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Babies and Barbells

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Trimester-by-Trimester Exercise Guide

What's safe in your first, second, and third trimester. What to modify, what to avoid, and what an NASM-CPT with pre/postnatal certification actually programs.

1

First trimester

Weeks 1–13

Exhaustion, nausea, and a body that looks the same. Continue what you were doing if you feel okay.

Do these

  • Maintain pre-pregnancy strength training — drop volume if needed
  • Cardio you're already used to (keep talk-test pace)
  • Hydrate +500 ml/day, sleep more, eat more
  • Pelvic floor + diaphragmatic breathing daily, 5 min

Modify

  • Reduce RPE to 6-7/10 instead of pushing maxes
  • Listen for new joint pain (relaxin is starting)

Avoid

  • Hot yoga, saunas, anything that overheats core temp
  • Brand-new high-intensity classes (CrossFit, F45 first-time)
  • Caffeine above ~200mg/day per most OB guidelines

2

Second trimester

Weeks 14–27

Energy returns. Nausea fades. Peak training window — most modifications start around week 20.

Do these

  • Full strength training — squats, deadlifts, presses, rows
  • Pelvic floor + deep core work every session
  • Labor prep: deep squats, hip mobility, controlled breath
  • Walking 20+ min daily

Modify

  • Stop supine work (lying flat on back) after ~20 weeks — use incline bench or side-lying
  • Drop crunches/sit-ups entirely once the bump is visible
  • Watch for coning on planks/push-ups — regress if you see it

Avoid

  • Lying flat on back for sustained periods
  • Heavy front-loaded compressive movements (front squats heavy, hanging)
  • Hot yoga, saunas, prolonged overheating

3

Third trimester

Weeks 28–40+

Everything-changes-weekly. Energy dips. Mobility shifts. Birth prep takes priority.

Do these

  • Continue lifting — drop loads, slow tempo, increase rest
  • Mobility daily: hips, ankles, thoracic spine, pelvic floor releases
  • Birth-prep: deep squat holds, pelvic floor down-training, breath work
  • Walk. A lot.

Modify

  • Switch to goblet squats, DB RDLs, KB DL, or trap bar (no bar across back)
  • Drop weights and slow tempo — RPE 5-7
  • Use box or wall for balance if needed

Avoid

  • Long planks, hanging movements
  • Box jumps, high-impact plyometrics, anything with fall risk
  • Anything that triggers pelvic pain or instability

Universal red flags

Stop training and call your OB if…

  • Vaginal bleeding or fluid leakage
  • Persistent dizziness, faintness, or visual changes
  • Calf pain or swelling (DVT signs)
  • Reduced fetal movement after week 28
  • Painful uterine contractions
  • Chest pain or shortness of breath disproportionate to effort

Want me to program for you?

Lehigh Valley's only NASM-CPT with pre/postnatal certification.

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lexi@babiesandbarbellslv.com (267) 730‑3265
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