I watched it. Unless there's something left out, I didn't see anything that you can 100% say the way ICE handled her caused a miscarriage. Maybe they threw her down on the ground before the person started filming? Who knows. But leftists lie constantly, so I'm very skeptical of the sensationalist headline.
She doesn't appear any farther along than maybe early to mid second trimester, but it's hard to tell with the coat bulk. You can usually still lay on your stomach at that stage, even if it's a bit uncomfortable. And the agents are kneeling on her butt, not her back, so they're not putting extra pressure on her stomach into the snow.
I don't think the way they're dragging her would cause a miscarriage either. Babies are pretty insulated in the womb, especially earlier in the pregnancy. Again, maybe they left something out of the video. Hate to sound like a ghoul, but I'm not convinced by what I saw in the video they posted. Just my two cents as an experienced pregnant lady.