You can certainly do resistance and cardio training during your pregnancy, but you should wait until after the pregnancy to make significant improvements in fitness levels.
Weight Gain During Pregnancy
In general, the amount of weight you should gain during your pregnancy depends on your weight prior to becoming pregnant. Excess weight gain and failure to lose this weight six months postpartum are predictors of long-term obesity.
Weight Gain Norms during Pregnancy
If you are at a normal weight prior to pregnancy: gain 25-32 lbs.
If you are underweight prior to pregnancy: gain 40 lbs.
Exercise Risks For Pregnant Women
Physician approval for exercise is always required for pregnant women. Risks for the mothers include:
1. hypoglycemia (low blood sugar),
2. fatigue and
3. musculoskeletal injuries.
The baby is at risk for:
1. hyperthermia (overheating) and
2. decreased uterine blood flow.
You should stop exercising before fatigue sets in and follow the recommended guidelines for exercise mode, frequency, intensity, and duration. Should any of the following warning signs occur, stop exercising immediately and consult your physician.
Exercise warning signs during pregnancy include:
1. vaginal bleeding
2. muscle weakness
3. shortness of breath prior to exercise
4. calf pain or swelling
6. pre-term Labor
8. decreased fetal movement
9. chest pain
10. amniotic fluid leakage
Some pregnant women should not exercise. Women with cardiac disease or restrictive lung disease may not be able to exercise. Pregnancy-induced hypertension, cervix problems, second and third trimester bleeding, and premature rupture of membranes are conditions that will make exercise inappropriate.
Walking, stationary cycling, and swimming are popular exercise modes for pregnant women. Women who were participating in resistance training (including bodyweight exercises) prior to pregnancy should continue to do so.