There are four reasons for dystocia during pregnancy. The first one is when the uterine forces are insufficiently strong or inappropriately coordinated to efface and dilate the cervix. Second reason would be abnormalities in the mother’s bony pelvis. The diameter of the mother’s pelvis is decreased when the sacrum is displaced. Third reason is abnormalities of presentation, position, or development of the fetus. The cause of this malposition is due to the imbalance in the muscles and torsion in the ligaments leading to intrauterine constraint. Intrauterine constraint is any force external to the developing fetus and obstructs the normal movement of the fetus. The three ligaments we are talking about are the Broad ligament, uterosacral ligaments and the round ligaments. The broad ligament is the wide fold of peritoneum that connects the sides of the uterus to the walls and the floor of the pelvis. The uterosacral ligaments extend from an attachment posteriorlaterally to the supravaginal portion of the cervix to encircle the rectum and thence insert into the fascia over the second and third sacral vertebrae (Williams Obstetrics 21st Edition). Posterior subluxation or malposition of the sacrum may result in tightening and torsion of the utero-sacral ligament contributing to an imbalance in the uterus leading to the intrauterine constraint that I mentioned earlier. They prevent the uterus from displacing anterior and inferior. A sacral dysfunction will transmit the torque force by the utero-sacral ligament on the uterus and shearing it out of its proper position, resulting in restricting tension within the uterine wall. The round ligaments extend from the lateral portion of the uterus, arising below and anterior to that of the oviducts. Each round ligament is located in a fold of peritoneum that is continuous with the broad ligament and extends outward and downward to the inguinal canal, through which it passes to terminate in the upper portion of the labia majus. It joins with the inguinal ligament approximately half way on its inferior course. During pregnancy, the round ligaments undergo considerable hypertrophy and increase in length and diameter (Williams Obstetrics 21st Edition). The round ligaments prevent the uterus from moving posterior, keeping it in a normal anterior position. Unilateral tension in the round ligament is thought to increase the total torque on the uterus as it is off center position is further enhanced. The tension of the uterine walls will further increase. The fourth reason for dystocia would be abnormalities of the soft tissues of the reproductive tract that form and obstacle to fetal descent, for example a fibroid tumor (Williams Obstetrics 21st Edition).
As you may realize some of these issues can very well be treated with chiropractic care specifically the Webster technique. Webster Technique is a specific chiropractic analysis and adjustment which reduces nerve system stress, improves pelvic muscle and ligament function reducing torsion to the uterus and potential intrauterine constraint allowing the baby to get into the best possible position for birth (ICPA). Depending on my findings I will perform a sacral adjustment on the side I found restricted and then contact the opposite round ligament to release some of the tension put on the ligament due to the restricted sacrum.