Maternal Changes in Preg

Question 1

Why are pregnant women chronically volume overloaded?

Answer 1

1. INcrease in TBW
2. Active sodium and water retention
   - due to changes in osmoreg and RAAS

Question 2

RAAS in pregnancy

Answer 2

Early pregnancy changes cause decreased MAP –>

Marked increases in all components !
including aldosterone: increases sodium retention and prevents Na+ loss

Question 3

ANP and BNP in pregnancies

Answer 3

Normally ANP and BNP are elevated in path states of vol overload

In preg:
ANP slightly increased (w/in nl range)
BNP increases in 3rd tri: especially those complicated by preeclampsia (but lower than lvls seen in CHF)

*many phys states in preg mimic heart disease

Question 4

What hormone affects plasma vol most during pregnancy?

plasma vol increases by ~50% starting at 6-8 weeks

Answer 4

Increased Progesterone

–> lead to decreased smooth muscle tone and increased volume capacity.

Question 5

Blood pressure fx in pregnancy

Answer 5

blood pressure decreasing during the first 14-16 weeks, stabilizing and then increasing back to baseline during the third trimester.
- This decrease in SVR is due primarily to effects on smooth muscle by progesterone as well as increased NO production decreasing vascular tone/resistance

*the blood pressure is USUALLY never be higher than baseline blood pressure in a normal pregnancy.

Question 6

What accounts for the 40% increase in CO in pregnancy?

Answer 6

Stroke vol increase

• Also due to increase in HR by 10-20 beats/min

Question 7

What position can we see the greatest increase in CO?

Answer 7

in left lateral pos

- the BP of the superior arm is 10-12 mm lower than the inferior arm.

Question 8

Changes in heart due to preg

Answer 8

1. Hypertrophy of vent muscle
2. Increase in preload: due to increased venous return
3. Decrease in afterload due to decreased vascular resistance

Question 9

CO increases perfusion to many organs, except which ones?

Answer 9

Brain and liver

*it does increase perfusion to kidney, breasts, skin, uterus

Question 10

Which murmur is nl in pregnancy?

Answer 10

Systolic ejection murmur along Left sternal border (96%)
- due to more volume
S3 common
- due to vent enlargement to increase EDV

*diastolic mumur very uncommon –> echo

Question 11

How common are arrhythmias in preg?

Answer 11

Common: almost all women will have some typ

- heart moves closer to the chest wall –> more likely to notice palpitations

Question 12

When will you see highest increase in CO?

Answer 12

10-30 min after delivery

• Symp stim (pain, anxiety)
• Uterine autotransfusion (500cc blood forced fr uterus –> systemic circ during each contraction)

Question 13

What type of lesions on heart valves are more tolerable? Regurgitant or stenotic?

Answer 13

Regurgitant

*Pts with AS have a fixed stroke vol. so CO depends mainly on HR
- very limited:
bradycardia –> hypotension
Tachycardia –> hypotension

Question 14

What should you avoid in pts with pregnancy regarding fx on bp?

Answer 14

Vasodilators: it can lead to a precipitous drop in systemic blood pressure.

Thus, during pregnancy, the decrease in SVR can lead to precipitous drops in BP as well, and higher rates of syncopal episodes.

Question 15

What hormone affects the sensitivity of respiratory centers to CO2 resulting in hyperventilation?

Answer 15

Progesterone
- minute ventilation is increased (RRx TV)

Resp. rate remains unchanged

Question 16

Why is there decreased levels of PaCO2 in preg?

Answer 16

due to increased gas exchange

Question 17

Are resp muscles affected by preg?

Answer 17

nope

- max insp and exp pressures are unchanged

Question 18

Minute ventilation (RRxTV) increases in preg, how is maternal pH maintained?

