Labour and Birth Processes Flashcards
Factors Affecting Labour: 5 P’s
Passenger
Passageway
Powers
Position of laboring woman
Psychologic state of laboring woman
Passenger: Size of the fetal head
- bones in the fetal skull
- fontanels
- molding
Passenger: presentation of the fetus
the part of the fetus that enters the pelvic inlet first and leads through the birth canal during labor
- cephalic (head)
- breech
- shoulder
Passenger: Fetal lie
the relaxation of the long axis (spine) of the fetus to the long axis (spine) of the mother
- longitudinal
- vertical
Passenger: Fetal attitude
the relation of the fetal body parts to one another
- general flexion
- critical measurements of fetal head
Biparietal diameter
Suboccipitobregmatic diameter
Biparietal diameter
smallest, 9.25 cm
vertex presentation
one side of the parietal bone to the other
Suboccipitobregmatic diatmeter
anterior fontanel to bottom of occiput
9.5 cm
Passenger: Fetal Position
the relationship of a reference point on the presenting part to the four quadrants of the mother’s pelvis
- position is denoted by a three-part letter abbreviation (ex. ROA, LSP)
Passenger: Fetal Station
a measure of the degree of descent of the presenting part of the fetus through the birth canal
Passenger: Fetal engagement
usually corresponds to 0 station
Passageway:
Birth Canal:
- Body pelvis: 4 types
Gynecoid
Android
Anthropoid
Platypelloid
- Soft tissues
Powers: primary
Primary powers: contractions
- frequency (beginning of one contraction to the beginning of the next), duration (how long), intensity (at peak of contraction)
Effacement
The shortening and thinning of the cervix during the first stage of labor. Effacement generally progresses significantly in first-time term pregnancy before more than slight dilation occurs. In subsequent pregnancies, effacement and dilation of the cervix tend to progress together. Degree of effacement is expressed in percentages from 0% to 100%
Dilation
The enlargement or widening of the cervical opening and the cervical canal that occurs once labor has begun. The diameter of the cervix increases from being close to full dilation to allow birth of a term fetus
Ferguson Reflex
: increased intrauterine pressure that puts the pressure on the descending part of the fetus against the cervix. Muscles contracting and pulling the cervix up and the pushing of the baby. And then mom bearing down to help. Ferguson reflex makes mom feel like she needs to push. Might feel like this at 7-8 cm but she has to wait until filly dilated
Secondary Powers
Bearing-down efforts
- Valsalva maneuver
Process of Labour: Labor
process of moving fetus, placenta, and membranes out of the uterus and through the birth canal
process of labour: signs preceding labor
Lightening - sensation of decreased abdominal distention produced by uterine descent into the pelvic cavity as the fetal presenting part settles into the pelvis; it usually occurs 2 weeks before the onset of labour. as head settles into the pelvis the woman can sense greater room - sense of easier respirations.
Blood show - vaginal discharge that originates in the cervix and consists of blood and mucus; increases as cervix dilates during labour. associated wth thinning cervix. (mucus plug)
- Baby is descending into the true pelvis
- Frequency of urine (because the baby is pushing on the bladder)
- Uterus grows overtop of the bladder (anteflexion) beginning of pregnancy, frequency of urine. Later the uterus grows up and the bladder is fine until the lightening
- Test urine every visit
- She can lie down again to sleep because she feels she is getting more oxygen again
- Everything is getting ready for the birth. Ligaments are softening and becoming looser (back pain, imbalance)
- Everything is getting ready! Braxton Hicks are irregular contractions
- Mother might be losing some weight
- Nesting (a lot of energy, all aspects working together) mom is going to need that energy
- Flu-like symptoms close to birth.
Psychological State of Woman
What is happening with mom and the family. Culture, situation that resulted in the baby, might be all by herself, extreme rural area, age, adolescent pregnancy, language barriers. Emotional and psychological state of labouring woman impacts the labour significantly
Onset of Labour
- Cannot be ascribed to a single cause
- Progesterone is falling
- Oxytocin is increasing
- Prostaglandins
- All working together for strong rhythmic uterine contractions
- All of these things are working together
Stages of Labour
First Stage:
Latent phase (slow descent and slow dilation)
Active phase (when there is dilation of the cervix)
Transition phase
Second Stage
Third Stage
Fourth Stage
Turns and adjustments necessary in human birth process: Seven cardinal movements of mechanism of labor
- Engagement
- Descent
- Flexion
- Internal rotation
- Extension
- Restitution and external rotation
- Expulsion
Physiologic Adaptation to Labor: Fetal adaptation
- Fetal heart rate: reliable and predictive information about the condition of the fetus related to oxygen
- Fetal circulation
- Fetal respiration
Physiologic Adaptation to Labor: Maternal adaptation
Women exhibits both objective and subjective symptoms
- cardiovascular changes
- respiratory changes
- renal changes
- integumentary changes
- musculoskeletal changes
- neurologic changes
- gastrointestinal changes
- endocrine changes
Key Points
- Labour and birth are affected by the five Ps: passenger, passageway, powers, position of the woman, and psychologic response
- because of its size and relative rigidity, the fetal head is a major factor in determining the course of birth
- the diameters at the plane of the pelvic inlet, the midpelvis, and the outlet plus the axis of the birth canal determine whether vaginal birth is possible and the manner in which the fetus passes down the birth canal
- Involuntary uterine contractions act to expel the fetus and placenta during the first stage of labor; these are augmented by voluntary bearing-down efforts during the second stage
Stages of labor key points
- The first stage of labor lasts from the time dilation begins to the time when the cervix is fully dilated
- the second stage of labor lasts from the time of full cervical dilation to the birth of the infant
- third stage of labor lasts from the infants birth to the expulsion of the placenta
- the fourth stage of labor begins with the delivery of the placenta and includes at least the first 2 hours after birth
Cardinal movements key points
- the cardinal movements of the mechanism of labor are engagement, descent, flexion, internal rotation, extension, restitution and external rotation, and explusion of the infant
- although the events precipitating the onset of labor are unknown, many factors, including changes in the maternal uterus, cervix, and pituitary gland, are thought to be involved
- a healthy fetus with an adequate uterofetolacental circulation is able to compensate for the stress of uterine contractions
- as the woman progresses through labor, various body systems adapt to the birth process
