Cardiac output maximum in pregjtancy-
Ans. is 'c1 i.e., 32 weeks Cardiac Output in pregnancyo The cardiac output starts to increase from the 5th week of pregnancy: reaches its peak 40 - 50% at 30 - 34 weeks.o Thereafter the cardiac output remains static till term when the observation is made at lateral recumbent position.o Cardiac output is lowest in the sitting or supine position and highest in the right or left lateral or knee chest position.Hemodynamic change in pregnancyo Blood volume is markedly raised. Starting to increase at 6 weeks & reaching max 40-50% above the nonpregnant level at 30-32 weeks.o Plasma volume is also increased. Starting to increase at 6 weeks & reaching max upto 50% at 30 weeks. Total plasma volume increases to the extent of 1.25 litres.o RBCs & Hb RBC mass increases upto 20-30% & volume increase is about 350ml. The disproportionate increase in plasma & RBC volume produces a state of hemodilution. Thus even though there is increase in the total mass of Hb but fall in concentration upto 2%.o Leucocytes & immune system Leucocyte count increases upto 10-15,00/mm3. Innate & humeral response increases.o Total protein Total plasma protein increases but due to hemodilution plasma protein concentration falls. Normal A:G ratio of 1:7 is diminished to 1:1.o Blood coagulation factors Pregnancy is a hypercoagulable state. Fibrinogen level is raised by 50%.ESR is raised. Platelet count is either static or decreases. Gestational thrombocytopenia is due to increased consumption. Increased activity of X, IX. VIII, VII & I. Level of XI & XIII are decreased. Levels of coagulation factors normalises 2 weeks postpartum.Cardiovascular systemo Anatomical changes Heart is pushed upwards & outward. Apex beat is shifted in 4th intercostals space. A systolic murmur can be heard in apical or pulmonary area. Mammary murmur is a continuous hissing murmur audible over tricuspid area in left 2nd & 3rd intercostals space. ECG showrs left axis deviation. S3 and rarely S4 can be beard,o Cardiac output Starts to increase from 5th week of pregnancy, reaches its peak 40-50% at about 30-34 weeks. It is lowest in sitting or supine position & highest is the right or left lateral or knee chest position. CO further increases by 50% duimg labour and immidiatly following delivery. CO returns to pre labour values by one hour following delivery and to the pre-pregnant level by another 4 weeks.o Blood pressure Systemic vascular resistance (SVR) decreases. Maternal BP is decreased.o Venous pressure Femoral venous pressure is raised,o Supine hypotension syndrome (postural hypotension)o Regional distribution of blood flow Uterine blood flow is increased from 50 ml per minute in non-pregnant state to 750m! near term. Pulmonary blood flow is increased by 2500 ml /minrenal blood flow- increases by 400ml/min. The blood flow through skin and mucous membrane increases by 500ml/min.
24 weeks
36 weeks
32 weeks
38 weeks
Cardiovascular System