ella is an FDA-approved emergency contraceptive for use within 5 days of unprotected sex or contraceptive failure, which is why it is sometimes referred to as “the week-after pill.” It is estimated taking ella will reduce the number of expected pregnancies from 5.5% to 2.2%.[15]

Pregnancy from a previous sexual encounter should be ruled out before taking ella. It is to be used only once during a menstrual cycle.

ella may reduce the chance of pregnancy by preventing or postponing ovulation.[16] It also may work by preventing a fertilized egg from implanting in the uterus, which is a very early abortion.[17]ella is a chemical cousin to the abortion pill. Both share the progesterone-blocking effect of disrupting the embryo’s attachment to the womb, causing its death.[18]

The most common adverse reactions of ella include headache, nausea, stomach (abdominal) pain, menstrual cramps, fatigue, and dizziness.[19] Women who experience abdominal pain 3 to 5 weeks after using ella should be evaluated right away for an ectopic pregnancy.

Much is unknown about the drug, including its effect on women: