Table 1.
Characteristics of the Sample by Groups
| Characteristic | n | Nonpregnant | Day 15 | Day 17 | Day 19 | Day 20 | Day 21 | Statistics |
|---|---|---|---|---|---|---|---|---|
| Rat age, d* | 78 | 215 (25) | 108 (14) | 108 (14) | 108 (14) | 110 (13) | 111 (11) | F5,72 = 93.61; P < .0001 |
| Rat weight, g | 78 | 301 (17) | 286 (15) | 298 (16) | 323 (39) | 349 (24) | 353 (36) | F5,72 = 14.86; P < .0001 |
| No. of pups | 65 | 0 | 13 | 12 | 11 | 13 | 13 | F4,60 = 0.84; P = .51 |
| Pup weight, g | 65 | 0 | 0.4 (0.1) | 1.1 (0.2) | 2.7 (0.4) | 4.2 (0.3) | 5.4 (0.6) | F4,60 = 5.26; P < .0001 |
| Duration of experiment, min† | 78 | 99 (51) | 90 (10) | 95 (33) | 108 (53) | 88 (32) | 105 (37) | F5,72 = 0.50; P = .77 |
| Rat cervix weight, mg | 78 | 66 (13) | 74 (10) | 88 (11) | 97 (11) | 99 (18) | 114 (23) | F5,72 = 17.33; P < .0001 |
| Cervix length, mm | 78 | 5.9 (0.6) | 6.4 (0.5) | 6.7 (0.6) | 6.8 (0.8) | 5.8 (0.8) | 5.9 (0.7) | F5,72 = 5.26; P < .0001 |
| Cervix width, mm | 78 | 3.0 (0.4) | 3.1 (0.5) | 3.4 (0.4) | 3.3 (0.6) | 3.3 (0.5) | 3.7 (0.6) | F5,72 = 3.28; P = .01 |
| Cervix depth, mm | 78 | 4.4 (0.4) | 4.7 (0.5) | 4.7 (0.7) | 4.7 (0.7) | 5.1 (0.4) | 6.1 (1.1) | F5,72 = 9.82; P < .0001 |
Values are expressed as mean (standard deviation); n = 13 rats in each group.
*
Age was not significantly different among pregnant groups; F4,60 = 0.14; P = .96.
†
Time from euthanasia until the cervix specimen was frozen.