IQR) | 7(4–10) |
| ≤4 | 973(31.1%) |
| 5–8 | 1109(35.42%) |
| 9–12 | 676(21.6%) |
| ≥12 | 373(11.9%) |