Introduction

The round ligament of the uterus is fibro-muscular connective tissue. It appears like a round band of rope. One side of the round ligament is attached to the superior and lateral aspect of the uterus. This attachment with the uterus is at the cornu of the uterus. From the cornu of the uterus, the round ligament crosses the pelvis through the deep inguinal ring which then traverses the inguinal canal and then enters the labia majora, where it terminates with its fibers blending into the mons pubis. There are 2 round ligaments, one on each side of the uterus. Each round ligament is about 10 to 12 centimeters long. The round ligament is covered by folded peritoneum and comprises the superior margin of the broad ligament on each side of the uterus. The medial side of the broad ligament is attached to the lateral side of the uterus on each side. It fans out to the pelvic sidewall. The broad ligament contains the round ligament, the fallopian tube, arteries, veins, lymphatics, nerve fibers and loose connective tissue.

Structure and Function

The uterus is a pear-shaped muscular organ of the female reproductive system. The uterus is divided into the fundus, lower uterine segment, and cervix uteri. The uterus hosts and nourishes the embryo and fetus until delivery.

• The fallopian tubes are 2 tubular structures attached to the uterus on each side. The fimbriated ends of the fallopian tubes are freely floating next to ovaries, on each side in the pelvis.
• The round ligament of the uterus originates at the uterine cornu of the uterus and blend with the tissue of the mons pubis and labia majora.
• The cardinal ligament is the inferior demarcation at the base of the broad ligament. The 2 cardinal ligaments support for the uterus and the cervix uteri.
• The broad ligament is the peritoneal fold around the round ligament, parametrial connective tissue, arteries, veins, lymphatics, and nerves.
• The uterosacral ligaments are anteriorly attached to the cervix uteri. The uterosacral ligaments are posteriorly attached to sacral vertebrae.
• The ovaries rest in ovarian fossa in the lateral part of the pelvic cavity next to the iliac vessels. The ovaries contain germ cells.
• The ovarian ligaments are attached to the posterolateral aspect of the uterus.
• The infundibulopelvic ligaments are peritoneal reflections of the broad ligaments.
• The bladder is located anterior to the uterus.  The ureters are inserted into the trigon.
• The rectum is located between the vagina and the sacrum.
• The pelvic diaphragm supports all the viscera.
• The round ligament helps maintain the anteversion position of the uterus during pregnancy. The cardinal ligaments support the uterus.

Embryology

The round ligament of the uterus develops from the gubernaculum. In a fetus, the gubernaculum is an undifferentiated mesenchymal tissue attached to ovarian tissue in a female fetus and testicular tissue in a male fetus. During the early stages of urogenital development in the female fetus, the gubernaculum develops as a connective tissue band.  This connective tissue ligamentous band is attached to the ovary on one side and the labia majora on the other side. During its course, from the ovary, it runs to the cornu of the uterus and adheres to the uterus.  Then it continues upward to the labia majora.

In adults, the gubernaculum develops into the following two parts:

• The round ligament of the uterus: The part between the cornu of the uterus and the labia majora. It is also called ligamentum teres uteri, and it is longer than the ovarian ligament.
• The ovarian ligament: The ovarian ligament is the part between the cornu of the uterus and the ovary.

Blood Supply and Lymphatics

The round ligament receives blood from Sampson's artery or the artery of the round ligament. The common iliac artery divides into the external and internal iliac arteries. The Internal iliac artery branches into the uterine artery, vaginal artery, superior, vesical artery, obturator artery, inferior gluteal artery, internal pudendal artery and obliterated umbilical artery. Simpson’s artery, a branch of the uterine artery, runs along the length of the round ligament. Ovarian arteries originate directly from the aorta. The left ovarian vein drains into the left renal vein. The right ovarian vein drains directly into the inferior vena cava. The uterine vein drains to the pelvic nodes and para-aortic. The cervical vein drains to the parametrial nodes, obturator nodes, pelvic nodes and para-aortic nodes. The ovarian vein drains to the pelvic nodes and para-aortic nodes.

Clinical Significance

In some rare cases, the gubernaculum may fail to adhere to the uterus. This may cause the ovaries to descend through the inguinal canal into the labia majora. This abnormal position of the ovaries may resemble the testes.[1][2][3]

During the reproductive years, pelvic endometriosis may penetrate round ligaments. Endometriosis is defined as the presence of ectopic endometrial glands and stroma outside the uterus. This may lead to severe dysmenorrhea, dyspareunia, chronic pelvic pain, and infertility. Pelvic endometriosis can affect the uterosacral ligaments, rectum, vagina, cul-de-sac, and urinary bladder. The pelvic endometriosis may infiltrate the round ligaments of the uterus when it is deep and extensive. Magnetic Resonance Imaging (MRI) is helpful for the diagnosis of the round ligament lesions. If medical therapy fails, surgery remains the best therapeutic treatment for advanced endometriosis.   

Round Ligament Varices (RLV) are conditions where veins become tortuous and twisted.  This condition develops during pregnancy. Venous blood from the round ligament and the inguinal canal is drained into the inferior epigastric vein. During pregnancy, there is an increase of blood volume and cardiac output.  An enlarged gravid uterus increases pressure leading to stagnation of blood in these veins. The increased amount of progesterone contributes to venous dilatation and smooth muscle relaxation. Increased venous return and engorgement of veins and tributaries progress to Round ligament varices (RLV). The patient may present with bilateral asymptomatic inguinal swellings during pregnancy. Ultrasound examination may help diagnose and differentiate Round ligament varices (RLV) from an inguinal hernia. Multiple dilated vessels without bowel contents may be visualized on ultrasound examination. There is conservative management, and close monitoring is recommended throughout pregnancy. After pregnancy, the hormonal effects of progesterone and the pressure of the gravid uterus are relieved, leading to spontaneous resolution during the postpartum recovery period.

Round Ligament Pain

The round ligaments of the uterus increase in diameter and length during pregnancy.  During mid-trimester, the round ligaments may cause cramping and pain due to stretching and contractions of the round ligaments. At times, this pain may be sharp and can cause pulling sensations. This pain is considered to be physiological in normal pregnancy. Usually, the pain of the round ligaments is temporary and resolve spontaneously by resting. The round ligaments pain is not considered a symptom of any disease. If pain persists, immediately follow up is recommended to rule out other causes of pain during pregnancy. There is a sharp reduction of hormones levels after delivery. After the postpartum period, the uterine size is reduced to the normal non-pregnant state. The hypertrophic round ligaments of the uterus also shrink to the normal, non-pregnant state. Following postpartum recovery, the round ligaments pain may happen, but it is unlikely to happen because of sudden movements of pelvic organs.

In a non-pregnant female, the round ligaments pain may happen, but it is unlikely. In a non-pregnant female, the round ligament is a firm and flexible structure. Sudden movements of pelvic organs may not cause any symptoms.

Conservative Management

Warm compresses to the area may relieve pain. Acetaminophen is safe to take during pregnancy.

Acetaminophen is the most prescribed analgesic during pregnancy.

Rest during pregnancy is one of the best remedies for the round ligaments Pain.

Sudden active movements are discouraged to prevent worsening of the round ligaments Pain.

Prolonged standing and heavy lifting should be avoided to prevent worsening of the round ligaments Pain.

Daily stretching exercise may be helpful. Bending and flexion of the hip joint may reduce the pulling sensations and discomfort from stretching.

Pregnant patients are encouraged to find pain triggers and to avoid those discovered triggers.