Reuters .

Morning After Pill, Plan B One-StepPhoto: John Nacion/NurPhoto/Shutterstock Editorial/Profimedia

A leaflet distributed with the morning-after pills, known as Plan B One-Step, which have been available to everyone since 2013, now clearly states that their mechanism of action does not prevent a fertilized egg from implanting in the uterus or cause miscarriage.

It explains that the one-step Plan B works before the egg is released and therefore usually stops or delays the release of the egg.

Contraception has come under increasing pressure in the United States since the Supreme Court in June overturned the landmark 1973 case Roe v. Wade, which guaranteed women’s right to abortion and legalized termination of pregnancy nationally.

Several US states, led by conservative Republicans, have already enacted full or partial abortion bans following the Supreme Court ruling last year.

The FDA has also published an updated question and answer section on its website, where the answer to the question “Does one-step Plan B cause abortion” is “No.”

The FDA said that current science suggests that One-Step Plan B works by suppressing or delaying ovulation and mid-cycle hormonal changes. He said the evidence supports the conclusion that the pill has no direct effect on fertilization or implantation.