Chapter 12: Processes of Birth Flashcards
1
Q
characteristics of contractions
A
- coordinated
- involuntary
- intermittent: to allow for blood flow in intervillous space, b/c during contraction, no blood flow to baby, and they only have a certain amount of reserve
2
Q
acme
A
peak of contraction–>where contraction is the strongest
3
Q
uterine activity during labor
A
- Uterine Activity during labor is characterized by opposing features.
- Upper 2/3 actively contracts to push the fetus down.
- The lower third of the uterus remains less active , promoting downward passage of the fetus.
- The cervix is passive.
- The net effect of labor contractions is enhanced because the downward push from the upper uterus is accompanied by reduced resistance to fetal descent in the lower uterus..
- Myometrial cells in the upper uterus remains shorter at the end of each contractions rather than returning to their original length; myometrial cells in the lower uterus become longer with each contraction.
- These two characteristics enable the upper uterus to maintain tension between contractions to preserve the cervical changes and downward fetal progress made with each contraction.
- The opposing characteristics of myometrial contraction in the upper and lower uterine segments cause changes in the thickness of the wall during labor.
- The upper uterus becomes thicker while the lower uterus becomes thinner and is pulled upward during labor.
- The physiologic retraction ring marks the division between the upper and lower segment of the uterus.
- Opposing characteristics of contractions in the upper and lower uterine segments change the shape of the uterine cavity, which becomes more elongated and narrow as labor progresses.
- This change in uterine shape straightens the fetal body and efficiently directs it downward in the pelvis.
4
Q
cervical changes during labor
A
- effacement: thinning of the cervix
- 0 to 100% OR 3.5 cm to 0 cm
- dilation: opening of the cervix
- 0-10 cm
5
Q
difference in cervical changes during labor in nulliparous and multiparous women
A
- nullipara: has to efface before dilate
- multipara: starts to dilate, then gradually goes thru effacement
6
Q
Maternal CV Response to Labor
A
- blood flow to placenta dec during contractions
- 300-500 mL of blood shunted from placenta to maternal system with contractions
- SO, maternal HR dec and BP inc
- therefore, take BP when uterus is relaxed
- 300-500 mL of blood shunted from placenta to maternal system with contractions
- Keep mom in LEFT lateral position and semi-Fowler’s
- avoid supine!
7
Q
Maternal Respiratory Response to Labor
A
- rate and depth inc slightly b/c uterus pushing up on diaphragm
- inc rate if pain and anxiety present
- hyperventilation–>respiratory alkalosis
- S/S tingling hands and feet, numbness, dizziness
8
Q
Maternal GI Response to Labor
A
- gastric motility reduced
- thirst remains, but appetite reduced
- dry mouth
- need to provide fluids–clear liquids (ice, popsicles, broth)
- n/v
9
Q
Maternal Urinary Response to Labor
A
- reduced sensation as labor progresses
- potential problem: distended bladder
- if epidural, often times don’t feel sensation to go
- full bladder can slow labor and inc risk of injury
- inhibits descent of fetus
- encourage patient to void at least every 2 hours
- intermittent or indwelling catheter may be used
- potential problem: distended bladder
10
Q
Maternal Hematopoietic Response to Labor
A
- assess blood loss after delivery
- vaginal birth: 500 mL is normal
- C-section: 1000 mL is normal
- during pregnancy, clotting factors and fibrinogen elevated
- Hgb of 11 and HCT of 33 or higher gives adequate margin for safety
- inc clotting and inc risk of thrombophlebitis PP–but helps prevent hemorrhage during delivery
- WBC elevated:
- 14,000-16,000 normal during labor
- early postpartum: can be upwards of 25,000
11
Q
Fetal Response in Labor: Placental Circulation
A
- placental circulation exchange takes place b/w contractions in the intervillous spaces
