Session 8 - Preggers changes

Question 1

Give 6 main physiological changes in pregnacny

Answer 1

o	Cardiovascular system
o	Urinary system
o	Respiratory system
o	Metabolic changes
   	Carbohydrate
   	Thyroid hormones
o	Gastrointestinal System
o	Immune system

Question 2

What are the five main CVS changes of pregnancy

Answer 2

o	Blood volume increases
o	Cardiac output increases
o	Stroke volume increase
o	Heart rate increases
- Blood pressure DECREASES

Question 3

What causes hypotension in T1 and T2?

Answer 3

Progesterone decreases systemic vascular resistance

Question 4

What causes hypotension in T3

Answer 4

 T3 – Aortocaval compression by gravid uterus. Reduced return to the heart.

Question 5

Give four main effects of pregnancy on the urinary system

Answer 5

o Renal plasma flow increases
o Glomerular Filtration Rate (GFR) increases
 ~55%
o Filtration capacity intact
o Functional renal reserve decreases as GFR increases

Question 6

Why does urinary stasis occur in pregnancy?

Answer 6

Progesterone relaxes the smooth muscle in the walls of the ureters, which can result in stasis, hydroureter, UTIs and pyelonephritis.

Question 7

Why is pyelonephritis dangerous in pregnancy?

Answer 7

Pre-term labour

Question 8

What is the main effect of foetus on respiratory system?

Answer 8

Diaphragm is displaced

Question 9

What 7 changes occur in respiratory system?

Answer 9

	O2 consumption increases 20%
	Decreases functional residual capacity
	Vital capacity unchanged
	Tidal volume increases
	Respiratory minute volume increased
	Alveolar ventilation rate increased
	Respiratory rate unchanged

Question 10

What does progesterone generate in resp system?

Answer 10

Physiological hyperventilaton, so mother can blow off the extra CO2 the foetus produces.

This leads to respiratory Alkalosis, which the kidneys compensate for by producing and reabsorbing less bicarbonate.

Question 11

How is carbohydrate metabolism changed in pregnancy?

Answer 11

Glucose and amino acid metabolism are altered in pregnancy to favour nutritional supply to the fetus

Question 12

What does progesterone stimulate in terms of carbohydrate metabolism?

Answer 12

Progesterone stimulates appetite in the first half of pregnancy and diverts glucose into fat synthesis

Question 13

What does oestrogen stimulate in terms of carb metabolism?

Answer 13

. Oestrogen stimulates an increase in prolactin release, which, along with other hormones, generates a maternal resistance to insulin

Question 14

Why is it good to increase insulin resistance in mother?

Answer 14

More glucos for foetus

Question 15

How are mothers energy needs met later in the pregnancy?

Answer 15

etabolising peripheral fatty acids.

Question 16

What is gestational diabetes?

Answer 16

o Carbohydrate intolerance first recognised in pregnancy and do not persist after delivery
o Risks associated with poor control
 Macrosomic fetus
 Stillbirth
 Increased risk of congenital defects
o Oral glucose tolerance test required

Question 17

How do pancreatic b cells meet increased demand for insulin secretion

Answer 17

by b-cell hyperplasia and hypertrophy as well as the increased rate of insulin synthesis in the b-cell.

Question 18

Why does gestational diabetes arise?

Answer 18

In some women, the endocrine pancreas is unable to respond to the metabolic demand of pregnancy and the pancreas fails to release the increased amounts of insulin required.

Question 19

What happens to lipid metabolsim in pregnancy?

Answer 19

o Increase in lipolysis from T2
o Increase in plasma concentration of free fatty acids on fasting
 Free fatty acids provide substrate for maternal metabolism, leaving glucose for the fetus
o Increased utilisation of free fatty acids increases the risk of Ketoacidosis
 Combined with pregnancy’s state of compensated respiratory alkalosis this can be extremely bad.

Question 20

What happens to thyroid in pregnancy?

Answer 20

o Thryoid binding globulin production increased
o T3 increased
o T4 increased
o Free T4 in normal range due to increased binding globulin

o hCG has a direct effect on the Thryoid, stimulating T3 and T4 production
 TSH can be decreased in normal pregnancies as a result of negative feedback from T3 and T4 produced due to hCG secretion

Question 21

What anatomical GI changes occur during preg?

Answer 21

o Alterations in the positions of viscera

 E.g. appendix moves from RLQ to LUQ as the uterus enlarges

Question 22

What physiological GI changes occur in preg?

Answer 22

o Smooth muscle relaxation by Progesterone
 GI – Delayed emptying
 Biliary tract – Stasis
 Pancrease – Increased risk of pancreatitis

Question 23

What happens to blood in preg?

Answer 23

o High amount of fibrin deposition at the site of implantation
 Increased fibrinogen and clotting factors
 Reduced fibrinolysis
o Stasis, venodilation

Question 24

Why is pro-thrombotic state sometimes disease causing?

Answer 24

o Results in Thromboembolic disease in pregnancy

 Cannot give warfarin – Crosses the placenta and is teratogenic

Question 25

How does anaemia occur in preg?

Answer 25

o Plasma volume increases
o RBC mass also increases, but not to the same degree
o Physiological anamiea
 Not a true anaemia, just a mismatch between volume and haemocrit

o Anaemia due to iron and folate deficiency can also occur

Question 26

Why doesn’t mother attack foetus immunologically?

Answer 26

o Non-specific suppression of the local immune response at the materno-fetal interface

Question 27

Why is thyroid disease dangerous in perg?

Answer 27

o Graves disease and Hashimoto’s Thyroiditis
 Antibodies will cross the placenta and either stimulate TSH receptors on or destroy developing fetal thyroid respectively.

Question 28

Give three methods of antenatal screening

Answer 28

o	History and examination
   	Risk factors – E.g. for gestational diabetes
o	Blood test
   	Blood group
   	Haemoglobin
   	Infection
o	Urinalysis
   	Protein

Question 29

What is pre-eclampsia?

Answer 29

Normal Pregnancy
o Vasodilated
o Plasma-Expanded
o Blood pressure not raised in normal pregnancy

Pre-Eclamptic Pregnancy
o	Vasoconstricted
o	Plasma-Contracted
o	Raised blood pressure
o	Proteinuria
o	Pitting oedema

Question 30

Outline what you discussed with Alex in terms of alveolar ventilation

Answer 30

Respiratory rate does NOT increase to blow off CO2.

Instead, alveolar ventilation rate increases due to tidal volume increase.

Question 31

Define alveolar ventilation

Answer 31

(Tidal volume - Dead Space) * Respiratory Rate