Risk Assessment!

I work in a very stressful job as a night health care assistant in a 3 floored nursing home. There is another person at my work who is also pregnant and the manager told her she does not do risk assessments until the pregnant woman is 12 weeks which I personally think is wrong. I phoned ACAS up and explained to them the situation.. They said "as soon as you tell your manager they should do a risk assessment straight away there is no limit on how many weeks you have to be"

Well... I then told the duty manager this last night as the main manager is off sick at the moment and she said no.. It's when your 12 weeks. We had an argument and I explained to her that I've already spoken to acas.. but she still hasn't done anything about it and I told my work nearly 3 weeks ago. It's stressing me out and it's getting me rather down cause work is causing me alot of pain and im just so worried ill lose the baby as I'm only 6 weeks and 2 days pregnant.

Has anyone else had this problem with their work??