Weight Training During Pregnancy

Stay Fit and Strong During Pregnancy

weight lifting in pregnancy
Weights workout in pregnancy. Getty Images, Blend Images

Weight training or aerobic workouts may not be high on your 'to do' list when you're going through the changes of pregnancy. Nausea, swelling and discomfort aside, keeping active and fit can provide advantages for you and your developing baby.

The American College of Obstetricians and Gynecologists (ACOG) issues guidelines for exercise during pregnancy and the postpartum period.

If you're pregnant, or even considering getting pregnant, you should ask your doctor before you continue, plan or commence an exercise or weight training program.

There is a reasonably long list of conditions in which aerobic exercise is not approved, and other conditions for which it is advised with caution. Perhaps not surprisingly, less is known about resistance training exercise.

For healthy women, the overall assessment from ACOG is that modest exercise during pregnancy is not a high-risk activity for the fetus. They state: "In the uncomplicated pregnancy, fetal injuries are highly unlikely. Most of the potential fetal risks are hypothetical."

If the pregnancy is planned, then a workup period of at least three months prior to pregnancy should allow your body to adapt to this activity during pregnancy.

How Much Exercise?

The Centers for Disease Control and Prevention and the American College of Sports Medicine (CDC-ACSM) have recommended the accumulation of 30 minutes of moderate-intensity physical activity on most, and preferably all, days of the week.
This need not be different for exercise in pregnancy, within the limits of medical restrictions. Allowing for nausea and blood glucose fluctuations, you can be more flexible with your program in the first three months before developmental restrictions become apparent.

Reasons to Restrict Exercise

Pregnancy involves increased body mass along with hormonal preparation of joints for birth.
A combination of these factors may make joints more susceptible to injury on impact or sudden extension. Experienced joggers may be able to continue for some time with supervision, but pregnancy is not the time to take up jogging or any other impact exercise. Water activities, in which body weight is supported, may offer alternatives -- although not scuba diving.

ACOG says:

"Despite a lack of clear evidence that musculoskeletal injuries are increased during pregnancy, these possibilities should nevertheless be considered when prescribing exercise in pregnancy".

Here are ten warning signs that exercise should be ceased during pregnancy, some of which apply to non-pregnant exercisers as well.

  • Vaginal bleeding
  • Breathlessness before exertion
  • Dizziness
  • Headache
  • Chest pain
  • Muscle weakness
  • Calf pain or swelling (need to rule out blood clot)
  • Preterm labor
  • Decreased fetal movement
  • Amniotic fluid leakage

Posture, Position and Heart Function

The cardiovascular changes associated with body posture is important for pregnant women at rest and during exercise.
After the first three months, the supine, or lying face up position, results in decreased heart output, which may lessen blood supply to the fetus. Therefore, lying on the back exercises should be avoided as much as possible from the fourth month. Motionless standing is also associated with a significant decrease in heart output. You should avoid this posture for extended periods where possible.

Core Body Temperature

When body core temperature rises beyond 102 F (39C), there is a chance of injury to the developing baby. Normal exercise at low to moderate intensity at low to moderate temperatures and with adequate fluid intake should not cause any problems. High-intensity exercise in hot and humid conditions should not be contemplated.

Exercise Prescription

Aerobic exercise of up to 30 minutes a day is appropriate for most pregnant women. High-impact exercises or those with higher risk of falls such as skiing or skating should be considered more carefully, if not abandoned altogether, especially after the first trimester. 

Regular brisk walking, subject to restriction for medical reasons and perhaps environmental conditions such as extreme heat, provides excellent exercise during pregnancy if you have not been active previously.Fitter women with a history of exercise may be able to exercise at a higher intensity after evaluation and initial supervision, and with due vigilance of overheating.

Strength and weight training has not received as much study although the general opinion is that within the bounds of the risks discussed above -- supine position, temperature regulation, standing immobile for lengthy periods, joint, balance and falls issues -- weight training utilizing somewhat lighter weights than normal is suitable. Dumbbell and bodyweight exercises utilizing a fitness ball is ideal for the later months when seated exercise and support is preferable.

Heavy weights and isometric exercises like pushing against a solid object or another body part are best avoided because of the increase in blood pressure that results. Sudden and explosive joint straightening or extreme stretching should be avoided.Breathe normally when lifting weights and don't hold the breath. With due consideration of the constraints, you can train with weights with caution when pregnant.

Check the beginners guide for more weight training information. Paige Waehner has a great list of fitness ball and similar exercises for women.


R Artal, M O'Toole and S White. Guidelines of the American College of Obstetricians and Gynecologists for exercise during pregnancy and the postpartum period Br J Sports Med. 2003;37;6-12.

Continue Reading