Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

OBGYN > Obstetric Physiology > Flashcards

Obstetric Physiology Flashcards

1
Q

What happens to the location of the maternal heart during pregnancy?

A

it is displaced upward and to the left, assuming a more horizontal position as the apex moves laterally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens to the four chambers of the maternal heart during pregnancy?

A
  • there is an increase in ventricular muscle mass

- there is an increase in left atrial and ventricular volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does maternal cardiac output change over the course of pregnancy and what parameters account for this change?

A
  • cardiac output increases primarily in the first half of pregnancy, due to an increase in stroke volume
  • it further increases in the second half as a result of increased maternal heart rate while stroke volume returns to normal
  • late in pregnancy, it often declines as venous return is impeded by vena canal obstruction by the gravid uterus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the timeline for changes in maternal blood volume during pregnancy.

A
  • the volume begins to increase by 6-8 weeks gestation

- it peaks around 32 weeks gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happens to maternal systemic vascular resistance during pregnancy and why?

A

resistance decreases as the result of…

  • progesterone-induced smooth muscle relaxation
  • increased production of vasodilatory substances
  • arteriovenous shunting to the uteroplacental circulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When a pregnant individual lays supine, the uterus often compresses and obstructs the vena cava late in pregnancy. How does this affect their cardiovascular status and what happens to the obstructed blood?

A
  • this change reduces venous return and thus cardiac output

- instead, blood is shunted through the dilated paravertebral collateral circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The uterus receives how much of the maternal cardiac output at term?

A

about 20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens to blood pressure during the course of pregnancy?

A

diastolic pressure decreases beginning around week 7 and reaches a maximal, 10 mmHg, decline between 24-26 weeks before trending upward again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens to maternal pulse during the course of pregnancy?

A

it increases as pregnancy progresses to about 10-18 bpm greater than the non-pregnant value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What maternal cardiovascular changes are seen during pregnancy?

A
  • the heart is shifted up and to the left, laying more horizontal
  • ventricular mass and left-sided cardiac volume increase
  • diastolic blood pressure declines
  • pulse quickens
  • blood volume peaks around week 32
  • cardiac output increases, first due to stroke volume and then due to changes in pulse
  • vascular resistance decreases
  • vena caval return is obstructed by the growing uterus when supine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is inferior vena cava syndrome?

A
  • a syndrome seen in late pregnancy
  • caused by a growing uterus which may compress and obstruct the inferior vena cava while supine
  • presents with dizziness, light-headedness, and syncope
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What changes are expected during auscultation of the maternal heart during pregnancy?

A
  • widened S2 split
  • possible S3 gallop
  • low-graded systolic ejection murmur
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What kinds of auscultation findings are never considered normal during pregnancy?

A

S4 heart sounds and diastolic murmurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What anatomic changes are seen in the maternal respiratory system during pregnancy?

A
  • the diaphragm is elevated about 4 cm

- the subcostal angle wides as chest diameter and circumference increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What functional changes are seen in the maternal respiratory system during pregnancy?

A
  • there is an increase in total body oxygen consumption
  • diaphragmatic elevation reduces the residual and functional residual capacity as well as total lung volume
  • respiratory rate is unchanged and tidal volume increases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do maternal respiratory rate and pulse change during pregnancy?

A
  • pulse quickens by 10-18 bpm

- respiratory rate is unchanged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does maternal minute ventilation change during pregnancy?

A
  • the respiratory rate is unchanged
  • the tidal volume increases
  • the minute ventilation increases proportionally
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does acid-base status change during pregnancy?

A

there is a metabolically compensated respiratory alkalosis with no change in overall pH due to…

  • an increase in minute ventilation secondary to an increase in tidal volume
  • progesterone increasing central chemoreceptor sensitivity to carbon dioxide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does the material system compensate for the respiratory alkalosis induced by progesterone and expansion of the tidal volume?

