The normal position for a 36-week fetus is the vertex position, which means that the head of the fetus is toward the pelvic intestine. Breech presentation is a poor presentation of the fetus in which the buttock or lower limb presents first in the maternal pelvis. There are three types of breech presentation which are: foot, full and frank. Foot formation occurs when one or both feet of the fetus point downward and will come out first. Full is when the buttock is down with the legs bent at the knees and the feet close to the buttock. Frank occurs when the buttock of the fetus is directed into the birth canal and the legs stick out in front of the body with the feet near the head. The probability that a fetus is breech is as follows: 3-4% at term, 7% at 32 weeks, and 25% at less than 28 weeks. There are large risk factors involved in vaginal delivery of a breech baby. For example, the baby’s head is the largest part and it can be difficult to pass it, which would be quite dangerous if it were trapped inside, while the rest of the body was outside the mother’s birth canal. The doctor could not use forceps if necessary. There is also the possibility of cord prolapse, which means that the cord tightens when the baby ascends into the canal. This would slow down the oxygen and blood supply and could cause fetal distress.
The Webster technique alleviates the musculoskeletal cause of intrauterine restriction which can prevent the vertex position of the fetus and, in turn, prevent a vaginal delivery. When used correctly, this technique has been found to be 82% effective. The Webster technique is most often used in the eighth month of pregnancy because, at this point, the fetus is unlikely to convert to the vertex position on its own. When it comes to breech presentation, 34 weeks gestation is the magic number to remember. After 34 weeks, the fetus is unlikely to convert on its own. There are three ligaments that suspend the uterus: uterosacral, ovarian, and round. The uterus-sacrum originates from the posterior wall of the uterus and inserts on the anterior surface of the sacrum at the S2 / 3 level. This ligament creates tension on the cervix dorsally and prevents anterior / inferior displacement of the uterus. The round ligament originates from the fundus of the uterus and proceeds inferiorly / laterally to the labia majora and joins the inguinal ligament approximately midway. This ligament provides uterine support and limits the posterior movement of the uterus, thus maintaining the anterior position of the uterus.
The mother is examined for an anterior / inferior (AI) sacrum, a posterior sacrum (also known as a fixed SI joint), and a contracted round ligament. The combination of these three findings will lead to torsion of the uterus that constricts fetal movement and interferes with the ability of the fetus to convert to the vertex position. To assess the pregnant patient, both knees are flexed simultaneously and light pressure pushes the feet toward the ipsilateral buttock. A fixed SI joint can be identified by resistance near the end of one foot movement. The foot on the fixed SI side would not travel as far as the foot on the other side. Let’s say the fixed SI is on the left. The LA sacrum and the contracted round ligament would both be found on the right side of the patient.
The Webster Technique includes two steps. First is the adjustment and second is to decrease the spasm and tension of the abdominal muscles. The purpose of the adjustment is to relieve tension on the uterus due to sacral rotation and to restore proper perimetry and biomechanics of the pelvic intestine. The adjustment also frees the SI joint (the posterior sacrum). A very common technique used is Logan’s Basic Technique Sacral Unlocking Technique. To do this, the clinician uses the upper hand to straddle the blocked SI using the thenar eminence on the sacral wing and the hypothenar on the iliac bone. The lower hand will be placed firmly on the lower part of the opposite buttock. The purpose of the lower hand is to block any excessive pelvic movement on that side. The patient is instructed to “walk” by alternately moving the hips up and down as if walking. The patient is told to “walk” 4-6 times to unlock the fixed SI and then the SI joint is reassessed. The patient then lies supine so the doctor can relax the round ligament. To do this, the doctor must first locate it by drawing a lower and lateral imaginary line at 45 degrees from the umbilicus and another lower and medial line at 45 degrees from the ASIS. The round ligament must be at the junction of these two lines. At this point in a woman’s pregnancy, the ligament is about the thickness of a woman’s index finger and is easy to feel through the skin. Using the lower hand and the practitioner, lightly hook the thumb under the round ligament (similar to the Logan Basic thumb contact) and support it. The direction of correction is higher and towards the opposite shoulder. The doctor maintains this contact until the ligament relaxes and possibly coils under the thumb, which usually takes 1 to 3 minutes. The frequency of care depends on the urgency of the individual patient. The closer the patient is to her due date, the more aggressive the approach needs to be. A patient may be seen every day, every other day, or three days a week, depending on the severity of the condition. Some babies return to the vertex position after just 1-2 adjustments, but it may take longer.