Tryingtoconceive2014,
Very sorry to hear about your losses. Have you considered TCM to 安胎?can pm me if you need recommendation as I am seeing one now and I think he is good.
As for Dr Loh, I think it's good that he referred you to another specialist who might be able to follow up and help you further. I am sure he has exhausted the options to help.
I previously saw a specialist who didn't put me through the proper tests as she was not an expert in that area and I feel indirectly resulted in my loss.

was a very painful experience and I wished she had referred me to an expert instead.
If you have not tried TCM, I really feel you can consider. But do see Dr Mahesh as Dr Loh had suggested, to find out the problem. Only by knowing the problem, we can have a solution to it.
Stay strong.