I had a hospital birth with my first. I had a fast labor and birth, and no control over pushing. My body just ejected the baby in one swoop, and I did end up with a 3rd degree tear as his shoulder caught me. It was bad enough that my fp requested the on-call OB to sew me up. I believe I tore because they tried to slow things down by putting me on my back so I would get all the antibiotics (thus working against my body), and because I ended up pushing in stirrups. However, I was still playing soccer at 6 weeks pp without any issues or problems. I healed just fine.
With my second, I chose a homebirth, and my mw said she RARELY sees bad tears... usually if stitches are even needed, it's only a couple of stitches. That time I birthed even faster, and my body again ejected the baby without any conscious direction on my part, BUT there was a natural pause between birthing his head and his shoulders. My mw arrived after his head was out, so no time for perineal support or the waterbirth I'd planned. But, my body''s rhythms were never interrupted, and I pushed on my hands and knees where I felt most comfortable. I had only a tiny tear that did not require any special treatment.
Melissa , wife to Tom , mom to The Baron , the Bean , Little Bear , and Baby Beaver