Plan B One-Step TM (Morning-After Pill) is intended to prevent pregnancy after known or suspected contraceptive failure, unprotected intercourse or forced sex. It contains large amounts of levonorgestrel, a progestin hormone found in some birth control pills. It may work by preventing the egg and sperm from meeting by delaying ovulation; it won’t disrupt an implanted pregnancy, but may prevent a newly formed life from implanting in the uterus. [1]

Plan B One-Step TM consists of one pill taken within 72 hours of sex. [2]

Side effects may include changes in periods, nausea, lower abdominal pain, fatigue, headache and dizziness. [3] If your period is more than a week late, you may be pregnant from a prior sexual encounter. Plan B One-Step TM should not be taken during pregnancy nor used as a routine form of birth control. [4], [5]

There is evidence that Plan B One-Step TM use may increase the risk for ectopic (tubal) pregnancy, a potentially life-threatening condition.[6] Women who have severe abdominal pain may have an ectopic (tubal) pregnancy, and should get immediate medical help.

It is reported that Plan B One-Step TM prevents an average of 84% of expected pregnancies. [7], [8]  There are no long-term studies on the safety of Plan B One-Step TM in women under 17, after repeated use or effects on future fertility. [9]


ella® [10]

ella® (ulipristal) is an FDA-approved emergency contraceptive for use within 5 days of unprotected sex or contraceptive failure. Pregnancy from a previous sexual encounter should be ruled out before taking ella®. It is to be used only once during a menstrual cycle. It is estimated that takingella® will reduce the number of expected pregnancies from 5.5% to 2%. ella® may reduce the chance of pregnancy by preventing or postponing ovulation. It also may work by preventing a fertilized egg from implanting in the uterus, which is a form of early abortion. 4 ella® is a chemical cousin to the abortion pill Mifeprex. Both share the progesterone-blocking effect of disrupting the embryo’s attachment to the womb, causing its death. [11]

The most common adverse reactions of ella® include headache, nausea, stomach (abdominal) pain, menstrual cramps, fatigue and dizziness. Women who experience abdominal pain three to five weeks after using ella® should be evaluated right away for an ectopic pregnancy. Much is unknown about the drug, including its effect on women who are under 18 or over 35 years of age, taking other hormonal contraception, pregnant from a previous encounter, taking ella® repeatedly during the same cycle or are breast-feeding.



[1] Plan B One-Step Prescribing Information. Mechanism of action.

[2] Plan B One-Step Prescribing Information. Dosage and administration.

[3] Plan B One-Step Prescribing Information. Adverse reactions.

[4] Plan B One-Step Prescribing Information. Contraindications.

[5] Plan B One-Step Prescribing Information. Indications and usage.

[6] Plan B One-Step Prescribing Information. Ectopic pregnancy.

[7] Plan B One-Step Prescribing Information. Clinical studies.

[8] American Congress of Obstetricians and Gynecologists. Emergency contraception. Practice Bulletin No. 112, May 2010.

[9] Plan B One-Step prescribing information.

[10] Watson Pharma, Inc. ELLA – ulipristal acetate tablet.

[11] Harrison DJ, Mitroka JG. Defining reality: the potential role of pharmacists in assessing the impact of progesterone receptor modulators and misoprostol in reproductive health. The Annals of Pharmacotherapy. Dec 21, 2010; 45(1):115-9.