Maternal Physiology Flashcards
The total body water ____________ during pregnancy.
increases (from 6.5 L to 8.5 L)
Why does the cardiac output increase during pregnancy?
There is hemodilution with physiologic anemia in the context of increased demand.
What is the normal range for pregnancy weight gain in women of normal prepregnancy weight?
25 - 35 lbs
Vascular resistance decreases in pregnancy due to ______________.
progesterone (as well as increased NO production by the placenta)
The placenta inactivates ____________.
ADH
Serum sodium usually ______________ during pregnancy.
drops by 3-4 mM
This occurs because water retention outpaces sodium retention in pregnancy.
The RAAS system ____________ during pregnancy.
increases
Note: the plasma volume increases by about 50% during pregnancy.
The HR increases by about __________ during pregnancy.
10 - 20 BPM
Note: SV also increases by about 20 mL per beat, so net CO increases.
The perfusion to the brain and liver does not usually increase with the increased CO found in pregnancy, but the perfusion to _________ does.
the uterus, skin, and breasts
What is the upper limit of normal HR in pregnancy?
100 BPM
Which heart murmur is found in almost 100% of pregnant women?
Systolic ejection murmur (also S3)
Overall, the cardiac changes seen in pregnancy mimic those of _______________.
congestive heart failure (e.g., orthopnea, edema, S3, increased HR, increased RAAS, and increased levels of BNP)
During labor, there is an increase of CO of about _________.
51%
Initially, the Valsalva maneuver __________ venous return.
decreases (because of increased intrathoracic pressure)
“Valsalva = VeinS ALl VAcant”
What amounts of blood loss are considered normal during delivery?
Vaginal delivery: 500 mL
Caesarean section: 1000 mL
The severity of aortic stenosis is determined by ________________.
pressure gradient across the aortic valve (mild = less than 36; moderate = 36 –63; severe = greater than 63)
What pulmonary changes occur during pregnancy?
- Tidal volume increases
- Progesterone increases sensitivity of the medullary respiratory center to CO2
- Decreased residual volume (and thus decreased TLC)
- Mild respiratory alkalosis develops
Minute ventilation is equal to _________.
RR x TV
During pregnancy, pCO2 _________.
decreases to 27 - 32 mmHg (compared to 40 mmHg normal)
Similarly, HCO3 decreases to maintain a normal pH.
True or false: pCO2 decreases in pregnancy due to increased RR.
False. RR does not change during pregnancy. The decrease in pCO2 is due to increased TV.
In terms of renal adaptation, there is a relative ____________ in pregnancy.
hydronephrosis
The uterus is usually right-leaning, so ____________ more commonly arises in the right kidney.
pyelonephritis (due to urinary stasis)
True or false: GFR usually decreases by 25% during pregnancy.
False. GFR increases by ~50% (to almost 200 mL/min).
Creatinine and BUN usually _________ during pregnancy.
decrease
