MATERNAL PHYSIOLOGY

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MATERNAL PHYSIOLOGY

• TOSSY SANDERS
• JULY 6, 2005

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Cardiovascular System

• Blood volume
• Plasma volume-45 increase, max _at_ 32w
• RBC mass- 30 increase
• Physiologic anemia
• Anatomic changes
• Ventricular wall muscle mass end diastolic
  volume increase
• Softening of collagen
• Cardiac output
• 30-50 increase to 6L/min
• Heart rate- 15-20 beats/minute by 32wks
• Posture
• Selective distribution of CO- increase to uterus,
  kidneys, skin, breast

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Cardiovascular System

• Blood Pressure
• Peripheral vascular resistance
• Symptoms of normal pregnancy
• Dyspnea
• Decreased exercise tolerance
• Signs of normal pregnancy
• Peripheral edema
• Heart sounds
• PMI displaced to left
• CXR
• EKG

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Cardiovascular System

• Intrapartum hemodynamics
• 1st stage 12-31 rise in CO
• 2nd stage 49 rise in CO
• Postpartum hemodynamics
• 80 vs. 60 increase in CO

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Kidneys Urinary Tract

• Kidneys
• Lengthen by 1cm
• 30 increase in weight
• Ureters
• Dilation is mechanical hormonal
• RL
• Clinical consequences
• Increased incidence of pyelonephrosis
• Difficulty interpreting radiographs
• Interference with studies of renal blood flow,
  GFR, tubular function

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Renal Function

• Plasma flow
• 2nd tri increases 75
• 3rd tri 50 above prepregnancy rates
• GFR increases by 50
• Creatnine clearance increases 150-200 ml/min
• Decrease in BUN, creatnine, uric acid

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Renal excretion of nutrients

• Sodium net reabsorption
• Potassium net retention
• Calcium net excretion
• Glucose excretion increases 10-100 fold
• Proteins unchanged

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Respiratory System

• Nose
• Thoracic cage
• Lung volume capacities
• Respiratory rate- unchanged
• Vital capacity- unchanged
• Inspiratory reserve volume- unchanged
• Inspiratory capacity- increased 5
• Tidal volume- increased 30-40
• Functional residual capacity- decreased 20
• Expiratory reserve volume- decreased 20
• Residual volume- decreased 20
• Total lung capacity- decreased 5

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Respiratory System

• Gas exchange
• Minute ventilation increases 30-40
• Oxygen consumption increases 15-29
• Compensated respiratory alkalosis
• Drop in PaCO2 facilitates CO2 transfer from fetus
  to mother
• Dyspnea of pregnancy (60-70)
• Etiology not well understood

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Gastrointestinal

• Appetite dulled sense of taste
• Nonpregnant- 2200kcal
• Pregnant- 2400kcal
• Lactating- 2800kcal
• IBW- 25-35lbs
• Underweight- 28-40 lbs
• Overweight- 15-25 lbs
• Mouth
• Ptyalism- may lose 1-2L/day decrease starch
• Pyogenic granulomas- pedunculated lesions
• Stomach
• Progesterone decreases tone motility
• GERD- decreased sphincter tone _at_ GE junction
• Decreased gastric acid secretion increased
  mucus, decreased incidence of peptic ulcer
  disease

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Gastrointestinal

• Small bowel
• Decreased motility
• Absorption of nutrients unchanged iron
• Colon
• Constipation- mechanical, motility, absorption
• hemorrhoids
• Gallbladder- increased gallstones
• Increased biliary cholesterol saturation
• Decreased proportion of chenodeoxycholic acid
• Liver (changes may mimic liver disease)
• Normal changes- spider angiomata, palmar
  erythema, reduced serum albumin, elevated alk
  phos, elevated cholesterol
• N/V Pregnancy (70)
• Starts _at_ 4-8wks lasts til 14-16wks
• Tx reassurance avoidance of trigger fooods
• Hyperemesis- weight loss, ketonemia, eletrolyte
  imbalance, dehydration

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Skin

• Vascular changes- increased estrogen
• Spider angiomata
• Palmar erythema
• Vascular spiders
• Connective tissue- striae gravidarum (50)
• Initially pink/ purple then white/silver
• Genetic predisposition
• Not secondary to weight gain
• Pigmentation- increased due to estrogen,
  progesterone, alpha melanocyte stimulating
  hormone (nipple,umbilicus,axillae, perineum,
  linea)
• Melasma- forehead, cheeks, nose lip brunette
  blonde
• Nevi- preexisting nevi may enlarge, darken
• Hair
• 30 in telogen phase postpartum- hair loss
  2-4months pp

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Hematologic

• Leukocytes- increase due to increased PMNs
• 1st tri mean 9.5
• 2nd 3rd tri mean 10.5
• Labor mean 20-25
• Platelets- decrease throughout pregnancy due to
  increased destruction (9.2d vs. 9.7d)
• Plasma volume
• RBC mass

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Coagulation

• Increase- fibrinogen, factors I,VII-X
• Same- PT, V, XII, bleeding time, clotting time
• Decrease- Plt, XI, XIII
• Thromboembolism
• RR 1.8 during pregnancy
• RR 5.5 during puerperium