I have written extensively about this subject (Vitamin Euphoria) in my book The Key to health and Rejuvenation, which I believe would be be a very useful guide to ensure that you and your baby receive adequate nourishment. You will come to understand that taking vitamins doesn't necessarily mean mean they will reach the cells in body. Actually, 95% of the vitamins contained in most vitamin pills never make it there. They just place a burden on the kidneys and acidify cell invironment. You can harm your body more by taking them than doing nothing at all.
Contrary to common belief fed by misinformatio, you don't need to stockpile vitamins in the body. Ingesting too many of them, can cause serious health problems for mothers and babies (see the research shown in my book), often the very same diseases they were supposed to prevent. By eating a balanced diet according to your body type, you will certainly not run out of vitamins, even if your liver isn't clean yet. The "necessity" to fill up pregant mothers with vitamins is a gimmick created for other reasons than promoting health. I would suggest you muscle test your vitamins and see for yourself whether your body can tolerate them or not (directions are provided in the book).