It is not uncommon to experience numbness in the calves during pregnancy. There can be multiple reasons for this.
First, changes in hormone levels during pregnancy can affect the autonomic nervous system, which can affect blood flow to the lower extremities and cause numbness in the distal extremities. It is important to note that unhealthy use of the back during pregnancy can cause lumbar spine disorders and cause compression of the sciatic nerve. This can also cause pregnant women to feel numbness in their calves.