Ligaments supporting the uterus and connecting it to the groin region are collectively known as the round ligaments. Women often experience a sharp pain (round ligament pain) in this region during pregnancy due to the normal changes the body goes through during this time . It does not harm the baby, but may lead to serious pain and discomfort for the mother. Round ligament pain (RLP) is most common during the second trimester , but can occur earlier in cases of twin pregnancies.
During pregnancy, the uterus grows considerably in size with certain ligaments holding it in suspension within the abdomen. The growing size and weight of the uterus puts extra stress on the ligaments, which gradually become very thin and long .
As mentioned above, the round ligament is one of the principal ligaments holding the uterus in place, connecting it to the groin area (the region where the legs attach to the pelvis). The significant pressure put on this ligament by the growing uterus makes it stretch too much during pregnancy . Then the ligament starts pulling and tugging on the nerve fibers and other sensitive structures located nearby, leading to moderate to severe pain . An involuntary contraction of the round ligament is the most common cause of the pain.
The pain may be triggered by exercises like running and jogging as well as sudden movements like:
The pain may be triggered by baby movements (e.g. kicking) as it flexes the uterus, putting pressure on the ligament.
It may be confused with labor pain , but the latter does not generally occur until later in the third trimester. In case of pre-term labor, the nature, location and severity of the pain can help to distinguish it from RLP. Some women may also confuse it with Braxton Hicks contractions – another common pregnancy symptom occurring during the second and third trimesters. But unlike RLP, Braxton Hicks contractions do not usually cause any pain, which helps to differentiate between the two.
RLP does not require any diagnostic tests and exams as it is a common and harmless type of abdominal pain associated with pregnancy. However, doctors may perform a physical examination, blood tests, ultrasonography and urine tests to rule out more serious condition that may lead to similar symptoms .
It is advisable to contact one’s health care provider in case of the following symptoms as they may indicate a more serious condition:
The pain often goes away automatically as the pregnancy progresses .
The doctor may prescribe an over-the-counter medication, such as acetaminophen (Tylenol) , for relieving severe RLP.
The duration of RLP may vary from one woman to another. It usually goes away completely once the baby is born  as it allows the ligament to go back to its normal size and shape.
Its ICD-9 code is 625.9  while the ICD-10 code is R10.2 .