Socioeconomic Status As a Risk Factor for Unintended Pregnancy in the Contraceptive CHOICE Project

OBJECTIVE: To evaluate the association of low socioeconomic status as an independent risk factor for unintended pregnancy. METHODS: We performed a secondary analysis of data from the Contraceptive CHOICE project. Between 2007 and 2011, 9,256 participants were recruited and followed for up to 3 years. The primary outcome of interest was unintended pregnancy; the primary exposure variable was low socioeconomic status, defined as self-report of either receiving public assistance or having difficulty paying for basic necessities. Four contraceptive groups were evaluated: 1) long-acting reversible contraceptive method (hormonal or copper intrauterine device or subdermal implant); 2) depot medroxyprogesterone acetate injection; 3) oral contraceptive pills, a transdermal patch, or a vaginal ring; or 4) other or no method. Confounders were adjusted for in the multivariable Cox proportional hazard model to estimate the effect of socioeconomic status on risk of unintended pregnancy. RESULTS: Participants with low socioeconomic status experienced 515 unintended pregnancies during 14,001 women-years of follow-up (3.68/100 women-years; 95% CI 3.37-4.01) compared with 200 unintended pregnancies during 10,296 women-years (1.94/100 women-years; 95% CI 1.68-2.23) among participants without low socioeconomic status. Women with low socioeconomic status were more likely to have an unintended pregnancy (unadjusted hazard ratio [HR] 1.8, 95% CI 1.5-2.2). After adjusting for age, education level, insurance status, and history of unintended pregnancy, low socioeconomic status was associated with an increased risk of unintended pregnancy (adjusted HR 1.4, 95% CI 1.1-1.7). CONCLUSION: Despite the removal of cost barriers, low socioeconomic status is associated with a higher incidence of unintended pregnancy.