It’s not giant hogweed, which is the one in the media with the horrendous burns etc... but looking at the leaves it could be the smaller version, it’s hard to tell from the photos though.
If it is common hogweed, don’t panic! It’s actually used as an edible forgaged food and isn’t normally considered much of a risk to anyone.
It seems that some people do have a sensitivity to it, or develop a sensitivity after repeated exposure to it, and it might cause a mild rash or a mild uv sensitivity, although not an the same scale as it’s bigger cousin! It seems up for debate about why it happens, apparently even parsnips need pulling out of the ground with gloves on a sunny day, as that whole plant family has this ability to cause UV sensitivity, so, there you go!
But, best not to take any risks, so wash the area thoroughly and keep your baby out of the sun for a couple of days.
But really, it’s not the same as the giant hogweed and no need to panic. Keep an eye out of course, but don’t be too scared...