Nighttime leg cramps are the result of sudden muscle tightening for which the cause is not always known, according to Mayo Clinic. These harmless spasms are usually related to overuse of muscles or nerve problems.
Other conditions that can lead to nighttime leg cramps include cold temperatures, a lack of minerals in the blood, and dehydration, notes WebMD. Blood flow problems and maintaining the legs in an awkward position while sleeping can result in leg cramps. Medications, such as statins, birth control pills and diuretics, can also lead to leg cramps at night. Pregnant women and people who are middle-aged or older have an increased likelihood of experiencing nighttime leg cramps, states Cleveland Clinic.