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Lecture 10

Nursing Care of a Family �During Labor and Birth

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Objectives

Define labor, lightening, vaginal show, effacement, and cervical dilatation.
Describe common theories explaining the onset of labor.
Identify the component of labor, passenger, passage, and power.
Describe fetal attitude, fetal lie, and fetal presentation.
Discuss major nursing interventions to promote comfort during labor & birth.

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Labor

Labor: is a series of events by which uterine contractions and abdominal pressure expel a fetus and placenta from a woman’s body.
Regular contractions cause progressive dilatation of the cervix and sufficient muscular force to allow the baby to be pushed to the outside.

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Theories explaining the onset of labor�

Labor normally begins when a fetus is sufficiently mature to cope with extrauterine life yet not too large to cause mechanical difficulty with birth.
The trigger that converts the random, painless Braxton Hicks contractions into strong, coordinated, productive labor contractions is unknown.

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Theories explaining the onset of labor�

In some instances, labor begins before a fetus is mature (preterm birth). In others, labor is delayed until the fetus and the placenta have both passed beyond the optimal point for birth (postterm birth).
Although a number of theories have been proposed to explain why labor begins, it is believed that labor is influenced by a combination of factors originating from the mother and the fetus.

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Factors originating from the mother and the fetus to initiate labor

Uterine muscle stretching, which results in release of prostaglandins.
Pressure on the cervix, which stimulates the release of oxytocin from the posterior pituitary.
Oxytocin stimulation, which works together with prostaglandins to initiate contractions.
Placental age, which triggers contractions at a set point.

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Factors originating from the mother and the fetus to initiate labor

Change in the ratio of estrogen to progesterone (increasing estrogen in relation to progesterone stimulates uterine contractions).
Rising fetal cortisol levels, which reduce progesterone formation and increase prostaglandin formation.
Fetal membrane production of prostaglandin, which stimulates contractions.

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Signs of Labor:Preliminary Signs of Labor

1. Lightening:

It is the descent of the fetal presenting part into the pelvis.
This changes a woman's abdominal contour, because the uterus becomes lower and more anterior.
Gives a woman relief from the diaphragmatic pressure and shortness of breath that she has been experiencing and in this way “lightens” her load.
Lightening probably occurs early in primiparas because of tight abdominal muscles (10 to 14 days before labor begins).
In multiparas, it usually occurs on the day of labor or even after labor has begun.

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Cont. Lightening

The mother may experience:

Shooting leg pains from the increased pressure on the sciatic nerve.
Increased amounts of vaginal discharge.
Urinary frequency from pressure on the bladder

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Signs of Labor: Preliminary Signs of Labor

2. Increase in Level of Activity:

A woman may awaken on the morning of labor full of energy, in contrast to her feelings of chronic fatigue during the previous month.
This increase in activity is related to an increase in epinephrine release that is initiated by a decrease in progesterone produced by the placenta.

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Signs of Labor:Preliminary Signs of Labor

3. Braxton Hicks Contractions:

In the last week or days before labor begins, a woman usually notices extremely strong Braxton Hicks contractions, which she may interpret as true labor contractions.
A woman may be admitted to the labor unit of a hospital or birthing center because false contractions so closely simulate true labor.

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Signs of Labor: Preliminary Signs of Labor

4. Ripening of the Cervix:

It is an internal sign seen only on pelvic examination. Throughout pregnancy, the cervix feels softer than normal, similar to the consistency of an earlobe (Goodell's sign).
At term, the cervix becomes still softer (described as “butter-soft”), and it tips forward.
Ripening is an internal announcement that labor is very close at hand.

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Signs of True Labor

Signs of true labor involve uterine and cervical changes.

Table 18-1

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TABLE 18.1 Differentiation Between True and False Labor Contractions

False Contractions	True Contractions
Begin and remain irregular.	Begin irregularly but become regular and predictable.
Felt first abdominally and remain confined to the abdomen and groin.	Felt first in lower back and sweep around to the abdomen in a wave.
Often disappear with ambulation and sleep.	Continue no matter what the woman's level of activity.
Do not increase in duration, frequency, or intensity	Increase in duration, frequency, and intensity.
Do not achieve cervical dilatation.	Achieve cervical dilatation.

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Signs of True Labor

1) Uterine Contractions:

The surest sign that labor has begun is productive uterine contractions. Because contractions are involuntary and come without warning, their intensity can be frightening in early labor.

