Kristen A Hahn1, Elizabeth E Hatch2, Kenneth J Rothman3, Ellen M Mikkelsen4, Susan B Brogly2, Henrik T Sørensen5, Anders H Riis4, Lauren A Wise6. 1. Department of Epidemiology, Boston University School of Public Health, Boston, MA. Electronic address: kahahn@bu.edu. 2. Department of Epidemiology, Boston University School of Public Health, Boston, MA. 3. Department of Epidemiology, Boston University School of Public Health, Boston, MA; RTI Health Solutions, Research Triangle Park, NC. 4. Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark. 5. Department of Epidemiology, Boston University School of Public Health, Boston, MA; Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus N, Denmark. 6. Department of Epidemiology, Boston University School of Public Health, Boston, MA; Slone Epidemiology Center, Boston University, Boston, MA.
Abstract
PURPOSE: To examine the association between pregravid oral contraceptive (OC) use and spontaneous abortion (SAB). METHODS: In an Internet-based preconception cohort study of 4862 Danish pregnancy planners, we used Cox proportional hazards models to estimate adjusted hazard ratios and 95% confidence intervals (CIs) for the association between OC use and SAB. We controlled for maternal age, physical activity, parity, education, alcohol and caffeine consumption, body mass index, and smoking. RESULTS: Compared with women who discontinued OCs >1 year before conception, HRs were 0.95 (95% confidence interval (CI) = 0.77-1.17), 0.99 (95% CI = 0.82-1.19), and 0.80 (95% CI = 0.60-1.06) for women who discontinued OCs 7-12, 2-6, and 0-1 months before conception, respectively. Compared with less than 4 years of OC use, HRs for 4-7, 8-11, and 12 years or more of OC use were 1.05 (95% CI = 0.80-1.37), 0.92 (95% CI = 0.71-1.19), and 0.88 (95% CI = 0.65-1.19), respectively. Dose of estrogen and generation of progestin were not materially associated with SAB risk. CONCLUSIONS: We found no evidence that pregravid OC use is associated with an increase in SAB. Use within 1 month of conception was associated with a slightly lower risk of SAB, but this may be due to increased reproductive fitness in women who conceive quickly after discontinuation of OCs.
PURPOSE: To examine the association between pregravid oral contraceptive (OC) use and spontaneous abortion (SAB). METHODS: In an Internet-based preconception cohort study of 4862 Danish pregnancy planners, we used Cox proportional hazards models to estimate adjusted hazard ratios and 95% confidence intervals (CIs) for the association between OC use and SAB. We controlled for maternal age, physical activity, parity, education, alcohol and caffeine consumption, body mass index, and smoking. RESULTS: Compared with women who discontinued OCs >1 year before conception, HRs were 0.95 (95% confidence interval (CI) = 0.77-1.17), 0.99 (95% CI = 0.82-1.19), and 0.80 (95% CI = 0.60-1.06) for women who discontinued OCs 7-12, 2-6, and 0-1 months before conception, respectively. Compared with less than 4 years of OC use, HRs for 4-7, 8-11, and 12 years or more of OC use were 1.05 (95% CI = 0.80-1.37), 0.92 (95% CI = 0.71-1.19), and 0.88 (95% CI = 0.65-1.19), respectively. Dose of estrogen and generation of progestin were not materially associated with SAB risk. CONCLUSIONS: We found no evidence that pregravid OC use is associated with an increase in SAB. Use within 1 month of conception was associated with a slightly lower risk of SAB, but this may be due to increased reproductive fitness in women who conceive quickly after discontinuation of OCs.
Authors: Claudia L Nassaralla; Joseph B Stanford; K Diane Daly; Mary Schneider; Karen C Schliep; Richard J Fehring Journal: J Womens Health (Larchmt) Date: 2011-01-10 Impact factor: 2.681