Thank you for your query on Healthcare Magic.
Usually there is no home remedy to prevent pregnancy
after having sex and if available they may not be safe or they may not be effective to prevent pregnancy.
But I advise you to go for emergency contraception
like taking i-pill or plan-B and this can be taken orally as early as possible within 72 hours of having sex.
But I think this emergency contraception is a prescribed medication under the age of 8 years in some counties, so I advise you to consult the doctor immediately for the prescription of this medication.
And I advise you to have protected sex by using the condoms in future as this method will prevent unwanted pregnancy and the spread of sexually transmitted diseases.
Hope I have answered your query.