Hmm. I've never heard of such a thing. There are vitamins you are supposed to stop taking after O? I started taking prenatal vitamins when we started TTC, I never stopped taking them at any point. Interesting, I may have to look into it.
If any of those I would guess Maca, because Vitex and B6 are both used to lengthen LPs so you would definitely want to take them after Oing as well. But I really don't know anything about Maca so I'm not sure, I just know that the others are safe for the whole cycle.