- placenta has a reserve to fetus usually tolerates the intermittent interruption
- reduced placental fcn with GDM and HTN so can put stress on fetus during contractions
- during labor:
- blood supply dec during contractions and eventually stops temporarily
- spiral As are compressed by uterine M on contraction
- placental circulation has enough reserve compared w/ fetal basal needs to tolerate periodic interruption of blood flow
12
Q
Fetal Response in Labor: CV System
A
- indicator of fetal well-being
- average FHR: 110-160
- alterations in rate and rhythm: from normal labor effects or suggests fetal intolerance of stress of labor
- Preterm Infant: has a rate at the higher end of 110-160
- this is b/c the PNS takes longer to develop (peaks at 28 weeks), so before that point, the fetal HR will be higher
13
Q
Fetal Response in Labor: Pulmonary System
A
- Fetal lungs
- production of amniotic fluid allows for normal development
- lung fluid must be cleared to allow normal breathing after birth
- labor speeds up the absorption of lung fluid
- some expelled with birth (thoracic squeeze–chest wall of infant compressed during labor then recoils when borm–>helps initiate breathing)
- catecholamines: epi and NE
- produced by fetal adrenal glands in response to stress of labor
14
Q
What are the 4 factors affecting birth? (The “Critical Factors”)
A
- Powers
- Passage
- Passenger
- Psyche
15
Q
What are the three components of uterine contractions?
A
- Frequency: from beginning of one to the beginning of the next
- Duration: from beginning of one to the end
- Intensity: strength during peak or acme
16
Q
What are the “Powers?”
A
- they are the forces of labor:
- contractions: during the 1st stage of labor–>onset to full dilation
- contractions are the primary force that moves fetus
- pushing (which utilize the abdominal muscles): during 2nd stage of labor–>full dilation to birth
- contractions AND maternal pushing efforts help push fetus out
- contractions: during the 1st stage of labor–>onset to full dilation
17
Q
What is the increment of a contraction?
What is the acme?
What is the decrement?
A
- increment: period of inc strength
- occurs as contraction begins in fundus
- acme: peak
- strongest point
- decrement: period of dec strength/intensity
18
Q
What are components of the “Passage?”
A
- size of pelvis
- type of pelvis
- ability to efface and dilate
19
Q
What are components that dictate the size of the pelvis?
A
- inlet: upper border of the true pelvis
- mid-pelvis: pelvic cavity
-
outlet: lower border of the true pelvis
- pubic arch to ischial tuberosities
20
Q
What are the 4 types of pelvis? describe them?
A
- gynecoid
- android
- platypelloid
- anthropoid
21
Q
what is the weight of the average baby born in the US?
A
- 7.5 pounds (3.5 kg)
- range b/w 5.5-10 lbs
22
Q
What are the 3 components of the “Passenger?”
A
- fetus
- membranes
- placenta
- presentation
- fetal lie
- attitude
- position
23
Q
what is fetal lie?
What are the different types?
A
- fetal lie: orientation of the long axis of the fetus to the long axis of the woman
- longitudinal: majority of cases
- head or buttocks of fetus enters pelvis 1st
- transverse: long axis of fetus is at right angle to woman’s long axis
- almost always have to have a cesarean section
- oblique: lie b/w longitudinal and transverse
- longitudinal: majority of cases
24
Q
which fetal head diameter is ideal, and how long is it?
A
- ideally, head would be fully flexed and the AP diameter would be submentobregmatic which is 9.5 cm
25
what does presentation of the fetus mean?
What is the ideal presentation and why?
* _presentation_: fetal part that enters the pelvis first
* can be cephalic, breech, or vertex
* ideally, _cephalic presentation w/ head flexed_
* most favorable b/c fetal head is largest part, fetal head can mold to pelvis, and the head is smooth, round, and hard
26
what are the 4 variations of cephalic presentation?
