Prenatal Fitness – Part 4. Training in the Third Trimester

Most pregnant women can and should keep exercising during the third trimester (with physician approval). With a naturally reduced venous return during the third trimester, it’s very important for a pregnant woman to keep moving to help stave off edema (commonly found in her ankles). This focus on maintaining movement may also lead to a slightly lower birth weight. Stopping exercise in late pregnancy tends to produce a larger baby who has more body fat. A woman in the latter half of her pregnancy will generally require adjustments to her training program based on the unique changes she is experiencing. Here are two specific considerations:

Postural Deviations

From the beginning of a woman’s pregnancy, the hormone relaxin (which causes ligamentous laxity) has been flowing through her body, allowing for essential skeletal shifts that allow for the baby’s growth. However, the presence of relaxin can also lead to exaggerated shifts as a woman moves through her third trimester. The increased weight she is likely carrying can cause an anterior pelvic tilt (lordosis), which may lead to prominent low-back pain. The anterior weight shift also occurs at the breasts throughout pregnancy, profoundly more so in the third trimester. This pull adds to increased kyphosis at the cervical and thoracic spine. Kyphosis pulls her out of a neutral spinal position, which may lead to neck and upper-back pain, as well as diminished power and range of motion when she is operating out of proper posture.


As a woman transitions into the later portion of her pregnancy, her mindset often becomes less focused on her own fitness and more on her upcoming labor and delivery. All of a sudden, she’s is much larger than she wants to be, is tired of being kicked by the baby, doesn’t sleep well and wonders if the baby is healthy and what labor and delivery will be like. As a result, her attention turns away from herself to prepare for the labor, the birth and the new baby.

According to the American Congress of Obstetricians and Gynecologists, “…more than 60% of all pregnant women experience low back pain. Strengthening of abdominal and back muscles could minimize this risk”. With the forward shifting of weight as a baby grows, the strength of a pregnant woman’s core musculature is critical to maintaining a neutral spine, and ultimately, helping to decrease muscle fatigue and pain. Without good trunk strength, the weight of the growing baby can pull the pelvis forward, causing a sway back (lordosis). This prolonged position can lead to a very uncomfortable malalignment in the spine. Increasing core strength during pregnancy will aid in getting the pelvis back into a neutral position. In addition to aerobic activity, prenatal core exercises are recommended.

Training program should:

  1. Focus on improving core strength. As previously mentioned, most women experience an anterior weight shift during the third trimester, which makes core strength essential for helping to pull the pelvis back into neutral. Focusing on strengthening your pregnant client’s three-dimensional core musculature will also help to keep her lumbo-pelvic complex from making shifts, as well. These shifts can lead to pain at the sacroiliac joint and the pubic symphysis.
  2. Reengage the posterior muscular chain. During pregnancy, the muscles of a woman’s upper back (mid/lower trapezius and rhomboids) become weakened and elongated, while the muscles of the low back (erector spinae) shorten and tighten in lordosis. Finally, the glutes tend to “shut off,” which means she must rely more heavily on her quadriceps. This disengagement of the glutes also leads to unwanted shifts at the pelvis. Reengaging the posterior chain requires exercises that focus on strengthening the glutes.
  3. Enhance pelvic floor strength (and elasticity). Going into the third trimester, the weight of the baby in utero can drop the pelvic floor up to an inch. Kegel exercises to strengthen the pelvic floor are recommended throughout pregnancy and especially during the third trimester as the pressure is the greatest during this time.


“Specific Considerations and Exercises for Late-term Pregnancy”, Farel Hruska, national fitness director of FIT4MOM