Pregnancy: physiological changes

Question 1

Cardiovascular system

Answer 1

SV up 30%, HR up 15% & cardiac output up 40%

Question 2

BP

Answer 2

systolic BP is unaltered

diastolic BP is reduced in the 1st and 2nd trimester, returning to non-pregnant levels by term

Question 3

interfere with venous return is due to what

Answer 3

enlarged uterus

Question 4

interfere with venous return results in

Answer 4

Ankle oedema, supine hypotension and varicose veins

Question 5

Respiratory system

Answer 5

Pulmonary ventilation up by 40%, tidal volume from 500 - 700ml (due to effect of progesterone on respiratory centre)

Question 6

Oxygen requirements increase by

Answer 6

only 20%

Question 7

over breathing leads to

Answer 7

fall in pCO2 - this can give rise to a sense of dyspnoea that may be accentuated by elevation of the diaphragm

Question 8

BMR increases by?

Why?

Answer 8

15% - this may be due to increased thyroxine and adrenocortical hormones -

Question 9

women may find warm/cold conditions uncomfortable

Answer 9

warm

due to raised bmr

Question 10

Maternal blood volume

Answer 10

up 30%, mostly in 2nd half - red cells up 20% but plasma up 50% Hb falls

Question 11

coagulant activity

Answer 11

Low grade increase in coagulant activity
rise in fibrinogen and Factors VII, VIII, X
fibrinolytic activity is decreased - returns to normal after delivery (placental suppression?
Platelet count falls

Question 12

WCC & ESR rise/fall

Answer 12

rise

Question 13

Salt and water reabsorption is increased by what?

Answer 13

elevated sex steroid levels

Question 14

Urinary system

Answer 14

blood flow increase by 30%
GFR increases by 30-60%
Salt and water reabsorption
Urinary protein losses increase

Question 15

Calcium

Answer 15

Calcium requirements increase during pregnancy
especially during 3rd trimester + continues into lactation
calcium is transported actively across the placenta
serum levels of calcium and phosphate actually fall (with fall in protein)
ionised levels of calcium remain stable
Gut absorption of calcium increases substantially - due to increased 1,25 dihydroxy vitamin D

Question 16

hepatic blood flow doesn’t change

Answer 16

true

Question 17

Hepatic biomarkers

Answer 17

ALP raised 50%

Albumin levels fall

Question 18

Uterus weight changes

Answer 18

100g → 1100g

Question 19

Uterus is hyerplastic in pregnancy

Answer 19

hyperplasia → hypertrophy later

Question 20

increase in cervical ectropion & discharge

Answer 20

true

Question 21

What are Braxton-Hicks contractions

Answer 21

non-painful ‘practice contractions’ late in pregnancy (>30 wks)

Question 22

Effect of uterus retroversion

Answer 22

retroversion may lead to retention (12-16 wks), usually self corrects