Fetal and Neonatal circulation

Question 1

describe CO changes in the CVS during pregnancy

Answer 1

• CO increase mainly from SV but also HR
• increase mainly in 1st trimester, slightly in 2nd and 3rd trimester
• renal blood flow increases, uterine flow increases, blood flow to the heart, skin and breasts increases

Question 2

describe changes in BP during pregnancy

Answer 2

• systemic arterial pressure falls during the 1st trimester, reaches lowest point in mid pregnancy and returns to normal
• decrease in BP as a result of fall in systemic vascular resistance caused by:
  
  • gestational hormonal activity by progesterone and estradiol
  • increased heat production by the developing fetus
  • formation of low resistance circulation in the pregnant fetus

Question 3

describe hemodynamic changes during labor and delivery

Answer 3

• hemodynamics altered as a result of uterine contractions, pain and anxiety
• CO rises because of increased SV and HR
• both S and D BP increase
• postpartum: temp. increase in venous return results in a raised SV and CO
• mean BP and SV return to normal by 24 hrs after delivery