Systemic changes:
Respiratory system:
Tidal volume, minute ventilatory volume, minute oxygen uptake are increased.
Functional residual capacity & residual volume of air are decreased due to elevated diaphragm.
Critical closing volume is considered to be higher in pregnancy.
Dyspnoea during early pregnancy is due to decreased pco2 because of increased tidal volume & increased respiratory effort.
Low pco2 is parelleled by low plasma Hco3 to maintain normal pH & this increase shifts the oxygen dissociation curve to the left.
Increased blood pH also stimulates an increase in 2,3dpg in maternal erythrocytes & this shifts the O2 dissociation curve to the right.
Cardiovascular system:
During pregnancy blood volume, heart rate, cardiac output, stroke volume will increase.
Blood pressure and systemic vascular resistance will decrease.
Blood volume increases about 40 to 45% above their non pregnant levels due to estrogen mediated activation of RAS(Renin Angiotensin System).
RBC mass increases by 18% & is less than the blood volume resulting in physiological anemia.
MCV(mean corpuscular volume) is the most sensitive indicator of iron deficiency.
Blood pressure:
Arterial blood pressure decreases to a nadir at about midpregnancy & rises there after.
Diastolic B.P decreases more than systolic B.P.
The antecubital venous pressure remains unchanged, but in supine position femoral pressure rises steadily.
Cardiac natriuretic peptides:
Atrial natriuretic peptide, B-type natriuretic peptide, C-type natriuretic peptide, prostaglandins: pgE2, pgI2 and endothelin are responsible for these changes.
Altered Heart sounds:
Exaggerated splitting of S1 with increased loudness of both components, no definitive changes in S2.
S3 is loud & easily heard.
Systolic murmur is present in 90% of pregnant women & disappears immediately after delivery.
Presence of diastolic murmur is pathognomonic.
All clotting factors are increased except factor 11&13.
With increased levels of high mol.wt fibrinogen complexes.
Platelet concentration is relatively decreased.
-Physiological adaptations in pregnancy - anatomical changes
-Physiological adaptations in pregnancy - weight gain, protein and fat metabolism
-Physiological adaptations in pregnancy - electrolyte and mineral metabolism
-Physiological adaptations in pregnancy - respiratory and cardiovascular systems
-Physiological adaptations in pregnancy - GIT, CNS, urinary and endocrine systems
Respiratory system:
Tidal volume, minute ventilatory volume, minute oxygen uptake are increased.
Functional residual capacity & residual volume of air are decreased due to elevated diaphragm.
Critical closing volume is considered to be higher in pregnancy.
Dyspnoea during early pregnancy is due to decreased pco2 because of increased tidal volume & increased respiratory effort.
Low pco2 is parelleled by low plasma Hco3 to maintain normal pH & this increase shifts the oxygen dissociation curve to the left.
Increased blood pH also stimulates an increase in 2,3dpg in maternal erythrocytes & this shifts the O2 dissociation curve to the right.
Cardiovascular system:
During pregnancy blood volume, heart rate, cardiac output, stroke volume will increase.
Blood pressure and systemic vascular resistance will decrease.
Blood volume increases about 40 to 45% above their non pregnant levels due to estrogen mediated activation of RAS(Renin Angiotensin System).
RBC mass increases by 18% & is less than the blood volume resulting in physiological anemia.
MCV(mean corpuscular volume) is the most sensitive indicator of iron deficiency.
Blood pressure:
Arterial blood pressure decreases to a nadir at about midpregnancy & rises there after.
Diastolic B.P decreases more than systolic B.P.
The antecubital venous pressure remains unchanged, but in supine position femoral pressure rises steadily.
Cardiac natriuretic peptides:
Atrial natriuretic peptide, B-type natriuretic peptide, C-type natriuretic peptide, prostaglandins: pgE2, pgI2 and endothelin are responsible for these changes.
Altered Heart sounds:
Exaggerated splitting of S1 with increased loudness of both components, no definitive changes in S2.
S3 is loud & easily heard.
Systolic murmur is present in 90% of pregnant women & disappears immediately after delivery.
Presence of diastolic murmur is pathognomonic.
All clotting factors are increased except factor 11&13.
With increased levels of high mol.wt fibrinogen complexes.
Platelet concentration is relatively decreased.
-Physiological adaptations in pregnancy - anatomical changes
-Physiological adaptations in pregnancy - weight gain, protein and fat metabolism
-Physiological adaptations in pregnancy - electrolyte and mineral metabolism
-Physiological adaptations in pregnancy - respiratory and cardiovascular systems
-Physiological adaptations in pregnancy - GIT, CNS, urinary and endocrine systems
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