Labor, Delivery, Post-Natal Changes Flashcards
Effacement
Process by which the cervix prepares for delivery
After the baby enlarges the pelvis it will drop closer to the cervix
The cervix will soften, shorten, and become thinner
Once mom has a 100% effacement the baby is ready to come out
Parturition
Process of giving birth
Placental Stage of Labor
3rd Stage of Delivery
Occurances: Delivery of the placenta
Time Prima (1st baby) 3-45 minutes
Time Multi 4-5 minutes
Pelvic Stage of Labor
2nd Stage of Delivery
Occurances: Pushing, Full dilation and effacement to delivery of the fetus
Time Prima (1st baby) 1-2 hours
Time Multi 20 minutes
Cervical Stage of Labor
1st stage of Labor
Occurances: Onset of contractions to full dilation and effacement of cervix (10 cm).
Time Prima (1st baby) 16-18 hours
Time Multi 7-12 hours
The Cervical Stage of Labor is Further Divided into What Stages
1) Early (Latent) Labor
2) Active Labor
3) Transitional (Advanced) Labor
The First Phase: Early (Latent) Labour
- The cervix will dilate (open) to 3 cm
- If not dilated to 3 cm the mom will be sent home
- The cervix begin effacement
- Mild to moderate contraction that last 30-45 seconds
- Spaced 5-20 minutes apart
Active Labor
Phase of Cervical stage of labor
Contractions will grow stronger and longer
Usually lasts from 2-3.5 hours
Cervix dilates to 7-8 cm
Contractions last 40-60 seconds which are spaced 3-4 minutes apart
Transitional (Advanced) Labour
- Last and most intense phase of labor
- ~15-60 minutes
- Cervix will dilate to 10 cms
- Contraction are very strong at this point
- Usually 60-90 seconds long with intense peaks
- Spaced 2-3 minutes apart
- This is the point where the baby is being pushed out
What is the order of events when everything goes right during birth
Mom delivers baby
Baby is taken care of and assessed
A regular newborn will have peripheral cyanosis, be centrally pink, and crying
Mom delivered placenta
Abdominal/pelvic exam is done to ensure that there is no bleeding, infection, or injury
Mom receives post partum care and gets to hold her baby
Pain Management Taught in Pre Natal Classes
Relaxation Techniques
Distraction/Concentration Techniques
Entenox
Nitrous oxide-Laughing Gas
Used as pain mangement in labor
Not a respiratory depressant for mom or baby
Used when there is not enough time for an epidural
Morphine/Demerol
Used as pain mangement in labor
Given systemically
Potentially can depress the infant as it can cross the barrier
Types of Local Anesthesia givn for Pain Management in Labor
Epidural
Pudendal
Paracervical
Epidural
Given directly into the epidural or subarachnoid space or the spine
Will not depress the infant
A catheter will be inserted and then a continuous infusion is given
Pudendal
Given directly into the vagina and perineum
No depression of the infant
Paracervical
Given directly into the cervix and surrounding tissue
Some depression of the infant can occur
Spinal
A spinal will be given as a single dose
Different than an epidural and a epidural is preferred
When in general ananesthesia used for labor pain management
Will be used in an emergency
Why is it important to know what type of pain management is being used for mom in labor
- Also known as a spinal block
- A narcotic or anesthetic such as fentanyl, bupivacaine, or lidocaine is injected below the spinal column directly into spinal fluid
- These medications can cross the placenta and enter into the blood stream
- These will be injected once with a single dose
- Different than an epidural and a epidural is preferred
- Used in more complex or emergency situtations
Fetal Distress During Labor
A tocodynamometer is a abdominal transducer and is the most common way to measure fetal responses to labor
Will measure strength of contraction and fetal heart rate
What will they do if fetal HR does not look good in labor
When doing a scalp pH they will have to go through mom and rupture the membrane
Similar to a capillary blood gas on the surface of the head
Normal Fetal HR
A normal fetal HR
Varies between 120-160 and should demonstrate a continually changing heart rate within 5 to 10 beats (normal baseline variability)
Accelerations
Accelerations: Short increases in HR during contractions which are normal and show that the babe is responding well to the contractions [a stressor]
Should always be occurring during labor
Abnormal fetal heart rates:
Below 100 or above 180
i.e. Too low or too high
Early Decelerations (HC)
FHR drops with the contraction, but once the contraction is done the HR should immediately recover
Heart rate will not vary more than 20-30 below baseline
Smooth and shallow
Mirror contraction