A

there is an increase in renal excretion of bicarbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Pregnancy women often experience what respiratory symptoms during pregnancy?

A
  • dyspnea is common

- allergy-like symptoms secondary to mucosal hyperemia, nasal stuffiness, and increased nasal secretions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What hematologic changes are seen during pregnancy?

A
  • increase in plasma volume
  • increase in red cell volume
  • increase in total blood volume
  • increase in total coagulation factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

By how much do we expect plasma volume, red cell volume, and blood volume to change during pregnancy?

A
  • plasma volume increases by 50%
  • red cell volume increases to 450 mL
  • maternal blood volume increases 35%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why do we use supplemental iron during pregnancy? How much is required? What happens if there are insufficient levels?

A
  • recommend 27 mg of supplementation each day to achieve the required 60 mg a day in conjunction with diet
  • iron is actively transported to the fetus so fetal hemoglobin levels will be unaffected by maternal iron stores
  • so supplementation is essential for preventing iron deficiency of the mother as red cell volume expands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens to the white count during pregnancy?

A

there is an increase in granulocytes and therefore white cell count secondary to stress-associated demargination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

The amount of which clotting factors increases during pregnancy? Which decrease and which remain unchanged?

A
  • most increase
  • FII, FV, and FXII are unchanged
  • protein C and S are decreased
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What happens to hemoglobin during pregnancy?

A
  • total hemoglobin increases

- hemoglobin concentration decreases due to dilution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the threshold for anemia during pregnancy?

A

when hemoglobin drops below 11 g/dL, this is indicative of iron deficiency and anemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What anatomic change is observed in the maternal kidney during pregnancy?

A
  • an enlargement and dilation of the kidneys and urinary collecting system
  • the kidneys lengthen due to greater interstitial volume and distended vasculature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Why does the right ureter often dilate to a greater degree than the left during pregnancy?

A

because the uterus classically undergoes dextrorotation as it enlarges, compressing the right ureter to a greater degree

30
Q

Give two reasons why the ureters dilate during pregnancy?

A
  • compression by the uterus leads to distention and dilation

- progesterone levels promote smooth muscle relaxation

31
Q

What happens to the total capacity and residual volume of the bladder during pregnancy? Why?

A
  • the uterus compresses the bladder, reducing total capacity

- elevated progesterone levels relax smooth muscle and decrease bladder tone, raising residual volume

32
Q

What functional changes are seen in the kidneys during pregnancy?

A
  • there is an increase in renal plasma flow and GFR
  • as a result urinary glucose excretion increases and excretion of amino acids and water-soluble vitamins also increases
  • there is no change in protein excretion
  • the increase in filtration of electrolytes is compensated for by an increase in tubule reabsorption so there is no change in electrolyte metabolism in the kidneys
  • serum creatinine and BUN decrease as clearance increases
33
Q

What finding on UA is never normal during pregnancy?

A

while increased glucose, amino acids, and water-soluble vitamins are commonly found in the urine, an increase in urinary proteins is never normal

34
Q

What are the clinical implications of bladder changes during pregnancy?

A
  • urinary frequency
  • stress incontinence
  • urinary stasis predisposing to pyelonephritis
35
Q

What happens to urinary glucose, sodium, BUN, creatinine, and protein; GFR; and RPF during pregnancy?

A
  • GFR and RPF both increase during pregnancy
  • glucose excretion increases
  • sodium filtration increases but so does reabsorption so excretion is unchanged
  • BUN clearance increases
  • creatinine clearance increases
  • there should be no change in urinary protein
36
Q

What part of the GI tract increases in size?

A

the portal vein; the stomach, intestines, liver, biliary tract, etc. do not change in size

37
Q

What functional changes are observed in the maternal GI system during pregnancy?

A
  • progesterone produces relaxation of the lower esophageal sphincter, decreased GI motility, and impaired gallbladder contractility
38
Q

What causes gastroesophageal reflux during pregnancy?

