Why the second HCH shot 6 DPO???

I took a trigger shot (ovidrel 250 microgram in 0.5 mL) to trigger last wednesday. After my IUI, the RE gave me another ovidrel (same dose) to take the following wednesday. Why would I need to take another HCG shot?

[Siciliana1411]

hey im not really 100% sure but i did gonal-f this cycle and at cd15 i gived myself my ovidrel shot and went back the next day for my IUI on the day i got my trigger shot they did blood work and told me i dint need my other ovidrel beacuse my levels were already high enough for me to ovulate so thas what i think its for...maybe your leves werent high enough and to make sure they do the other one..but i could be wrong..sorry :(