Oral contraceptive use is associated with a systemic acute phase response

Objective: We determined whether reported intake of oral contraceptives is associated with an acute phase response, since inflammation is important in atherogenesis and may contribute to the thrombo-occlusive complications seen in users of oral contraceptives.

Design: Cross-sectional study.

Setting: General Community of Augsburg.

Subjects: Eight hundred and forty-four women aged 25–44 years, drawn from a random sample of the general population, participating in the MONICA Augsburg survey 1994/95. Two hundred and thirty women used oral contraceptives and 614 did not take any hormones; pregnant women were excluded.

Main outcome measures: Plasma C-reactive protein, fibrinogen, and albumin, plasma viscosity and blood cell counts.

Results: Age-adjusted plasma levels of C-reactive protein in users of oral contraceptives were almost three times as high as in non-users (2.59 vs. 0.81 mg/l, P<0.001). Conversely, albumin levels were considerably lower in those on oral contraception compared to non-users (40.71 vs. 43.55 g/l,P <0.001). Plasma viscosity was marginally higher in users (P =0.05), but fibrinogen and blood cell counts did not differ between the two groups. The results did not change appreciably after adjustment for other relevant risk factors, including cigarette smoking, body mass index, lipid profile and alcohol consumption, remaining statistically significant at the same level.

Conclusion: These results indicate that use of oral contraception is associated with a modest, but statistically highly significant, acute phase response, and may be one mechanism by which oral contraceptives increase thromboembolic risk.