About 11-27 percent of pregnant women will experience restless leg syndrome (RLS) at some point. Unfortunately, many women will notice these symptoms in the third trimester, which can be uncomfortable enough as it is! Women who’ve had RLS when they weren’t pregnant are likely to experience it again when they become pregnant, and about 30 percent of pregnant women who had it in one pregnancy will experience it in another.
RLS is characterized by four main criteria:
- The urge to move the legs (usually with an unpleasant sensation occurring at the same time)
- Symptoms that show up during rest
- Symptoms that improve with movement
- Worsening of these issues at night
Unfortunately, pregnant women experience RLS 2-3 times more frequently than the non-pregnant population.
RLS is a strange phenomenon, and exactly why it happens is still a bit of a mystery. One leading theory is that iron deficiency anemia (low iron levels that lead to low blood counts) can cause it. In some ways, the abnormal levels of iron lead to metabolic dysfunction that causes these symptoms. However, we don’t know the exact mechanisms or pathways by which this all occurs. Genetics may play a role as well, so if you’ve got a family member with RLS you may be at higher risk for developing it.
Women who are pregnant and experience RLS should be evaluated for iron deficiency anemia with a simple blood test. And with pregnant women already at risk for this type of anemia, treating it with simple supplementation via a pill or increasing iron-rich foods may help address the symptoms.
But what if that doesn’t help or a pregnant woman’s blood count is perfectly normal? Other treatments do exist, with the goal to make quality of life more bearable. Drugs in a few different classes are used to treat RLS, including dopamine agonists (such as drugs used to treat Parkinson’s disease), opioids (such as oxycodone), benzodiazepines (such as clonazepam), and antiepileptics (like gabapentin). Unfortunately, many of these drugs have not been extensively tested in pregnant women, and some that have been tested have been linked to dependence and withdrawal symptoms in babies.
Overall, women with very bothersome RLS should let their obstetric provider know so iron deficiency anemia can be ruled out or treated if it is diagnosed. If this is not the issue, a plan can be made to find the safest treatment for a woman based on how severe her symptoms are and how bothersome RLS is to her life.
Reviewed by Dr. Jen Lincoln, April 2020
- Restless leg syndrome (RLS) affects pregnant women much more than the non-pregnant population.
- One thought is that iron deficiency anemia leads to RLS symptoms, so this should be evaluated in a woman with RLS.
- Genetics may also play a role in developing RLS.
- Other medical treatments do exist, but their roles are limited in the pregnant population.