Pregnant women who develop restless legs syndrome in their third trimester face nearly triple the risk of depression compared to those who don’t, according to new research tracking thousands of expectant mothers in Japan.
Quick Take
- A Japanese study of 2,435 pregnant women found restless legs syndrome in the third trimester linked to a threefold higher risk of perinatal depression.
- The link showed up only in the third trimester, not the second, pointing to a late-pregnancy window that matters most.
- Other studies, including one from Morocco, found restless legs syndrome tied to anxiety but not a confirmed depression link, showing the science isn’t settled everywhere.
- Doctors say the findings support watching for restless legs symptoms late in pregnancy, even though no study has yet proven that treating it prevents depression.
What The Study Actually Found
Researchers followed 2,435 pregnant women for an average of 6.5 months. Sixty-nine of them developed perinatal depression. Women who had restless legs syndrome in their third trimester had a hazard ratio of 3.04 for developing depression, meaning their risk ran roughly three times higher than women without the condition. The same group also showed a higher rate of depressive symptoms measured by a standard postnatal screening scale, with a hazard ratio of 2.12.
The American Academy of Sleep Medicine, which highlighted the research, noted the association showed up specifically when restless legs syndrome appeared in the third trimester. Women who had it earlier, in the second trimester, did not show the same elevated depression risk. That timing detail matters. It suggests something about late pregnancy, whether hormonal shifts, physical strain, or disrupted sleep, that makes this particular stretch especially risky for mental health.
Why Restless Legs And Mood May Be Connected
Restless legs syndrome causes an uncomfortable, often irresistible urge to move the legs, usually worse at night. It wrecks sleep. Lost sleep and depression feed each other in a well-documented cycle, so a pregnancy-related condition that steals rest night after night is a reasonable candidate for raising depression risk. A medical review on managing the condition during pregnancy states plainly that it can lead to insomnia, depression, and other problems for mothers and babies.
Other research backs up the broader pattern even if the numbers differ. A 2025 study found pregnant women with restless legs syndrome had more than double the odds of antenatal depressive symptoms. An earlier study tracking women before and during pregnancy found elevated odds of depression-related symptoms at multiple points, including nearly five times higher odds early in pregnancy for women with moderate to severe symptoms. The direction of the evidence keeps pointing the same way, even when the exact size of the risk shifts from study to study.
Not Every Study Agrees On Depression
A study of 178 pregnant women in Morocco found those with restless legs syndrome had significantly higher anxiety, but researchers did not find a statistically confirmed link to depression in that sample. That’s a real, documented result, not a dismissal of the broader finding. Differences in sample size, measurement tools, and population likely explain why one study found a depression link and another didn’t. Science rarely produces identical results across every country and every research design.
The numbers behind the headline figure also carry some built-in uncertainty worth understanding. Only 3.5% of women in the Japanese study had restless legs syndrome in the third trimester, a small slice of the total group. The confidence interval around the threefold risk estimate stretched from 1.22 to 7.58, a wide range that still clears the bar for statistical significance but leaves room for the true effect to be smaller or larger than the headline number suggests.
What This Means For Expecting Mothers
None of this proves that restless legs syndrome causes depression, and no study yet shows that treating the sleep condition stops depression from developing. What the research does show, consistently across multiple countries and multiple research teams, is that the two conditions tend to show up together far more than chance would predict. For a condition affecting a meaningful share of pregnant women, that overlap is worth taking seriously.
Doctors managing high-risk pregnancies already watch for depression screening markers. These findings give them another reason to ask about leg discomfort and sleep quality in the final trimester, when the stakes for a new mother’s mental health are highest. Treatment during pregnancy has real limits, since many standard restless legs medications aren’t considered safe for expecting mothers, but iron supplementation and sleep counseling remain reasonable first steps doctors already use.
Common sense says a mother losing sleep night after night in her final weeks of pregnancy is more vulnerable to depression, and this research gives that common sense some solid numbers behind it. The next step for scientists is figuring out whether fixing the sleep problem actually protects her mood, a question still waiting for a clear answer.
Sources:
pubmed.ncbi.nlm.nih.gov, journals.copmadrid.org, journals.lww.com, pmc.ncbi.nlm.nih.gov
