After giving birth you will have lochia (similar to menses but it's not menses) for 4-6 weeks and it's usually in small amount, mine was on and off too. I doubt it has to do with the herbal soup you drink.
Herbs can cause bleeding. My gynae, who is also trained in TCM, recommended for me to not take herbal soups during my confinement.
I dont remember drinking herbal soup..better to check with a TCM physician
Better to consult a qualified TCM physician for personalised advice...
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