Is it effective to take birth control pills after implantation of the fertilized egg?

Patient's question:

No

Doctor's answer:

Hello, the situation you mentioned refers to taking emergency contraception within 72 hours after intercourse, which has an effectiveness rate of 98%. According to what you said, if the fertilized egg implants, emergency contraception contains high levels of progesterone, which can reduce the movement of the fallopian tubes and inhibit the proliferation of the endometrium. This makes it unfavorable for the fertilized egg to implant.