Physiological changes in pregnancy

Question 1

How much weight will a woman roughly put on?

What happens to blood pressure?

Answer 1

• 10-15kg
• drop in Peripheral vascular resistance leads to drop in BP by 15%
• returns to normal later in pregnancy due to increased blood volume

Question 2

What cardiovascular changes are there?

Answer 2

• 40% increase in total body water and plasma volume
• EPO increases, but not as much as blood volume leading to physiological anaemia of pregnancy (10.5d/dl)
• Na+ and H20 retention due to oestrogen stimulation of RAAS

Question 3

What happens to coagulation?

what is the risk of VTE in pregnancy?

Answer 3

• increased clot formation due to higher levels of factors
• decreased clot lysis due to increased plasminogen activator inhibitors (placenta)
• increased protein C and S resistance
• 5x risk of VTE

Question 4

What are the respiratory changes?

Answer 4

• increased 02 consumption due to foetal demands
• 40% increase in tidal volume, more alveolar ventilation
• RR and VC stay same
• increased PaC02 sensitivity of chemoreceptors, increase respiration but result in disproportionate sense of dyspnoea

Question 5

Renal changes?

Answer 5

• increased blood flow due to rise in CO and blood volume
• increased GFR, but urea and creatinine lowered due to same level of production
• bladder capacity decreases so increased micturition, tendency towards UTIs

Question 6

GI changes?

Answer 6

• Altered appetite: cravings
• lower oesophageal pressure and incompetence of cardia
• decrease motility, gastric emptying transit time and increased H20 reabsorption
• consequences: NVP, constipation, reflux