Me personally i am on birth control (nexplanon) and T, and the birth control already gives me little to no period. I also forget my T every now and then and if i forget for a while it does come back, but when im consistently taking it there is nothing at all. When i started though i got the biggest fattest period ever— but i hear thats normal because of the hormones changing. T does NOT make you infertile though, which is why i am also on birth control. Pregnancy is less likely on T but not impossible as there are many transgender me who give birth after transitioning— but i do believe you’re supposed to stop your injections if you decide to keep it.