Pregnancy massage is great when its offered by someone who has had extensive trainnig and qualification in just that! The main thing here is to make sure they are properly qualified and understand the changes and needs of ones body during pregnancy.
I would highly recommend reading Gowri Motha's book 'A gentler birth' which incudes tips on massage adn teh best types at thaat time. She is a leading birth specialist in London and I have received her patients at a pilates studio many years ago and they all did very well on her plans! She can recommend the best people, practitioners and how to find them.
A doula is good if you can find one! (birth companion) see doula.com or try a massage with our Ayurveda Consultant, and Massuese of over 30 years who has extensive qualification and experience in Pregnancy massage. You can visit her at her spa in Suffolk, or book a day with her in London. See http://www.vital-body.co.uk/tanyabradbury