I have read several studies on using Omega III fish oil for bipolar. I started using it for my daughter and I see a large difference in her up's and down's
I have taken care of many pacients with bipolar disorder while pregnant and I feel safe using quetiapine. Some recents studies have shown greater benefit despite quetiapine is risk C, supporting better result when there is no answer with most known drugs like litium and valproic acid. Be careful with hypotension and consider omega 6 as colleagues said earlier.
It depends on a number of factors. In fact, for some women lithium may be safer than the risk of untreated illness with a risk of relapse, risk-taking, alcohol and drug use... Generally it is preferable to stay away from anticonvulsants.
It depends on the stage of Bipolar illness and occurrence of episode interval. If I assume the episodes are rare and the lady is in remission then even a drug free interval can be tried especially for 1st trimester. If the chances for episode occurrence after drug discontinuation si high, it's better to select the least teratogenic among the drugs which she has responded well in the past