This is what I found on the Web.
Prenavite forms, composition and dosages:
- Tablet; Oral; Calcium Carbonate 125 mg; Ferrous Fumarate 50 mg; Folic Acid 1 mg; Sodium Ascorbate 100 mg; Vitamin A Acetate 4000 units; Vitamin D 400 units
Why are you asking your gyn for vitamins after DS?
I don't know where you are in your DS journey, but the doses are low, the forms of the vitamins are not ideal, and many vitamins and minerals that are needed are not included. You should search this site, because there is a lot of helpful vitamin/mineral information here.
I know the doc won't take a consumer website for advice, but these official guidelines will educate him/her about where to start.
Parrott J, Frank L, Dilks R, Craggs-Dino L, Isom KA, Greiman L. American Society for Metabolic and Bariatric Surgery Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient 2016 Update: Micronutrients. Surgery for Obesity and Related Diseases. 2017 Jan 19.