The uterus, like most organs, has ligaments to support it in place. Two of these ligaments are known as the round ligaments. They are attached to the upper corner of the uterus on either side. Normally these ligaments have to contend with a small uterus but during pregnancy it faces massive strain from the expanding uterus that is now heavier. As a result it can lead to pain known as round ligament pain. This is one of the causes of pregnancy-related abdominal pain. Sometimes it continues even after childbirth.
There are several ligaments in the body that are known as the round ligament. Therefore it is important to differentiate the round ligament of the uterus from the round ligament elsewhere on the body. The uterine round ligament is about 4 to 5 inches in length. It is composed of muscle, connective tissue, nerves, blood vessels and fibrous tissue. While the lower part of the uterus is supported by fibrous tissue in the pelvis, the upper part of the uterus requires the support of the round ligaments and the broad ligament of which the round ligament is a part of.
Abdominal and pelvic pain is common in pregnancy. There are many reasons why it occurs. One of the more common cause is abdominal wall pain as the muscles stretch during pregnancy and may occasionally go into painful spasms. In these instances it has nothing to do with the round ligament. However, round ligament pain can arise for largely the same reasons as abdominal wall pain during pregnancy.
Two of the common reasons why pain may originate from the round ligament during pregnancy is due to stretching and spasm. It is a consequence of the expanding uterus in pregnancy. As the uterus becomes heavier it places strain on the ligament which can stretch or its muscle fibers can go into spasm. Since the round ligament lies in close proximity to other structures like the fallopian tubes, these other structures may also be strained as the uterus grows and may be the source of the pain.
It is important to note that the round ligament can stretch during pregnancy without causing pain. The hormone progesterone allows it to stretch significantly during pregnancy. This is a gradual process that continues throughout pregnancy. However, quick movements can stretch the ligament suddenly which may then result in pain. If the muscle fibers n the round ligament go into spasm then it may lead to a cramping type of pain.
The declining hormone levels after pregnancy allows the uterus to gradually return to its normal size and position. Other organs and structures around it that accommodated the large pregnant uterus also return to the pre-pregnancy positions. Sometimes during this process the uterus tilts backwards or remains more mobile than it should be . Sudden movements can cause the round ligament to stretch or go into spasm which may then elicit pain. This type of round ligament pain usually subsides with time once the uterus and ligament return to normal.
Sometimes round ligament pain occurs yet is not related to pregnancy. It may even arise in women who have never been pregnant. In these instances the round ligament pain may be associated with conditions like polycystic ovarian syndrome and endometriosis. The pain in these conditions may have nothing to do with the round ligament. There is important to have any abdominal or pelvic pain assessed whether pregnant or not, especially if it is a persistent or recurrent pain.