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Chapter 12: The Process of Labor and Birth

Terms in this set (155)

Early labor
-*contractions characteristically weak and irregular*
-*Last about 30 seconds; last 5-7 mins*
-*Labor patterns become established when duration = 60 seconds, occur every 2-3 mins, and increased intensity*
-contractions involuntary and are most efficient when there is a regular rhythmic coordinated labor pattern

Uterine contractions bring changes to pelvic floor musculature:
-Forces of labor cause the levator ani muscles and fascia of the pelvic floor to draw the rectum and vagina upward and forward
-During descent, fetal head exerts increasing pressure and causes thinning of the perineal body from 5cm to less than 1 cm in thickness.
-*Continued pressure causes maternal anus to evert, and the interior rectal wall is exposed as the fetal head descends forward. *

Coordinated efforts of contractions help bring about the effacement and dilation of the cervix:

*Effacement-process of shortening and thinning of the cervix*

*Dilation- opening and enlargement of the cervix that progressively occurs throughout the first stage of labor. Cervical dilation is expressed in centimeters, and FULL dilation is 10 cm*

*First stage of labor which begins the onset of true labor, concludes when cervical effacement and dilation are complete. Effacement and dilation occur concurrently but at different rates.*

Nulliparous patient (no born offspring)- most cervical effacement is completed early during the process of cervical dilation

Multiparous cervix - often patulous (distended) before effacement begins.

Vaginal examination provides important information regarding the diameter of the opening of the cervix which ranges from 1 cm to 10 cm, the status of amniotic membranes (ruptured/ intact), and the fetal presentation and the station, or the extent of fetal descent through the maternal pelvis.

*Once the cervix is fully dilated and retracted up into the lower uterine segment, IT CAN NO LONGER BE PALPATED*
-*Occurs when the widest diameter of the fetal presenting part has passed through the pelvic inlet.*
-Can be determined by external palpation or by vaginal examination.

-*Refers to the level of the presenting part in relation to the maternal ischial spines.*
-*Ischial spines, blunted prominences located in the midpelvis, have been designated as a landmark to identify station zero.*
-*Engagement has occurred when the presenting part is at station zero*.
-*When the presenting part lies above the maternal ischial spines, it is a minus station*.
-*Positive numbers indicate that the presenting part has descended past the ischial spines*
-*Station of +4 indicates that the presenting part is at the pelvic outlet.*
*-5 is at pelvic inlet*
*+5 is crowning*
-*Refers to the location of a fixed reference point on the fetal presenting part in relation to a specific quadrant of the maternal pelvis*
-*Right (R) or left (L) side of the maternal pelvis*
-*Landmarks of the presenting part: occiput (O), mentum (M), sacrum (S), or acromion process (A)*
-*Anterior (A), posterior (P), transverse (T); This designation depends on whether the landmark is in the front, back, or side of the maternal pelvis*

*It is important for the nurse to assess the position of the fetus to identify whether the fetus is in an optimal position for vaginal birth.*

*Identification of malpresentation such as footling breech or transverse lie is important because the presence of malpresentation may signal the need for a C-section.*
*After the birth of the infant, the nurse observes for signs that the placenta has separated from the wall of the uterus.*

*Uterus is palpated to determine the rise upward and the characteristic change in shape from one resembling a disk to that of a globe.*

Nurse may ask the woman to push again to facilitate in the delivery of the placenta.

*If 30 minutes has elapsed from completion of the second stage of labor and the placenta has not yet been expelled, it is considered to be "retained"*.

Oxytocin meds (Pitocin) are often administered at the time of delivery of the placenta. These drugs are used to stimulate uterine contractions, thereby minimizing the bleeding from the placental attachment site and reducing the risk of postpartum hemorrhage.

IV infusion= 10-20 units may be added
IM= 10 units may be added

If excessive blood loss= 40 units of oxytocin per liter

*Methylergonovine (Methergine) or Carbropost (Hemabate) may be given IM to control blood loss; During this time, the nurse continues to assess the volume of blood loss and monitor the patient's vital signs, paying close attention to the blood pressure and heart rate.*

*Once placenta has been delivered, the nurse carefully examines it to ensure that all cotyledons are intact. If any part of the placenta is missing, the nurse immediately reports this finding to HCP. Retained placental fragments can contribute to postpartum hemorrhage or infection, physician may perform manual exploration of the uterus to remove any remaining placental tissue.*
-*Once the infant is born (and is stable), health care team places infant on the mothers abdomen in the modified trendelenberg position (feet and pelvis above the head)*

-Immediate birth skin-to-skin contact between mother and the newborn provides reassurance to the mother regarding the overall well-being of the baby and begins the attachment process.

