As long as your doctor medically approved trying to conceive immediately after having the IUD removed, there is no need to wait one cycle before trying. Halachically, as long as you are tehorah, there is no need to go to mikveh before conceiving.
Please note that some women do experience some type of bleeding after having an IUD removed. Our position is that bleeding that begins shortly after the procedure and continues for up to two days may be attributed to trauma and does not render you niddah.
It is also not unusual to experience further bleeding after having the Mirena removed due to the withdrawal of the hormones. Bleeding that begins more than 24 hours after the IUD is removed, or that continues for more than 48 hours after the removal, cannot be attributed to trauma and may render you niddah. You may take precautions against becoming niddah if you only experience staining, but an actual flow would render you niddah. See our article on stains for more details.
Please feel free to get back to us with any further questions.
B’Hatzlacha!