When did it become a recommendation for pregnant woman and caregivers to get the Tdap booster?

I got it, and I told my parents, my parents in law, and my husband to get the booster, but forgot SIL and my childcare person for April-May. I'm waiting to hear back from them but hoping they got it with their most recent pregnancies. Also, DH can't remember if he got it or just got the flu shot so he's calling the doctor tomorrow.

How far back / what years do you remember getting this recommendation? Like, if you were pregnant in 2012, did you get a booster?