I'm sure if you explained the situation to your Doctor he could write you a certificate to be on 'light' duties untill a set date. Unless you are really sick in the 1st trimester I don't see why you couldn't still go to work.
The first 3 months you need to relax and let your body do the work - eat right, minimal stress and get all the rest your body wants. I MC my first at 10 weeks but with my second (current pregnany) I was so sick in the first 3 months I just wanted to die! But I took my morning sickness tabs and was right to go to work by 9am! I also spoke to my boss to let her know what was happening - I didn't need to but in case I was late/had to have time off etc she understood why.
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