Thanks ladies for your replies.

My OB has been great and ordered blood tests and a post-mortem. All the blood tests came back neg and we're waiting on the PM results, though initial inspection yielded nothing.

The only health problem I have I can think of that may be related is I have low levels of anti-cardiolipin antibodies, so was taking clexane for first 12 weeks, then stopped on OB's advice (after he spoke to a few hematologists). But if my understanding is correct if that were the cause it would have been from a blood clot, which they didn't find. Anyway, I have a feeling no cause will be found.

My OB has said that next preg, though he'll still be my doctor, he'll send me for regular check-ups to the public hospital, because it's a teaching hospital they're up on all the latest reading and see this sort of thing more than he does, so that's reassuring. One man can't know it all I suppose

Thanks