OBJECTIVE:

To estimate how number of oral contraceptive pill packages dispensed relates to subsequent pregnancies and abortions.

METHODS:

We linked 84,401 women who received oral contraceptives through the California family planning program in January 2006 to Medi-Cal pregnancy events and births conceived in 2006. We compared pregnancy rates for women who received a 1-year supply of oral contraceptive pills, three packs, and one pack.

RESULTS:

Women who received a 1-year supply were less likely to have a pregnancy (1.2% compared with 3.3% of women getting three cycles of pills and 2.9% of women getting one cycle of pills). Dispensing a 1-year supply is associated with a 30% reduction in the odds of conceiving an unplanned pregnancy compared with dispensing just one or three packs (confidence interval [CI] 0.57-0.87) and a 46% reduction in the odds of an abortion (95% CI 0.32-0.93), controlling for age, race or ethnicity, and previous pill use.

CONCLUSION:

Making oral contraceptives more accessible may reduce the incidence of unintended pregnancy and abortion. Health insurance programs and public health programs may avert costly unintended pregnancies by increasing dispensing limits on oral contraceptives to a 1-year supply.