I Was Taking 15 Mg Iron Supplement And My Period

I was taking 15 mg iron supplement and my period stopped/late on arrival. I stopped taking the iron thinking thinking it might be the cause for my delayed period and 4 days later, my period came on. I resumed iron supplement after my period ended and when I was due for my next period, it didn't come yet again. So I stopped taking the iron and my period came on a few days later. Can iron supplements cause this and why? Seems too much of a coincidence.
Also my periods are very heavy.