Hi Nina!
Exercise during pregnancy is absolutely safe, provided you do it the right way. If you were a regular exerciser before your pregnancy, you can carry on your routine as normal. From the second trimester onwards, avoid exercise in the ‘supine’ position – abdominal crunches and other exercises done on your back are off-limits. Don’t exercise your abs aggressively, as this could actually aggravate your degree of diastasis recti, where the ab muscles separate to accommodate your bump. High impact sports are also a no-go, and whilst research is questioning previous advice to limit your heart rate to 140, this is still a good guideline for your maximum heart rate during cardio exercise. You do need to remember that exercise during pregnancy is for maintenance, and should not be results-driven. Your frequency and intensity should decrease gradually as you complete your term, rather than intensifying. In the final weeks of your pregnancy, stick to walking and swimming, and reduce the weights during strength routines.