Characteristic | Singletons (n) | Male (n) | Sex ratio(%) | P-value |
---|---|---|---|---|
Blastocyst quality | Â | Â | Â | <0.001 |
 High | 638 | 383 | 60.0 |  |
 Poor | 572 | 284 | 49.7 |  |
Maternal age | Â | Â | Â | 0.261 |
 <35 | 971 | 543 | 55.9 |  |
  ≥ 35 | 239 | 124 | 51.9 |  |
Maternal BMI | Â | Â | Â | 0.173 |
 <18.5 | 47 | 32 | 68.1 |  |
 18.5 ~ 24.9 | 772 | 425 | 55.1 |  |
  ≥ 25 | 391 | 210 | 53.7 |  |
Type of infertility | Â | Â | Â | 0.887 |
 Primary | 541 | 297 | 54.9 |  |
 Secondary | 669 | 370 | 55.3 |  |
Cause of infertility | Â | Â | Â | 0.537 |
 Female factor | 661 | 363 | 54.9 |  |
 Male factor | 307 | 178 | 58 |  |
 Combined factor | 193 | 102 | 52.8 |  |
 Unexplained | 49 | 24 | 49 |  |
Type of fertilization | Â | Â | Â | 0.191 |
 IVF | 855 | 461 | 53.9 |  |
 ICSI | 355 | 206 | 58.0 |  |
Day of frozen embryo | Â | Â | Â | 0.774 |
 D5 | 783 | 434 | 55.4 |  |
 D6 | 427 | 233 | 54.6 |  |