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Exercising Through the Second Trimester

Exercising Through the Second Trimester

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As we continue with this blog post series and break down the pregnancy trimesters, this post focuses on the second trimester. The second trimester is marked from weeks 13-27. For some women, this trimester can bring a little more comfort and less nausea and fatigue that is often experienced in the first trimester. In fact, the second trimester can sometimes be referred to as the “honeymoon trimester” because women often feel the best during this point in their pregnancy. They aren’t experiencing quite the level of physical discomforts of the third trimester yet and are often past the feelings of morning sickness. Therefore, this point in the pregnancy is important to start establishing consistent exercise habits if none have been set into place thus far. Having a consistent workout routine during pregnancy will help make it easier for the mother to return to exercise following the birth of her child. 

Physiological Changes 

SI Joint Pain 

While women tend to start feeling better during this time, risk for injury can increase as structural changes in the body are taking place. A contributing factor is the hormone relaxin. This hormone is responsible for relaxing the joints, tendons, and ligaments to get the body ready for childbirth. As a result, there might be some instability in the joints. While this hormone is secreted during the first trimester, a large increase in secretion occurs during the second trimester around week 16. It is important to be mindful of this while exercising because along with a change in center of gravity due to the mother’s increased weight gain from the developing baby, the joints become unstable, especially the pelvic joints including the SI joint (sacroiliac joint, located where the ilium and sacrum meet). The ligaments surrounding the SI joint are weakened from the relaxin hormone. Additionally, the pelvic bones actually start separating due to the downward pressure from the growing baby. While this is vital for delivery as the birth canal is widened, it can lead to a great deal of pain in the pelvic area. Pain is usually experienced on the tailbone or in the lower back. During exercise, a sharp pain might also be experienced in the upper part of the glute. If sharp pain is experienced in these areas, it is advised to stop exercising at this point to let the pain subside. 

Pregnancy Posture 

Posture is also affected during the second trimester due to an increase in weight of the growing uterus and an increase in relaxin. A woman’s center of gravity is shifted causing the pelvis to tilt forward and the lower back to sway. This increase in curvature of the lower spine is called lordosis and puts a strain on the muscles of the lower back. Additionally, the hamstrings tighten to help protect the spine, and the abdominal muscles lengthen and weaken. On the flip side, the upper back will experience kyphosis: the shoulders round forward and the head juts forward due to the hypermobility and instability of the lower back as well as from the increased weight of the breasts. If these postural misalignments are not addressed, it will carry on into the third trimester and post pregnancy. These postural misalignments can be improved through awareness and strength training. Abdominal exercises and exercises like low rows and lat pull downs, for example, are exercises that will help to strengthen the muscles needed to improve posture. 

Round Ligament Pain 

The round ligament attaches the uterus to the pelvic bone. As the uterus grows, the round ligament is also growing, up to 12 inches by the end of the pregnancy. (For reference, pre-pregnancy length is about 2 inches). Because of this, pain and cramping are common along both sides of the pelvis and deep in the belly. When training, to help alleviate some of the round ligament pain, it is important to engage the abdominals and keep the hips and shoulders aligned to avoid any twisting. Any sudden twisting or jolting can trigger round ligament pain. 

Synovial Fluid 

Synovial fluid works as a cushion between the joints and works to lubricate them to help with the body’s range of motion. During pregnancy less synovial fluid is made. Therefore, joints rest more tightly together and up and down movement is limited. It takes more time for the synovial fluid to mobilize and actually lubricate the joints. Because of this, when working out, it is important to allow for a proper warm up, around 8-12 minutes, so the joints can be properly lubricated with the synovial fluid. 

Supine Hypotensive Syndrome 

During the second trimester, women often find it uncomfortable to lay flat on their back for a long period of time. Women may start to feel dizzy, lightheaded, numbness or tingling in their legs. This condition is called supine hypotensive syndrome. Over time, as the baby grows in size, the baby may start to compress the vena cava (the vein that returns blood back to the heart) when the mom is laying on her back. To avoid this discomfort, it is advised to only do short bouts of exercise while laying directly flat (90 seconds to 2 minutes). However, exercises that are usually performed on the back can still be performed with a slightly elevated surface (to at least 30 degrees) like a stability ball or be performed from a side lying position. Additionally, heart burn is also a common occurrence during the second trimester when laying flat on the back. If this, too, persists during exercises performed flat on the ground, try modifying the positioning to either on your side or elevated, or stop to let the symptoms subside. 

Goals of Exercise During the Second Trimester

As you can see, there is a great deal going on during the second trimester of pregnancy. The main focuses of exercise during this trimester are to work on proper positioning and posture, to continue core strengthening, and to work on balance. In addition, pelvic floor exercises and Kegels should still be incorporated into workouts during this time. Focusing on these key areas during this pivotal time in the pregnancy will help the mother to feel stronger which will ultimately help with the delivery of the baby. 

If you would like to learn more about the specific exercises we recommend during the first trimester, please reach out and let’s work together!

Yours in Wellness,



Oh Baby! Fitness Prenatal and Postpartum Training