My wife is 40 weeks pregnant. She has been lifting, going to the gym, and exercising right through her pregnancy. I think that is awesome.

I say that as her husband, but also as an Accredited Exercise Physiologist who works with people in the antenatal and postnatal period.

The fear-based messaging around pregnancy and exercise is something I hear about constantly. On social media. In waiting rooms. Sometimes from well-meaning health professionals.

• "Be careful with that."
• "Maybe ease off the weights."
• "Is that really safe for the baby?"

It comes from a caring place. But it rarely comes from the evidence.

So let's look at what four recent peer-reviewed studies actually say about resistance training during pregnancy. The science is a lot more reassuring than the noise.

First, where did all these rules come from?

Most restrictions around exercise in pregnancy were never based on evidence. They were based on expert opinion. Conservative caution, handed down through guidelines that were never properly tested.

A 2020 systematic review set out to examine the evidence behind each reason given for avoiding prenatal exercise (Meah et al., 2020). What it found was striking.

The review looked at 44 studies and found that most "contraindications" lacked any real support. It also found that inactivity itself carries genuine risk.

The following are no longer considered a barrier to exercise:

• Gestational hypertension
• Chronic hypertension
• Overweight or obesity
• Recurrent miscarriage
• Short cervix
• Twin pregnancies
• Epilepsy
• Anaemia
• Orthopaedic limitations
• Sedentary history
• Prior preterm labour

To be clear, real reasons to avoid or modify exercise do still exist. But the list is much shorter than most people think. Every pregnant person deserves an individual conversation, not a blanket "take it easy."

But what about lifting weights?

Until recently, high-intensity resistance training in pregnancy was discouraged simply because no one had directly studied it. Not because it had been shown to cause harm. The data did not exist.

That changed in 2025 (Moolyk et al., 2025).

This was the first direct study of heavy compound lifting in pregnancy: barbell squat, bench press, and deadlift at 70 to 90% of a 10-rep maximum. Fetal heart rate, umbilical blood flow, and other key measures were monitored before and after each set.

Ten healthy pregnant participants took part. On average they were 26 weeks along, and all had at least two years of lifting experience. They completed squats, bench press, and deadlifts, including with the Valsalva manoeuvre (holding the breath to brace during a heavy lift).

This detail matters. These findings apply to experienced lifters in the late second trimester. They do not apply to someone starting resistance training from scratch during pregnancy.

Here is what happened:

• Zero cases of fetal bradycardia (a slow fetal heart rate) at any intensity
• Umbilical blood flow stayed within normal ranges through all sets
• All babies born healthy at term
• Safe even with the Valsalva manoeuvre, which was previously considered off-limits

The authors concluded that near-max resistance exercise using compound movements is well tolerated by both mother and baby, including with the Valsalva manoeuvre (Moolyk et al., 2025).

What about fetal heart rate changes?

One of the most common worries is that a changing fetal heart rate during exercise signals distress. A 2024 overview addresses this directly (Duchette et al., 2024).

Changes in fetal heart rate during resistance training reflect increased fetal wakefulness and activity. They are not a sign of distress, and they are not linked to any risk of low oxygen.

The same overview found that resistance training during pregnancy can:

• Reduce the risk of gestational diabetes, preeclampsia, and a larger-than-average baby
• Improve labour and delivery outcomes
• Support fetal development and infant health, possibly into adulthood
• Reduce postpartum anxiety, depression, and incontinence

And what does it do for mum?

A 2025 systematic review looked specifically at how strength training affects quality of life during pregnancy (Redondo-Delgado et al., 2025). It analysed nine randomised controlled trials involving 1,581 pregnant people.

The results were consistently positive:

• Low back pain, sciatica, and total pain were significantly reduced
• Energy, vitality, and sleep quality improved
• Anxiety, sadness, and fatigue were reduced
• Strength, physical function, and general health improved
• Excessive weight gain was reduced

A simple, evidence-based starting point

For many healthy pregnancies, the research points to a sensible structure:

• Frequency: 1 to 2 sessions per week
• Intensity: moderate to vigorous (around RPE 12 to 16 out of 20)
• Duration: about 60 minutes per session
• Type: full-body, circuit-based training, with attention to the core and pelvic floor

An important note

Real reasons to avoid or change exercise in pregnancy do exist. Exercise should always be matched to your health, fitness, circumstances, and preferences.

This article is educational. It is not a substitute for an individual assessment, and it is not personal medical or exercise advice.

The studies above involve specific groups, such as experienced lifters, particular stages of pregnancy, and healthy pregnancies without complications. Every pregnancy is different. Always check with a qualified health professional before starting or changing exercise during pregnancy.

The takeaway

The point is not that everyone should be deadlifting at 90% of their max while pregnant.

The point is that the fear-based messaging many pregnant people hear, the "just rest, be careful, don't push it," often has no evidence behind it. And sitting still carries its own real risks.

The real risk is not lifting. It is sitting out of your own health because someone scared you away from it.

Ready to move with confidence during pregnancy?

Our Exercise Physiologists work with pregnant people across the antenatal and postnatal period. We build safe, individual programs grounded in the latest evidence.

If that sounds like what you need, enquire about EP support at thebiomechanics.com.au.

More Movement. Better Life.

References

Duchette, C., Perera, M., Arnett, S., et al. (2024). Benefits of resistance training during pregnancy for maternal and fetal health: A brief overview. International Journal of Women's Health, 16, 1137–1147. PMID: 38912201

Meah, V. L., Davies, G. A. L., & Davenport, M. H. (2020). Why can't I exercise during pregnancy? Time to revisit medical 'absolute' and 'relative' contraindications. British Journal of Sports Medicine, 54(23), 1395–1404. PMID: 32513676

Moolyk, A. N., Wilson, M. K., Matenchuk, B. A., et al. (2025). Maternal and fetal responses to acute high-intensity resistance exercise during pregnancy. British Journal of Sports Medicine, 59(3), 159–166. PMID: 39694629

Redondo-Delgado, P., Blanco-Giménez, P., López-Ortiz, S., et al. (2025). Effects of strength training on quality of life in pregnant women: A systematic review. Acta Obstetricia et Gynecologica Scandinavica, 104(7), 1231–1243. PMID: 40230063