Table 1.
Patient characteristics.
| Characteristic | Overall (n = 1,103) | Day-5 blastocyst group (n = 941) | Day-6 blastocyst group (n = 162) | P value |
|---|---|---|---|---|
| Female | ||||
| Age at retrieval, y | 34.7 ± 4.3 | 34.6 ± 4.4 | 34.9 ± 3.6 | .447c |
| BMI, kg/m2 | 23.3 ± 4.4 | 23.3 ± 4.3 | 23.6 ± 4.8 | .582c |
| Women actively smokinga | 104 (9.4) | 82 (8.7) | 22 (13.6) | .050d |
| Parity | 0.2 ± 0.5 | 0.2 ± 0.5 | 0.2 ± 0.4 | .755c |
| Previous history of miscarriage | 205 (18.6) | 172 (18.3) | 33 (20.4) | .527d |
| Ovarian reserve at day 3 | ||||
| AFC | 21.7 ± 12.6 | 22.2 ± 12.8 | 18.7 ± 11.3 | <.001c |
| AMH (ng/mL) | 4.1 ± 4.2 | 4.2 ± 4.4 | 3.4 ± 2.6 | .020c |
| FSH (IU/L) | 6.8 ± 2.2 | 6.8 ± 2.2 | 6.9 ± 2.2 | .725c |
| Male | ||||
| Age, y | 38.8 ± 6.9 | 38.8 ± 6.8 | 38.7 ± 7.4 | .735c |
| BMI, kg/m2 | 24.7 ± 3.9 | 24.7 ± 3.9 | 24.5 ± 4.0 | .369c |
| Couple | ||||
| Type of infertility | .348d | |||
| Primary | 790 (71.6) | 669 (71.1) | 121 (74.7) | |
| Secondary | 313 (28.4) | 272 (28.9) | 41 (25.3) | |
| Cause of infertility | .774d | |||
| Tubal factor | 101 (9.2) | 88 (9.4) | 13 (8.0) | |
| Male factor | 335 (30.3) | 281 (29.8) | 54 (33.3) | |
| Endometriosis | 292 (26.5) | 253 (26.9) | 39 (24.1) | |
| Ovulatory factor | 73 (6.6) | 65 (6.9) | 8 (4.9) | |
| Idiopathic | 117 (10.6) | 97 (10.3) | 20 (12.3) | |
| Diminished ovarian reserve | 42 (3.8) | 34 (3.6) | 8 (4.9) | |
| More than one etiology | 143 (13.0) | 123 (13.1) | 20 (12.3) | |
| ART cycle rank,b n | 1.7 ± 1.1 | 1.6 ± 1.1 | 2.1 ± 1.4 | <.001c |
Note: Data are presented as mean ± standard error of the mean or n (%). AFC = antral follicle count; AMH = antimüllerian hormone; ART = assisted reproductive technology; BMI = body mass index.
a
Women actively smoking (19, 20): defined as a patient who answered “yes” to the following question: “Did you smoke a cigarette during the past 30 days?” (18).
b
Cycle rank: total number of ART cycles performed per woman.
c
Mann-Whitney test.
d
Pearson chi-square test.