* vertex presentation
* military presenation
* brow preseantation
* face presentation
27
Vertex Presentation
* type of cephalic presenation
* most common
* fetal head is fully flexed
* allows for smallest suboccipitobregmatic diameter
28
Military Presentation
* type of cephalic presenation
* head in neutral position
* longer occipitofrontal diameter presenting
29
Brow Presentation
* type of cephalic presentation
* fetal head is partly extended
* unstable
* longest supraoccipitomental diameter presenting
30
Face Presentation
* type of cephalic presentation
* head is in full extension
* fetal occiput in near fetal spine
* submentobregmatic diameter presenting
31
Molding
* sutures and fontanels allow for this
* it is shaping of the fetal head thru the birth canal
32
What is normal molding?
* Caput should be central
33
What is fetal attitude?
What is normal?
* it is relation of the fetal body parts to one another
* normal: flexion--\>head is flexed toward the chest and arms and legs flexed over thorax
* back curved in a C shape
34
what is breech presentation?
when is breech presentation most common?
what are the variations in breech presentation?
* breech: fetal buttocks near pelvis first
* more common w/:
* preterm births
* births with hydrocephalus
* births with placenta previa
* 3 variations:
* Frank breech
* full (complete) breech
* footling breech
35
describe a Frank breech
* fetal legs extended across abdomen toward shoulders
36
describe a full (complete) breech
* reversal of normal cephalic
* head, knees, and hips flexed, but buttocks is presenting
37
when is a shoulder presentation most common?
* preterm
* high parity
* PROM
* hydramnios
* placenta previa
* MUST have a CS
38
Explain the position of the passenger
* relationship of a fixed landmark on presenting part to front/back and side (L/R) of the maternal pelvis
* 3 parts to description:
* presenting part: occiput (vertex position), mentum (face presentation), or sacrum (breech presentation)
* maternal side: anterior or posterior or transverse
* maternal side: left or right
* designate by 3 letter: L O A
39
what is fetal station?
* measurement of descent of the fetal presenting part in relation to the ischial spines on the maternal pelvis
* Ischial spines is a zero station
* Numbers above are negative
* Numbers below are positive
* Fetus should move from a -5, -4, -3, -2, -1, 0, +1, +2, +3, +4, +5
* -5 to +5
40
What are the components of "Psyche?"
* anxiety: catecholamines inhibit contractions and placental blood flow
* fear
* relaxation augments natural process of labor
* culture and expectations
* relationship with partner
* family presence
* past experience
* present pregnant experience
* safety
* education
* technology: maintain focus on mother not technology
41
when will the baby be born?
* term gestation between 38-42 weeks
* go full 40 weeks if possible, even though elective inductions often at 39 weeks
42
What are the factors that appear to have a role in starting labor?
* changes in ratio of maternal estrogen to progesterone so that estrogen is higher than progesterone
* Progesterone keeps uterine muscles relaxed
* As estrogen rises, it makes the uterus more sensitive to PGs and oxytocin and cause and inc in the number of gap junctions
* PGs secreted by fetal membrane
* inc secretion of oxytocin maintains labor and oxytocin receptors on the uterus inc
* likely fetal role in secreting cortisol
* mechanical factors: stretching, pressure, and irritation
* feedback loop: fetal head stretches cervix and causes release of oxytocin--\>fundus of uterus contracts--\>pushes fetal head against cervix--\>more fundal contractions
* protein produced when fetal lungs mature
43
what are the premonitory signs of labor?
