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Number of Oral Contraceptive Pill Packages Dispensed and Subsequent Unintended Pregnancies

Foster, Diana Greene PhD; Hulett, Denis; Bradsberry, Mary; Darney, Philip MD, MSc; Policar, Michael MD, MPH

doi: 10.1097/AOG.0b013e3182056309
Original Research

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.


Dispensing a 1-year supply of oral contraceptives in a clinic visit is associated with lower rates of pregnancy and abortion in the subsequent year.

From the Bixby Center for Global Reproductive Health, Department of Obstetrics, Gynecology, and Reproductive Sciences, San Francisco General Hospital, University of California, San Francisco, San Francisco, California.

See related articles on pages 551 and 558.

Corresponding author: Diana Greene Foster, PhD, 1330 Broadway, Suite 1100, Oakland, CA 94162; e-mail:

Financial Disclosure The authors did not report any potential conflicts of interest.

© 2011 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.