38 & 39 Physiology of pregnancy

Question 1

In early pregnancy (first 20 weeks of pregnancy), the energy status is mainly catabolic/ anabolic.

In late pregnancy, the energy status is mainly catabolic/ anabolic.

Answer 1

anabolic;

catabolic

Question 2

What is the relationship between estrogen, progesterone and insulin during early pregnancy?

Answer 2

Estrogen stimulates pancreatic beta cells hypertrophy and hyperplasia > progesterone augments insulin secretion
> exaggerated insulin response

a. decrease gluconeogenesis
b. Increase peripheral glucose utilization
c. Increase glycogen storage (in muscles, liver)
d. Increase protein synthesis (uterus, muscle, breast)
e. Increase lipid synthesis and storage (breast, adipose tissue)

Question 3

Under the effects of human placental growth hormone (hPGH) , human chorionic somatomammotrophin (hCS), elevated cortisol (from maternal adrenal gland), other hormones (estrogen, progesterone), adipocytokines and free fatty acids, mother presents with —————————— and develops into catabolic/diabetogenic state.

Answer 3

insulin resistance

• hPGH/HCS (GH-like actions)
  ○ Induce insulin resistance
  ○ Stimulate lipolysis
• Cortisol
  ○ Induce insulin resistance
  ○ Decrease protein synthesis and stimulate proteolysis
  ○ Promote lipolysis

Question 4

OGTT is used to demonstrate glucose intolerance in late pregnancy.
The glucose level will be ________ than non-pregnant women.
The insulin response will be _______ than non-pregnant women.

Answer 4

Higher;
more exaggerated
(due to increased resistance to insulin action)

Question 5

During pregnancy, fasting state is indicated by _____ blood glucose level due to _____________________ and ______ free fatty acid levels.

Answer 5

Low;
continuous transfer of glucose from maternal to fetal circulation ;
elevated

Question 6

4 significant changes of maternal metabolism?

Answer 6

1. Spare glucose for use by fetus
2. Increase lipolysis to mobilize free fatty acids and ketones as major metabolic fuels for maternal use (fatty acid also for fetal use)
3. Limit the use of amino acids by lipid catabolism
4. Restrict protein anabolism to increase a.a. supply to fetus (under the effect of cortisol)

Question 7

Gestational diabetes is defined as diabetes diagnosed in ____________ trimester of pregnancy based on ________.

Answer 7

second or third;

OGTT

Question 8

Unlike the non-pregnant state, the cut off for:

1. fasting blood glucose is higher/lower
2. 2 hours post 75g OGTT plasma glucose levels is higher/lower

Answer 8

lower (accelerated starvation);

higher (impaired glucose tolerance)

Question 9

Which of the following are effects of maternal/gestational diabetes?

A. Fetal hyperglycemia
B. Macrosomia and organomegaly
C. Mental retardation of infant
D. Neonatal hypoglycemia

Answer 9

All except C

A: maternal hyperglycemia can give rise to fetal hyperglycemia

B: increased somatic growth under the anabolic effect if insulin and IGF

D: due to hyperinsulinemia and depleted glycogen store in the first few hours after birth

Question 10

Macrosomia can lead to?

Answer 10

increased difficulty in vaginal delivery, risk of birth injuries (shoulder dystocia)

Question 11

Why is there an increase in total body water during pregnancy?

Answer 11

Water retention occurs due to a reduction in the threshold for ADH release under the action of relaxin and estrogen on the brain.

AngII, relaxin and prolactin stimulate thirst sensation.

Excess water retained is eliminated after the birth of baby in postpartum diuresis.

Question 12

Name 2 causes of expansion in plasma volume and its counteractive mechanism.

Answer 12

• ECF volume increases due to Na+ and water retention (aldosterone)
  VS
  Increased Na+ excretion: natriuretic effect of progesterone and ANF, due to increased GFR

Renin production is stimulated by estrogen and is increased due to fall in blood pressure under the vasodilatory effect of progestrone, estrogen, relaxin
VS
Pressor effect of angiotensin
: Hepatic production of angiotensinogen is stimulated by estrogen

Question 13

Why is it pathological to fluid accumulation in pregnant women?

