Is a trigger really needed with injectables if you already ovulate normally?
Well, that’s probably something that really has to be assessed on a case-by-case basis. Maybe not, but it might also be that, if you’re using injectibles already, the doc wants to make sure that all of those nice big follies release eggs so the timing of intercourse or IUI is good and you have the best chance you can get. With the trigger shot, you’re going to have a high enough dose of HCG that you should ovulate most or all of your big, ready follicles, while waiting for your body to do it naturally could mean it’s unpredictable. Could be all, could be some part. Also, they know the trigger takes 24-36 hours to take effect, so you’re not bd-ing too early or late and missing the fertile window.
However, always a good question for the doctor–if you don’t want to do the trigger, ask them if you don’t have to! They might be fine with it.