Restless Legs Syndrome in Pregnancy: Overview
Incidence and Prevalence
RLS affects approximately 20-31% of pregnant women, representing a 2-3 fold increase compared to the general population. 1, 2, 3 This substantially elevated prevalence makes pregnancy one of the most common conditions associated with secondary RLS.
- The prevalence varies across studies, with reported rates of 22% 2 to 31.33% 4, compared to approximately 10% in non-pregnant Caucasian populations 5
- Approximately 75% of pregnancy-related RLS cases are secondary, meaning symptoms occur only during pregnancy 4
- Among affected pregnant women, 41% experience moderate severity and 40% have severe RLS 2
Timing During Pregnancy
RLS symptoms typically emerge or worsen in the third trimester, with peak intensity occurring in the final weeks before delivery. 2, 3, 4
- Prevalence increases progressively with advancing gestational age 2, 3
- The number of previous pregnancies (parity) also influences prevalence 3
- Symptoms usually resolve after delivery, with most cases showing improvement within days to weeks postpartum 3, 4
- Greater weight gain during pregnancy correlates with higher RLS risk 2, 4
Clinical Impact
Pregnancy-related RLS significantly impairs quality of life and maternal health:
- Over 50% of affected women report sleep disturbances 4
- Physical health scores, physical functioning, pain scores, emotional role functioning, and social function scores are all significantly lower in pregnant women with RLS compared to those without 2
- RLS can result in insomnia, depression, and other adverse outcomes 1
- There is a marginally significant increase in pregnancy and labor complications among women with RLS 4
Treatment Approach
First-Line Management: Non-Pharmacologic Interventions
The American Academy of Sleep Medicine emphasizes that non-pharmacologic methods are the primary recommended treatment for RLS in pregnancy and lactation. 6, 1
The initial management step must address exacerbating factors 6:
- Discontinue or avoid alcohol and caffeine
- Review and eliminate antihistaminergic medications (common in pregnancy for nausea)
- Avoid serotonergic medications when possible
- Screen for and treat obstructive sleep apnea if present
Iron Assessment and Supplementation
Check serum ferritin and transferrin saturation in all pregnant women with clinically significant RLS, ideally in the morning after avoiding iron-containing supplements and foods for 24 hours. 6
Iron supplementation guidelines for pregnancy-related RLS 6:
- Institute oral or IV iron if serum ferritin ≤ 75 ng/mL or transferrin saturation < 20%
- Consider IV iron only if serum ferritin is between 75-100 ng/mL
- Iron deficiency is a key pathophysiologic mechanism in pregnancy-related RLS 1, 3
Critical caveat: Many pregnant women cannot tolerate oral iron or have severe symptoms despite oral iron replacement 1. In these cases, IV iron formulations may be necessary, though evidence specific to pregnancy is limited.
Pharmacologic Treatment Considerations
The American Academy of Sleep Medicine explicitly states that prescribers must consider the pregnancy-specific safety profile of each treatment being considered, as RLS is common in pregnancy. 6
For non-pregnant adults, first-line pharmacologic treatments include 6:
- Gabapentin enacarbil (strong recommendation)
- Gabapentin (strong recommendation)
- Pregabalin (strong recommendation)
However, standard medications for treating RLS during pregnancy are not established, and most medications have been used based on evidence from non-pregnant patients. 3 The decision to use pharmacologic treatment must balance symptom relief against maternal and fetal risk 3.
Treatment Algorithm for Pregnancy-Related RLS
Identify and eliminate exacerbating factors (caffeine, alcohol, antihistamines, serotonergic drugs) 6
Check iron studies (ferritin and transferrin saturation) 6
Supplement iron based on laboratory values using pregnancy-specific thresholds 6
If symptoms persist and are severe (causing significant sleep disturbance, depression, or functional impairment), consider pharmacologic treatment only after careful risk-benefit discussion 1, 3
Reassure patients that symptoms typically resolve after delivery and prognosis is generally good 3, 4
Key Clinical Pitfalls to Avoid
- Do not dismiss mild symptoms: Even though symptoms may be transient, severe RLS with sleep deprivation can impact pregnancy course and delivery 4
- Do not use standard population iron thresholds: Pregnancy-related RLS requires higher ferritin targets (≤75 ng/mL) than general population guidelines 6
- Do not automatically prescribe dopaminergic agents: These carry augmentation risk and lack established safety data in pregnancy 3
- Do not forget to screen for RLS mimics: Leg cramps, venous stasis, and leg edema are common in pregnancy and can be confused with RLS 6