I can't give you advice on whether to try the flushes or not. It's too personal a decision. If you read the archives there is at least two posts from someone who was pregnant and did them.
What I can tell you is that I now think that gallbladder attacks were what caused me to go into preterm labour. At the time the doc couldn't figure out why it was happening and I wasn't aware of how the liver feels when it's contracting or that the weird pain I had out of nowhere was a gallbladder attack. I wound up delivering only two weeks preterm, which is a piece of cake but it might not have turned out so well.
So I would advise you to do something, even if it's just that swish thing people talk about. But I can't advise as to what.