Pose little threat to the fetus (vagal response)
Head compression
Late Decelerations
Smooth shallow drop with nadir (low point) after the peak of contraction
Likely to due to utero-placental insufficiency
Decreased placental perfusion
Can lead to fetal asphyxia
Indicates high probability of fetal distress
Worrisome
Fetal Scalp Sampling [scalp pH]
If fetal distress is noted or even suspected then a transvaginal sample of fetal blood can be obtained via a scalp puncture and collecting blood through a very long capillary tube
Variable Decelerations
- “V” shape pattern with abrupt drop and return from baseline
- With contractions
- Variable in duration
- May be associated with cord compression
- If persistent & severe fetal scalp blood pH
- >7.25 “reassuring” & likely benign
- <7.15 risk of profound acidemia [and if that exists hypoxia probably does too]
Fetal Hemoglobin
- ~75-80% of hemoglobin is fetal
- Fetal hemoglobin will be the main oxygen transport protein of the human fetus in the last 7 months of development in the uterus
- It will take months to convert fetal hemoglobin to adult hemoglobin
- Will take more time if the baby is sick
- It will take less time if the baby is transfused
*
Fetal Hemoglobin and Oxyhemoglobin Curve
- Fetal hemoglobin will shift the curve to the left
- Greater affinity for O2 giving the fetus between access to oxygen from the mothers bloodstream
- The greater affinity for oxygen is due to the lack of interaction with 2, 3, DPG
- Greater affinity for O2 giving the fetus between access to oxygen from the mothers bloodstream
- The P50 value for fetal hemoglobin is lower than adult hemoglobin
- P50 value is the partial pressure of oxygen at which the protein is 50% saturation so lower values represent a greater affinity (~19 mmHg for fetal hemoglobin and 26 for adult hemoglobin)
- Neonates will have a higher SpO2 with a lower PaO2 than adults
- Moms may even have right curve shift
Normal Scalp pH
- Normal Scalp pH
- >7.25
- If pH is <7.15 it is an indication of fetal acidosis
- Facilitate delivery of the baby immediately (often via C-section)
pH During 2nd Stage of Labor
pH- 7.29
PCO2-46
PO2-16
HCO3- 17
pH During 1st Stage of Labor
pH- 7.33
PCO2-44
PO2-22
HCO3- 20
Cord Gas Umbilical Vein
pH- 7.32
PCO2-38
PO2-27
HCO3- 20
Cord Gas Umbilical Artery
pH- 7.24
PCO2-49
PO2-16
HCO3- 19
Arterial Sample
60 Minutes
pH- 7.33
PCO2-36
PO2-63
HCO3- 19
Arterial Sample
30 Minutes
pH- 7.30
PCO2-38
PO2-54
HCO3- 18
Arterial Sample
5-10 Minutes
pH- 7.21
PCO2-46
PO2-50
HCO3- 17
Types of Cord Complications
Nuchal
Knots
Prolapse
Nuchal Cord Complications
Umbilical cord is “coiled” around the baby’s neck
This is quite common
Occurs 25-35% of the time
Most nuchal cords are single coils and are loose
It is rare that the baby’s cord will be wrapped so tightly that the cord is compressed and oxygen delivery to the baby is compromised
When this occurs the c-section is prudent
Knots in Umbilical Cord
Knots that occur in the umbilical cord
Rare occurrence that is only found after delivery and when the umbilicus is abnormally long
Unless the knot has been pulled tight there will be no negative impact on fetal blood flow
When the knot is tight the patient may have atypical pattern of variable deceleration and may be compromised
Prolapse Cord Complication
The umbilical cord is squeezed between the fetus and delivery canal decreasing the blood flow to the fetus
Will be diagnosed through the fetal heart monitoring (especially bradycardias or profound deceleration after membrane rupture)
Treatment is to decrease compression of the presenting part usually by changing the position of the mother or immediate delivery via c-section
Not that common, occurring in one out of every 300 births
Failure to Progress
- When there is maternal fatigue contractions will become weak and ineffective and the baby is stuck
- Extraction techniques
- Vacuum
- Forceps
- Low and high
- C-Section
- Extraction techniques
- Baby is too big and mom us at a risk for tearing
- Episiotomy
Episiotomy
Cutting the vagina to make it bigger
Less common than it used to be, as now they might try natural tearing
Measured in degrees. Degree four is a tear all the way to the anus
If baby is in danger or we think it will be a degree 4 tear anyways then we do this
Vacuum
Vacuum extraction will use a cup-shaped extractor to apply a gentle suction to the top of the baby’s head
The vacuum can be used to assist the monitor while she is pushing during the contraction
Forceps
Forceps are sometimes used when the baby is not moving down the birth canal (vagina).
Used to hurry delivery when the mother or baby is in distress during labour.
