Table 2.
Association of infertility, miscarriage, and stillbirth with non-fatal and fatal stroke
| Reproductive histories | Sample size | No of events | Incidence rate | Non-fatal stroke | Sample size | No of events | Incidence rate | Fatal stroke | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Crude HR (95% CI) | Adjusted HR (95% CI) | Crude HR (95% CI) | Adjusted HR (95% CI) | |||||||
| Models with single reproductive histories | ||||||||||
| History of infertility* | ||||||||||
| Never | 77 976 | 2292 | 47.6 | Reference | Reference | 34 488 | 177 | 7.6 | — | — |
| Ever | 16 211 | 453 | 46.0 | 1.13 (1.05 to 1.21) | 1.14 (1.08 to 1.20) | 5168 | 27 | 7.8 | — | — |
| History of miscarriage† | ||||||||||
| Never | 197 303 | 5812 | 43.0 | Reference | Reference | 455 363 | 3255 | 11.3 | Reference | Reference |
| Ever | 65 315 | 2124 | 47.7 | 1.11 (1.08 to 1.15) | 1.11 (1.07 to 1.15) | 89 983 | 712 | 11.8 | 1.18 (1.04 to 1.35) | 1.17 (1.07 to 1.29) |
| No of miscarriages† | ||||||||||
| 0 | 197 303 | 5812 | 43.0 | Reference | Reference | 455 363 | 3255 | 11.3 | Reference | Reference |
| 1 | 46 681 | 1454 | 45.6 | 1.06 (1.04 to 1.09) | 1.07 (1.04 to 1.10) | 66 227 | 479 | 10.8 | 1.08 (0.91 to 1.28) | 1.08 (0.96 to 1.21) |
| 2 | 11 988 | 395 | 48.4 | 1.13 (1.07 to 1.18) | 1.12 (1.07 to 1.17) | 15 805 | 137 | 12.9 | 1.26 (1.18 to 1.36) | 1.26 (1.07 to 1.49) |
| ≥3 | 6588 | 271 | 58.1 | 1.44 (1.34 to 1.56) | 1.35 (1.27 to 1.44) | 7897 | 96 | 18.0 | 1.93 (1.72 to 2.16) | 1.82 (1.58 to 2.10) |
| History of stillbirth‡ | ||||||||||
| Never | 243 859 | 7070 | 42.4 | Reference | Reference | 510 586 | 3479 | 10.7 | Reference | Reference |
| Ever | 8547 | 411 | 69.5 | 1.46 (1.18 to 1.82) | 1.31 (1.10 to 1.57) | 24 673 | 451 | 27.1 | 1.13 (1.08 to 1.18) | 1.07 (1.00 to 1.13) |
| No of stillbirths‡ | ||||||||||
| 0 | 243 859 | 7070 | 42.4 | Reference | Reference | 510 586 | 3479 | 10.7 | Reference | Reference |
| 1 | 7310 | 349 | 68.9 | 1.46 (1.23 to 1.72) | 1.32 (1.15 to 1.51) | 19 749 | 275 | 20.8 | 1.02 (0.97 to 1.06) | 0.97 (0.91 to 1.03) |
| ≥2 | 1225 | 62 | 73.6 | 1.53 (0.93 to 2.53) | 1.29 (0.84 to 1.98) | 4914 | 176 | 51.1 | 1.38 (1.27 to 1.50) | 1.26 (1.15 to 1.39) |
| Model with miscarriage and stillbirth§ | ||||||||||
| No of miscarriages | ||||||||||
| 0 | 190 991 | 5554 | 42.5 | Reference | Reference | 449 055 | 3236 | 11.4 | Reference | Reference |
| 1 | 43 855 | 1321 | 44.2 | 1.04 (1.02 to 1.06) | 1.05 (1.02 to 1.08) | 63 509 | 469 | 11.1 | 1.07 (0.91 to 1.27) | 1.08 (0.96 to 1.21) |
| 2 | 11 147 | 350 | 46.2 | 1.08 (1.05 to 1.12) | 1.08 (1.04 to 1.12) | 14 988 | 132 | 13.1 | 1.23 (1.14 to 1.33) | 1.23 (1.04 to 1.46) |
| ≥3 | 6032 | 236 | 57.9 | 1.38 (1.27 to 1.50) | 1.31 (1.23 to 1.41) | 7351 | 91 | 18.3 | 1.85 (1.67 to 2.06) | 1.76 (1.53 to 2.03) |
| No of stillbirths | ||||||||||
| 0 | 243 589 | 7056 | 42.4 | Reference | Reference | 510 320 | 3477 | 10.7 | Reference | Reference |
| 1 | 7231 | 344 | 68.6 | 1.43 (1.21 to 1.68) | 1.29 (1.13 to 1.47) | 19 689 | 275 | 20.9 | 1.01 (0.96 to 1.05) | 0.96 (0.90 to 1.02) |
| ≥2 | 1205 | 61 | 73.7 | 1.45 (0.90 to 2.32) | 1.23 (0.81 to 1.85) | 4894 | 176 | 51.4 | 1.34 (1.23 to 1.45) | 1.23 (1.12 to 1.34) |
Incidence rate (per 100 000 person years). Crude hazard ratios (HRs) took the cluster and fixed effects of study into account. Adjusted HRs were additionally adjusted for race or ethnicity, body mass index, smoking status, and education level, and stratified by history of hypertension.
Six studies (Australian Longitudinal Study on Women’s Health 1946-51 cohort—ALSWH-mid, Utrecht contribution to the European Prospective Investigation into Cancer and Nutrition cohort, Netherlands—Prospect-EPIC, Japan Nurses’ Health Study—JNHS, United Kingdom MRC National Survey of Health and Development—NSHD, United States Study of Women’s Health Across the Nation—SWAN, and Swedish Women’s Lifestyle and Health Study—WLH) and two studies (ALSWH-mid and JNHS) were included for non-fatal and fatal stroke, respectively.
Six studies (ALSWH-mid, China Biobank, Prospect-EPIC, NSHD, SWAN, and UK Biobank) and four studies (ALSWH-mid, China Biobank, Prospect-EPIC, and UK Biobank) were included for non-fatal and fatal stroke, respectively.
Five studies (China Biobank, Prospect-EPIC, NSHD, SWAN, and UK Biobank) and three studies (China Biobank, Prospect-EPIC, and UK Biobank) were included for non-fatal and fatal stroke, respectively.
Five studies (China Biobank, Prospect-EPIC, NSHD, SWAN, and UK Biobank) and three studies (China Biobank, Prospect-EPIC, and UK Biobank) were included for non-fatal and fatal stroke, respectively.