Effects of synthetic progestagens on autonomic tone, neurohormones and C-reactive protein levels in young healthy females in reproductive age.

BACKGROUND: Heart rate variability and baroreceptor sensitivity are measures of autonomic control. While progestagen-containing replacement therapy in postmenopausal women adversely affects autonomic balance, the impact of hormonal contraceptives with synthetic progestagens on autonomic activity, neurohormones and C-reactive protein levels is not well characterized. METHODS AND
RESULTS: We analyzed parameters of heart rate variability and baroreceptor sensitivity in young healthy females without (n = 27) or on oral contraceptives with synthetic progestagens (n = 31). Demographic characteristics were not different among the examined groups. Total power (controls: 5682+/-3618 vs. hormones: 4800+/-2957 ms2; NS), standard deviation of beat-to-beat intervals (SDNN; 66+/-24 vs. 63+/-20 ms; p = 0.74), other time- and frequency-dependent parameters of heart rate variability and baroreceptor sensitivity (6.0+/-3.2 vs. 6.5+/-2.7 ms/mm Hg; NS) were not significantly different among the groups. Total cholesterol and triglyceride as well as C-reactive protein (CRP) levels were significantly higher in users of hormonal contraceptives than in non-users (cholesterol: 187+/-37 vs. 166+/-28 mg/dL; p = 0.05; triglycerides: 110+/-35 vs. 68+/-30 mg/dL; p = 0.01; CRP: 2.7+/-2.1 vs. 1.0+/-1.4 mg/L; p < 0.001). Heart rate variability, baroreceptor sensitivity, lipid parameters and CRP levels were not affected during the ovarian cycle in non-users of hormonal contraception.
CONCLUSIONS: The use of oral contraceptives containing synthetic progestagens was not associated with a modulation of autonomic tone, while lipid parameters and CRP levels were adversely affected. These data suggest that synthetic progestagens in modern oral contraceptives do not modulate the autonomic balance, but probably affect the atherogenic risk profile of young females in reproductive age.