You can get them from your Doctor or over the counter.
I didnt like the ones my doctor gave me I got a sick .. so I keep taking one a day prenatal vitamins. .. you can get prenatal vitamis at any big store.
You have to find the one that makes you feel ok, everyone is different..I started with over the counter centrum and was miserable for about 4 wks (not knowing it was the vitamin) then dr prescibed citranatal harmony and it was night and day, bn feeling great after that. ..
I'm a first time mom too at 37 weeks. My doctor kept giving me samples of different prenatal vitamins. I found that constantly changing them up gave me diarrhea and some of really gave me no energy at all. I ran out and went to rite aid and picked up Bayer prenatal with DHA. It was over the counter and on sale. It gave me so much energy and no nausea. But I guess everyone's physiology is different so you really have to find what works for you. I suggest just giving each one you try two weeks or so before changing otherwise it could mess with your stomach bigtime.
I don't know where you're from but I'm in the UK and got some from my widwife then had more at my 12 week scan. You get them free from the NHS automatically. They're healthy start vitamins with everything you need in one little pill. I've had no problems with them whatsoever and neither has anyone else that I'm aware of
Depending on your insurance you might be able to get a free prescription from your doctor:) otherwise, you can get them at walgreens or any pharmacy