Restless legs during pregnancy: the role of ferritin

Abstract

Introduction RLS affects 5–10% of the general population, but it also affects 25% of pregnant women. Although iron, genetics and central nervous dopamine have been shown to play a major role in RLS unrelated to pregnancy, it’s etiology in pregnancy remains unclear. The aim of this study was to determinate risk factors associated to RLS in pregnancy. Materials and methods Healthy pregnant women treated at the Vistahermosa Hospital Gynecology Department were asked to complete IRLSSG criteria by self-administered questionnaire and a sleep specialist made the clinical diagnosis of RLS by telephone interview. PCR was registered with a recording of the movements of both legs. Ferritin levels were determined. Results Fifty patients were registered and 35 (70%) completed all questionnaires and everyone was studied by PCR. Average age was 34 ± 4.20% were in the first trimester, 37% in the second and 43% in the third. Ferritin levels were determined in 66% of cases. 20% of the patients met IRLSSG criteria, when asked by both a self assessment questionnaire and when they had a telephone interview with a sleep specialist. 85% of them had iron supplementation during pregnancy. We found low ferritin levels (⩽40 ng/dl) in a high percentage of pregnant women (75%) and 83% of RLS symptomatic patients had low ferritin levels. The difference was not significant. Family history was positive in 43% of the cases. Of the patients who had delivered at the time 57% reported resolution of the symptom, 75% immediately after delivery and in one case two weeks after it. Conclusion Pregnancy is a period with special conditions affecting the development of RLS but it has not been well investigated. We have found a family history of RLS in almost 50% of the patients, results indicate a genetic predisposition maybe manifested for first time during pregnancy. We also investigated ferritin levels, and although low ferritin levels were frequent during pregnancy in our sample it was not significantly associated with RLS symptoms. Both results and the fact that symptoms usually resolved in the days after delivery, suggests in our opinion that there must be other mechanisms implicated. Acknowledgements We want to thank to all pregnant women who have participated in the study.