The normal position for a 36 week fetus is the vertex position which means the fetus’ head is down towards the pelvic bowel. Breech presentation is a malpresentation of the fetus in which the buttock or lower limb present first into the maternal pelvis. There are three types of breech presentation which are: footling, complete, and frank. Footling occurs when one or both of the fetus’ feet point down and will come out first. Complete is when the buttock is down with the legs folded at the knees and the feet are near the buttock. Frank occurs when the fetus’ buttock is aimed toward the birth canal and the legs stick up in front of the body with the feet near the head. The probability that a fetus will be in the breech presentation is as follows: 3-4% at term, 7% at 32 weeks, and 25% at less than 28 weeks. There are big risk factors involved in the vaginal delivery of a breeched baby. For example, the baby’s head is the largest part and can be difficult to pass which would be quite dangerous if it were stuck inside, while the rest of the body were outside of the mother’s birth canal. The doctor would be unable to use forceps if needed. There is also the possibility of cord prolapse, which means the cord would be squeezed as the baby ascends into the canal. This would slow the supply of oxygen and blood and could cause fetal distress.
The Webster Technique relieves the musculoskeletal cause of intrauterine constraint which can prevent fetus vertex position and in turn prevent a vaginal birth. When used correctly, this technique has been found to be 82% effective. The Webster Technique is most often used in the 8th month of pregnancy because at this point, the fetus is unlikely to convert to the vertex position on its own. When dealing with 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 uterosacral originates at 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 an anterior/inferior displacement of the uterus. The round ligament originates at the fundus of the uterus and proceeds inferior/laterally to the labia majora and joins with the inguinal ligament about one halfway through its course. This ligament provides uterine support and limits posterior movement of the uterus, thus maintaining anterior uterine position.
The mother to be is examined for an anterior/inferior (AI) sacrum, a posterior sacrum (AKA fixated SI joint), and a contracted round ligament. The combination of these three findings will lead to the torsion of the uterus which constricts fetal movement and interferes with the fetus’ ability to convert to the vertex position. In order to assess the pregnant patient both of her knees are flexed simultaneously and a light pressure pushes the feet toward their ipsilateral buttock. A fixated SI joint can be identified by a resistance near the end of motion of one of the feet. The foot on the side to the fixated SI would not travel as far as the foot on the other side. Lets say that the fixated SI is on the left. The AI sacrum and the contracted round ligament would then both be found on the patient’s right side.
The Webster Technique includes two steps. First is the adjustment and second is to decrease abdominal muscle spasm and tension. The purpose of the adjustment is to relieve tension on the uterus due to sacral rotation and restore proper perimetry and biomechanics of the pelvic bowel. The adjustment also frees the SI joint (the posterior sacrum). A very common technique used is the sacral unlock technique from the Logan Basic Technique. To do this the doctor uses the superior hand to straddle the locked SI using the thenar eminence on the sacral ala and the hypothenar on the iliac bone. The inferior hand will be firmly positioned at the bottom of the opposite buttock. The purpose of the inferior hand is to block any excess pelvic movement on that side. The patient is instructed to “walk” by moving hips alternately superiorly and inferiorly as if they were walking. The patient is told to “walk” 4-6 times to unlock the fixated SI and then I the SI joint is reassessed. The patient then lies down in the supine position so that the doctor can relax the round ligament. To do this, the doctor must first locate it by drawing an imaginary line inferior and lateral 45 degrees from the umbilicus and another line inferior and medial 45 degrees from the ASIS. The round ligament should be found at the junction of these two lines. At this point in a woman’s pregnancy, the ligament is about the thickness of the woman’s index finger and is easy to palpate through the skin. Using the inferior hand and the doctor lightly hooks their thumb under the round ligament (similar to the Logan Basic thumb contact) and holds. The direction of correction is superior and toward the opposite shoulder. The doctor holds this contact until the ligament relaxes and possibly rolls under the thumb which usually takes about 1-3 minutes. The frequency of the care depends on the urgency of the individual patient. The closer the patient is to her due date, the more aggressive the approach should 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 flip to the vertex position after only 1-2 adjustments but it can take longer.