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Signs of True Labor

2) Show:

As the cervix softens and ripens, the mucus plug that filled the cervical canal during pregnancy (operculum) is expelled.
The exposed cervical capillaries seep blood as a result of pressure exerted by the fetus.

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Signs of True Labor: Show

The blood, mixed with mucus, takes on a pink tinge and is referred to as “show” or “bloody show.”
Women need to be aware of this event so that they do not think they are bleeding abnormally.

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Signs of True Labor

3) Rupture of the Membranes:

Labor may begin with rupture of the membranes, experienced either as a sudden gush or as scanty, slow seeping of clear fluid from the vagina.
Two risks associated with ruptured membranes are intrauterine infection and prolapse of the umbilical cord.
In most instances, if labor has not spontaneously occurred by 24 hours after membrane rupture and the pregnancy is at term, labor is induced to help reduce these risks.

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Component of Labor

A successful labor depends on four integrated concepts:

(1) The woman's pelvis (the passage) is of adequate size and contour.

(2) The passenger (the fetus) is of appropriate size and in an advantageous position and presentation.

(3) The powers of labor (uterine factors) are adequate.

(4) A woman's psyche is preserved, so that afterward labor can be viewed as a positive experience.

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Passage

The passage refers to the route a fetus must travel from the uterus through the cervix and vagina to the external perineum.
Two pelvic measurements are important to determine the adequacy of the pelvic size: the diagonal conjugate (the anterior-posterior diameter of the inlet) and the transverse diameter of the outlet.
At the pelvic inlet, the anteroposterior diameter is the narrowest diameter; at the outlet, the transverse diameter is the narrowest.

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Components of Labor (cont’d)

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Passenger

The passenger is the fetus. The body part of the fetus that has the widest diameter is the head, so this is the part least likely to be able to pass through the pelvic ring.
Whether a fetal skull can pass or not depends on both its structure (bones, fontanelles, and suture lines) and its alignment with the pelvis.
Structure of the Fetal Skull

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Figure 18- 2

Fetal skull

structure

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�Passenger:�Structure of the Fetal Skull�

The cranium, the uppermost portion of the skull, comprises eight bones.
The four superior bones—the frontal (actually two fused bones), the two parietal, and the occipital—are the bones that are important in childbirth.
The other four bones of the skull (sphenoid, ethmoid, and two temporal bones) lie at the base of the cranium; they are of little significance in childbirth because they are never presenting parts.
The chin, referred to by its Latin name mentum, can be a presenting part.

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�Passenger:�Structure of the Fetal Skull�

The bones of the skull meet at suture lines. The sagittal suture joins the two parietal bones of the skull.

The coronal suture is the line of juncture of the frontal bones and the two parietal bones.

The lambdoid suture is the line of juncture of the occipital bone and the two parietal bones.

The suture lines are important in birth because, as membranous interspaces, they allow the cranial bones to move and overlap, molding or diminishing the size of the skull so that it can pass through the birth canal more readily.

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Passenger:�Diameters of the Fetal Skull

Suboccipitobregmatic diameter (is from the inferior aspect of the occiput to the center of the anterior fontanelle ): approximately 9.5 cm.
Occipitofrontal diameter: from the bridge of the nose to the occipital prominence, is approximately 12 cm.
The occipitomental diameter, which is the widest anteroposterior diameter (approximately 13.5 cm), is measured from the chin to the posterior fontanelle.

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The anteroposterior diameter that will be presented to the birth canal is

determined by the degree of flexion of the fetal head

Complete flexion allows the smallest diameter of the head to enter the pelvis.
(B) Moderate flexion causes a larger diameter to enter the pelvis.

(C) Poor flexion forces the largest diameter against the pelvic brim,

but the head is too large to enter the pelvis.

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�Passenger: Molding�

Molding is the change in shape of the fetal skull produced by the force of uterine contractions pressing the vertex of the head against the not-yet-dilatated cervix.
Because the bones of the fetal skull are not yet completely ossified and therefore do not form a rigid structure, pressure causes them to overlap and cause the head to become narrower and longer, a shape that facilitates passage through the rigid pelvis.
Molding is commonly seen in infants just after birth.
The overlapping of the sagittal suture line and, generally, the coronal suture line can be easily palpated in the newborn skull.

