Flow of participants in the control and contraception groups over 24 months.
COC1: adolescents receiving an oral contraceptive containing 20 μg ethinylestradiol/150 μg desogestrel; COC2: adolescents receiving an oral contraceptive containing 30 μg ethinylestradiol/3 mg drospirenone.At baseline, no significant differences in chronological age, bone age, or lumbar spine or subtotal body densitometric values were observed between the three groups. The mean age was 15.3 years in the control group, 15.8 years in the COC1 group, and 15.8 years in the COC2 group (p = 0.294) (