Sivin I, Mishell D R, Victor A, Diaz S, Alvarez-Sanchez F, Nielsen N C, Akinla O, Pyorala T, Coutinho E, Faundes A, Roy S, Brenner P F, Ahren T, Pavez M, Brache V, Giwa-Osagie O F, Fasan M O, Zausner-Guelman B, Darze E, Gama daSilva J C, Diaz J, Jackanicz T M, Stern J, Nash H A
Contraception. 1981 Oct;24(4):359-76. doi: 10.1016/0010-7824(81)90004-4.
Comparative clinical trials of 2 sizes of contraceptive vaginal rings and of an oral contraceptive were undertaken at 8 investigational sites (9 clinics). More than 500 women enrolled on each of the 3 study regimens. Side effects of the rings and of Nordette, the oral contraceptive, were evaluated by noting spontaneous complaints, by recording medications taken and by physical examination. Inquiries about changes in the frequency of specific conditions were made at the end of the subjects participation in the first year of the study. The incidence of spontaneous complaints was similar among users of the 2 different-sized rings and of the pill.