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Passenger

Fetal presentation and position play a part in whether a fetus is lined up in the best position to be born.
Fetal presentation and position (Attitude, Engagement, Station, Fetal Lie).
Types of fetal presentation (cephalic, breach, shoulder).
Types of fetal position.
Cardinal movements of labor: descent, flexion, internal rotation, extension, external rotation, and expulsion (Fig. 18.8).
Shoulder Presentation (acromion process).

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Fetal Presentation and Position

Attitude: describes the degree of flexion a fetus assumes during labor or the relation of the fetal parts to each other (Fig. 18.4).
A fetus in good attitude is in complete flexion: the spinal column is bowed forward, the head is flexed forward so much that the chin touches the sternum, the arms are flexed and folded on the chest, the thighs are flexed onto the abdomen, and the calves are pressed against the posterior aspect of the thighs (see Fig. 18.4A).

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Figure 18- 4: Fetal attitude.

(a) Fetus in full flexion presents smallest (suboccipitobregmatic) anteroposterior diameter of skull to inlet in this good attitude (vertex presentation).

(b) Fetus is not as well flexed (military attitude) as in A and presents occipitofrontal diameter to inlet (sinciput presentation).

(c) Fetus in partial extension (brow presentation).

(d) Fetus in complete extension presents wide (occipitomental) diameter (face presentation).

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Engagement: refers to the settling of the presenting part of a fetus far enough into the pelvis to be at the level of the ischial spines, a midpoint of the pelvis.
The degree of engagement is assessed by vaginal and cervical examination.
A presenting part that is not engaged is said to be “floating.” One that is descending but has not yet reached the ischial spines is said to be “dipping.”

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Station: refers to the relationship of the presenting part of a fetus to the level of the ischial spines (Fig. 18.5).
When the presenting part is at the level of the ischial spines, it is at a 0 station (synonymous with engagement).
If the presenting part is above the spines, the distance is measured and described as minus stations, which range from -1 to -4 cm.
If the presenting part is below the ischial spines, the distance is stated as plus stations (+1 to +4 cm).
At a +3 or +4 station, the presenting part is at the perineum and can be seen if the vulva is separated (i.e., it is crowning).

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Figure 18- 5:

Station, or degree of engagement, of the fetal head is designated by centimeters above or below the ischial spines. At:
-4 station, head is “floating.
” At 0 station, head is “engaged.
” At +4 station, head is “at outlet.”

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Fetal Lie: is the relationship between the long (cephalocaudal) axis of the fetal body and the long (cephalocaudal) axis of a woman's body; in other words, whether the fetus is lying in a horizontal (transverse) or a vertical (longitudinal) position.

Approximately 99% of fetuses assume a longitudinal lie (with their long axis parallel to the long axis of the woman).

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Types of Fetal Presentation

Cephalic: is the most frequent type of presentation, occurring as often as 95% of the time. With this type of presentation, the fetal head is the body part that will first contact the cervix.
Breach: means that either the buttocks or the feet are the first body parts that will contact the cervix. Breech presentations occur in approximately 3% of births and are affected by fetal attitude.
Shoulder: In a transverse lie, a fetus lies horizontally in the pelvis so that the longest fetal axis is perpendicular to that of the mother. The presenting part is usually one of the shoulders (acromion process), an iliac crest, a hand, or an elbow (Fig. 18.6).

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Figure 18- 6:

Transverse or shoulder presentation.

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Position is the relationship of the presenting part to a specific quadrant of a woman's pelvis

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Types of Fetal Position

Figure 18-7: Fetal position. All are vertex presentations.

A = Anterior;

L = Left;

O = Occiput;

P = Posterior;

R = Right; T = Transverse.

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Powers of Labor

The powers of labor, supplied by the fundus of the uterus, are implemented by uterine contractions.

A process that causes cervical dilatation and then expulsion of the fetus from the uterus.

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Powers of Labor

After full dilatation of the cervix, the primary power is supplemented by use of the abdominal muscles.
It is important for women to understand they should not bear down with their abdominal muscles until the cervix is fully dilatated. Doing so impedes the primary force and could cause fetal and cervical damage.

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Powers of Labor

Uterine contractions: origins, phases, contour changes

Cervical contractions: effacement, dilatation

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Powers of Labor: Uterine Contractions

Origins: labor contractions begin at a “pacemaker” point located in the myometrium near one of the uterotubal junctions.
Each contraction begins at that point and then sweeps down over the uterus as a wave. After a short rest period, another contraction is initiated and the downward sweep begins again.
Reverse, ineffective contractions, and they may actually cause tightening rather than dilatation of the cervix.