Answer 13

Generalized edema in pre-eclampsia/eclampsia will happen due to hypoalbuminea from proteinuria

(eclampsia = generalized vasoconstriction)

Question 14

Estrogen effects on cardiovascular system

A. Cause vasoconstriction
B. Retention of water and salt by altering threshold for stimulation of ADH
C. Increase plasma level of angiotensinogen by stimulatory effect on liver
D. Lower chances of atherosclerosis
E. Increase the coagulability of blood

Answer 14

Only A is wrong

Causes vasodilation due to NO production (NO synthase and increase prostacyclin)

D: by increasing HDL and decrease LDL

E: Significant increase in fibrinogen and blood clotting factors and inhibit antithrombin III formation

Question 15

Hematological changes in pregnancy:
A. Increase in plasma volume by 30-40%
B. Decrease in hematocrit and Hb concentration
C. Hemodilution
D. Increased levels in anti-coagulation factors
E. Increased fibrinolysis

Answer 15

Only D is wrong

D: decreased levels of anti-coagulant factors (protein S activity, antrithrombin III) > prone to develop thromboembolic diseases

Question 16

What is the importance of hemodilution?

Answer 16

decreased viscosity of blood allows maternal cardiac output to increase with a smaller relative increase in cardiac work

Question 17

Cardiovascular changes in pregnancy:

A. Increase in peripheral resistance by 20%
B. Increase in cardiac output by 40-50%
C. Decreased MAP

Answer 17

All except A

A: decrease in peripheral resistance (TPR) due to vasodilatory effects of progesterone, estrogen and relaxin, dilation of cutaneous blood vessels for thermoregulation, decreased blood viscosity …

C: Despite increase in CO, MAP decreases due to
(MAP=COx TPR)
- diastolic blood pressure decrease due to fall in TPR
- pulse pressure increases (SP-DP)
- both SP and MAP decreases as the effect of TPR is greater than CO

Question 18

Supine hypotension:
A. starting from 2nd trimester
B. due to aortocaval compression (aorta/IVC)
C. reduction in venous return and CO is not compensated
D. establishment of paravertebral collateral circulation (Batson’s plexus) that allow venous return to bypass vena cava
E. alleviated by rolling towards the side when in supine position

Answer 18

B,D,E

A: 3rd trimester
C: compensated partially by baroreceptor reflex

Supine hypotensive symptoms arise from:

1. Poor paravertebral collateral circulation
2. Inadequate baroreceptor response

Question 19

What are the changes in respiration in pregnant women?

Answer 19

1. Hyperventilation
2. Diaphragmatic elevation:
   flaring of lower ribs, increased subcostal angle; total lung capacity is not significantly reduced ; no change in lung compliance
3. Long volume: residual lung volume decreases due to elevated diaphragm, increased tidal volume

Question 20

How is hyperventilation achieved in pregnant women?

Answer 20

• minute ventilation increases by 30-50% due to increase in tidal volume mainly, and respiratory rate
• Progesterone effect: rest respiratory center to higher sensitivity to CO2
• Relaxation of bronchial and thoracic muscles under the effect of progesterone to reduce work of breathing

Question 21

Changes in renal function during pregnancy:

A. Increase in GFR
B. Increase in RPF
C. Increase in plasma creatinine and urea levels
D. Increase in bicarbonate levels

Answer 21

Only A and B

A. due to higher RPF and lower plasma oncotic pressure

B. due to the vasodilatory effect of relaxin and progesterone + rise in CO

C. should be decrease by 40%

D. should be decrease

Question 22

Changes in urogenital system during pregnancy:

A. Dilation of ureters
B. Obstructed outflow of urine due to ureteral compression
C. Hold larger volume of urine > hydronephrosis and hydroureter
D. Increased risk of urinary tract infection (bacteriuria)
E. Decreased tone and increased residual volume of urinary bladder
F. Increase urinary frequency

Answer 22

All of the above
D: especially in the presence of glucosuria
E: smooth muscle relaxation under the effect of progesterone
F: decreased bladder capacity and incomplete voiding