Answer 18

increase in bicarb excretion

- nl in preg = 18-21

Question 19

Dyspnea of pregnancy

Answer 19

Dyspnea is mild, doesn’t interfere with daily activities. DOES NOT OCCUR AT REST.
- common complaint

Question 20

Pregnancy is a state of primary _____ with a compensatory ______

Answer 20

resp. alkalosis

metabolic acidosis

• There is an increase in arterial PO2, a decrease in PCO2, but a concomitant decrease in HCO3- to compensate
• Thus, in spite of the physiologic hyperventilation that ensues, pH is relatively unchanged, or increases slightly by several hundredths of a point. In order to compensate for the decrease in arteriolar C02 levels, renal bicarb excretion is increased resulting in a decrease in serum levels.

Question 21

Nl PCO2 in pregnancy vs nl

Nl O2 in preg

Answer 21

Nl PCO2: 40

Pregnancy: 27-32 mmHg
- 40 would be a sign of impending resp failure

Nl O2 sat: >95% or hypoxemic

Question 22

Does GFR and renal plasma flow increase or decrease in pregnancy?

Answer 22

Increase both

*thus filtration fraction GFR/RPF actually falls
Importantly, the increase in hyperfiltration occurs without an increase in glomerular pressure, which if it occurred , could have the potential for injury to a woman’s kidney with long term consequences.

Question 23

High GFR and plasma vol does what to Cr and BUN?

Answer 23

Lowers both

A Cr of 0.8 and above can be seen as a red flag in pregnancy as a sign of decreasing renal function.

Question 24

Pts with renal insufficiency are at risk for what?

Answer 24

1. Worsening renal disease
2. Preeclampsia
3. IUGR
   (intrauterine growht restrictions)
4. PTB

Question 25

Anemia in preg

Answer 25

There is this increase in plasma volume, by about 50%, however there is only about a 20-30% increase in red blood cell mass, thus there is a concomitant dilutional anemia.
- presyncopal and syncopal episodes and fatigue. Any symptomatic patient should be begun on iron supplementation if labs point to iron deficiency.

Question 26

T cell shift in pregnancy

Answer 26

Shift from T helper cells (TH1) away from cell mediated immunity towards humoral (TH2) response

Question 27

Do increase in clotting factors play a role in objective tests of clotting such as PT, PTT or clotting times?

Answer 27

No the increase in coagulability is not due to increase in clotting factors
- concentration in the serum is not dramatically affected.

The increase in DVT and PE: most likely secondary to other aspects of Virchow’s triad. In pregnancy, there is much more stasis of blood flow in the lower extremities secondary to compression of the pelvic vessels by the uterus.

Question 28

DVT is more common on which side?

Answer 28

Left
- L common iliac vein is more compressed due to R common iliac artery overlying it

DVT is one of the most common cause of maternal mortality

Question 29

Std prophylaxsis for DVT and PE

Answer 29

LMW heparin (long half life)
- but must switch to unfractionated heparin at 36 weeks to prevent hemorrhage during pregnancy

Question 30

Why is warfarin (coumadin) contraindicated?

Answer 30

Nasal hypoplasia

Stippling of bones, brachydactyly

Question 31

Decreased tone and motility in preg is due to what?

This decreases your risk of _____. and INcreases your risk of ______.

Answer 31

Progesterone

Decreases risk of peptic ulcer disease
- (increased gastric mucin production leading to protection of the gastric mucosa; reduced gastric acid secretion; and enhanced immunological tolerance to H. pylori, the infectious agent that causes PUD.)

Increases risk of gastroesophageal reflux

Question 32

Protein levels in preg

Answer 32

Increased total protein production but free concentrations unchanged

• serum alk phos
• fibrinogen
• transferrin
• TH
• Vit D
• Drug [ ]

Question 33

N/V begins when and resolves by when

Answer 33

4-8 weeks

14-16 weeks

• more nausea with more HCG and multiple gestation

Question 34

Most common pregnancy induced liver disorder

Answer 34

cholestasis
- itching over palms and soles then generalized itching WITHOUT RASH

• assoc w. Hep C and multiplke gestations
• elevated serum bile acids

Question 35

What stimulates melanocytes

Answer 35

hCG

*not progesterone