Table 1.
Demographic characteristics of participants in the prospective and retrospective cohorts.
| Prospective | Retrospective | |
|---|---|---|
| Age (Median, IQR) | 30 (27–35) | 33 (29–29) |
| Cycle length, days (Median, IQR) | 28 (27–30) | 28 (27–30) |
| Hormonal contraception | ||
| No hormonal contraception | 63 (79.7%) | 1,117 (87.6%) |
| Combined pill | 7 (8.9%) | 53 (4.2%) |
| Progesterone only pill | 3 (3.8%) | 17 (1.3%) |
| IUS | 5 (6.3%) | 47 (3.7%) |
| Contraceptive patch | 1 (1.3%) | 3 (0.2%) |
| Contraceptive implant | 0 (0%) | 2 (0.2%) |
| Contraceptive injection | 0 (0%) | 2 (0.2%) |
| Vaginal ring | 0 (0%) | 2 (0.2%) |
| Other | 0 (0%) | 10 (0.8%) |
| Not specified | 0 (0%) | 5 (0.4%) |
| Previous diagnoses | ||
| Abnormal menstrual bleeding | 4 (5.1%) | 22 (1.7%) |
| Heavy menstrual bleeding | 12 (15.2%) | 150 (11.8%) |
| Endometriosis | 3 (3.8%) | 60 (4.7%) |
| Polycystic ovaries | 7 (8.9%) | 87 (6.8%) |
| Uterine fibroids | 5 (6.3%) | 21 (2.4%) |
| Currently breastfeeding | ||
| Yes | 6 (7.6%) | 89 (7.1%) |
| No | 73 (92.4%) | 1,179 (92.5%) |
| Not specified | 0 (0%) | 5 (0.4%) |
| Previous pregnancies | ||
| 0 | 45 (57.0%) | 572 (45%) |
| 1 | 15 (19.0%) | 219 (17.2%) |
| 2 | 7 (8.9%) | 220 (17.3%) |
| 3 or more | 8 (10.1%) | 252 (19.8%) |
| Not specified | 4 (5.1%) | 10 (0.8%) |
| Vaccine | ||
| Pfizer | 65 (82.3%) | 778 (61%) |
| Moderna | 11 (14.0%) | 136 (10.7%) |
| AstraZeneca | 3 (3.8%) | 346 (27.1%) |
| Janssen | 0 (0%) | 8 (0.6%) |
| Not specified | 0 (0%) | 5 (0.4%) |