The Prevalence, Severity, and Predictive Factors of Restless Legs Syndrome in Pregnancy

The current study aimed to search the prevalence and severity of restless legs syndrome (RLS) in pregnancy according to the three trimesters and predictive factors of RLS in pregnancy based on validated diagnostic tools and a thorough literature review.

The cross-sectional descriptive study included 500 pregnant women without comorbidities who were interviewed face-to-face. Age, height, weight, week of pregnancy, smoking, alcohol, caffeine use, regular exercise, and lab test results from the last visit were all included in the data. Only women satisfying the RLS diagnostic criteria were given the Restless Legs Syndrome Rating Scale.

The prevalence of RLS was found to be 29.2% with the highest rate in the third trimester (64.4%). In all trimesters, low ferritin (first trimester: p = 0.004; second trimester: p < 0.001; third trimester: p < 0.001), folic acid (first trimester: p = 0.001; second trimester: p < 0.001; third trimester: p < 0.001), vitamin B12 (first trimester: p = 0.003; second trimester: p < 0.001; third trimester: p < 0.001), and hemoglobin (first trimester: p < 0.001; second trimester: p < 0.001; third trimester: p < 0.001) levels were associated with RLS. In the second and third trimesters, low magnesium (p < 0.001 and p < 0.001, respectively) and high creatinine (p = 0.027 and p < 0.001, respectively) levels were associated with RLS. Higher thyroid-stimulating hormone and free T4 levels were associated with RLS in the third trimester but not in the first and second trimesters (median: 2.4 vs. 2.1, p < 0.001; median: 1.5 vs. 1.2, p < 0.001). In the multivariate regression analysis, age (p = 0.034, OR: 1.060, 95% CI: 1.005-1.119), present BMI (p < 0.001, OR: 1.8884, 95% CI: 1.597-2.222), BMI before conception (p < 0.001, OR: 0.607, 95% CI: 0.513-0.718), gravida (p < 0.001, OR: 2.172, 95% CI: 1.547-3.049), low ferritin level (p < 0.001, OR: 6.396, 95% CI: 0.00744-0.010405), low vitamin B12 (p < 0.001, OR: 10.347, 95% CI: 0.00120-0.00176), low folate (p < 0.001, OR: 5.841, 95% CI: 0.00616-0.01240), RLS history before conception (p = 0.013, OR: 4.963, 95% CI: 1.402-17.57), and RLS family history (p < 0.001, OR: 7.914, 95% CI: 0.18760-0.31151) were found to be predictive factors for RLS in pregnancy.

More attention is needed to RLS during pregnancy to prevent or treat this syndrome.