Exercising During the Third Trimester

The third trimester of pregnancy is an exciting and joyful time, as preparation for the upcoming birth reaches its peak. Of course, the final weeks of pregnancy are not without their demands on physical and mental health.

A central concern among expecting mothers is the desire to maintain a healthy pregnancy. This can start to feel overwhelming given the increasingly challenging physical limitations presented by the final stretch of pregnancy.

Back pain, fatigue, difficulty sleeping, swelling, and shortness of breath are examples of the common health issues experienced in the third trimester. This brings us to a question many pregnant women ask, especially those who are used to an active lifestyle: is it safe to exercise in the last trimester?

Exercising during the third trimester—even vigorous exercise, if that is a part of your routine—is a good idea. Regular exercise is an excellent way to alleviate some of those uncomfortable symptoms of pregnancy. However, it is important to exercise within your limits in a manner that is safe for both you and your child. Guidelines typically recommend 20 to 30 minutes of moderate exercise every day, or 150 minutes a week.

The goal of exercising during pregnancy is to improve fitness and relieve discomfort without any increased risk to the mother and baby. Mothers should decide if their exercise behavior prior to pregnancy falls under one of two categories:

• Previously sedentary: Those used to no exercise or lower intensity exercise should follow a gradual progression of mild to moderate exercise, beginning with something like a simple walking program.
• Previously Active: It is most likely safe to continue previous workout routines (with some simple modifications to avoid putting pressure on the abdomen) if the mother regularly exercised before and has had an uncomplicated pregnancy.

Whether you were previously sedentary or active, you should consult with your OBGYN before starting any new exercise routine if your pregnancy is considered “high risk.” This categorization will affect what the mother can and cannot do, as vigorous exercise may carry potential risks for her and the baby.

• Limit your exercise time to 40 minutes. While 40 mins of moderate exercise are beneficial to women with a low-risk pregnancy, anything beyond that may cause some issues such as a decrease in maternal glucose levels.
• Always be sure to hydrate adequately.
• Pregnant women should avoid activities with:
  • High risk of falling, high impact exercises
  • High heat or humidity
  • Exertion at high altitudes
  • Putting pressure on the abdomen (e.g. twisting, bending at the back, lying on the back or stomach) Most importantly, you should immediately stop exercising if any of the following occur:
  • Vaginal bleeding or leaking fluids
  • Steady contractions
  • Dizziness, headache, or chest pain
  • Muscle weakness that affects balance
  • Calf pain or swelling

Perhaps more importantly, it can lower your risk of experiencing some pregnancy complications, including gestational diabetes, preeclampsia, and cesarean section (c-section). For mothers that are already experiencing gestational diabetes, moderate exercise can help improve the body’s control over blood glucose levels. Exercise is also effective in lowering instances of excessive gestational weight gain and gestational hypertensive disorders.

Regular exercise can even help decrease labor time. It makes a woman twice as likely to progress from 4 to 10 cm dilation in less than four hours, while also reducing the length of the second stage of labor from an average of 60 minutes to an average of 36 minutes. Exercise also has several postpartum benefits, such as a shortened recovery time, a reduced risk of postpartum depression, and increased heart health for the child.

What Type of Exercise Should I Do in Third Trimester?

Walking

Naturally, walking is the simplest and most accessible low impact method of exercising during the third trimester. Find a comfortable and supportive pair of shoes for walking. If your lower back or pelvis starts to hurt during a walk, it may help to try wearing a back or pelvic brace for lumbar support.

Swimming and Water Aerobics

Swimming is arguably the best way to exercise during the final trimester of pregnancy because it is an extremely low impact method that also focuses on strengthening your core and pelvic floor. This will help significantly with stability, overall comfort, and labor. Being in the water takes significant weight and stress off of your joints and ligaments, which allows for more movement with less discomfort. Joining a water aerobics class or even just doing slow, easy laps in the pool are both great ways to exercise.

Yoga

Yoga is an excellent exercise routine for pregnant women in their third trimester for several reasons. It is a multifaceted exercise that encourages focused breathing, stretching, and mental centering.

Practicing prenatal yoga has been shown to reduce stress and depression, decrease pelvic pain, and possibly even improve birth outcomes. Overall, research suggests that prenatal yoga is safe and beneficial to both mother and baby.

However, mothers should avoid poses that involve twisting, lying on the back or stomach, deep bends, and any other pose that puts pressure on the abdomen. Bend from the hips, not the back, to keep the spine straight.

In the end, it is important to remain realistic about what your body can and cannot do during the third trimester. This can be frustrating if you are more used to an active lifestyle than others. There will be plenty of days where it will seem like a struggle just to finish basic, everyday chores or errands – let alone get out and exercise regularly – and this is completely normal as your body is using enormous amounts of energy to prepare for the birth of your baby. Exercise regularly to the extent that you can manage while still listening to your body’s needs.

Research Studies

1. “The effects of vigorous intensity exercise in the third trimester of pregnancy: a systematic review and meta-analysis” by Kassia S. Beetham, et al., BMC Pregnancy and Childbirth, 2019.
   In a study to test whether or not vigorous physical activity is safe for women in their third trimester, studies found that it appears to be safe for most healthy pregnancies.
2. “Recommendations Regarding Exercise During Pregnancy Made by Private/Small Group Practice Obstetricians in the USA” by Pauline L. Entin and Kelly M. Munhall, 2006.
   An investigation into how much and how often private obstetricians across the United States recommend aerobic exercise to pregnant women.
3. “Why do pregnant women stop exercising in the third trimester?” by Lene A.H. Haakstat, et al., Acta Obstetricia et Gynecologica Scandinavia, 2010.
   Despite the fact that current guidelines recommend that pregnant women should be exercising during pregnancy, many women remain sedimentary throughout. This study compares demographic and health-related factors in pregnant women that are exercising during the third trimester vs. those who are not.
4. “Aerobic exercise in pregnancy” by Pat J. Kulpa, et al., American Journal of Obstetrics and Gynecology, 1987.
   A study on 141 low-risk pregnant subjects tested their aerobic capacity during the first trimester, the third trimester, and postpartum. Results showed that exercise had no associated increase in neonatal morbidity or obstetric complications.
5. “Regular Maternal Exercise Dose and Fetal Heart Outcome” by Linda E. May, et al., Medicine & Science in Sports & Exercise, 2012.
   The purpose of this study was to determine whether there is a “dose-response relationship” between maternal physical activity and fetal heart rate. In other words, does the fetus’s heart health respond to the external stimulus of its mother’s exercise? The study found that this was the case, supporting current ACOG recommendations that encourage pregnant women to engage in regular moderate to vigorous exercise.
6. “Using the Theory of Planned Behavior to predict pregnant women’s intention to engage in regular exercise” by Ching-Fang Lee et al., Midwifery, 2016
   The Theory of Planned Behavior (TPB) is a model linking one’s beliefs to one’s behavior. The theory is based on the fact that if we plan to do something ahead of time, we are more likely to do it. According to the theory, intention (planning) is the product of behavioral attitudes (perception of the behavior, i.e. is exercise enjoyable or beneficial?), subjective norms (i.e. encouragement given by family and doctor, do other pregnant women exercise, too?) and perceived behavioral control (am I capable/confident I can do this?). In this study, researchers found that pregnant participants’ positive exercise intention was linked most strongly to perceived behavioral control—this means that doctors and loved ones may want to focus on helping pregnant women feel like they can overcome the obstacles of exercise.