You may have heard emergency contraception referred to as the morning-after pill or brand names Plan B One-Step™ and ella®. Emergency contraception is a term used for drugs taken after sex with the intent to prevent pregnancy. The most common brands of emergency contraception in America are Plan B and ella®.

Morning After Pill

Plan B One-Step™ (morning-after pill) consists of one pill taken within 72 hours of sex. It 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 (this is a form of early abortion).

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

There is evidence that Plan B One-Step™ may increase the risk for ectopic (tubal) pregnancy, a potentially life threatening condition. 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™ prevents an average of 84% of expected pregnancies. There are no long-term studies on the safety of Plan B One-Step™ in women under 17 after repeated use or effects on future fertility.


ella® (ulipristal) is an FDA approved emergency contraceptive for use within 5 days of unprotected sex, contraceptive failure, or forced sex. Pregnancy from a previous sexual encounter should be ruled out before taking ella®. It is estimated that taking ella® 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. 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.

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. ella® may not be as effective if taken with certain drugs and may change the effectiveness of certain drugs.

Much is unknown about the drug, including its effect on women who are under 18 or over 35 years of age, pregnant women, women who are breast-feeding, or women taking ella® repeatedly during the same cycle.

Anyone considering taking any type of Emergency Contraceptive should take a laboratory pregnancy test to be sure there is not a pre-existing pregnancy.

Dr. Richard A. Zinni

Dr. Richard A. Zinni

D.O. Certified In Internal Medicine

The content on this page has been reviewed and approved by our Medical Director: Dr. Richard A. Zinni