Original ArticleOpen-label study of the efficacy and safety of intravenous ferric carboxymaltose in pregnant women with restless legs syndrome

ObjectiveThe objective of this study was to test the efficacy and safety of intravenous ferric carboxymaltose (FCM) in pregnant women with restless legs syndrome (RLS) and iron deficiency or anemia. The open-label pilot study (exploratory) was performed at the University Hospital of Zürich and the Neurocenter of Southern Switzerland (Lugano).Patient and MethodsNineteen women in the third trimester of pregnancy with moderate-to-severe RLS and serum ferritin levels <35 µg/l or hemoglobin (Hb) < 11.0 g/dl were included in the study. RLS was graded according to the International Restless Legs Syndrome (IRLS) Study Group rating scale. All participants had a score of ≥20 or had RLS ≥3 times/week. Based on the Hb levels, 500 or 700 mg of FCM was administered over 20 min. The primary end point was a ≥ 50% reduction in the mean IRLS score one week after FCM infusion. The secondary end points included periodic limb movements (PLMs; assessed using nocturnal foot actigraphy), sleep quality (assessed using the Pittsburgh Sleep Quality Index), and safety.ResultsThe IRLS score decreased from 23 ± 7 (baseline) to 13 ± 7 (P <0.01), whereas the PLM index decreased from 35 ± 26 (baseline) to 25 ± 20 (P <0.001). Significant improvement in sleep quality was also reported (P <0.029), and treatment was well tolerated. Three serious adverse events were reported, but they were considered unrelated to treatment.ConclusionsThese data provide promising evidence on the safety and efficacy of FCM for moderate-to-severe RLS in pregnant women with iron deficiency or anemia. Therefore, a future placebo-controlled study is warranted.