Chapter 13: Labor and Delivery - Labor and Birth Processes

Mississippi College: NUR 390 - Maternal, Newborn, and Women's Health

at least how many factors affect the process of labor and delivery?

five

what are the five P’s affecting labor?

• passenger

• passageway

• powers

• position of mother

• psychologic response

what are the components that make up the “passenger”?

• size of fetal head 

• fetal presentation 

• fetal lie 

• fetal attitude 

• fetal position 

what factors determine the size of fetal head?

• skull bones

• sutures 

• anterior and posterior fontanels 

• molding 

what is fetal presentation?

it is when part of the fetus first enters the pelvic inlet during labor at term

what are the three main fetal presentations?

• cephalic

• breech

• shoulder

what is fetal lie?

relation of long axis of fetus to long axis of mother

what are the two primary lies?

• longitudinal 

• horizontal 

what is fetal attitude?

relation of fetal body parts to one another

what is general flexion?

chin to chest, thighs on abdomen, arms crossed, umbilical cord between arms and legs

how long is biparietal diameter?

9.25 cm

what is fetal position?

• relationship of a reference point on fetus to the 4 quadrants of the mother

what is the fetal position denoted by?

3 letter abbreviation

what does the middle letter in the 3 letter abbreviation refer to?

fetal presenting part

O = occiput

S = sacrum

M = mentum

Sc = scapula

what does the first and third letter in the 3 letter abbreviation refer to?

• L or R of maternal pelvis 

• front or back of maternal pelvis A = anterior, P = posterior, T = transverse 

what is station?

relationship of presenting part to maternal ischial spines

how would we chart station if the presenting part is level with the ischial spines?

0, also considered to be engagement of fetal part

how would we chart station if the presenting part is above the maternal ischial spines and is higher in the maternal pelvis?

-1 to -5 cm 

how would we chart station if the presenting part is below the maternal ischial spines and occurs as fetus descends through the pelvis?

+1 to +5 cm

what does floating or ballotable mean in terms of fetal station?

-3 or “high”

what does zero or lower “engaged” mean in terms of fetal station?

+3 or crowning

what is the passageway composed of?

bony pelvis and soft tissue 

what makes up the bony pelvis (true pelvis involved in birth)?

• inlet or brim

• midpelvis

• outlet

what makes up the soft tissues?

• cervix

• pelvic floor 

• vagina 

• introitus 

what are the two types of power?

primary powers and secondary powers

what are the primary powers?

involuntary uterine contractions that signal the beginning of labor and described in terms of frequency, duration, and intensity. responsible for the effacement and dilation of the cervix and descent of the fetus

what are the secondary powers?

voluntary bearing-down efforts by the woman 

what fact do we want to keep in mind when positioning a laboring woman?

gravity helps!

what are some signs of preceding labor?

• lightening or dropping

• return of urinary frequency

• backache

• stronger Braxton Hicks contractions

• surge of energy

• bloody show

• cervical ripening

• possible rupture of membranes (ROM)

is onset of labor multifactorial or caused by a single factor?

multifactorial

what are some causes that bring the onset of labor?

• hormonal changes

• increased uterine distention and pressure

what are some hormonal changes that bring on the onset of labor?

• increased levels of estrogen, oxytocin, and prostaglandins

• decreasing level of progesterone

how many stages of labor are there?

4

what happens during the first stage of labor?

onset of contractions to full dilation of the cervix

what happens during the second stage of labor?

full dilation to birth

what happens during the third stage of labor?

birth of the fetus until delivery of the placenta

what happens during the fourth stage of labor?

1-4 hours postdelivery of the placenta 

what are the seven cardinal movements of the mechanism of labor that occur in vertex presentation?

• engagement

• descent

• flexion

• internal rotation

• extension

• restitution and external rotation

• expulsion (birth)

what are the 3 fetal adaptations to labor?

• fetal heart rate

• fetal circulation 

• fetal respiration

what is the normal fetal heart rate range?

110-160 beats/min 

do healthy fetus’ compensates well during fetal circulation?

yes

during fetal respiration, chemoreceptors prepare fetus for initiating _____ immediately after birth? 

respirations 

what are some cardiovascular maternal adaptations to labor?

• cardiac output increases by 51%

• heart rate decreases

• blood pressure increases during contractions

• supine hypotension

• increased WBCs

what maneuver do you not want to perform during supine hypotension?

valsalva maneuver

what are some respiratory maternal adaptations to labor?

• increased respiratory rate 

• oxygen consumption 

what are some renal maternal adaptions to labor?

• spontaneous voiding may be difficult

• proteinuria of 1+ normal finding

what are some integumentary maternal adaptations to labor?

• great stretching of vaginal introitus 

what are some musculoskeletal maternal adaptions to labor?

• increased muscle activity 

• fatigue 

• possible increased temperature 

• possible leg cramps 

what are some neurologic maternal adaptations to labor?

• euphoria

• followed by increased seriousness

• then amnesia between contractions

• endogenous endorphins raise pain threshold

what are some GI changes maternal adaptations to labor?

• GI motility and absorption decreased

• N&V can occur, especially as a reflex response to full cervical dilation

what are some endocrine changes maternal adaptations to labor?

• metabolism increases 

• blood glucose levels may decrease with labor 

a pregnant woman, who is in the 3rd trimester, asks the nurse how to know “labor is getting closer to starting.” which of the following would be an appropriate response?

a. weight gain of 1.5 to 2kg (3 to 4 lbs)

b. increase in fundal height 

c. urinary retention 

d. surge of energy 

D. surge of energy