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Powers of Labor: Uterine Contractions

Phases: a contraction consists of three phases:

- the increment, when the intensity of the contraction increases;

- the acme, when the contraction is at its strongest;

- the decrement, when the intensity decreases

- Between contractions the uterus relaxes. As labor progresses, the relaxation intervals decrease from 10 minutes early in labor to only 2 to 3 minutes.

The duration of contractions also changes, increasing from 20 to 30 seconds to a range of 60 to 90 seconds.

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Contour Changes: As labor contractions progress and become regular and strong, the uterus gradually differentiates itself into two distinct functioning areas.
The upper portion becomes thicker and active, preparing it to be able to exert the strength necessary to expel the fetus when the expulsion phase of labor is reached.
The lower segment becomes thin-walled, supple, and passive, so that the fetus can be pushed out of the uterus easily.
As these events occur, the boundary between the two portions becomes marked by a ridge on the inner uterine surface, the physiologic retraction ring.

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If the fetus is larger than the birth canal, the round ligaments of the uterus become tense and may be palpable on the abdomen. The normal physiologic retraction ring may become prominent and observable as an abdominal indentation.
Termed a pathologic retraction ring or Bandl's ring, it is a danger sign that signifies impending rupture of the lower uterine segment if the obstruction to labor is not relieved.

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Mechanisms of Labor

Descent : Descent is the downward movement of the biparietal diameter of the fetal head to within the pelvic inlet. Full descent occurs when the fetal head extrudes beyond the dilated cervix and touches the posterior vaginal floor.
Flexion: As descent occurs and the fetal head reaches the pelvic floor, the head bends forward onto the chest, making the smallest anteroposterior diameter (the suboccipitobregmatic diameter) the one presented to the birth canal. Flexion is also aided by abdominal muscle contraction during pushing.

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Mechanisms of Labor

Internal Rotation: During descent, the head enters the pelvis with the fetal anteroposterior head diameter (suboccipitobregmatic, occipitomental, or occipitofrontal, depending on the amount of flexion) in a diagonal or transverse position.
Extension: As the occiput is born, the back of the neck stops beneath the pubic arch and acts as a pivot for the rest of the head. The head extends, and the foremost parts of the head, the face and chin, are born.

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Mechanisms of Labor

External Rotation: In external rotation, almost immediately after the head of the infant is born, the head rotates (from the anteroposterior position it assumed to enter the outlet) back to the diagonal or transverse position of the early part of labor.
Expulsion: Once the shoulders are born, the rest of the baby is born easily and smoothly because of its smaller size. This movement, called expulsion, is the end of the pelvic division of labor.

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Figure 18- 8: Mechanism of normal labor and cardinal positions of the fetus from a left occipitoanterior position.

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Powers of Labor: Cervical Contractions

Effacement is shortening and thinning of the cervical canal. Normally, the canal is approximately 1 to 2 cm long. With effacement, the canal virtually disappears (Fig. 18.11). This occurs because of longitudinal traction from the contracting uterine fundus.
Dilatation refers to the enlargement or widening of the cervical canal from an opening a few millimeters wide to one large enough (approximately 10 cm) to permit passage of a fetus (see Fig. 18.11).

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Effacement and dilation of cervix.

(A) Beginning labor.
(B) Effacement is beginning; dilation is not apparent yet.
(C) Effacement is almost complete.
(D) After complete effacement, dilation proceeds rapidly.

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Psyche

The fourth “P,” or “psyche,” refers to the psychological state or feelings that a woman brings into labor
Ranges from apprehension, fright, excitement, awe
Those with strong self – esteem and meaning support system manage best in labor
“A positive attitude during labor yields a positive outcome.”
A woman who is: relax, aware and participating in the birth process: shorter, less intense labor
A woman who is: fearful has high levels of adrenaline which slows uterine contractions

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Nursing Care

Assessment

Assessment of a woman in labor must be done quickly yet thoroughly and gently
Assess how much discomfort a woman in labor is having

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Nursing Care

Nursing Diagnosis

Pain related to labor contractions
Anxiety related to process of labor and birth
Health-seeking behaviors related to management of discomfort of labor
Situational low self-esteem related to inability to use prepared childbirth method

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Nursing Care

Implementation

Interventions in labor must always be carried out between contractions if possible, so that the woman is free to use a prepared childbirth technique to limit the discomfort of contractions
Assess early in a woman's labor whether she might benefit from such caring measures as having her hand held or her back rubbed.

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QUESTIONS