For women who are physically active before pregnancy, the question of how to navigate exercise during pregnancy — and whether the approach changes after 35 — is both practical and emotionally significant. Physical activity is closely tied to wellbeing, stress management, and identity for many women, and uncertainty about what is safe and beneficial during pregnancy can create unnecessary anxiety. The research landscape on prenatal exercise has grown substantially in recent decades, and the current evidence is reassuring: for most women with uncomplicated pregnancies, regular physical activity is not only safe but actively beneficial.
Understanding the evidence-based guidance on prenatal exercise, the modifications that are typically recommended as pregnancy progresses, and the specific considerations that may be relevant after 35 can help women approach this topic with confidence rather than apprehension.
What Major Health Organizations Say About Exercise in Pregnancy
The American College of Obstetricians and Gynecologists (ACOG) recommends that women with uncomplicated pregnancies engage in at least 150 minutes of moderate-intensity aerobic activity per week — the same recommendation as for non-pregnant adults. This guidance reflects a substantial shift from earlier, more conservative approaches to prenatal exercise, and is supported by a growing body of research demonstrating the maternal and fetal benefits of prenatal physical activity.
ACOG and similar organizations in other countries (including guidelines from NICE in the UK and the Society of Obstetricians and Gynaecologists of Canada) all emphasize that the decision about exercise during pregnancy should be made in dialogue with a healthcare provider, taking individual health status, pregnancy complications, and exercise history into account. For women with certain pregnancy complications — including placenta previa, preterm labor risk, or certain cardiovascular conditions — exercise recommendations may differ significantly from the general guidance.
Evidence-Based Benefits of Exercise in Pregnancy
Research has documented a range of potential benefits associated with regular moderate-intensity exercise during uncomplicated pregnancies:
Gestational Diabetes Prevention
Gestational diabetes mellitus (GDM) is a concern in pregnancies after 35, as risk increases somewhat with age and other factors. Research indicates that regular aerobic exercise during pregnancy is associated with a reduced risk of GDM, likely through improved insulin sensitivity. A 2017 meta-analysis published in the British Journal of Sports Medicine found that exercise interventions during pregnancy were associated with a significant reduction in GDM incidence. For women over 35 who may carry additional GDM risk factors, this represents a potentially meaningful modifiable factor.
Gestational Weight Gain
Appropriate gestational weight gain — within ranges recommended by health guidelines based on pre-pregnancy BMI — is associated with better maternal and neonatal outcomes. Research suggests that regular prenatal exercise is associated with more appropriate gestational weight gain trajectories, though it is worth emphasizing that pregnancy is not a time for weight restriction, and adequate nutrition for both mother and baby is paramount.
Sleep Quality
Research on exercise and sleep during pregnancy suggests that physically active pregnant women may experience improved sleep quality compared to sedentary counterparts. Given the sleep challenges that many pregnant women — particularly those over 35 — experience (discussed in our guide on second trimester sleep changes after 35), exercise represents a behavioral approach to sleep support with a safety profile well-established in pregnancy research.
Mood and Anxiety
The relationship between physical activity and psychological wellbeing is robustly established outside of pregnancy, and research in pregnant populations supports a similar association. A systematic review published in Clinical Psychology Review found that exercise during pregnancy was associated with reduced symptoms of depression and anxiety. For women who used exercise as a significant tool for stress management before pregnancy, maintaining physical activity — within safe parameters — can support emotional wellbeing throughout gestation.
Labor and Recovery Outcomes
Some research suggests associations between prenatal exercise and shorter labor duration, reduced risk of cesarean delivery, and improved postpartum recovery. The evidence in this area is somewhat less consistent than for other outcomes, and confounding factors are challenging to fully account for, but the overall picture is supportive of prenatal activity for women who are able to engage in it safely.
How Exercise Recommendations Evolve by Trimester
General principles for adapting exercise during pregnancy include:
First Trimester
For women who were exercising before pregnancy, continuing familiar activities at comparable intensity is generally supported through the first trimester for uncomplicated pregnancies. Fatigue and nausea are common during this period and may naturally reduce exercise capacity; listening to the body and adjusting intensity as needed is appropriate. Staying well-hydrated and avoiding overheating are consistent recommendations across guidelines.
Second Trimester
As the abdomen grows during the second trimester, some adaptations typically become relevant. Activities involving lying flat on the back for extended periods are often modified after mid-pregnancy because of potential pressure on the inferior vena cava. Balance changes as the center of gravity shifts, which may affect comfort and safety in activities requiring agility. Many women find this trimester a relatively comfortable period for exercise before the physical demands of the third trimester increase.
