The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
Because it is a herb specifically indicated to treat postpartum spasms as can be seen on Stinging Nettle Leaf's page.
Stinging Nettle Leaves is a Cold herb that tastes Bitter and Pungent. It targets the Liver.
Its main actions are: Clears the meridians and expel wind-dampness. Smooth digestion and kills parasites.
Rheumatism Hypertension Constipation Snake bites Intestinal parasites Indigestion Muscle cramps Hives