My dad has been running haunted attractions for 30 years and I've worked at and helped run them. On all of our signs, we recommend that pregnant women don't go through for a number of reasons. There are dark hallways, monsters and animatronics pop out, other people could push or shove, there are potential tripping hazards, tight spaces etc. I usually go through at least 5+ houses a year but for both pregnancies I refrained from going through :'( kills me because I love them so much but I would never forgive myself if something went wrong!