Low is forceps at the head
High forceps is used more around the body
C-Section
- Delivery of fetus through an incision in the abdomen
- A C-Section will be done when
- Labor is considered unsafe for mother or fetus
- Delivery is necessary, but labor cannot be induced
- An emergency mandates an immediate delivery and the vaginal route is not possible or suitable
- Mom request an elective
C-Section Anaesthia
Mom will require a general or spinal anesthesia
This is an operation and it done under a sterile technique in an OR and with a surgeon and anaesthetist present
C-Section Maternal Complications
- Same risks as with any other surgery
- Post op recovery
- Long healing times
- Difficultly moving and lifting
- Complications can include intraoperative bowel and bladder injury
- The bladder or bowel can be cut and sometimes it is not noticed and will result in the mom going septic
- Increased occurrence of endometriosis
C-Section Indications
- Failure to progress in labor
- Fetal distress
- Large head
- Placental abnormalities
- Cord problem
- Genital herpes (active)
- Twins
- Breech
- Severe anomalies
- Prior c-section
- VBAC more common
C-Section Baby Complications
Surgical wounds and trauma for the baby
Infants delivered by c-section are not exposed to partial purging of fetal lung fluid provided by compression during passage through the birth canal
Fetus prepared for delivery (pulmonary)
Alveolar type II pneumocytes will produced surfactant after 26 weeks
Alveoli are open, stable, and at near normal neonatal lung volume
Pulmonary and bronchial circulation are well developed
Neuromuscular control of respiration is established with active fetal breathing periods
Everything is ready for the fetus to shift from placental support to pulmonary gas exchange and from liquid to gaseous ventilation
Hormonal changes in labor
Will begin just before labor starts
Catecholamines reduce the amount of water in the lungs
Epinephrine has been shown to inhibit secretions of fetal lung fluid
Vasopressin and prostaglandin which is secreted around the time of birth and may reduce the production of lung liminal liquid
Fetal Movement at Labor
Labour begins and the fetus starts to move downwards
As the fetus progresses down the birth canal, the chest is compressed by pressures of 30 to 160 cm H2O
This can eject as much as 30 ml of amniotic fluid
Removal of Fetal Lung Fluid at Labor
Some fetal lung fluid will be removed through compression during a vaginal delivery
Removal of lung liquid continues after birth.
When breathing begins, air inflation shifts residual liquid from the lumen into distensible perivascular spaces around large pulmonary blood vessels and bronchi.
Acculmulation of Fetal Lung Fluid After Birth
Accumulation of liquid in connective tissue spaces, which are distant from the sites of respiratory gas exchange, allows time for small blood vessels and lymphatics to remove the displaced liquid with little or no impairment of neonatal lung function at this critical juncture
Most of the time this will not affect ventilation even though there are increased risk for TTPN
Baby’s First Breath
Baby’s First Breath Lung Mechanics
- The neonate may demonstrate a high WOB for the first few minutes of life until the alveolar capillary interface and FRC are well established
- Once the lung is ventilated, FRC is 95% established within the first few minutes
- Inflation pressures decrease dramatically = Decreased WOB
- Most lungs, once aerated, can be inflated with pressures of 12 - 25 cm H2O and volumes of 5 mL (~4mL/kg)
- Compliance is approximately 2 mL/cm H2O/kg
Stimulation of First Breath
Stimulation of the first breath can be cause by tactile or thermal
Clamping of the cord will cause a low pH making the baby hypoxic, hypercapnic, and acidotic to help babies increased babies drive to breath with a strong respiratory stimuli
Post Natal Changes
Umbilical Vessels
The umbilical arteries and the umbilical vein make up the umbilical cord; these are shed at birth along with the placenta.
Post Natal Changes
Ductus Venosus
Ductus venosus, will become the ligamentum venosum of the liver
Post Natal Changes
Foramen Ovale
The foramen ovale functionally closes once pulmonary circulation is established.
Structural closure (~ 9 months)to a mere depression (fossa ovalis) in the wall of the right atrial septum.
Post Natal Changes
Ductus Arteriosus
The ductus arteriosus will becomethe ligamentum arteriosum
Closes in 5-7 days but there is a bunch of different things that will delay this closure
Cord Clamping
In most healthy term babies we will delay cord clamping for 30s -1 min
They find that if the baby is still attached to placenta they can still get gas exchange
They wont due this is there is fetal compromise
Delaying clamping will allow for a mass transfusion which leads to a lot of good things
Decrease blood pressure and volume (in a good way)
Decreased iron deficiency
Because the gas exchange is still happening at the placenta there will still be fetal lung fluid in the lungs so the baby will not be crying
Mucotranslucency Scan
Mucotranslucency scan is used to indicate down syndrome
