For a typical stimulated IUI cycle , many clinics start stims on cycle day 2, 3, or sometimes 3–5 , after a baseline ultrasound confirms the ovaries are resting. The exact day depends on the clinic’s protocol and how your body is responding.

Typical timeline

  • Day 1: First day of your period.
  • Day 2–5: Baseline ultrasound and start of stims in many protocols.
  • Day 10–13: Follow-up monitoring to check follicle growth.
  • Around Day 13–15: Trigger shot and then IUI about 24–36 hours later.

What this means in practice

If your clinic uses letrozole or clomid , a common pattern is to begin medication early in the cycle, often right after the period starts, then monitor a few days later. Some clinics adjust timing based on ultrasound findings, follicle development, or your specific fertility plan.

Bottom line

Most people start stims very early in the cycle, usually day 2 or 3 , but your clinic may choose day 3–5 depending on the protocol.