Table 3.
Further analyses and restrictions to evaluate the association between bleeding and miscarriage, Right From the Start study (2000–2008)
| No bleeding | Any bleeding | Spotting/Light | Heavy | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | n SAB* | OR | n | n SAB* | OR** (95% CI) | n | n SAB* | OR** (95% CI) | n | n SAB* | OR** (95% CI) | |
| Changing episode definition | ||||||||||||
| 4 days (overall analysis results) | 3285 | 381 | 1.0 | 1204 | 131 | 1.1 (0.9, 1.3) | 1106 | 108 | 1.0 (0.8, 1.2) | 97 | 23 | 3.0 (1.9, 4.6) |
| 7 days | 3306 | 402 | 1.0 | 1183 | 110 | 0.9 (0.7, 1.1) | 1091 | 93 | 0.8 (0.6, 1.0) | 91 | 17 | 2.1 (1.3, 3.5) |
| Gestational age*** | ||||||||||||
| 3 days | 1408 | 53 | 1.0 | 532 | 21 | 1.2 (0.7, 2.0) | 495 | 18 | 1.1 (0.6, 1.8) | 37 | 3 | 2.5 (0.8, 8.2) |
| 7 days | 2124 | 82 | 1.0 | 797 | 33 | 1.2 (0.8, 1.8) | 743 | 29 | 1.1 (0.7, 1.7) | 54 | 4 | 2.4 (0.9, 6.5) |
| Loss and interview timing | ||||||||||||
| Loss before interview | 2904 | 244 | 1.0 | 1073 | 61 | 0.9 (0.6, 1.1) | 998 | 52 | 0.8 (0.6, 1.0) | 74 | 9 | 2.1 (1.1, 4.1) |
| Interview before loss | 2904 | 135 | 1.0 | 1073 | 67 | 1.5 (1.1, 2.0) | 998 | 54 | 1.3 (0.9, 1.8) | 74 | 13 | 4.5 (2.5, 8.0) |
| Restriction | ||||||||||||
| Women in first pregnancy | 1087 | 98 | 1.0 | 419 | 46 | 1.4 (1.0, 2.0) | 391 | 41 | 1.4 (0.9, 2.0) | 27 | 5 | 2.7 (1.1, 6.8) |
| Women with fetal cardiac motion | 3203 | 321 | 1.0 | 1180 | 117 | 1.2 (1.0, 1.5) | 1084 | 95 | 1.0 (0.8, 1.3) | 95 | 22 | 3.4 (2.2, 5.3) |
*
SAB: spontaneous abortion, or miscarriage
**
unadjusted odds ratio
***
only including pregnancies whose gestational age calculated by last menstrual period and by ultrasound agree within the specified amount (3 days or 7 days).