[09.24] Maternal Physiology_ Metabolic Changes V2

Profound metabolic changes

What kind of changes take place during pregnancy to meet the increased demands of a rapidly growing fetus and placenta?

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Increases by 10-20%

How does basal metabolic rate change during pregnancy compared to the nonpregnant state?

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10% more

How does basal metabolic rate change in twin pregnancies?

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85 kcal/day more

How much does the basal metabolic rate increase during the 1st trimester?

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285 kcal/day more

How much does the basal metabolic rate increase during the 2nd trimester?

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475 kcal/day more

How much does the basal metabolic rate increase during the 3rd trimester?

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77,000 kcal for the whole term

What is the total energy demand for the whole term of pregnancy?

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Conserving energy and doing less physically demanding activities

How do pregnant women compensate for increased energy needs?

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Accumulation of blood volume, increase in size and mass of the uterus and breasts, expansion of blood and extracellular fluid

What factors account for weight gain during pregnancy?

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Maternal reserve

What is the accumulation of water, cellular fat, and protein in the maternal tissues due to pregnancy hormones called?

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~12.5 kg or 27.5 lbs

What is the average weight gained over the whole length of pregnancy?

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1 kg/month

What is an acceptable rate of weight gain per month during pregnancy?

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Goes to the placenta, amniotic fluid, uterus, breasts, and extravascular fluid

Where does most of the weight gained during pregnancy (fluid) go?

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650 g

Around how much maternal weight gain should occur during the first 10 weeks of pregnancy?

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5 g

Around how much should the fetus weigh around the first 10 weeks of pregnancy?

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4 kg

Around how much maternal weight gain should occur around 20 weeks of pregnancy?

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300 g

Around how much should the fetus weigh around 20 weeks of pregnancy?

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8.5 kg

Around how much maternal weight gain should occur around 30 weeks of pregnancy?

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9.5 kg

Around how much should the fetus weigh around 30 weeks of pregnancy?

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10.5 kg

Around how much maternal weight gain should occur around 40 weeks of pregnancy?

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11.4 kg

Around how much should the fetus weigh around 40 weeks of pregnancy?

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Vasopressin/antidiuretic hormone (ADH)

What hormone is secreted from the posterior pituitary gland to prevent excretion of water?

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Resets osmotic thresholds for the blood plasma

What do pregnancy hormones (estrogen and progesterone) do to osmotic thresholds?

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↓ Plasma osmolality, ↑ ADH secretion, ↓ Interstitial colloid osmotic pressure, ↑Water retention

What occurs in water metabolism during pregnancy?

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Increased visible pitting edema of the legs

What is the manifestation of increased water retention?

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Fluid accumulation in the extracellular and extravascular space, increased venous pressure below the level of the rapidly enlarging uterus

What causes pitting edema?

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~3.5 L

How much water content gain goes to the fetus, placenta, and increasing amniotic fluid?

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~3.0 L

How much water is from increased maternal blood volume going to the enlarging uterus and breasts?

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9 L

If the normal blood volume of a non-pregnant person is 6 L, how much does it become in pregnant women?

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~6.5 L

What is the minimum amount of water accrued over 9 months of gestation?

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Proteins go into the creation, formation, and growth of the products of conception: fetus, placenta, growing uterus, and expanding maternal blood

Where do the proteins go to preferentially during pregnancy?

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Maternal blood

Which has less amount of protein and amino acid concentration: maternal blood or the fetal compartment?

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500 g

How much protein goes to the fetus and placenta?

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Creation of contractile proteins, breasts primarily in the glands for milk production, maternal blood as hemoglobin (from bone marrow) and plasma proteins

What is the 500 g of proteins also used for?

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Increased nitrogen balance

What increases with gestational age?

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Screener of what is essential and non-essential for the baby

What role does the placenta play in protein metabolism?

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Maternal muscle breakdown is not required to meet maternal metabolic demands

Is maternal muscle breakdown required to meet maternal metabolic demands?

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Mild fasting hypoglycemia, postprandial hyperglycemia, hyperinsulinemia

What characterizes normal pregnancy in relation to carbohydrate metabolism?

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Slight peripheral insulin resistance

What do mothers have in order to ensure that glucose proceeds to the baby?

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Increased serum glucose, insulin, and longer suppression of glucagon

What happens immediately after eating in carbohydrate metabolism?

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False results

What can random blood sugar tests on pregnant mothers result in?

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Growth hormone-like action

What kind of action does human placental lactogen have?

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Increases lipolysis and release of free fatty acids (FFA) in the blood

What is increased due to growth hormone-like action of human placental lactogen?

