When to Modify Workouts During Pregnancy: Advice from a CPT and Prenatal Exercise Specialist

pregnancy med ball workout, prenatal workout

Pregnancy is an incredible journey—and it calls for smart, intentional movement. As a certified personal trainer and prenatal exercise specialist, I often get asked: “When should I start modifying my workouts during pregnancy?” The truth is, there’s no one-size-fits-all answer—but there are key signs and stages where prenatal exercise modifications are essential for your safety and your baby’s.

I get deep into exercise modifications, pregnancy nutrition, and so much more in my GOOD // SWEAT Pregnancy Guide – where I provide 26-weeks of workouts, specifically segmented to guide you through your second and third trimesters – but I wanted to share a solid overview here.

Support for Every Trimester

My goal here is to give you peace of mind, so you can feel more confident as you approach exercising safely at any stage of pregnancy.

As always, I encourage you to trust your gut, listen to your body and make adjustments as needed, and of course, consult your healthcare provider. Also—consider working with a physical therapist, pelvic floor therapist, and/or prenatal fitness specialist to tailor your exercise routine to your needs.

Understanding Your Body’s Changes

As early as the first trimester, hormonal shifts can impact joint stability, while rising fatigue and nausea may change how your body responds to physical activity.

Exercise safety during pregnancy is highly individual and can vary based on how your body responds to different movements. Your pre-pregnancy activity level, your trimester, and how you feel during exercise are all important factors.

Listening to your body is crucial—but so is knowing how to adjust your routine with professional and evidence-based guidance.

When to Modify Workouts During Pregnancy

You should begin to modify workouts during pregnancy as soon as your body or provider gives you the signal—or ideally, proactively. Here are some times to consider changes:

First trimester: scale intensity and stay cool—avoid exercising in hot, humid conditions, and wear breathable clothing to prevent overheating (recommended for all 3 trimesters, really)
Second trimester: begin to avoid exercises lying flat on your back and incorporate more core-safe movements
Third trimester: prioritize mobility, strength maintenance, and pelvic floor-friendly movements

The main takeaway? At any and all points of pregnancy, modify for comfort: always adjust the intensity, range of motion, and duration of exercises to match your current energy levels and comfort.

What Modifications Might Include

Every pregnancy is different, and some weeks you just might not feel your best. I know many women experience rough first tri’s and don’t gain most of their energy back until about Week 13. Whether it’s nausea, low energy, or just sore muscles, it’s completely normal. It’s about staying active at a pace that feels good to you—don’t hesitate to switch things up as needed!

Modifying workouts for pregnancy might look like:

Switching from high-impact to low-impact workouts
- Think: activities like brisk walking, swimming, or prenatal yoga.
Reducing intensity or volume to support energy levels
Incorporating core and pelvic floor support exercises
Avoiding movements that feel unstable or cause coning in your abdomen
- Opt for core-safe movements like pelvic tilts, side-lying leg lifts, or bird-dogs. Focus on exercises that engage your core without placing too much strain on the abdominal muscles.

These adjustments help ensure you’re engaging in safe pregnancy workouts that support your strength, stamina, and recovery. Any time you experience discomfort, pain, dizziness, or shortness of breath, it’s important to stop immediately and modify, and/or take breaks as needed. And don’t forget to stay hydrated!

Ready to Move Safely Through Pregnancy?

Trust me, mamas—I know how important it is to have a structured fitness routine throughout pregnancy. We’re all just trying our best out here!

If you’re looking for a clear, trimester-by-trimester pregnancy workout guide (starting at Week 13), I created this just for you: my GOOD // SWEAT Pregnancy Guide (click here!). It’s designed to take the guesswork out of fitness while pregnant—so you can move with confidence, every step of the way.