-*Several physiological adaptations must occur to facilitate the adjustment of the newborn to the extrauterine environment. Of primary importance is the initiation of newborns respirations.* A process that results in the replacement of fetal lung fluid with air.

- *In most situations, the actions of drying the newborn and performing nasopharyngeal suctioning, if needed, provide adequate stimulation to initiate the newborn's respiratory effort. *

-While respirations are being established, the newborn's cardiovascular system is also undergoing adaptations to allow the flow of deoxygenated blood into the lungs for gas exchange.

-Fetal circulation transitions to neonate circulation after the closure of ductus arteriosus, the foramen ovale, and ductus venosus.

-*Modified trendelendberg facilitates the drainage of mucus from the newborn nasopharynx and trachea. Nurse suctions newborns nose and mouth with bulb syringe PRN.*

-*Before the infant is placed on the mother's abdomen, the nurse dries the infant, discards the wet linens, and applies warm blankets. Skin to skin contact between the mother and the baby also helps maintain newborns temperature.*
*Sustained (greater than 10 minutes) baseline FHR of less than 110 bpm*

Associated with:
-*Late fetal hypoxia: Myocardial activity becomes depressed and lowers the FHR*
-*Medications (Beta-adrenergic drugs>> propronalol)*
-*Maternal Hypotension: Results in decreased blood flow to the fetus and can lower the FHR. Maternal Hypotension can result from positioning (supine hypotension) and is a common side effect associated with epidural or spinal anesthetic*
-*Maternal or fetal hypothermia and dehydration*
-*Prolonged umbilical cord compression: Stimulates fetal baroreceptors that cause vagal stimulation and decreased FHR*
-Fetal bradyarrhythmias: With complete heart block, the FHR baseline is often as low as 70-90 bpm
-*Uterine tachysystole* (Hyperstimulation)
-*Abruptio placentae*
-*Uterine rupture or vasa previa*
-Vagal stimulation during the second stage (fetal recovery is possible because this condition does not involve hypoxia)
-*Chronic fetal head compression*

*When bradycardia is observed, the nurse FIRST confirms that the EFM is monitoring the FHR, rather than the maternal HR, then assesses the fetal movement and the fetal response to fetal scalp stimulation (performed when the FHR is between contractions). A vaginal exam is performed to assess for umbilical cord prolapse*

Assessment of maternal vital signs and hydration status with prn fluid administration may be useful in reducing contractions and in promoting fetal oxygenation.

Depending on other factors (FHR variability), other actions may be appropriate including changing the maternal position, d/c oxytocin, administering oxygen (8-10 L/min by mask), modifying the patient's pushing pattern, and notifying HCP

-Decelerations that are variable in terms of onset, frequency, duration, and intensity

-*Visually abrupt decrease in FHR below the baseline is 15 bpm or more, lasts @ least 15 seconds, and returns to baseline in less than 2 minutes from the time of onset*

-*Appear in shape as U, W, V on graph*

-Sometimes, a variable deceleration is preceded and followed by a brief acceleration of the FHR known as "shouldering"

-A shoulder is a compensatory response to hypoxemia and is an increase in the FHR of 20 bpm for less than 20 seconds.

-"overshoot" or "rebound overshoot" is a gradual smooth acceleration in FHR of 10-20 bpm for more than 60-90 seconds.

-*MOST COMMON decleration pattern seen in labor, variable decelerations, are though to be a result of UMBILICAL CORD COMPRESSION, which triggers vagal response that slows FHR*

-A cord that is briefly compressed by the fetus may manifest as a very abrupt decrease in the FHR, with a rapid return to baseline

-*A cord that is wrapped around the fetal neck (nuchal cord) progressively becomes more compressed as the fetus descends into the maternal pelvis. THIS SITUATION IS MOST LIKELY TO RESULT IN LONGER, MORE SEVERE DECELERATIONS!!.*

-Variable decelerations may also occur with sudden descent of the fetal head late in the active phase of labor. When related to head compression, variable decelerations are usually non-repetitive and irregular in shape

-Occasional declerations are considered benign

-Repetitive decelerations cause for concern and further investigation which can cause nursing actions of:
> Intrauterine resuscitation
>Assessment of cervix (prolapsed cord and labor progress), uterine activity (tachysystole), maternal vital signs (fever and hypotension)

>Position changes
>IV fluids
> Maternal mother and partner support