The warning that one poster gave is correct. ALWAYS check with your doctor before taking any supplements especially while pregnant, but I think this site is for the purpose of sharing information and opinions so here is some info that I can share.
I am pregnant too and am a little concerned about swine flu and getting the swine flu vaccine once it is available. In looking for other options, I have been doing a little research. Here is a link to one article that I found and at the bottom it has recommendations on how much vitamin D to take.
http://health.usnews.com/blogs/on-women/2009/08/05/how-mu...
Although vitamin D is fat soluble which means you can overdose on it, I think that the dose has to be extremely high before toxicity is likely. Some will say 3800 IUI is the limit, but most feel that it is much much higher than that. I think that if you take 1,000-2,000 IUI you should be safe. Also make sure that it is a vitamin D3 source (it should say on the label).
You could take just 800-1,000 IUI and then you will also get some additional vitamin D that will be in your prenatals and in foods that you eat (fish, fortified milk etc.). You can also get plenty of vitamin D by going outside with bare arms and face (no sunscreen) for 15-20 minutes a day and your body will naturally produce a good amount of vitamin D. This is a little hard to do in the coldest months of the year though.
Vitamin D is a benefit to the baby too:
http://www.blackmores.com.au/Pregnancy/News/Detail.aspx?A...
Also- FYI- You can get you and your family's blood tested to see if you are deficient in vitamin D or other nutrients. My Naturopath had me tested and I was not deficient in vitamin D (apparently many people are). I try to eat as much whole food as possible and since you like to cook very healthfully too, that will probably go a long way in protecting you and your family this winter.
I wish you and your family the best of health!
B.