From: Oral contraceptive use before first birth and risk of breast cancer: a case control study
Use of OC | Cases | Controls | Crude | Adjusted* | |
---|---|---|---|---|---|
n | n | OR | OR | 95% CI | |
User after 1st birth † | 7 | 12 | 0.8 | 0.8 | (0.2, 2.5) |
User before 1st birth | 74 | 143 | 1.1 | 1.0 | (0.5, 1.7) |
User, no births | 32 | 62 | 1 | 1 | |
Order of use and births** not known | 1 | 5 |