A
  • progesterone-induced relaxation of the lower esophageal sphincter
  • increased intragastric pressure relative to intraesophageal pressure
39
Q

Why are pregnant women more likely to suffer from gallstones?

A
  • progesterone relaxes and thus impairs contraction of the gallbladder, leading to stasis
  • estrogen inhibits intraductal transport of bile acids which lower the solubility of bile
40
Q

During what portion of pregnancy is morning sickness most prevalent?

A

beginning between weeks 4-8 and ending around weeks 14-16

41
Q

What is hyperemesis gravidarum?

A

severe nausea and vomiting of pregnancy which can result in weight loss, ketonemia, and electrolyte imbalance

42
Q

What is ptyalism?

A

a perceived excess production of saliva, which is likely to due an inability of nauseated woman to swallow the normal amounts of saliva being produced

43
Q

What contributes to constipation during pregnancy?

A
  • mechanical obstruction of the colon
  • reduced motility within the GI tract
  • increased water reabsorption
44
Q

Intense pruritis during pregnancy may be indicative of what GI dysfunction?

A

may be indicative of intrahepatic cholestasis and increased serum bile acid concentrations

45
Q

What changes are seen in the gums during pregnancy?

A

they become edematous and soft, bleeding easily with brushing

46
Q

What happens to total albumin and serum albumin during pregnancy?

A
  • total albumin increases

- but there is a dilutional decrease in serum albumin

47
Q

How does thyroid function change during pregnancy?

A

although there are many changes in regulation, there is an overall euthyroid state

  • the thyroid enlarges without producing thyromegaly or goiter
  • B-hCG in the first trimester stimulates T4 secretion and a transient rise in free T4 concentration
  • as the pregnancy progresses and B-hCG drops, estrogen induces hepatic synthesis of TBG and an increase in total T4
  • the concurrent stimulation causes free T4 and T3 levels to be unchanged
48
Q

What adrenal changes are observed during pregnancy?

A
  • estrogen drives hepatic synthesis of cortisol-binding globulin and the concentration of free plasma cortisol progressively increases
  • corticotropin levels rise in conjunction
  • aldosterone levels increase
  • estrogen drives renal synthesis of deoxycorticosterone rather than increased adrenal production
49
Q

Through what mechanism does deoxycorticosterone levels rise during pregnancy?

A

estrogen drives renal synthesis; there is limited change in adrenal production

50
Q

What happens to DHEAS levels during pregnancy?

A

levels decrease due to hepatic uptake and conversion to estrogen

51
Q

How does carbohydrate metabolism change during pregnancy?

A
  • there is a diabetic effect characterized by insulin, hyperinsulinemia, and hyperglycemia as a result of human placental lactose, which increases insulin resistance in peripheral tissues
  • secondarily, there is an increase in hepatic glycogen synthesis and storage and inhibition of gluconeogenesis
52
Q

Through what transport mechanism does glucose reach the fetus?

A

facilitated diffusion across the placenta

53
Q

How does pregnancy affect lipid metabolism?

A
  • there is an increase in circulating lipids, cholesterol, lipoproteins, and apolipoproteins
  • early in pregnancy central fat storage predominates and then in later pregnancy, lipolysis predominates
54
Q

What happens to the spine during pregnancy and why?

A

there is a state of lumbar lordosis (anterior convexity) which helps keep the woman’s center of gravity over her legs but leads to complaints of low back pain

55
Q

When does the pubic symphysis relax and separate and under the control of which hormones does this occur?

A

it occurs between approximately 28-30 weeks gestation under the control of relaxin and progesterone

56
Q

Describe changes in calcium metabolism during pregnancy.

A
  • maternal serum-ionized calcium is unchanged but maternal total serum calcium decreases
  • a rise in parathyroid maintains serum calcium without affecting the skeleton due to protection by calcitonin
  • although the rate of bone turnover increases, there is no loss of bone density
57
Q

What dermatologic changes are expected during pregnancy?

