Table 1.
Risk factors for postpartum thyroiditis (PPT) in a cohort of 412 pregnant women.*
| Risk factor | PPT, Yes [n = 63] | PPT, No [n = 349] | Statistics |
|---|---|---|---|
| Smoking status | |||
| Currently, n = 18 (4.4%) | 2 [3.2%] | 16 [4.6%] | χ2 = 0.26, P = 0.88 OR = 1.13 (0.56–2.30) |
| Formerly, n = 79 (19.2%) | 12 [19.0%] | 67 [19.2%] | |
| Never, n = 315 (76.4%) | 49 [77.8%] | 266 [76.2%] | |
| Previous miscarriage | |||
| Yes (59/412 = 14.3%) | 10/63 = 15.9% | 49/349 = 14.0% | χ2 = 0.15, P = 0.70 OR = 1.15 (0.55–2.42) |
| No (353/412 = 85.7%) | 53/63 = 84.1% | 300/349 = 86.0 | |
| Personal history (autoimm. nonthyroid diseases) | |||
| Positive, n = 109 (26.5%) | 29 [46.0%] | 80 [22.9%] |
χ2 = 14.65, P = 0.0001 OR = 2.87 (1.64–5.0) |
| Negative, n = 303 (73.5%) | 34 [54.0%] | 269 [77.1%] | |
| Family history (thyroid diseases) | |||
| Positive, n = 127 (30.8%)§ | 27 [42.9%] | 100 [28.7]% |
χ2 = 5.05, P = 0.025 OR = 1.87 (1.08–3.24) |
| Negative, n = 285 (69.2%) | 36 [57.1%] | 249 [71.3%] | |
| +ve for Hashimoto’s thyroiditis, n = 25 (6.1%)§ | 15 [23.8%] | 10 [2.9%] |
χ2 = 41.1, P = 6 × 10−10 OR = 10.6 (4.5–24.92) |
| Graves’ disease, n = 5 (1.2%)§ | 3 [4.8%] | 2 [0.6%] |
P = 0.027 OR = 8.67 (1.42–53) |
| Hashimoto’s t. and/or Graves’ d., n = 28 (6.8%)§ | 16 [25.4%] | 12 [3.4%] |
χ2 = 40.6, P = 8 × 10−10 OR = 9.6 (4.26–21.50) |
| Thyroid nodules, n = 66 (16.0%)§ | 11 [17.5%] | 55 [15.8%] | χ2 = 0.11, P = 0.73 OR = 1.13 (0.56–2.30) |
| No further specified, n = 45 (10.9%)§ | 6 [9.3%] | 39 [11.2%] | χ2 = 0.15, P = 0.70 OR = 0.84 (0.34–2.07) |
| Family history (autoimm. nonthyroid diseases) | |||
| Positive, n = 191 (46.4%) | 43 [68.2%] | 148 [42.4%] |
χ2 = 14.34, P = 0.0002 OR = 2.92 (1.65–5.17) |
| Negative, n = 221 (53.6%) | 20 [31.7%] | 201 [57.6%] | |
| TPOAb status, regardless of TgAb | |||
| TPOAb, positive at ≥ 101 U/ml, n = 56 (13.6%) | 39 [61.9%] | 17 [ 4.9%] |
χ2 = 148, P = 5 × 10−34 OR = 31.7 (15.7–64.2) |
| , negative at ≤ 100 U/ml, n = 356 (86.4%) | 24 [38.1%] | 332 [95.1%] | |
| , positive at ≥ 61 U/ml, n = 68 (16.5%) | 42 [66.7%] | 26 [7.4%] |
χ2 = 136, P = 2 × 10−31 OR = 24.8 (12.8–48.0) |
| , negative at ≤ 60 U/ml, n = 344 (83.5%) | 21 [33.3%] | 323 [92.6%] | |
| TgAb status, regardless of TPOAb | |||
| TgAb, positive at ≥ 101 U/ml, n = 29 (7.0%) | 17 [27.0%] | 12 [3.4%] |
χ2 = 45.2, P = 1.8 × 10−11 OR = 10.4 (4.66–23.12) |
| , negative at ≤ 100 U/ml, n = 383 (93.0%) | 46 [73.0%] | 337 [96.6%] | |
| , positive at ≥ 61 U/ml, n = 42 (10.2%) | 26 [41.3%] | 16 [4.6%] |
χ2 = 78.4, P = 8 × 10−19 OR = 14.6 (7.19–29.73) |
| , negative at ≤ 60 U/ml, n = 370 (89.8%) | 37 [58.7%] | 333 [9.5%] | |
| Thyroiditis at ultrasound | |||
| Present, n = 144 (35.0%) | 52 [82.5%] | 92 [26.4%] | χ2 = 74.1, P = 7.5 × 10−18 OR = 13.2 (6.60–26.40) |
| Absent, n = 268 (65.0%) | 11 [17.5%] | 257 [73.6%] | |
*
The denominator to calculate percentages in the column “Risk factor” is 412, and in the columns “PPT, Yes” or “PPT, No” is 63 or 349, respectively. Statistically significant differences are highlighted by the bold print. Lack of a χ2 value in the last column indicates that statistical analysis was by the Fisher’s exact test.
§
In the breakdown of positivity, numbers do not add up to 127 because a given woman may have more than one consanguineous with thyroid disease.