Maternal Physio - Metabolic Flashcards Preview

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Flashcards in Maternal Physio - Metabolic Deck (23):
1

By 3rd trimester, maternal BMR is increased by how many percent?

10-20%

 

Note:

  • Additional 10% in women with twin gestation

2

WHO estimate of additional energy demand per trimester

  • 1st - 85 kcal/day
  • 2nd - 285 kcal/day
  • 3rd - 475 kcal/day

3

Average weight gain

Approximately 12.5 kg or 27.5 lbs

4

Weight gain

  • Normal pre-pregnancy weight
  • BMI < 19
  • BMI > 26

  • Normal pre-pregnancy weight
    • 25-35 lb
  • BMI < 19
    • 28-40 lb
  • BMI > 26
    • No more than 20 lb

 

Summary:

  • 20, 25 or 28-35 depending on BMI

5

Ideal weight gain by trimester

  • T1: 1.5-3 lb gained
  • T2 and T3: 0.8 lb/week

6

Majority of the weight gained from pregnancy comes from:

  • Fetus – 3400 g
  • Maternal stores (fat) – 3345 g
  • Blood and extravascular fluid – 2930g

7

Factors causing edema (water retention)

  • ↑ venous pressure below the level of the uterus due to compression of the vena cava and pelvic veins by the gravid uterus
  • ↓ in interstitial colloid osmotic pressure
  • fall in plasma osmolality of approximately 10 mOsm/kg induced by a resetting of osmotic thresholds for thirst; and
  • vasopressin secretion

8

The minimum amount of extra water accrued during normal pregnancy is ≈ ___ L

  • 6.5 L
    • 3.5: water content of the fetus, placenta, and amnionic fluid plus
    • 3.0: increases in the maternal blood volume and in the size of the uterus and breasts

9

Carbohydrate metabolism (insulin sensitivity and resistance)

  • In the first 20 weeks
  • After 20 weeks

  • In the first 20 weeks
    • Insulin sensitivity ↑ in first half of pregnancy
    • Lower fasting glucose levels allow for glycogen synthesis and fat deposition
  • After 20 weeks
    • Insulin resistance develops and plasma insulin levels rise
    • Higher levels of both insulin and glucose stimulate utilization of glucose and lipids for energy

10

As a result of insulin, what is a common finding in pregnant women?

  • mild fasting hypoglycemia
  • postprandial hyperglycemia
  • hyperinsulinemia

11

Why is pregnancy-induced state of peripheral insulin resistance occur?

To ensure a sustained postprandial supply of glucose to the fetus

12

Hormones that mediate postprandial hyperglycemia

  • Progesterone and estrogen
    • mediate insulin insensitivity
  • Placental lactogen
    • increase lipolysis → liberation of free fatty acids → tissue resistance to insulin

13

The optimal time to screen for glucose intolerance

26–28 weeks gestation

14

Normal pregnancy state is:

  • Hyperlipemic
  • Glycosuric
  • Anabolic

15

Concentrations of lipids, lipoproteins, and apolipoproteins in plasma

  • During pregnancy
  • After delivery

  • They increase during pregnancy
  • They decrease after delivery

16

The storage of fat occurs primarily during which stage of pregnancy?

Mid-pregnancy

 

Note: Fat storage declines or ceases during the 3rd trimester

17

Where are fats deposited and its implication? What hormone is responsible?

  • Deposition
    • mostly in central rather than peripheral sites
  • Rationale
    • it becomes available for placental transfer during the last trimester when fetal growth rate is maximal along with essential fatty acids requirements
  • Mechanism
    • progesterone acts to reset a lipostat in the hypothalamus, and at the end of pregnancy, the lipostat returns to its previous nonpregnant level, and the added fat is lost

18

Leptin

  • Disease associated with deficiency
  • Disease associated with elevation

  • Secreted by
    • Adipose tissue, placenta
  • Action
    • Play a role in body fat and energy expenditure

 

Etymology:

  • leptos - "thin" ⇒ “the hormone of energy expenditure”
  • leptin - inhibiting hunger

19

Leptin

  • Disease associated with deficiency
  • Disease associated with elevation

  • Disease associated with deficiency
    • Anovulation
    • Infertility
  • Disease associated with elevation
    • Preeclampsia
    • GDM

 

Etymology:

  • leptos - "thin" ⇒ “the hormone of energy expenditure”
  • leptin - inhibiting hunger

20

Ghrelin

  • Secreted by
  • Action

  • Secreted by
    • Stomach in response to hunger
  • Action
    • Cooperates with leptin in energy homeostasis modulation

21

How much sodium and potassium are retained in normal pregnancy? Are these increased or decreased?

  • 1000 mEq of sodium and 300 mEq of potassium
    • Decreased

22

What happens to serum calcium level during pregnancy? Describe the mechanism.

Decreased; lowered plasma albumin concentration and, in turn, the consequent decrease in the amount bound to protein

23

What happens to serum magnesium level during pregnancy? Describe the mechanism.

Decreased; pregnancy is actually a state of extracellular magnesium depletion