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Augmented lipid synthesis and food intake allow maternal fat accumulation

What happens in the early two trimesters of pregnancy in relation to fat metabolism?

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Pregnant women use fat as their main energy source in the late 2nd to 3rd trimester

When do pregnant women use fat as their main energy source?

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Triacylglycerols, cholesterol, VLDL, LDL, HDL, leptin, ghrelin

What are the elevated levels in pregnant women in the late 2nd to 3rd trimester?

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Spares glucose and amino acids for growing fetus

What is the significance of using fat as the main energy source for the mother?

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Regulates body fat content and obesity

What does leptin primarily regulate?

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Food-searching hormone

What is ghrelin also known as?

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Leptin and ghrelin increase until 2nd trimester, after which, they drop

How do leptin and ghrelin change during pregnancy?

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Na+ = 1000 mEq, K+ = 300 mEq

How much sodium and potassium is retained over the whole normal pregnancy?

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Serum concentrations of these two electrolytes are slightly decreased due to expanded plasma volume

How are serum concentrations of sodium and potassium affected by pregnancy?

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Fetal skeleton demands 30 g of calcium by term

How much calcium does the fetal skeleton demand by term?

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Doubling maternal intestinal calcium absorption mediated by 1,25-dihydroxyvitamin D3

How is the fetal calcium demand met?

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Mother’s bones will be broken down

What happens if there is a calcium deficiency in the mother?

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1000-1,200 mg of calcium per day

How much calcium intake is necessary per day during pregnancy?

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Total and ionized magnesium concentrations decline during pregnancy

How do magnesium concentrations change during pregnancy?

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Phosphate levels remain unchanged

How do phosphate levels change during pregnancy?

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Increased maternal thyroxine (T4) production, increased fetal thyroid synthesis, greater iodine excretion because of increased glomerular filtration rate (GFR) by 30-50% over the nonpregnant state

What are the reasons for increased maternal iodine requirements in pregnancy?

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Starting 10-12 weeks of gestation

When will the fetus start making thyroid hormones for its own needs?

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The basal metabolic rate increases by 10-20%

What happens to the basal metabolic rate during pregnancy?

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Accumulation in blood volume, expansion of blood and extracellular fluid, increase in size and mass of breasts and uterus

What can maternal metabolic weight gain of roughly 1kg/month be accounted for by?

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Water Metabolism wherein there is increased water retention (~6.5 L) and there is a manifestation of pitting edema, Protein Metabolism wherein the amino acid concentration is higher in the fetus than in maternal circulation, Carbohydrate Metabolism wherein the mother experiences postprandial hyperglycemia, mild fasting hypoglycemia, and hyperinsulinemia, Fat Metabolism wherein pregnant women use fat as their main energy source in the late 2nd to 3rd trimester

What does normal physiological alteration of the maternal condition include?

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Leptin and ghrelin

Which hormones have opposite functions but may work in synergy for energy homeostasis?

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Increase in sodium and potassium is followed by an increase in plasma, maintaining equilibrium for resting potentials and cellular functions

What happens after an increase in sodium and potassium?

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A mother’s bones serve as a finite source of calcium needed for a baby’s bone development, and thus a mother would need calcium supplementation to avoid excessive depletion and osteoporosis

What serves as a finite source of calcium needed for a baby's bone development?

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Increase in iodine levels, decrease in calcium and magnesium levels, unchanged phosphate levels

What are the changes in electrolyte and mineral levels during pregnancy?

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Peripheral insulin resistance

What results in postprandial hyperglycemia?

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Isotonic

How would you describe maternal blood after an influence of sodium and potassium?

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False

The basal metabolic rate decreases during pregnancy. True or False?

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Peripheral insulin resistance

Postprandial hyperglycemia results from what?

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False

Maternal weight gain should average 4kg by 40 weeks. True or False?

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Serum phosphate levels lie within the nonpregnant range

Which of the following statements regarding metabolic changes in a pregnant woman is TRUE?

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Only the second statement is true

A fall in plasma osmolarity of 10 mOsm/kg is a normal physiological alteration of the maternal condition. Other physiologic changes include increased ADH secretion and decreased interstitial colloid osmotic pressure.

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Both statements are true

During pregnancy, the maternal iodine requirement is increased to maintain euthyroidism while supplying the growing fetus with iodine before the fetal thyroid is functional. Additionally, the increased glomerular filtration rate (GFR) also contributes to greater maternal iodine requirement because of greater iodine excretion.

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Isotonic

How would you describe maternal blood after an influence of sodium and potassium?

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8.5 kg and 1.5kg

How much weight would a mother gain and the fetus’s weight during 30 weeks into a pregnancy?

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