RESUMO
This trial was designed to determine the differences in effectiveness, clinical acceptability, and one-year discontinuation rates of two low-dose oral contraceptives: Lo-Estrin (norethindrone acetate 1.5 mg plus ethinyl estradiol 0.030 mg) and Lo-Femenal (norgestrel 0.30 mg plus ethinyl estradiol 0.030 mg) in 148 Mexican women. In addition, the effects of both oral contraceptive preparations on blood lipids were prospectively evaluated in a subgroup of 41 women. The results indicated that there were no differences in pregnancy rates, discontinuation or clinical acceptability between the two groups. The lipid changes observed were minimal for the Lo-Femenal subgroup and somewhat greater for the Lo-Estrin group, mainly an increase in serum triglycerides. These changes were interpreted as estrogen induced effects of norethindrone-containing oral contraceptives. Overall, the data indicate that both Lo-Femenal and Lo-Estrin are effective and safe combined oral contraceptives.