 [ Symptoms ] how long after mirena insertion can you have unprotected sex  my last period ended june 3rd i had the mirena iud inserted june 20th and had unprotected sex june 28th i have not had any spotting or cramping with the mirena and i have not started my period could i be pregnant or is the mirena immediately effective [ Disease ] hi well have just had something inserted in you uterus so this could have upset you womb that could be the reason of the absence of your period but waiting the 8 days were right for not having unprotected sex so your ok there but your periods do wain after 3 months and should be gone by the year after fitting sop sounds like your ok good luck