Third Trimester
Physical comfort and energy capacity typically shift considerably in the third trimester. Lower-impact activities — walking, swimming, prenatal yoga, and stationary cycling — tend to be well-tolerated and widely recommended. Pelvic girdle pain (SPD) may emerge or worsen with certain movements, and modifications to accommodate individual symptoms are important. Maintaining some level of activity, even if substantially reduced from earlier in pregnancy, remains beneficial for most women through this stage.
Specific Considerations After 35
Women who are pregnant after 35 may bring specific considerations to their prenatal exercise approach:
- Preexisting conditions: Women over 35 may be more likely to enter pregnancy with preexisting health conditions (such as hypertension, thyroid disorders, or musculoskeletal issues) that may require tailored exercise guidance. A thorough prenatal evaluation early in pregnancy provides the most reliable foundation for individualized exercise recommendations.
- Pelvic floor health: Pelvic floor changes become an important consideration during pregnancy and after delivery, and research supports pelvic floor physical therapy as a valuable component of prenatal and postpartum care for many women. Women who are very active before and during pregnancy may benefit from pelvic floor assessment to identify any adaptations that can help prevent or address pelvic floor dysfunction.
- Recovery and pacing: Women over 35 who have been exercising consistently before pregnancy may find that recovery takes somewhat longer — a pattern that research in general athletic populations also documents with aging. Being willing to adjust intensity, frequency, and recovery time based on how the body is responding is an important aspect of sustainable prenatal exercise.
Activities to Discuss with Your Provider
ACOG and similar guidelines generally recommend discussing with a healthcare provider before continuing or starting the following activities during pregnancy:
- High-impact contact sports or activities with fall risk (skiing, horseback riding, gymnastics)
- Scuba diving
- Exercise at high altitude (greater than 8,000 feet), particularly for women not acclimatized
- High-intensity interval training programs, particularly for women who were not engaged in high-intensity exercise before pregnancy
It is also important to know the warning signs that warrant stopping exercise and contacting a healthcare provider: chest pain, shortness of breath before exertion, dizziness, headache, calf pain or swelling, vaginal bleeding, or decreased fetal movement.
Frequently Asked Questions
Can exercise cause miscarriage in the first trimester?
Current evidence does not support a causal link between moderate-intensity exercise and miscarriage in uncomplicated pregnancies. Most first-trimester pregnancy losses are related to chromosomal abnormalities in the embryo, not physical activity. Women who have specific concerns or risk factors for pregnancy loss should discuss exercise with their healthcare provider, but for most women with uncomplicated first-trimester pregnancies, moderate exercise is considered safe.
Is running safe during pregnancy?
For women who were running before pregnancy, many continue running through the second trimester and sometimes into the third with appropriate modifications. As pregnancy progresses, modifications to pace, surface, and distance are typically warranted, and pelvic floor considerations become more relevant. Individual factors — including pregnancy health, pelvic floor status, and comfort — should guide decisions about running, ideally in discussion with an OB/GYN and potentially a pelvic floor physical therapist.
What if I wasn’t exercising before pregnancy?
ACOG’s guidance supports beginning moderate exercise during pregnancy even for women who were sedentary before conception, with appropriate gradual progression. Walking is widely recommended as an accessible starting point. Starting any new exercise program during pregnancy should be done in discussion with a healthcare provider who can account for individual health status and any pregnancy-specific factors.
How do I know if I am exercising too intensely during pregnancy?
The “talk test” — being able to carry on a conversation while exercising — is a simple and practically useful gauge of moderate intensity. Formal heart rate targets for pregnancy have been largely replaced by relative perceived exertion as the primary guide in current guidelines, because individual cardiovascular responses to exercise shift during pregnancy in ways that make absolute heart rate thresholds less reliable.
Key Takeaways
- Major reproductive health organizations, including ACOG, recommend at least 150 minutes of moderate-intensity aerobic activity weekly for women with uncomplicated pregnancies — consistent with general adult physical activity recommendations.
- Research supports potential benefits of prenatal exercise for gestational diabetes risk, gestational weight gain, sleep quality, mood, and possibly labor outcomes, making it a valuable component of prenatal wellness for many women.
- Exercise recommendations evolve by trimester as the body changes, and individual adaptation — particularly for women over 35 who may bring preexisting conditions or pelvic floor considerations — is an important aspect of sustainable prenatal activity.
- Discussing exercise plans with your OB/GYN or midwife early in pregnancy provides the most reliable, individualized framework for physical activity that supports both maternal and fetal wellbeing.
Medical Disclaimer
This content is for informational purposes only and does not constitute medical advice. Individual health situations vary significantly. Always consult a qualified healthcare provider before making decisions related to your health, fertility, or pregnancy.
About the Author
Emily Carter is a women’s health writer focused on fertility, pregnancy after 35, and sleep changes in midlife. She writes research-informed, non-alarmist content to help women navigate reproductive and hormonal transitions with clarity and confidence.