Maternal Physiology

Question 1

The total body water ____________ during pregnancy.

Answer 1

increases (from 6.5 L to 8.5 L)

Question 2

Why does the cardiac output increase during pregnancy?

Answer 2

There is hemodilution with physiologic anemia in the context of increased demand.

Question 3

What is the normal range for pregnancy weight gain in women of normal prepregnancy weight?

Answer 3

25 - 35 lbs

Question 4

Vascular resistance decreases in pregnancy due to ______________.

Answer 4

progesterone (as well as increased NO production by the placenta)

Question 5

The placenta inactivates ____________.

Answer 5

ADH

Question 6

Serum sodium usually ______________ during pregnancy.

Answer 6

drops by 3-4 mM

This occurs because water retention outpaces sodium retention in pregnancy.

Question 7

The RAAS system ____________ during pregnancy.

Answer 7

increases

Note: the plasma volume increases by about 50% during pregnancy.

Question 8

The HR increases by about __________ during pregnancy.

Answer 8

10 - 20 BPM

Note: SV also increases by about 20 mL per beat, so net CO increases.

Question 9

The perfusion to the brain and liver does not usually increase with the increased CO found in pregnancy, but the perfusion to _________ does.

Answer 9

the uterus, skin, and breasts

Question 10

What is the upper limit of normal HR in pregnancy?

Answer 10

100 BPM

Question 11

Which heart murmur is found in almost 100% of pregnant women?

Answer 11

Systolic ejection murmur (also S3)

Question 12

Overall, the cardiac changes seen in pregnancy mimic those of _______________.

Answer 12

congestive heart failure (e.g., orthopnea, edema, S3, increased HR, increased RAAS, and increased levels of BNP)

Question 13

During labor, there is an increase of CO of about _________.

Answer 13

51%

Question 14

Initially, the Valsalva maneuver __________ venous return.

Answer 14

decreases (because of increased intrathoracic pressure)

“Valsalva = VeinS ALl VAcant”

Question 15

What amounts of blood loss are considered normal during delivery?

Answer 15

Vaginal delivery: 500 mL

Caesarean section: 1000 mL

Question 16

The severity of aortic stenosis is determined by ________________.

Answer 16

pressure gradient across the aortic valve (mild = less than 36; moderate = 36 –63; severe = greater than 63)

Question 17

What pulmonary changes occur during pregnancy?

Answer 17

• Tidal volume increases
• Progesterone increases sensitivity of the medullary respiratory center to CO2
• Decreased residual volume (and thus decreased TLC)
• Mild respiratory alkalosis develops

Question 18

Minute ventilation is equal to _________.

Answer 18

RR x TV

Question 19

During pregnancy, pCO2 _________.

Answer 19

decreases to 27 - 32 mmHg (compared to 40 mmHg normal)

Similarly, HCO3 decreases to maintain a normal pH.

Question 20

True or false: pCO2 decreases in pregnancy due to increased RR.

Answer 20

False. RR does not change during pregnancy. The decrease in pCO2 is due to increased TV.

Question 21

In terms of renal adaptation, there is a relative ____________ in pregnancy.

Answer 21

hydronephrosis

Question 22

The uterus is usually right-leaning, so ____________ more commonly arises in the right kidney.

Answer 22

pyelonephritis (due to urinary stasis)

Question 23

True or false: GFR usually decreases by 25% during pregnancy.

Answer 23

False. GFR increases by ~50% (to almost 200 mL/min).

Question 24

Creatinine and BUN usually _________ during pregnancy.

Answer 24

decrease

Question 25

What hematologic complications are often seen in pregnancy?

Answer 25

Dilutional anemia and thrombocytopenia

Question 26

Describe the changes to immune cells that occur in pregnancy.

Answer 26

WBCs increase to an average of 8,500 cells/mL. During labor, WBCs can increase to 30,000 even without infection!

Question 27

It’s thought that the increases in coagulation factors has evolved to _______________.

Answer 27

protect against hemorrhage

Question 28

List the coagulation factors and whether each increases, decreases, or stays the same.

Answer 28

Increase: I, II, V, VII, VIII, IX, X, XII
Stay constant: III, C (“C is Constant”)
Decreases: XI, XIII, S (“S Sinks”), TPA, TPAI

Question 29

Women with a history of DVTs and PEs should receive prophylactic ___________.

Answer 29

LMWH or unfractionated heparin

Question 30

How many more calories are needed during pregnancy?

Answer 30

First trimester: 200/day

Second and third trimesters: 300/day

Question 31

What GI complications are often found with pregnancy?

Answer 31

• Decreased intestinal motility
• Constipation and diarrhea
• Hemorrhoids
• Increased risk of gallstones

Question 32

Signs of liver disease, including ______________ are often normal in pregnancy.

Answer 32

decreased albumin, increased alkaline phosphatase, and spider angiomata

Question 33

Describe the two types of vomiting and nausea seen in pregnancis.

Answer 33

• 70% of pregnancies: not serious; usually occurs between 4 weeks and 16 weeks and correlates with hCG
• 1-3% of pregnancies: refractory nausea and vomiting that requires hospitalization (called hyperemesis gravidum)

Question 34

Hyperpigmentation of the nipples or face (called melasma) occurs due to _____________ and may be permanent.

Answer 34

hCG stimulating melanocyte-stimulating hormone

Question 35

Impaired volume expansion has been linked to what two disorders?

Answer 35

Preeclampsia and poor fetal growth

Question 36

Increases in BNP are seen predominantly during _____________.

Answer 36

the third trimester

Question 37

___________ can often be displaced to the left during pregnancy.

Answer 37

The PMI

Question 38

Which PFTs decrease during pregnancy?

Answer 38

RV, ERV, TLC, and FRC

Question 39

True or false: like COPD, FEV/FVC decreases during pregnancy.

Answer 39

False. FEV/FVC remains unchanged.

Question 40

What happens to FF during pregnancy?

Answer 40

It falls. Although GFR hugely increases, RBF increases even more.

Question 41

What is ptyalism?

Answer 41

Increased saliva production