Physiology in Pregnancy Flashcards
1
Q
what mechanical changes happen in pregnancy?
A
- With weight gain, more blood flow and enlarging foetus, centre of gravity no long over feet so person leans back to avoid falling over and curves of their spine change and this is why pregnant people are more prone to back pain during and after pregnancy
- Relaxin (hormone produced during pregnancy), oestrogen and progesterone all cause increased pliability and extensibility of connective tissue. Ligamentous joints become less stable. Symphysis pubis and sacroiliac joints are particularly affected to allow birth of the baby. Normal pubic symphysial gap is 4-5mm and increases by around another 3mm in pregnancy
- Joint loosening starts as early as 10 weeks and returns to normal 4-12 weeks post partum. By term there is increased load of 2.8 times the normal value when standing
2
Q
what change sin metabolism happen in pregnancy?
A
- Basal metabolic rate increases in pregnancy to ensure foetal growth
- Pregnancy is a time of relative insulin insensitivity
3
Q
how does fatigue change in pregnancy?
A
- Hormonal changes cause fatigue, mainly in first trimester
4
Q
how does heartburn/reflux change in pregnancy?
A
- Food moves slowly in stomach and there is a delay in emptying
- Hormones cause relaxation of LOS
- General anaesthetic is high risk in pregnancy as risk of aspiration is higher
5
Q
does oedema occur in pregnancy?
A
- 80% develop some oedema due to increased sodium and water retention
6
Q
what happens to breasts in pregnancy?
A
- Increase in size, vascularity and become warm, tense and tender
- Increase pigmentation of areola and nipple and secondary areola appears
7
Q
what thyroid changes occur in pregnancy?
A
- Need more levels of iodine
- Thyrotoxicosis (overactive throid) occurs in approximately 1 in 500 pregnancies. It is most often due to Graves disease which is an autoimmune disorder
- Hypothyroidism (underactive thyroid) affects approximately 1% of pregnancies. The fetus is dependent on maternal thyroid function until fetal thyroid function begins at around 12 weeks gestation. It is important to ensure good thyroid replacement prior to pregnancy
8
Q
what happens to the immune system in pregnancy?
A
- General state of immunosuppression to allow for foetal tolerance and therefore increases maternal susceptibility to infection
9
Q
what changes occur in pregnancy to the cardiovascular system?
A
- Heart has to work harder
- People with heart conditions may suffer complications during pregnancy
- Circulating blood volume increases
- Increased CO as SV increases (amount of blood pumped out by the ventricle with each beat), also increased HR
- Increased oxygen consumption as the myocardium is working harder so it uses more
10
Q
what changes occur to the cardiovascular system postpartum?
A
- Most changes return to normal by 3rd month post delivery
11
Q
what changes happen to the respiratory system during pregnancy?
A
- Increased work and oxygen requirements
12
Q
what haematological changes occur during pregnancy?
A
- Blood volume increases by 50-70% and red cell mass by 40%
- Increase in plasma volume2-3 fold increase in iron
- Pregnancy is a hypercoagulable state. The factors which promote clotting increase, factors which reduce clotting decrease
- The risk of deep venous thrombosis in pregnancy is also increased by venodilation and reduced venous return increasing venous stasis in the lower limbs.
- Pulmonary embolus is one of the main causes of direct maternal mortality in the UK killing approximately 6-15 people per year in pregnancy or the puerperium.
- Pregnancy increases the risk of thromboembolism by 6x.
13
Q
what changes happen to the renal system during pregnancy?
A
- significant dilatation of the urinary collecting system due to relaxation of the smooth muscle of the ureter caused by progesterone as well as the mechanical compression by the growing uterus
- A physiological hydronephrosis can be seen and is usually more pronounced on the right
- Glomerular filtration rate and creatinine clearance increase by about 50% meaning that normal levels of urea and creatinine are much lower during pregnancy
- UTI more common
14
Q
- A 35 week pregnant patient collapses in the antenatal clinic. Cardiac arrest is diagnosed.
To have any chance of success what must be done prior to administering CPR?
- Baby must be delivered
- Patient must be put on a right lateral tilt
- The uterus must be manually displaced
- Patient must be moved to a labour ward as caesarean section will be required if CPR unsuccessful after 3 minutes
A
C – you will not be able to resuscitate any person with a gravid (pregnant) uterus who is lying flat because of the reduction in cardiac output this causes
15
Q
- Part of the antenatal check is a urinalysis. You notice that a patient has consistently had microscopic haematuria on the past 2 occasions. What would be your management?
- Check for urinary infection and ensure no protein in the urine. If both are negative organise an ultrasound of the renal system and if negative refer to urology urgently.
- Do nothing – because of increased renal blood flow during pregnancy there will often be traces of blood on urinlaysis.
- Check for urinary infection and if negative refer to the urologists as the patient will require cystoscopy to exclude bladder pathology.
- Check for urinary infection and ensure no protein in the urine. If both are negative and renal function normal, organise an ultrasound of the renal system and if also negative ask the GP to follow up postnatally – if haematuria is still present the patient will require referral to urology.
A
D – it is common so make sure no proteinuria, infection and renal ultrasound and function is normal and if so then the most likely cause is due to bleeding from small vessels in the dilated renal function
