My best friend recently moved to the UK where they have no family and only had a few people that they knew but were not yet "friends". She needed to arrange a babysitter, so once she found someone that she liked, she had the lady come to the house once a week for dinner for a few weeks so the kids could get used to her. Once she was happy that the kids were comfortable with the lady then she was confident to start leaving them with her few short periods of time. She gredually built it up over time. That might be an option for you seeings as you still have quite a bit of time before bub comes.