I actually don't think that's true at all. Clomid is what enables you to release multiple eggs. Ovidril (the trigger shot) just forces the mature follicles to ripen and release on a pretty accurate time frame. So it really just makes the chances of a successful IUI increase. And the IUI definitely doesn't increase the odds of conceiving multiples because all you're taking is Clomid, and all the Dr's do is insert the semen into your uterus, bypassing the cervix. So you're more likely to get pregnant, but not with multiples. Also I only took the trigger shot for 2 of my IUI's (out of a total of 6). My 2nd IUI, I didn't trigger, and was only taking 50mg of Clomid for days 3-7, and I released 2 eggs. So if OH didn't have problems with his swimmers, we would have been just as likely to conceive twins without the IUI.