Physio of Preg., Labor, and Delivery Flashcards
What are some mechanical changes that happen in mom’s thorax while pregnant?
Expanded circumference.
Subcostal angle becomes less acute.
Diaphragm rises higher.
Why might pregnant women get non-infectious or allergic nasal stuffiness and epistaxis?
Estrogen induces hyperemia and edema in the upper respiratory tract.
How does lung volume change in pregnancy? Implication?
Greater tidal volume, greater minute ventilation, less reserve.
Less reserve means more likely to have severe complications of asthma and resp. infections.
Is dyspnea of pregnancy common? What do you want to rule out?
Yes - happens to 60-70% of patients in later first or early second trimester.
Definitely rule out PE.
How does cardiac output change in pregnancy? What percentage does the uterus get?
Increases from about 4.5L/min to 6L/min.
Uterus will get about 17% of cardiac output by term.
How can physical posture affect C.O.?
Late in pregnancy, lying on back can cause gravid uterus to compress the IVC, decreasing C.O. and making everyone uncomfortable.
How do pregnant women adjust to the greater blood volume they have?
Progesterone decreases peripheral vascular resistance -> lower BP.
What is an observable effect of these CV changes on the heart?
Systolic ejection murmur is common.
diastolic murmur is not normal
Effect of increased body water on electrolytes?
Slightly reduced Na+ concentration, but not hyponatremic.
Do plasma volume and RBC volume increase by the same amount? What effect does this have? Why might this be good?
Plasma volume increases more, causing “physiologic anemia of pregnancy” -> decreased hematocrit.
This may actually be protective against hemorrhage, and help exchange of nutrients/waste/temperature.
What specific effects does estrogen have on coagulation?
Increases Factors I, VII, VIII, IX, and X.
Do PT and aPTT remain valid tests during pregnancy?
Yes.
How might you detect bleeding that you can’t see in a pregnant woman?
Bleeding will cause a drop in fibrinogen
Renal changes of pregnancy?
Renal hypertrophy, higher risk for infections, especially on the right side.
The uterus tends to rotate toward the right side…
Effect of pregnancy hormones on the kidney?
Progesterone causes dilated ureters and renal pelvises.. increased GFR… drop in creatinine… renal stuff.
Impact of progesterone on the GI tract?
All smooth muscle contractions are impaired, predisposing to…
Delayed stomach emptying.
Acid reflux.
Constipation.
Slow gall bladder emptying -> stones.
(increased portal venous pressure -> hemorrhoids… not sure if this is due to smooth muscle)
3 liver products increased in pregnancy?
Should LFTs be normal?
Fibrinogen, binding proteins (for steroids / thyroid hormone), clotting factors.
LFTs should be normal.
When does most nausea/vomiting of pregnancy occur?
4-16 weeks.
What are the 3 P’s of getting a baby out?
Passenger
Passage
Powers (“Push it.”)
3 aspects of the “passenger” that affect delivery?
Presentation (cephalic vs. breach / transverse)
Size
Position (which way head is facing)
Which position of the head is ideal as the baby is coming out?
Occiput-Anterior (face-down)
What is the “zero station”?
The ischial spines.
If the cervix is dilated by the baby isn’t descended, what do you suspect?
Cephalopelvic dysproportion.
4 things that induce uterine contraction, physiologically?
Prostaglandins (E2, F2alpha)
Anything that increases intracelullar Ca++
Gap junctions
Increased oxytocin receptors
