Table 3.
Hormonal contraceptive use and preterm birth by period of last use relative to conception, progestin type, and route of administration
| Exposure | Exposed(n) | Preterm (n) | OR (95% CI) | aORa (95% CI) |
|---|---|---|---|---|
| None | 23,421 | 964 | referent | referent |
| 0 - 12 weeks after | ||||
| Combination OC | ||||
| drospirenone and EE | 368 | 22 | 1.48 (0.96, 2.29) | 1.17 (0.76, 1.80) |
| levonorgestrel and EE | 545 | 34 | 1.55 (1.09, 2.21) | 1.20 (0.83, 1.74) |
| norethisterone and EE | 75 | 11 | 4.00 (2.10, 7.62) | 3.33 (1.69, 6.57) |
| Progestin only OC | ||||
| norethisterone | 146 | 11 | 1.90 (1.02, 3.52) | 2.02 (1.09, 3.75) |
| Otherb | 504 | 16 | 0.76 (0.46, 1.26) | 0.69 (0.41, 1.15) |
| 1 - >0 months before | ||||
| Combination OC | ||||
| desogestrel and EE | 295 | 25 | 2.16 (1.42, 3.27) | 2.09 (1.38, 3.16) |
| drospirenone and EE | 1,472 | 61 | 1.01 (0.77, 1.31) | 0.95 (0.73, 1.24) |
| levonorgestrel and EE | 2,521 | 120 | 1.16 (0.96, 1.41) | 1.11 (0.91, 1.36) |
| norethisterone and EE | 372 | 19 | 1.25 (0.79, 2.00) | 1.21 (0.76, 1.93) |
| Progestin only OC | ||||
| desogestrel | 690 | 17 | 0.59 (0.36, 0.96) | 0.65 (0.40, 1.06) |
| norethisterone | 483 | 13 | 0.64 (0.37, 1.12) | 0.74 (0.43, 1.29) |
| Vaginal ring | ||||
| etonogestrel and EE | 356 | 13 | 0.88 (0.51, 1.54) | 0.86 (0.49, 1.51) |
| Otherb | 276 | 7 | 0.61 (0.29, 1.29) | 0.60 (0.28, 1.28) |
| 4 - >1 month before | ||||
| Combination OC | ||||
| desogestrel and EE | 197 | 11 | 1.38 (0.75, 2.54) | 1.27 (0.69, 2.35) |
| drospirenone and EE | 1,227 | 56 | 1.11 (0.85, 1.47) | 1.07 (0.80, 1.41) |
| levonorgestrel and EE | 2,107 | 125 | 1.47 (1.21, 1.78) | 1.40 (1.15, 1.70) |
| norethisterone and EE | 302 | 21 | 1.74 (1.11, 2.72) | 1.67 (1.06, 2.62) |
| Progestin only OC | ||||
| desogestrel | 817 | 34 | 1.01 (0.71, 1.43) | 1.15 (0.81, 1.63) |
| norethisterone | 417 | 16 | 0.93 (0.56, 1.54) | 1.09 (0.66, 1.80) |
| Vaginal ring | ||||
| etonogestrel and EE | 352 | 12 | 0.82 (0.46, 1.47) | 0.80 (0.45, 1.43) |
| Otherb | 321 | 12 | 0.90 (0.51, 1.62) | 0.89 (0.50, 1.60) |
| 12 ->4 months before | ||||
| Combination OC | ||||
| desogestrel and EE | 215 | 17 | 2.00 (1.21, 3.30) | 1.86 (1.13, 3.09) |
| drospirenone and EE | 1,475 | 79 | 1.32 (1.04, 1.67) | 1.25 (0.99, 1.60) |
| levonorgestrel and EE | 2,605 | 122 | 1.14 (0.94, 1.39) | 1.09 (0.89, 1.33) |
| norethisterone and EE | 338 | 23 | 1.70 (1.11, 2.61) | 1.61 (1.05, 2.49) |
| Progestin only OC | ||||
| desogestrel | 1,031 | 42 | 0.99 (0.72, 1.36) | 1.13 (0.82, 1.55) |
| norethisterone | 640 | 22 | 0.83 (0.54, 1.28) | 0.95 (0.62, 1.47) |
| Vaginal ring | ||||
| etonogestrel and EE | 424 | 12 | 0.68 (0.38, 1.21) | 0.67 (0.38, 1.20) |
| Transdermal patch | ||||
| norelgestromin | 295 | 10 | 0.82 (0.43, 1.54) | 0.78 (0.41, 1.48) |
| Injectable | ||||
| medroxyprogesterone | 180 | 14 | 1.96 (1.13, 3.40) | 1.83 (1.06, 3.18) |
| Otherb | 267 | 8 | 0.72 (0.36, 1.46) | 0.79 (0.39, 1.60) |
a
adjusted for parity, maternal education, maternal pre-pregnancy BMI, maternal smoking, and maternal age at birth
b
hormonal contraceptive types with <10 exposed cases collapsed into a single “other” category