Nowadays, multiple supplements are being advised during pregnancy. But you should be careful of taking them – are they really necessary?
For e.g., iron supplements are advised if haemoglobin is low. However, this is a natural phenomenon where because of blood becoming thinner during pregnancy the Hb will be lower than normal. There is no need to supplement.
The only vitamins that you need on a plant-based diet, even during pregnancy, are vitamin B12 and D and that too only if you are deficient.