Table 3.
Odds ratios for the association between COVID-19 vaccination and ectopic pregnancy from multinomial logistic regression models
| Number of pregnancies | Number (%) of ongoing pregnancies | Number (%) of ectopic pregnancies | Odds ratio (95% CI)a | p-value | Adjusted odds ratio (95% CI)b | p-value | |
|---|---|---|---|---|---|---|---|
| Primary analysis (historical controls) | |||||||
| Unvaccinated | 31,710 | 23,438 (73.9%) | 379 (1.2%) | 1 | 1 | ||
| Vaccinated | 10,570 | 7328 (69.3%) | 126 (1.2%) | 1.05 (0.86–1.29) | 0.61 | 1.13 (0.92–1.38) | 0.25 |
| BNT162b2 subgroup analysis (historical controls) | |||||||
| Unvaccinated | 22,020 | 16,315 (74.1%) | 271 (1.2%) | 1 | 1 | ||
| Vaccinated | 7340 | 5124 (69.8%) | 87 (1.2%) | 1.02 (0.80–1.30) | 0.90 | 1.11 (0.87–1.42) | 0.39 |
| mRNA-1273 subgroup analysis (historical controls) | |||||||
| Unvaccinated | 3120 | 2405 (77.1%) | 22 (0.7%) | 1 | 1 | ||
| Vaccinated | 1040 | 705 (67.8%) | 13 (1.3%) | 1.99 (1.00–3.98) | 0.05 | 2.07 (0.98–4.38) | 0.06 |
| ChAdOx1-S/nCoV-19 subgroup analysis (historical controls) | |||||||
| Unvaccinated | 5862 | 4189 (71.5%) | 76 (1.3%) | 1 | 1 | ||
| Vaccinated | 1954 | 1264 (64.7%) | 26 (1.3%) | 1.12 (0.72–1.76) | 0.61 | 1.16 (0.74–1.83) | 0.52 |
| Supplementary analysis (contemporary controls) | |||||||
| Unvaccinated | 31,710 | 22,901 (72.2%) | 336 (1.1%) | 1 | 1 | ||
| Vaccinated | 10,570 | 7,328 (69.3%) | 126 (1.2%) | 1.17 (0.95–1.43) | 0.14 | 1.12 (0.90–1.40) | 0.31 |
| BNT162b2 subgroup analysis (contemporary controls) | |||||||
| Unvaccinated | 22,020 | 15,957 (72.5%) | 238 (1.1%) | 1 | 1 | ||
| Vaccinated | 7340 | 5124 (69.8%) | 87 (1.2%) | 1.13 (0.89–1.45) | 0.32 | 1.12 (0.86–1.46) | 0.41 |
| mRNA-1273 subgroup analysis (contemporary controls) | |||||||
| Unvaccinated | 3120 | 2308 (74.0%) | 26 (0.8%) | 1 | 1 | ||
| Vaccinated | 1040 | 705 (67.8%) | 13 (1.3%) | 1.62 (0.83–3.18) | 0.16 | 1.28 (0.55–2.99) | 0.57 |
| ChAdOx1-S/nCoV-19 subgroup analysis (contemporary controls) | |||||||
| Unvaccinated | 5862 | 4117 (70.2%) | 63 (1.1%) | 1 | 1 | ||
| Vaccinated | 1954 | 1264 (64.7%) | 26 (1.3%) | 1.34 (0.84–2.13) | 0.21 | 1.15 (0.69–1.91) | 0.60 |
All analyses exclude women with confirmed SARS-CoV-2 infection between 6 weeks preconception and the earliest of either: end of pregnancy or the end of the exposure period at 2 + 6 weeks gestation.
CI confidence interval.
aAdjusting for matching factors: maternal age and gestational age at the date of vaccination of index vaccinated pregnancy (and season of conception for primary and primary subgroup analysis).
bAdditionally adjusting for deprivation, urban/rural status, and clinical vulnerability (and ethnicity and season of conception in supplementary analyses).