BOSTON — The route of hormonal contraceptive administration—transdermal or oral—does not make a difference in terms of the hormone's effect on plasma lipids and lipoproteins, according to the findings of a randomized crossover trial.
In the study, women on either a standard or extended-release contraceptive patch had higher levels of HDL cholesterol and its constituent apolipoprotein A1 (ApoA-1), compared with when they were taking oral contraceptives; however, the effects of patch and oral formulations on atherogenic lipoproteins were similar, Dr. Elizabeth Chan reported at a symposium sponsored by the International Atherosclerosis Society.
“Patch contraception results in 60% higher estrogen levels than oral contraception. It is the estrogen/progestin ratio that determines the overall lipoprotein effects in hormonal contraception formulations,” according to Dr. Chan, of the University of Washington Division of Cardiology in Seattle, and her colleagues.
Estrogen is known to increase triglycerides and HDL cholesterol, and progestin has been shown to increase LDL and decrease HDL, the authors explained. If differences in these effects do exist among the various administration methods, the cumulative effect could be considerable given women often remain on hormonal contraceptives for decades.
For the study, 35 healthy premenopausal women had a 2-month phase-in period on an oral contraceptive (Ortho-Cyclen; 35 mcg ethinyl estradiol and 0.25 mg norgestimate) and were then randomly assigned in a three-way crossover design to 2 months on either the oral contraceptive, a patch formulation (Ortho-Evra; approximating a daily dose of 20 mcg ethinyl estradiol and 150 mcg norelgestromin), or an extended-release patch (Extended Ortho-Evra). A total of 31 women completed all three treatments and were available for the final analysis.
The investigators found that the use of the standard patch formulation resulted in significantly higher levels of favorable lipids—HDL and ApoA1—compared with oral administration. The extended patch also had a significantly greater effect on HDL and ApoA1, compared with the standard patch.
But for all other lipid parameters—LDL, non-HDL cholesterol, apolipoprotein B, and triglycerides—there were no significant differences among the three contraceptive formulations.
The findings “do not provide compelling evidence for selection of one method of hormonal contraception versus another regarding their effects on lipids and lipoproteins,” the authors said.
The researchers reported having no conflicts of interest related to the study, which was supported by Ortho-McNeil, maker of the contraceptives tested.