Theme C Lecture 1

Question 1

What is the greatest physiological challenge facing women? Why?

Answer 1

Pregnancy,

It is a dynamic process with adaptations to anatomy, physiology, biochemistry, and metabolism.

Higher cardiac output and blood volume is required maintain uteroplacental perfusion and to maintain fetal demands.

Question 2

What are the metabolic changes that affect pregnant women?

Answer 2

Weight Gain

Altered body shape

Increase in uterus and breat size

Increase in blood volume

increase in maternal stores

Ideal weight gain - 10 - 13 kgs

Increase in metabolic rate, oxygen consumption, and fat stores

Question 3

Why is it important for babies to be breastfed from their mother rather than someone else?

Answer 3

As the fetus grows the breasts grow in a complementary way to accommodate the baby’s needs when he is born and breastfeeding.

Question 4

What is the primary source of energy for fetal and placental growth?

Answer 4

Glucose

Question 5

What happens to insulin resistance and blood sugar during pregnancy?

Answer 5

Hypoglycaemia occurs despite insulin resistance.

Question 6

What happens to insulin levels and what are the adaptations that accomodate that?

Answer 6

Insulin levels rise and pancreatic beta cells proliferate and grow.

Question 7

What happens to blood levels during delivery?

Answer 7

Blood is lost during delivery (500 - 600ml vaginal delivery. 800 - 1200 ml caesarian delivery)

Question 8

What happens to blood volume during pregnancy?

Answer 8

an increase in blood volume occurs very rapidly and begins at 6 weeks and peaks 32 weeks into pregnancy.

Question 9

How much of the increased blood volume is due to an increase in plasma volume and red blood cells? How does this occur?

Answer 9

Plasma volume = 40 - 50%

Red Blood Cells = 25 - 30%

This occurs via an increase in red blood cell production and erythropoetin production.

Question 10

What is the side effect of the rapid increase in blood volume?

Answer 10

Physiological anemia and hemodilution. This is because the increase in volume is quicker than the increase in rbc count. For some women the effect is a drop in iron levels and deficiency (this causes a decrease in blood viscosity)

Question 11

What happens to white blood cell count during pregnancy?

Answer 11

It increases by about 25 - 30% in the first trimester and plateaus in the second and third.

Question 12

What happens to platelet levels during pregnancy?

Answer 12

They get diluted in the increased plasma volume. This effect is seen in most plasma proteins and is the cause for increased edema.

Question 13

What happens to cholesterol levels in pregnant women?

Answer 13

They increase dramatically (40%) to increase production of steroid hormones.

Question 14

How does the body ensure that a woman doesn’t loose too much blood during delivery?

Answer 14

Increase in blood flow is associated with increase in coagulation to decrease blood loss during delivery.

Question 15

What are the output adaptations of the heart?

Answer 15

Left Ventricular Hypertrophy: This causes an increase in cardiac output and occurs when there is an increase in stroke volume (from 8 weeks), heart rate (from 5 weeks), and fluid retention

Question 16

What happens to BP during pregnancy?

Answer 16

During the first trimester BP drops and is at its lowest between 24 and 32 weeks.

Decrease is mostly due to drop in diastolic BP rather than systolic BP.

Question 17

Why does diastolic BP drop in pregnant women?

Answer 17

Progesterone and prostaglandins relax the blood vessels and in turn decrease the overall vascular resistance to direct the blood to the uteroplacental circulation.

Question 18

What is the effect of renin-angiotensin2 in pregnant women?

Answer 18

There is an increase in their concentrations but the effect is refractory and doesn’t increase the overall blood pressure.

Question 19

Fact

Answer 19

Some women experience something called supine hypotension. (read more about it to consolidate memory)

Question 20

What is the ECF?

Answer 20

intravascular plasma and extravascular interstitium compartment fluid

Question 21

What organs are important in maintaining ECF volume?

Answer 21

The kidneys because they have volume and pressure sensors to detect deviations from the ECF set point.

Question 22

What happens to ECF set point during pregnancy?

Answer 22

It is reset and so as a result there is an alteration of Renal Blood Flow (RBF), Glomerular Filtration Rate (GFR), and sodium+water excretion to maintain stable BP and to support the increased blood volume.

Question 23

What happens to RBF during pregnancy?

Answer 23

It increases by 40 - 80%

Question 24

What happens to GFR during pregnancy?

Answer 24

It increases by 30 - 50%

Question 25

What is creatinine clearance rate and what is it used for?

Answer 25

Volume of blood plasma cleared of creatine per unit time. It is a great measure of GFR.

Question 26

What happens to kidney size during pregnancy?

Answer 26

The kidney and glomerular vessels hypertrophy.

Question 27

What happens to urine production during pregnancy?

Answer 27

It increases due to increase in filtration.

Question 28

What is hemodilution?

Answer 28

Dilution of blood. This often occurs as a result of a mismatch between blood volume increase and RBC production.

Question 29

What happens to Na+ and water in the kidneys during pregnancy?

Answer 29

Renal tubules retain Na+ and water to maintain the blood/plasma volume.

Question 30

What is teh function of the placenta in the fetus?

Answer 30

Placenta is a substitute for fetal organs such as the lungs, kidneys, and the GI tract.

Question 31

How does oxygen go to and from the placenta?

Answer 31

Umbilical cord brings oxygenated blood via the umbilical vein. Deoxygenated blood goes through 2 umbillical arteries that branch into chorionic blood vessels within chorionic villi. Maternal blood bathes chorionic villi.