A comparative study on the effects of a contraceptive vaginal ring NuvaRing and an oral contraceptive on carbohydrate metabolism and adrenal and thyroid function.
OBJECTIVE
To compare carbohydrate metabolism, adrenal and thyroid function during use of a combined contraceptive vaginal ring (NuvaRing, NV Organon, Oss, The Netherlands) with those of a combined oral contraceptive.


METHODS
Healthy women aged 18-40 years used either the vaginal ring, delivering 15 microg ethinylestradiol and 120 microg of etonogestrel per day, or a combined oral contraceptive containing 30 microg ethinylestradiol and 150 microg levonorgestrel, for six cycles. Each cycle comprised 3 weeks of use of the ring or the pill followed by 1 ring- or pill-free week. The following parameters were measured at baseline and at the end of cycles 3 and 6: carbohydrate metabolism (glucose, insulin, glycosylated hemoglobin); adrenal function (total cortisol, cortisol binding globulin, dehydroepiandrosterone sulfate); thyroid function (thyroid stimulating hormone, free thyroxine).


RESULTS
Small and similar increases in insulin were seen in both groups. Concentrations of cortisol binding globulin and total cortisol rose significantly less during ring use than during combined oral contraceptive use (cycle 3, p= 0.0002; cycle 6, p < 0.0001). Levels of dehydroepiandrosterone sulfate did not change in either group. Thyroid stimulating hormone levels increased significantly more in the ring group at cycle 3 (p = 0.0016) but free thyroxine levels were unchanged in both groups.


CONCLUSIONS
Both the vaginal ring and the oral contraceptive have no clinically relevant effects on carbohydrate metabolism, adrenal or thyroid function.
Duijkers
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I
Dinox BV Medical Investigations, Nijmegen, The Netherlands.
Killick
S
S
Bigrigg
A
A
Dieben
T O M
TO
D000293:Adolescent; D000311:Adrenal Glands / Q000187:drug effects; D000328:Adult; D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism; D002352:Carrier Proteins / Q000097:blood / Q000187:drug effects; D003274:Contraceptive Devices, Female; D003277:Contraceptives, Oral, Combined / Q000008:administration & dosage / Q000494:pharmacology*; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D004334:Drug Administration Schedule; D004739:England; D004997:Ethinyl Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006442:Glycated Hemoglobin / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D016912:Levonorgestrel / Q000008:administration & dosage / Q000494:pharmacology*; D009426:Netherlands; D012606:Scotland; D013961:Thyroid Gland / Q000187:drug effects; D013972:Thyrotropin / Q000097:blood / Q000187:drug effects; D013974:Thyroxine / Q000097:blood / Q000187:drug effects; D016896:Treatment Outcome
D001786:Blood Glucose; D002352:Carrier Proteins; D003277:Contraceptives, Oral, Combined; D019314:Dehydroepiandrosterone Sulfate; D004997:Ethinyl Estradiol; D006442:Glycated Hemoglobin; D006854:Hydrocortisone; D007328:Insulin; D016912:Levonorgestrel; D013972:Thyrotropin; D013974:Thyroxine; C027091:cortisol binding globulin