At different times during your pregnancy, you might have sudden muscle spasms or pain in your legs, feet or thigh. They are typically followed by a general ache. They usually occur at night and are more common in the third trimester.
Leg cramps are usually due to a change in the way your body processes calcium. Low calcium levels in the blood can cause leg cramps, as well as a salt deficiency.
There is generally no risk to the baby.