Maternal Physiology (Exam II) Flashcards
Gravida refers to what?
Number of pregnancies (not babies)
Para refers to what?
numbers of births (>20weeks)
What is G0P0?
Nulligravida/Nulliparous
- No pregnancies
- No births
What would G3P2 refer to?
Multigravida/ Multiparous
- 3 pregnancies
- 2 births
How long is a pregnancy? When is a gestation “term”?
- 40 weeks
- Term at 37 - 40 weeks
What are the components that result in the 12kg weight gain typical of pregnancies?
- Uterus & Amniotic Fluid = 1kg
- Fetal/Placental Weight = 4kg
- New Fat/Protein stores = 4kg
- Blood volume increase = 2kg
lol this is 11kg…
Do women of all BMI’s gain weight the same during pregnancies?
No
How much does total blood volume increase during pregnancy?
30 - 35% increase
When does the increase in total blood volume of the typical pregnant woman occur?
8 - 32 weeks (Majority by 24 weeks)
Does plasma volume or RBC volume increase more during pregnancy?
Both increase but plasma volume increases more.
Why does blood volume increase during pregnancy?
To counteract delivery blood loss
Approximately when does maternal blood volume return to normal post-delivery?
6 weeks
Compare the blood volume of a pregnant patient and a non-pregnant patient in mL/kg.
Non = 65mL/kg
Pregnant= 85-90 mL/kg
CO will increase by ___% by term.
40%
In regards to hemodynamics, by 6 weeks there will be an increase in maternal _____ ____ and by 8 - 10 weeks there will be an increase in _____ _____.
Heart Rate : Stroke Volume
What is the mechanism for increased Stroke Volume in the pregnant patient?
↑ Plasma Renin = ↑aldosterone = ↑ Preload = ↑ SV
How much does uterine blood flow increase during pregancy?
Baseline = 50 mL/min
Term = 700 mL/min
20x increase!
What is the cause of the pregnancy symptoms of warm skin, flushing, and itching?
3-4x increase in skin blood flow
What changes in SVR occur in pregnancy?
20% lower
What hormones are responsible for maternal vasodilation?
- Progesterone
- Prostacyclin
- Relaxin
- Estrogen
Pregnancy is a ____ flow, _____ resistance state.
High flow : low resistance
↑ CO and ↓ SVR
Do the following increase or decrease during pregnancy?
- Blood volume
- Cardiac Output
- SVR
- Heart rate
- ↑ Blood volume
- ↑ Cardiac Output
- ↓ SVR
- ↑ Heart rate
What changes are seen in a maternal heart due to pregnancy?
Eccentric Hypertrophy (as much as 50%)
How does the heart shift due to pregnancy?
Why does this occur?
- Heart shifts anterior and leftward due to diaphragmatic elevation.
Where does the point of maximal impulse for auscultation shift in a pregnant patient?
4th ICS mid-clavicular line
What EKG changes are seen in a pregnant patient?
- Left Axis shift in 3rd trimester
- Lead III T-wave inversion
- PR interval shortened
- ST segment depressed
- QT interval increased
What are the most common EKG abnormalities in pregnant patients?
Tachydysrhythmias
(Sinus tach, PAC, PVC)
What valvular changes are typical of pregnancy?
- Tricuspid & Pulmonic regurgitation (>90% pts)
- Mitral regurgitation (~25% of pts)
These typically reverse postpartum.
What heart sound is often heard in the 3rd trimester?
What causes this?
Ventricular Gallop
Due to inrush of large blood volume into very compliant left ventricle.
What heart sound disappears at term?
4th heart sound
What murmur can occur due to cardiac enlargement?
Where is this best heard?
- Grade II SEM (systolic ejection murmur)
- Heard right side of heart, near sternal border
What occurs in the supine position of a pregnant woman?
Aortocaval compression
Uterus compresses great vessels.
Occurs as early as 13-16 weeks.
What exacerbates aortocaval compression?
Anesthesia due to vasodilation.
What are the s/s of aortocaval compression?
- Fetal Distress
- Tachycardia → bradycardia
- N/V
- Pallor
- Syncope
What is the treatment for aortocaval compression?
LUD (Left Uterine Displacement)
Done by tilting the patient to the left.
What cardiovascular changes occur during the first stage of labor?
- CO increases before & during contractions
- HR increases
- Autotransfusion of 300-500mls from uterus to general circulation w/ each contraction.
What cardiovascular changes occur during the second stage of labor?
CO increases by 50% due to:
- Pushing effort
- ↑ SV & HR
What cardiovascular changes occur during the second stage of labor?
CO increases by 60 - 80% due to
- Relief from vena cava obstruction
- Uterine contracts blood into circulation
When does CO return to normal post-delivery?
24 hours
What happens to the airway in obstetric patients?
What are the anesthetic implications of edematous airways?
- Smaller ETT necessary
- Avoid NGT/Nasal trumpets (bloody nose)
- Airway obstruction risk increases
How does the hormone estrogen effect the obstetric patient’s pulmonary system?
Estrogen will ↑ number and sensitivity of progesterone receptors in the respiratory center of the brain.
How does the hormone Progesterone effect the obstetric patient’s pulmonary system?
- ↑ respiratory center sensitivity to CO₂
- Bronchodilates
- Causes edematous airways
How does the hormone Relaxin effect the obstetric patient’s pulmonary system?
Causes ligamentous attachments to lower ribs to relax.
- subcostal angle increases
- widened AP & transverse diameter of chest wall.