Effects of a monophasic combined oral contraceptive containing nomegestrol acetate and 17β-oestradiol in comparison to one containing levonorgestrel and ethinylestradiol on markers of endocrine function

ABSTRACT

Objectives To compare the effects of two monophasic combined oral contraceptives, containing either nomegestrol acetate/17β-oestradiol (NOMAC/E2) or levonorgestrel/ ethinylestradiol (LNG/EE) on endocrine function, androgens, and sex hormone-binding globulin (SHBG).

Methods Randomised, open-label, multi-centre trial involving 121 healthy women, aged 18–50 years old. Participants received NOMAC/E2 (2.5 mg/1.5 mg) in a 24/4-day regimen (n = 60) or LNG/EE (150 μg/30 μg) in a 21/7-day regimen (n = 61) for six cycles. The primary outcome was the change from baseline to cycle 6 in markers of adrenal and thyroid function, androgens, and SHBG.

Results Total cortisol, corticosteroid-binding globulin (CBG), and thyroxine-binding globulin (TBG) increased from baseline in both groups, with significantly greater increases in the LNG/EE group. No relevant changes from baseline or differences between the groups were observed for thyroid-stimulating hormone (TSH) and free thyroxine (T₄). Androgens and androgen precursors decreased from baseline in both groups, with significantly greater decreases in the LNG/EE group (except for free testosterone). A greater increase in SHBG was observed with NOMAC/E2 than with LNG/EE.

Conclusions NOMAC/E2 has significantly less influence on markers of adrenal and thyroid function and androgens than LNG/EE. The clinical relevance of these findings requires further study.

KEYWORDS:

• Oral contraceptives
• Nomegestrol acetate
• 17β-oestradiol
• Adrenal
• Thyroid
• Androgen
• SHBG

ACKNOWLEDGEMENTS

The authors wish to thank Susan Abulhawa and A. Peter Morello III, PhD, of Evidence Scientific Solutions, Philadelphia, PA, for editorial and medical writing support, which was funded by Merck/MSD.

Declaration of interest: U. M. Ågren, W. F. Sommer, and E. Mommers are employees of MSD. At the time this study was performed, U. M. Ågren did not work for MSD, but she was an employee of FSHS Kuopio, Finland. M. Anttila, K. Mäenpää-Liukko, M. L. Rantala, and H. Rautiainen declare that they have no conflicts of interest. They also declare that they received no compensation or honoraria in association with this article.