Re: Starting my period!
I only ever noticed a supply drop with my cycle when I was pumping, but it was never anything major. I never noticed any change at all while nursing. I did take a calcium-magnesium-zinc supplement for other reasons, which may have helped but it's hard to say. I do think eating a bowl of oatmeal for breakfast helped a little on my low production days. I drank a Guinness one evening and had great output the next day, but that was the only time I drank then pumped the following day (I'm not a big drinker). It's impossible to determine a trend off just the one data point. I took my prenatal vitamins the entire first year (sometimes still, but I forget a lot). I've never taken fenugreek though.
If you are EBF, then I think things will be fine regardless of what you do as long as you continue to nurse on demand. You can even offer a little more frequently if you are worried. Are you pumping on the side that is not being nursed on? If so, you might just want to pump a little extra if you see a dip. Supply usually bumps back up after a couple days when there is a dip.
K. Sophia - Mama to my little lactivore, the amazing Mr. X (11/10).