Table 1 Demographic characteristics and FET parameters of the study population according to the initial day of estrogen usage
Parameters | Early initiation group (n = 128) | Late initiation group (n = 532) | p value |
|---|---|---|---|
Age, years | 30 (28, 34) | 30 (27, 32) | 0.063 |
BMI, kg/m2 | 21.8 (20.1, 24.6) | 22.0 (20.0, 24.5) | 0.830 |
Infertility type, n (%) | 0.486 | ||
Primary | 77 (60.2) | 302 (56.8) | |
Secondary | 51 (39.8) | 230 (43.2) | |
Infertility duration, years | 3 (2, 5) | 4 (2, 5) | 0.228 |
Infertility factor, n (%) | 0.061 | ||
Tubal factor | 69 (53.9) | 219 (41.2) | |
Male factor | 19 (14.8) | 93 (17.5) | |
Mixed male and female factor | 33 (25.8) | 191 (35.9) | |
Unexplained | 7 (5.5) | 29 (5.5) | |
Menstruation, n (%) | 0.993 | ||
Regular | 69 (53.9) | 287 (53.9) | |
Irregular | 59 (46.1) | 245 (46.1) | |
Duration of estrogen usage, days | 14 (11, 16) | 11 (9, 14) | < 0.001 |
Endometrial thickness at initial day of estrogen usage, mm | 5.0 (4.1, 5.8) | 5.9 (4.0, 5.7) | 0.469 |
Peak endometrial thickness, mm | 8.0 (7.4, 9.5) | 8.4 (7.8, 9.5) | 0.037 |
Optimal embryos transferred, n (%) | 107 (83.6) | 465 (87.4) | 0.255 |
Biochemical pregnancy, n (%) | 70 (54.7) | 362 (68.0) | 0.004 |
Clinical pregnancy, n (%) | 66 (51.6) | 342 (64.3) | 0.008 |
Ongoing pregnancy, n (%) | 60 (46.9) | 290 (54.5) | 0.120 |