* Braxton Hicks (irregular, mild uterine contractions)
* Lightening (descent of fetus towards pelvis inlet 2-3 wks before labor)
* may notice easier breathing, inc pressure on bladder, leg cramps and edema
* ROM
* cervical ripening (cervix softens)
* bloody show (effacement and dilation cause expulsion of mucus plug and rupture small cervical capillaries which lead to bloody show)
* sudden burst of energy (nesting)
* loss of 1-3 lbs (excretion of fluid r/t altered estrogen progesterone ratio)
44
Compare True Labor and False Labor
* True Labor:
* begins in back and radiates to abdomen
* intensity inc with walking
* inc duration, intensity, frequency of contractions
* **progressive effacement and dilation**
* regular intervals b/w contractions
* False Labor:
* discomfort in abdomen nad groin
* walking has no effect or may dec
* inconsistent in freq, duration, intensity
* no effacement, dilation, descent
* irregular contractions
45
First Stage of Labor
* cervical effacement and dilation occur
* longest stage
* Begins with the onset of true labor contractions and ends with complete dilation (10 cm) and 100% effacement
* rate:
* nullipara: dilate 1.2 cm/hour
* multipara: dilate 1.5 cm/hour
46
Phases of the First Stage of Labor
* Latent Phase
* Active Phase
* Transition Phase
47
Latent Phase of Labor
* lasts thru first 3 cm of dilation
* longer for nullipara (7-8 hours) than multipara (4-5 hours)
* contractions gradually inc in freq, duration, intensity
* interval b/w contractions should shorten to 5 min as progress to active labor
* duration inc to 30-40 sec
* back discomfort which encircles the lower abdomen with each contraction
* behavior: sociable, excited, cooperative, anxious
48
Active Phase of Labor
* cervix dilates from 4 to 7 cm more quickly than latent phase
* effacement complete
* fetus descends and internal rotation begins
* slightly longer if epidural
* contractions: 2-5 min apart and 40-60 sec long
* discomfort inc
* behavior: anxious, feel helpless, serious inward focus
49
Transition Phase of Labor
* dilate from 8-10 cm and fetus descends further
* bloody show often inc with complete dilation
* short but intense phase
* contractions: 1.5-2 min apart, 60-90 sec
* leg tremors, n/v, and urge to push
* behavior: irritability, loss of control
50
Second Stage of Labor
* Begins with complete dilation and full effacement and ends with the birth
* Varies depending on if a woman had an epidural (nulliparous: no epidural=53-57 min; w/ epidural=79 min; multiparous: no epidural=17-19 min; w/ epidural=45 min)
* Contractions: 2-3 min apart, 40-60 long
* as the fetus descends, it places pressure on the rectum and pelvic floor that causes an involuntary pushing response in the mother
* woman regains a feeling of control and feels tremendous relief and excitement with the birth
51
Third Stage of Labor
* Begins with birth of baby and ends with expulsion of placenta
* Shortest: lasts about 6 min
* When the infant is born, the uterine cavity becomes much smaller
* This causes the placenta to separate from uterine wall which is obvious by 4 signs:
* Uterus is spherical
* Uterus rises upward in abdomen as placenta descends
* Cord descends further from vagina
* Gush of blood
* Uterus must contract and remain contracted to compress open vessels and prevent hemorrhage
52
Fourth Stage of Labor
* From placental delivery thru first 1-4 hours after birth
* Should be able to palpate uterus as a firm, rounded mass about 10-15 cm
* If feels boggy and increasing in size, then may be assoc with postpartum hemorrhage
* Lochia: vaginal drainage after childbirth
* Most women feel chilled after childbirth most likely r/t sudden dec in effort, loss of heat produced by the fetus, dec in intraabdominal pressure, fetal blood cells entering maternal circulation
* Discomfort caused by birth trauma or afterpains
* Behavior: excited, tired
* Ideal time for bonding and best time to initiate breastfeeding
53
What are afterpains?
* Afterpains are intermittent contractions that occur after birth as the uterus begins to return to prepregnancy state—more common if multiparous, women who breastfeed, women who have large babies
54
What are the cardinal movements?
* _descent_: fetal presenting part moves into true pelvis
* _engagement_: when the largest diameter of the fetal presenting part has passed the pelvic inlet and entered the pelvic cavity
* Usually occurs when the station of the presenting part is 0 or lower
* _flexion_
* _internal rotation_: occiput rotates so sagittal suture is AP pelvic diameter
* _extension_
* __extension of head under symphysis
* _external rotation_
* __head turns back to side
* shoulders rotate to AP position
* _expulsion_
* __occurs first as anterior, then posterior, shoulder passes under symphysis
55
what is the most important intervention for AROM?
* listen to FHR--\>may indicate a prolapsed cord!
