Hello I appreciate your concern As soon as you finishes the pills you can very easily conceive in most of the cases since you have taken it 4 years so there could be a residual effects which can last maximum for next 2 or 3 cycles So you should have intercourse near ovulation which occurs 14 days prior to the next cycle, that also can be assessed by hormonal study or serial ultrasound Have multivitamin supplement especially folic acid maintain good hygiene Have good balanced and nutritious food Hope this answers your question follow up questions are most welcome East regards