Perineal protection: reducing tissue tension
The primary goal of obstetric assistance is to reduce the pressure of the pelvic floor soft tissues on the fetal head. The tissues are made more pliable by "borrowing" them from the labia area. This helps maintain normal circulation in the perineum and significantly increases its resistance to tears.
Execution Technique:
- Hand positioning: The right palm is placed on the perineum. Four fingers are firmly pressed against the left labium majus, and the maximally abducted thumb against the right. The fold between the thumb and index finger must lie strictly over the navicular fossa.
- Finger movement: The tips of all fingers gently press on the soft tissues along the labia majora, guiding them toward the perineum to reduce tension.
- Palm movement: Simultaneously, the palm gently presses the perineal tissues against the crowning head, providing them with reliable support.
Third maneuver: delivery of the fetal head
At this stage, it is crucial to properly regulate pushing efforts. When the head engages in the vulvar ring with the parietal eminences, the risk of perineal tears and excessive compression of the head increases sharply. Rapid descent leads to maternal and fetal trauma, despite the woman's irresistible urge to push. Prolonged descent (arrest) causes prolonged compression of the head by stretched tissues due to the cessation of pushing efforts.
Delivery algorithm (performed strictly between contractions):
- Starting condition: The head has engaged with its parietal eminences in the vulvar cleft, and the suboccipital fossa has reached beneath the pubic symphysis.
- Stopping the contraction: The parturient woman is asked to breathe deeply and frequently with her mouth open — in this state, it is physiologically impossible to push.
- Holding: With both hands, the physician restrains the descent of the head until the contraction ends completely.
- Actions after the contraction: The right hand uses sliding motions to carefully remove the tissues from the fetal face. The left hand slowly lifts the head anteriorly, facilitating its extension. If necessary, the woman is asked to push slightly for the final delivery of the head.
Fourth maneuver: birth of the shoulder girdle and torso
The final stage of the mechanism of labor involves internal rotation of the shoulders and external rotation of the head. During the next contraction, the head turns to face the mother's thigh: to the right in the first position and to the left in the second.
If spontaneous birth of the shoulders does not occur, the physician provides manual assistance:
- Grasps the head by the temporozygomatic regions with both palms.
- Performs traction posteriorly (without excessive force) until the anterior third of the anteriorly facing shoulder approaches the pubic symphysis.
- Lifts the head upward with the left hand while moving the perineal tissues away from the posterior shoulder with the right hand to release it.
Delivery of the torso: Index fingers are inserted into the armpits from the back. The torso is lifted anteriorly (along the pelvic axis) for rapid extraction.
Important: Delivery of the shoulder girdle requires extreme caution. Excessive stretching of the cervical spine must not be allowed. It is strictly prohibited to deliver the anterior arm first from under the pubic symphysis — this carries a high risk of fracturing the clavicle or the arm.
Surgical perineal protection and emergency situations
- Perineal incision: Justified by the fact that a clean-cut wound with smooth edges heals significantly better than a torn wound with contused edges. On the part of the mother, the indication is the threat of a rupture. On the part of the fetus, it is the need to accelerate the second stage of labor and prevent intracranial trauma (especially with a rigid perineum). Mediolateral episiotomy is used most frequently, while perineotomy (strictly along the midline) is used less often.
- Nuchal cord: If a loop of the umbilical cord is visible after the birth of the head, it is carefully slipped off. In case of a tight nuchal cord, when it becomes taut and hinders descent, it is immediately transected between two applied clamps, after which the torso is quickly delivered.
- After birth: The mother's bladder must be emptied using a catheter. The newborn's condition is assessed using the Apgar scale at 1 and 5 minutes (scores of 8–10 indicate a satisfactory condition).
To memorize the direction of traction during manual delivery of the shoulders: first pull posteriorly (to bring the anterior shoulder under the pubic symphysis), then upward (to release the posterior shoulder).
Class and exam questions
Why is a parturient woman asked to breathe with her mouth open during head delivery?
Deep and frequent breathing through an open mouth physiologically stops the pushing effort. This is necessary to safely deliver the head between contractions and prevent trauma.
In which direction does the fetal head turn after birth?
The head turns to face the mother's thigh. In the first fetal position — toward the right thigh, in the second position — toward the left.
What to do if the umbilical cord is tightly wrapped around the neck?
If the loop cannot be removed due to severe tension, the umbilical cord is immediately transected between two applied clamps, and the fetal torso is then quickly extracted.
Why is it forbidden to deliver the fetal anterior arm first?
This is strictly contraindicated due to the high risk of fracturing the newborn's arm or clavicle.
What else to study on this topic
- Technique of perineotomy and mediolateral episiotomy
- Criteria for assessing the newborn using the Apgar score
- Prevention of fetal intracranial trauma in the second stage of labor
- Signs of an impending perineal rupture in labor
- Features of the mechanism of labor in various fetal positions
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