The initial step in the management of a woman in active labor is to obtain vital signs and initiate supportive therapy, including obtaining venous access and monitoring the mother and fetus if fetal monitoring is available. A sample for "type and screen" should be sent to the blood bank to determine maternal Rh status and ABO blood type. If the pelvic examination reveals no remaining cervix and fetal presentation at the introitus, delivery is imminent. Labor can progress very rapidly in multiparous patients. The stage of labor and the parity of the patient should be taken into account when transport of a laboring patient to another facility is being considered.
As the cervix becomes fully dilated and effacement becomes complete, the fetus continues to descend and the patient experiences the urge to push. Patients delivering in the emergency setting may have difficulty controlling these expulsive efforts, and they are in even greater need of assistance, reassurance, and instruction. Preoccupation with the delivery should not exclude the needs of the mother or minimize the importance of maternal cooperation to accomplish a controlled delivery.
Determination of fetal position is best accomplished in the emergency setting by evaluation of the presenting portion of the infant. Pelvic examination should reveal evidence of the infant's position, including palpable skull sutures and fontanelles ( Fig 103-1) or, in the case of breech delivery, the infant's buttock or extremity.
Confirmation may be accomplished by personnel familiar with Leopold maneuvers.
FIG. 103-1. Movements of normal delivery. Mechanism of labor and delivery for vertex presentations. A. Engagement, flexion, and descent. B. Internal rotation. C. Extension and delivery of the head using the modified Ritgen maneuver. After delivery of the head the infant's nose and mouth should be suctioned and the neck checked for encirclement of the umbilical cord. D. External rotation bringing the thorax into the anteroposterior diameter of the pelvis. E. Delivery of the anterior shoulder. F. Delivery of the posterior shoulder. Note that after delivery, the head is supported and used to gently guide delivery of the shoulder. Traction should be minimized.
The typical delivery position is the dorsal lithotomy position, which allows maximum visualization and control of the delivery. As time allows, the perineum may then be prepared by washing with mild soap and water and swabbing with povidone-iodine. Drapes should be placed over the patient, and gowns, masks, and sterile gloves donned by medical personnel attending the patient. Pediatric and obstetric services should be notified as appropriate for the institution.
The process of fetal descent during labor and delivery is described by six cardinal movements: (1) engagement, (2) flexion, (3) descent, (4) internal rotation, (5)
extension, and (6) external rotation (Fig 103-1). As the fetus descends through the birth canal and reaches the introitus, the perineum bulges to accommodate the fetal head. Delivery can be aided by gentle digital stretching of the inferior portion of the perineum. The perineum will undergo gradual thinning and stretching to enable the passage of the fetus. The use of routine episiotomy for a normal spontaneous vaginal delivery has been discouraged in recent years and increases the incidence of third- and fourth-degree lacerations at the time of delivery. 6,7
If an episiotomy is necessary, it may be performed as follows. A solution of 5 to 10 mL of 1% lidocaine is injected with a small-gauge needle into the posterior fourchette and perineum. While protecting the infant's head, a 2- to 3-cm cut is made with scissors to extend the vaginal opening. The incision must be supported with manual pressure from below, taking care not to allow the incision to extend into the rectum.
Control of the delivery of the neonate is the major challenge. As the infant's head emerges from the introitus, the physician should support the perineum with a sterile towel placed along the inferior portion of the perineum with one hand while supporting the fetal head with the other. Mild counterpressure is exerted to prevent the rapid expulsion of the fetal head which may lead to third- or fourth-degree perineal tears.
As the infant's head presents, the left hand may be used to control the fetal chin while the right remains on the crown of the head, supporting the delivery. This controlled extension of the fetal head will aid in the atraumatic delivery. The mother is then asked to breathe through contractions rather than bearing down and attempting to push the baby out rapidly. Immediately following delivery of the infant's head, the infant's nose and mouth should be suctioned. This is particularly important in infants presenting with meconium in order to prevent aspiration. A simple bulb will assist in the routine clearing of the infant's nose and mouth. After suctioning, the neck should be palpated for the presence of a nuchal cord. This is a common condition, found in 25 percent of all cephalad-presenting deliveries. If the cord is loose, it should be reduced over the infant's head; the delivery may then proceed as usual. If the cord is tightly wound, it may have to be clamped in the most accessible area by two clamps in close proximity and cut to allow delivery of the infant.
After the airway is cleared, delivery of the body is allowed to progress. After delivery of the head, the head will restitute, or turn to one side or the other. As the head rotates, the physician's hands are placed on either side of it, providing gentle downward traction to deliver the anterior shoulder. Care should be taken to provide only gentle traction, as jerky or forceful movements may cause a brachial plexus injury. The physician's hand then gently guides the fetus upward, delivering the posterior shoulder and allowing the remainder of the infant to be delivered. At this point, it is very important to control delivery of the body to prevent perineal lacerations.
A point of practical concern is the need to maintain control of the newly born infant. The combination of amniotic fluid, blood, and white, cheesy desquamation called vernix makes the infant very slippery. It is useful to prepare for the delivery by placing the posterior (left) hand underneath the infant's axilla prior to delivering the rest of the body. The anterior hand may then be used to grasp the infant's ankles and ensure a firm grip. In obstetric training, the student is often instructed to hold the infant close to his or her chest "like a football."
The infant is then loosely wrapped in a towel and stimulated as it is dried. In the setting of an uncomplicated delivery, the mother may immediately hold the child while the cord is being cut provided that the child has responded well to initial stimulation and has a clear airway and good respiratory effort. The umbilical cord is double clamped and cut with sterile scissors; the infant is then further dried and warmed in an incubator, where postnatal care may be provided and Apgar scores calculated at 1 and 5 min after delivery. Scoring includes general color, tone, heart rate, respiratory effort, and reflexes.
In the case of suspected meconium aspiration, the infant is delivered, the cord is double clamped and cut immediately, and the infant is placed in an incubator for airway assessment and possible intubation prior to being stimulated to breathe spontaneously. Intubation allows for the trachea to be suctioned adequately prior to spontaneous breathing, thus reducing the risk of meconium aspiration. If a cyanotic or apneic child is delivered and does not immediately respond to stimulation, neonatal resuscitation is instituted (see Chap, 9, "Neonatal Resuscitation and Emergencies").
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