Types of combined oral contraceptives used by U.S. women, including women with risk of venous thromboembolism

Objective: To estimate the prevalence of types of combined oral contraceptive (COC) use among women in the United States.

Methods: We analyzed data from 12,279 women ages 15-44 years in the population-based reproductive health study, the National Survey of Family Growth. Data were collected continuously via in-person, computerized household interviews from 2006-2010. We focused on items pertaining to OC use at the time of interview. Analyses described proportions of women using COCs overall, by type (brand, dosage, generation, phase, regimen), across sociodemographic groups and among women with cardiovascular risks.

Results: Seventeen percent of women used COCs including 25% of those at risk of unintended pregnancy. COC use among women with cardiovascular risks ranged from 5% to 13%. COC users reported 88 different pill brands. More women used COCs with ≥30mcg versus <30mcg ethinyl estradiol (67% vs. 33%; 2% used 50mcg), monophasic versus multiphasic dosages (67% vs. 33%) and 21/7 versus extended cycle regimens (88% vs.12%); similar proportions used 1st (22%) and 2nd (19%) versus 3rd (41%) generation progestins. Factors associated with type of COC use included age, education, BMI, diabetic and gynecological histories, reasons for COC use and type of medical practice where COCs were received.

Conclusion: Although many modern COCs designed to improve method safety, tolerability and effectiveness are available in the U.S., women more commonly use earlier pill formulations. Further investigation of factors influencing women's use of types of COCs and their impact on adverse events, contraceptive behavior and unintended pregnancy rates at the population level is needed.