Body mass index does not affect the efficacy or bleeding profile during use of an ultra-low-dose combined oral contraceptive

Abstract

Objectives: Safe and effective contraceptive options for obese women are becoming more important due to the obesity epidemic within the United States. This study evaluated the impact of body mass index (BMI) on efficacy, safety and bleeding patterns during use of an ultra-low-dose combined oral contraceptive (COC).

Study design: Data are from a Phase 3 clinical efficacy and safety study of an ultra-low-dose COC containing 1.0-mg norethindrone acetate and 10-mcg ethinyl estradiol. Pearl Indices, adverse events and bleeding profile were calculated for BMI ranges of <25, 25-30 and >30 kg/m(2).

Results: Of the 1581 participants included in the analysis, 28.3% were overweight, and 18.0% were obese. For women aged 18-45 years, the Pearl Indices were 2.49, 2.32 and 1.89 for women with a BMI <25, 25-30 and >30 kg/m(2), respectively. The ultra-low dose of ethinyl estradiol did not impact scheduled bleeding or intensity of bleeding, but we observed a slight decline in amenorrhea and slight increase in unscheduled bleeding in obese women compared with other BMI categories.

Conclusions: Our analysis of an ultra-low-dose COC did not find clinically important differences in contraceptive failure rates, adverse events or bleeding profile with increasing BMI.

Implications: Our analysis of an ultra-low ethinyl estradiol dose COC did not find clinically important differences in contraceptive failure rates, adverse events or bleeding profile with increasing BMI. An ultra-low-dose COC provides another safe and effective contraceptive option for obese women.

Trial registration: ClinicalTrials.gov NCT00391807.

Keywords: Ethinyl estradiol; Norethindrone acetate; Obesity; Oral contraceptive; Weight.