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

To evaluate the association of low socioeconomic status as an independent risk factor for unintended pregnancy.

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.

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).

Despite the removal of cost barriers, low socioeconomic status is associated with a higher incidence of unintended pregnancy.