Pregnancy pain is inevitable.  50% of pregnant women suffer from some form of pain during pregnancy. 8% suffer from severe pain which affects their quality of life. The pain is first experienced in the first trimester. Most women recover from pregnancy pain in 6 months. However, in some women, pain lingers for a longer period of time.

The cause of pregnancy pain is not fully understood, however, there are some factors which are believed to be the likely causes. Examples of pregnancy pain include sacroiliac joint pain, low back pain, symphysis pubis pain, ligament pain, and sciatica pain.

The cause of pain during pregnancy is believed to be mechanically, and  hormonally influenced. Studies suggest that  as the mother gains weight during pregnancy, there is a forward shift in the body’s center of gravity, resulting in increased  low back curvature (lordosis). As the angle of the lordosis increases, the compression load on the low back increases, resulting in pain and discomfort.  In addition, as the abdominal muscles stretch to accommodate the enlarging uterus, muscle fatigue and weakness occur which result in the increasing load in the low back.

Ligamentous laxity

SIJP PainRelaxin is a hormone that regulates the content of the ligament during pregnancy. It softens the content of the ligament in preparation for pregnancy. It is estimated that relaxin increases by 10 fold during pregnancy, causing ligamentous laxity. This increased laxity in the ligaments  causes instability in the joint of the pelvis, and misalignment of the spine, resulting in pain and discomfort.

Sacroiliac joint pain (SIJP) is the most common pain during pregnancy. It is approximately four times more common than any other low back pain. The SIJP is felt in-between the buttock fold and the dimple on one side of the low back. It is described as deep, stabbing pain, on one side of the low back, and sometimes both sides of the low back, and is consistent. The pain may shoot to the hamstring muscle, or the knee, and calf but never to the foot. The pain is intense and disabling, and gets worse with bending over. Pushing on the dimple increases the pain, which may resemble low back pain, but it is different. The SIJP is joint related pain(see arrow in the above drawing).

Sacroiliac joint pain

The sacroiliac joint is an extremely stable joint via its strong ligaments. There is very little movement occurring in this joint. However, with the influence of the relaxin hormone, and increase in the low back lordosis, the movement in the joint increases to accommodate the infant. The ligaments around the sacroiliac joint loosen and make it unstable. There are nociceptors (pain sensitive receptors) in the ligaments, which provoke pain and discomfort when over-stretched. External support, such as a pelvic belt can provide support to the loose ligaments , hence helping to decrease pain.

Low back pain

Low back pain (LBP) is the second most common pain during pregnancy. The pain is localized in the muscles of the low back. It is higher and above the two dimples of the pelvis. There is tenderness in the muscles of the low back when pressure is applied. The pain is not as intense and is less disabling. The pain becomes worse with prolonged sitting and inactivity. Pain develops because these muscles are tight, shortened, and over-active. They have to work twice as hard to keep the body in balance from the protruding belly. Stretching and relaxing these muscles is one way to decrease pain and discomfort.

Pelvis pain during pregnancy

Pain in the front, and lower part of the pelvis is another common occurrence, in the above picture,  the elephant- ear- type bones (Ilia) join at the white cartilage in the front of the pelvis. This cartilage is stretched during pregnancy. The ilia have to open outward and turn to face downward to create more space for the head and the shoulder of the infant.

Pregnancy painFascinatingly, the space also allows the infant to rotate inside the womb before delivery, which is unique only to humans. The infant rotating inside the womb is of great importance for the survival of the mother and the child. Moreover, as the ilia are opening, the junction where the two ilia bones meet, called the symphysis pubis, spreads apart, causing pain in the lower pelvis. External support can be helpful in managing the pain in this situation.

Ligament pain

Ligament pain is caused by over-stretching and weakness. The ligament’s function is to hold the joints together, to maintain stability, as discussed above. The ligament also holds the uterus (womb). This ligament is called the round ligament. It is attached on both sides of the womb and in the back (see picture above). As the womb enlarges, the round ligament stretches and becomes weak. The ligament contains pain sensitive receptors, hence as it stretches, it causes pain and discomfort on the side of the belly, and the low back.

Helping the ligament to hold the womb by the use of an external pelvic belt is necessary to decrease pain and discomfort.

Sciatic pain during pregnancy

Sciatic pain is another  condition commonly reported during pregnancy. It is characterized by stabbing pain, shooting from the back, and into the buttock to the leg. It usually occurs in the third trimester. Sciatic pain occurs due to postural changes that occur during pregnancy. As the belly enlarges, the low back compensates by increasing its curvature (lordosis) to keep the body in balance.

The ilia also open soutward. This forces the knees to hyperextend and the hip to turn outward. This posture changes the angle of pull on a muscle in the buttock, called the piriformis muscle. The piriformis muscle lies on top of the sciatic nerve. The change in the angle of pull of the muscle irritates the sciatic nerve and pain shoots from the buttock to down the leg.

Another nerve, called the inferior gluteal nerve, exits under the piriformis muscle. Just like the sciatic nerve, the inferior gluteal nerve gets irritated and shoots pain in the buttock area. Another nerve, called the superior gluteal nerve, exits above the piriformis muscle. If this gets irritated, pain shoots to the buttock, and causes tenderness in the hip area. The sciatic pain comes from the piriformis muscle rather than the lower back. Hence, stretching the piriformis muscle is recommended if it is tight. If it is weak, then strengthening exercises are appropriate.

What exercise can do

Treatment of pain during pregnancy includes stretching, use of a stabilization belt, massage, relaxation, and acupuncture. All of the above have shown to be successful in the treatment of pain during pregnancy. Mobilization of the sacroiliac joint has also shown to be successful in pain management.

Call STARS if you have questions or seeking physical therapy for pain during pregnancy.

by Raj Issuree, MPT



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