Answer: "After this procedure, I must abstain from intercourse for at least 3 weeks."
Explanation:
Sterilisation procedure takes time to be effective and a person would be required to go back for a check up in order to be certain that it was successful .
A person may risk being pregnant if they just get back from the procedure and become sexual active in just few days.
Until one has gone for a check up to see that it was successful they still can not be considered to be sterile in a medical point of view.
Since this is a medical procedure a person needs to heal properly first before they engage into physically demanding activities like sexual intercourse.