Why Am I Not Menstruating Postpartum For 16 Months After My Tubes Were Tied?

Hi dr iam 30 years all. I haven’t seen my period after given birth for 16 months and iam not breastfeeding.and my dr say that my tubes are blocked.he did the flushing and uptill now nothing happens. What medicine should I take to bring back my period.I want to conceive.