It is not uncommon for foot chills to occur during pregnancy. This can have multiple causes.
First, changes in hormone levels during pregnancy can affect the autonomic nervous system, which in turn can affect blood flow to the lower extremities. In addition, the basal metabolic rate is higher during pregnancy. Due to the slightly elevated temperature, the surrounding air may feel chilly, especially in the lower extremities. Morning sickness with nausea and vomiting can cause a negative nitrogen balance in the body, making the person feel cold.
In addition, changes in hormone levels during pregnancy, especially thyroid hormones, may occur and cause hypothyroidism. This can also make a pregnant woman feel cold in her calves.