I have tried light therapy for my depression and have found it to be mildly useful...but I did it while I was not pregnant.  I was pregnant through 2004 and had a SEVERE depressive episode.  I took Lamictal and Paxil (now found to increase the risk of heart defects) and Klonopin.  My OB did not talk to me about the risk of depression during my pregnancy and the probablity it would worsen as my due date approached.  The pdoc was not entirely sure what to do...so I stayed miserable the whole time.  I DID get much worse as the pregnancy advanced and manifested my depression by incredible anxiety.  I was thought to be a nut case by the OB triage desk...as I showed up regularly to check out my baby.  My delivery was induced when the anxiety became extreme.  Then the delivery was followed by a horrendous post-partum depression...during which I lost custody of my baby girl to her father.  The extreme stress of the pregnancy and the PP depression coupled with the lawyers, hearings, etc., took a major toll and it took  2 years to recover.  Why am I writing this is a comment about light therapy during pregnancy?  My ramble hopefully will make anyone who is bipolar and cycling be extremely careful with their mood during pregnancy.  The typical antidepressants..Paxil, Zoloft, etc., have been found to be a possible cause of heart defects.  No drug is safe during pregnancy.  A light box cannot hurt.  And post-partum depression is EXTREMELY likey, so have a great support system ready for the first months.  Pergnancy can be a dangerous time for someone with Bipolar 1 or 2.