Table 3.
Effect of OC use status, and OC type on APC-r ratio, SHBG (nmol/L), and protein S (% of normal activity); Adjusted means with 95% confidence intervals (CI). The mean change is statistically significant within groups if the 95% CI does not include zero, and between groups if the p-value is <0.05.
| Effect | Group | Time | APC-r ratio (95% CI)1 | SHBG nmol/L (95% CI)2 | Protein S % (95% CI)3 |
|---|---|---|---|---|---|
|
OC use status | |||||
| Current OC use (n = 102) | Contraceptive ring (n = 57) | Pre | 2.93 (2.75, 3.11) | 145.0 (121.1, 169.0) | 85.1 (78.2, 92.0) |
| Post | 2.93 (2.75, 3.11) | 135.4 (111.5, 159.3) | 91.2 (84.3, 98.1) | ||
| Mean change | −0.003 (−0.12, 0.12) | −9.6 (−26.4, 7.2) | 6.1 (1.5, 10.6) | ||
| Contraceptive patch (n = 45) | Pre | 2.80 (2.62, 2.98) | 159.2 (135.0, 183.4) | 83.1 (76.1, 90.1) | |
| Post | 2.81 (2.63, 2.99) | 177.6 (153.4, 201.8) | 78.5 (71.5, 85.5) | ||
| Mean change | 0.01 (−0.12, 0.14) | 18.4 (−0.5, 37.3) | −4.6 (−9.8, 0.6) | ||
| Between groups p-value4 | 0.737 | 0.030 | 0.003 | ||
|
| |||||
| Recent OC use (n = 18) | Contraceptive ring (n = 8) | Pre | 2.65 (2.29, 3.02) | 51.1 (2.8, 99.5) | 91.7 (77.9, 105.6) |
| Post | 2.86 (2.50, 3.22) | 106.9 (58.6, 155.3) | 92.0 (78.2, 105.8) | ||
| Mean change | 0.21 (−0.11, 0.52) | 55.8 (11.0, 100.7) | 0.3 (−11.9, 12.4) | ||
| Contraceptive patch (n = 10) | Pre | 2.82 (2.50, 3.14) | 99.2 (56.2, 142.1) | 101.7 (89.4, 113.9) | |
| Post | 3.10 (2.78, 3.42) | 180.5 (137.6, 223.4) | 83.4 (71.1, 95.7) | ||
| Mean change | 0.28 (−0.003, 0.56) | 81.3 (41.2, 121.4) | −18.3 (−29.2, −7.4) | ||
| Between groups p-value4 | 0.861 | 0.403 | 0.026 | ||
|
| |||||
|
Effect of estrogen dose | |||||
| EE = 20 mcg (n = 16) | Contraceptive ring (n = 9) | Pre | 3.03 (2.65, 3.42) | 144.6 (89.9, 199.3) | 97.7 (83.9, 111.4) |
| Post | 2.92 (2.53, 3.31) | 147.9 (108.3, 187.5) | 95.8 (82.0, 109.6) | ||
| Mean change | −0.11 (−0.41, 0.18) | 3.3 (−33.5, 40.0) | −1.9 (−13.5, 9.9) | ||
| Contraceptive patch (n = 7) | Pre | 2.68 (2.28, 3.09) | 176.2 (121.0, 231.3) | 79.4 (64.9, 93.2) | |
| Post | 2.57 (2.17, 2.98) | 166.5 (113.7, 219.3) | 84.7 (70.2, 99.2) | ||
| Mean change | −0.11 (−0.45, 0.23) | −9.7 (−63.2, 43.8) | 5.3 (−8.0, 18.5) | ||
| Between groups p-value4 | 0.993 | 0.692 | 0.427 | ||
|
| |||||
| EE >20 mcg (n = 86) | Contraceptive ring (n = 48) | Pre | 2.94 (2.74, 3.15) | 142.0 (114.8, 169.3) | 82.8 (75.5, 90.0) |
| Post | 2.96 (2.76, 3.17) | 130.0 (108.1, 151.8) | 90.3 (83.1, 97.6) | ||
| Mean change | 0.02 (−0.11, 0.15) | −12.0 (−28.0, 3.9) | 7.5 (2.5, 12.6) | ||
| Contraceptive patch (n = 38) | Pre | 2.84 (2.64, 3.05) | 152.0 (124.8, 179.1) | 83.7 (76.3, 91.1) | |
| Post | 2.88 (2.67, 3.09) | 175.6 (149.3, 201.9) | 77.2 (69.7, 84.7) | ||
| Mean change | 0.04 (−0.11, 0.18) | 23.6 (0.6, 46.6) | −6.5 (−12.2, −0.7) | ||
| Between groups p-value4 | 0.854 | 0.013 | 0.001 | ||
|
| |||||
|
Effect of progestogen type | |||||
| 1st/2nd Generation (n = 25) | Contraceptive ring (n = 13) | Pre | 2.94 (2.62, 3.28) | 90.9 (47.2, 134.6) | 86.1 (74.2, 98.0) |
| Post | 2.89 (2.56, 3.23) | 109.6 (76.6, 142.6) | 91.6 (79.7, 103.6) | ||
| Mean change | −0.05 (−0.30, 0.19) | 18.7 (−11.1, 48.4) | 5.5 (−4.2, 15.3) | ||
| Contraceptive patch (n = 12) | Pre | 2.83 (2.50, 3.15) | 96.0 (58.2, 133.8) | 89.8 (78.2, 101.5) | |
| Post | 2.98 (2.66, 3.30) | 151.0 (110.3, 191.7) | 75.9 (64.3, 87.5) | ||
| Mean change | 0.15 (−0.11, 0.41) | 55.0 (15.4, 94.6) | −13.9 (−24.1, −3.8) | ||
| Between groups p-value4 | 0.259 | 0.149 | 0.007 | ||
|
| |||||
| 3rd generation (N = 66) | Contraceptive ring (n = 39) | Pre | 2.98 (2.76, 3.20) | 153.8 (126.1, 181.5) | 85.0 (77.2, 92.9) |
| Post | 3.00 (2.78, 3.21) | 136.4 (114.2, 158.7) | 90.0 (82.2, 97.9) | ||
| Mean change | 0.01 (−0.13, 0.16) | −17.4 (−34.5, −0.2) | 5.0 (−0.7, 10.6) | ||
| Contraceptive patch (n = 27) | Pre | 2.80 (2.56, 3.04) | 184.1 (156.8, 211.5) | 80.8 (72.3, 89.3) | |
| Post | 2.74 (2.51, 2.98) | 185.1 (156.0, 214.3) | 80.4 (71.8, 89.1) | ||
| Mean change | −0.06 (−0.23, 0.12) | 1.0 (−25.4, 27.4) | −0.4 (−7.2, 6.5) | ||
| Between groups p-value4 | 0.542 | 0.249 | 0.235 | ||
1
APC-r ratio, normal range > 2.19
2
SHBG, normal range 20–175 ng/mL
3
Protein S % of normal activity, normal range 73–149%
4
For comparison of pre-post mean change between ring and patch users within each category
Progestins were classified as either 3rd generation (norgestimate, desogestrel), 1st and 2nd generation (levonorgestrel, norgestrel, ethynodiol diacetate, norethindrone, or other (drosperinone).