Background: Leg cramp is the painful contraction of the muscles that often occurs at night. Pregnancy is the most common cause of muscle cramps that usually occur in the second trimester of pregnancy. Although the reasons of the spasms had not been determined, the imbalance between the absorption and elimination of serum electrolytes such as Ca, Mg and potassium and also insufficiency of some vitamins and probably the changes in activities of motor neurons of spinal cord, can be the source of these problems. The aim of this study was the evaluation of frequency and predisposing factors of leg cramps.
Methods: In a cross sectional descriptive analytic study, a group of 400 women in the third trimester of pregnancy were asked to record the symptoms of leg cramp. Their education level and job recorded and their total serum level of Ca and Mg was measured in the first visit. Exclusion criteria included systemic medical conditions such as thyroid disease, diabetes, osteoporosis and prenatal disorders such as gestational diabetes mellitus and preeclampsia and patient cooperation.
Results: In our study the prevalence of leg cramp was 54.75%. There was a statistically significant relationship between leg cramp and serum level of magnesium (p=0.04). There was no relation between calcium serum level and leg cramp (p=0.294). The women's age, their nutritional habits and individual characteristics were not signify-cantly related to occurrence of leg cramp.
Conclusion: Leg cramp is a common symptom in pregnancy and in patients with low serum levels of magnesium, a magnesium supplement can be helpful.