Depression and anxiety during pregnancy are common, underdiagnosed, and clinically significant. According to the American College of Obstetricians and Gynecologists (ACOG), up to 1 in 5 women experience mood or anxiety disorders during pregnancy or the postpartum period, with consequences that can affect both maternal and fetal outcomes. While psychotherapy and medication remain important tools, interest has grown in nonpharmacologic interventions that are safe, accessible, and empowering.
A newly published set of randomized clinical trials (RCTs) by Sánchez-Polán et al., featured in AJOG MFM (2025), provides strong evidence that structured, supervised physical activity during pregnancy can meaningfully reduce symptoms of depression and anxiety when adherence is high.
This article reviews the study findings, places them in the context of existing guidance from major health organizations, and discusses their implications for pregnant patients and clinicians.
Why Physical Activity Matters for Mental Health—Even More During Pregnancy
Outside of pregnancy, physical activity is well established as an effective intervention for mild to moderate depression and anxiety. The Mayo Clinic notes that regular exercise improves mood through multiple mechanisms, including increased endorphins, improved sleep, reduced inflammation, and enhanced self-efficacy (Mayo Clinic – Exercise and Depression).
Similarly, the Cleveland Clinic highlights that exercise can be as effective as antidepressant medication for some individuals with mild depression (Cleveland Clinic – Exercise and Mental Health).
Pregnancy, however, introduces unique physiological, hormonal, and psychosocial changes that raise an important question:
Does exercise still work for mental health when someone is pregnant?
Until recently, data were limited. Many prior studies were observational, small, or inconsistent in design. The Sánchez-Polán RCTs help fill this gap.
Study Overview: Two Randomized Clinical Trials in Spain
Background and Purpose
Sánchez-Polán and colleagues designed two randomized clinical trials to evaluate whether supervised physical activity during pregnancy could improve symptoms of:
- Depression
- Anxiety (both state and trait)
- Perceived stress
Study Design
- Trial periods:
- First RCT: 2020–2022
- Second RCT: 2022–2024
- Setting:
- 5 healthcare centers in Spain
- Participants:
- Pregnant women
- Enrolled between 12 and 16 weeks’ gestation
- Sample size:
- Intervention group: 271 women
- Control group: 271 women
Interventions
Participants in the intervention groups engaged in supervised physical activity programs from enrollment through delivery.
- First trial:
- Two live Zoom sessions per week
- One asynchronous session per week
- Second trial:
- One mandatory in-person session per week
- Two Zoom sessions per week
The control group received usual prenatal care without a structured exercise program.
How Mental Health Outcomes Were Measured
The researchers used validated, widely accepted screening tools, including:
- Depression
- Center for Epidemiologic Studies Depression Scale (CES-D)
- Edinburgh Postnatal Depression Scale (EPDS)
(also endorsed by ACOG)
- Anxiety
- State-Trait Anxiety Inventory (STAI)
- State anxiety
- Trait anxiety
- State-Trait Anxiety Inventory (STAI)
- Stress
- Perceived Stress Scale (PSS)
Statistical analyses included independent t-tests, Mann-Whitney U-tests, chi-square tests, and one-way ANOVA.
Key Findings: Exercise Works—But Adherence Is Critical
Depression Outcomes
At delivery, significantly fewer women in the intervention group showed symptoms associated with depression:
- Intervention group: 3.2%
- Control group: 12.2%
- P = 0.028
This represents a nearly fourfold reduction in depressive symptoms.
Anxiety Outcomes
In the second trial, the intervention group had significantly lower scores than controls for:
- Depression (P = 0.043)
- State anxiety (P = 0.015)
- Trait anxiety (P = 0.045)
- Combined state and trait anxiety (P = 0.021)
The Importance of Attendance
One of the most clinically important findings was the dose-response effect:
Women who attended more than 90% of exercise sessions had significantly lower scores than those with less than 70% attendance in:
- Depression (P = 0.003)
- State anxiety (P = 0.035)
In short, exercise works best when people actually do it consistently.
Why Might Exercise Improve Mental Health During Pregnancy?
The authors propose several plausible mechanisms:
- Hormonal regulation
Regular physical activity may help stabilize fluctuations in cortisol, serotonin, and endorphins, all of which influence mood. - Improved sleep quality
Exercise is strongly associated with better sleep, which directly affects anxiety and depression. - Social interaction
Supervised and group-based programs reduce isolation—a significant risk factor for prenatal depression. - Increased self-efficacy
Feeling physically capable during pregnancy can improve emotional well-being and confidence.
These mechanisms align with guidance from the National Institutes of Health (NIH) and CDC, both of which emphasize physical activity as a cornerstone of mental health promotion (CDC – Physical Activity and Mental Health).
Is Exercise During Pregnancy Safe?
Yes—for most people.
According to ACOG, most pregnant women should aim for at least 150 minutes of moderate-intensity aerobic activity per week, unless contraindicated (ACOG – Exercise During Pregnancy).
The Mayo Clinic similarly reassures that exercise during pregnancy is not only safe but beneficial for both physical and mental health, when appropriately tailored (Mayo Clinic – Pregnancy Exercise).
Notably, the Sánchez-Polán trials used supervised programs, which likely contributed to both safety and adherence.
What This Means for Patients and Clinicians
For Pregnant Patients
- Exercise is not just safe—it may significantly reduce symptoms of depression and anxiety.
- Consistency matters. Benefits were strongest with >90% attendance.
- Supervised or structured programs may offer added mental health benefits.
For Clinicians
- Physical activity should be discussed not only for physical outcomes, but also as a mental health intervention.
- Recommending structured, supervised programs may improve adherence and outcomes.
- Exercise can be a valuable adjunct to therapy and medication—not necessarily a replacement.
Bottom Line
The findings from these two randomized clinical trials strongly support what many clinicians have suspected:
Supervised physical activity during pregnancy can significantly reduce symptoms of depression and anxiety—especially when participation is consistent.
As prenatal care increasingly emphasizes whole-person health, structured exercise programs deserve a place alongside screening, counseling, and medical treatment.
Learn More – Primary Source
- Physical activity during pregnancy and depression, anxiety and stress: randomized clinical trials
The ObG Project (2025)
https://www.obgproject.com/2025/12/14/rct-results-does-physical-activity-in-pregnancy-improve-symptoms-of-depression-and-anxiety/
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