A
  • spider angiomata
  • palmar erythema
  • striae gravidarum
  • hyper pigmentation
  • linea alba darkens to become the lineage nigra
  • melasma
  • growth and increased pigmentation of existing skin nevi
  • eccrine sweating and sebum production increase
58
Q

How does hair growth change during pregnancy?

A

hair growth is maintained but more follicles are in the anagen, also known as growth phase

59
Q

What is leukorrhea of pregnancy?

A

a heavier vaginal discharge resulting from increased vascularity and transudation as well as stimulation of vaginal epithelium

60
Q

What happens to the uterus during pregnancy?

A

it grows significantly heavier through hypertrophy of existing myometrial cells

61
Q

What is the effect of estrogen and progesterone on the breasts during pregnancy?

A
  • estrogen stimulation results in ductal growth

- progesterone stimulation results in alveolar hypertrophy

62
Q

What is the most common ophthalmic complaint during pregnancy? Why does it occur?

A
  • blurred vision is most common

- caused by increased thickness of the cornea secondary to fluid retention and decreased intraocular pressure

63
Q

What is the primary metabolic substrate for placental metabolism?

A

glucose

64
Q

How do the following cross the placenta:

  • amino acids
  • free fatty acids
  • gases
  • glucose
  • iron
A
  • amino acids: active transport with higher levels in the fetus than mother
  • free fatty acids: very limited transfer with higher levels in mother than fetus
  • gases: via facilitated diffusion
  • glucose: via facilitated diffusion
  • iron: via active transport
65
Q

Describe the pathway of fetal blood flow.

A
  • oxygenated blood is delivered via the umbilical vein
  • it by passes the hepatic circulation as it enters the IVC via the ductus venosus
  • from there it is delivered into the right atrium and passes through the foramen ovale into the left atrium
  • it fills the left ventricle and is pumped into the ascending aorta to supply the head and body
  • deoxygenated blood from the superior vena cava returns to the right atrium and then fills the right ventricle
  • it is pumped out of the pulmonary artery but diverted through the ductus arteriosus into the aortic arch
  • blood in the aorta, then, is a mix of oxygenated and deoxygenated blood that passes through the body and exits the fetus via the umbilical arteries
66
Q

What structure does each of the following give rise to:

  • ductus arteriosus
  • foramen ovale
  • ductus venosus
  • umbilical vein
  • umbilical arteries
A
  • ductus arteriosus: ligamentum arteriosum
  • foramen ovale: fossa ovalis
  • ductus venosus: ligamentum venosum
  • umbilical vein: ligamentum teres
  • umbilical arteries: medial umbilical ligaments
67
Q

What happens to fetal blood that enters the right hepatic vein rather than the ductus venosus?

A

it enters the inferior vena cava and then flows preferentially through the tricuspid valve to the right ventricle

68
Q

What are the components of fetal hemoglobin?

A

two alpha-chains and two gamma-chains

69
Q

What is the key difference of fetal hemoglobin?

A

it binds 2,3-DPG with less affinity and thus has higher oxygen affinity and saturation than HbA

70
Q

What causes a transfer of oxygen from maternal blood to fetal blood at the placenta?

A
  • HbF has a greater affinity for oxygen than HbA
  • additionally, the maternal respiratory alkalosis facilitates transfer of CO2 from the fetal circulation to maternal
  • this loss of CO2 causes a rise in fetal blood pH, shifting the oxygen dissociation curve to the left, increasing oxygen-binding affinity
  • all while the opposite shift occurs in the maternal blood
71
Q

When during gestation does the gonadal tissue differentiate into testes? What if it differentiates into ovaries instead?

A
  • differentiation into testes occurs at 6 weeks

- otherwise differentiation into ovaries occurs at 7 weeks

OBGYN (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions