Thyroid stim hormone - both these impact/affect conception. Day 21 bloods check to see if you have in fact ovulated! The other two are just vitamin D and iron levels. Not sure how/if they impact conception but my specialist ordered them all together
I'd be looking at whats going on with your Thyroid too. My sister had dramas and it was her Thyroid. Shes had 3 pregnancies.

I have been put on ostilin because I was D deficient. Vitamin D is also needed for Calcium and Follate retention, as well as being linked to your blood sugar levels. I was also an ex smoker that seriously depleted my nutrients. I've heard some say cut the Coffee, but I really don't think the Coffee would make much dif. Women fall pregnant on much more servere recreationals (IUKWIM) than Coffee??? Cant hurt though.

Let us know if your thyroid is out of whack.

Cheers
June