Physiological Changes During Pregnancy Flashcards

1
Q

What are the major physiological changes that occur with pregnancy?

A
  • ↑organ weight
  • ↑respiratory rate
  • ↑urinary output
  • ↑heart rate & stroke volume
  • ↑blood volume & RBC
  • ↑blood lipids
  • ↑insulin resistance
  • ↑BMR
  • relazed GIT muscle tone (fart more)
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2
Q

What are the phases of physiological changes during pregnancy?

A
  • maternal anabolic phase: 0-20 weeks
  • maternal catabolic phase: 20 weeks-brith
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3
Q

What happens in the maternal anabolic phase?

A

“building up” of mother’s body to supply increased needs of fetus and infant so a lot of extra energy goes to mom here first
* ↑ blood volume, growth of maternal organs
* ↑ fat, glycogen, nutrient stores
* ↑ appetite, decreased exercise tolerance
* ↑ anabolic hormones

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4
Q

How much fetal growth occurs in the maternal anabolic phase?

A

10%

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5
Q

What happens in the maternal catabolic phase?

A

Delivering stored energy and nutrients to the growing fetus
* mobilization of stores
* accelerated fasting metabolism
* increased appetite and food intake (declines near term) and exercise tolerance
* increased catabolic hormones

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6
Q

What drive the maternal catabloic phase?

A

the placenta

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7
Q

What is the single best predictor of
a baby’s health at birth?

A

Birth Weight

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8
Q

What is an indicator related to an infants birth weight?

A

weight gain in mother is related to infant birth weight
* link between optimal weight gain and optimal health

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9
Q

What is the gestational weight gain for different weight categories?

A
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10
Q

What is the weight gain expected for the first, second and third trimesters?

A
  • 1st trimester: ~0.5 to 2kg, little weight gain expected
  • 2nd & 3rd trimester: ~0.4 kg/week healthy weight
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11
Q

Where does the added weight go?

A
  • metabolic changes (~58%)
  • things to support baby (~42%)
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12
Q

What are the metabolic changes associated with weight gain?

A
  • extra blood, fluids and protein
  • breasts and energy stores
  • uterus
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13
Q

What things to support the baby contrinute to weight gain?

A
  • placenta
  • baby
  • amniotic fluid
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14
Q

What is healthy weight gain during pregnancy?

A

Weight gain within the guidelines is associated with the best pregnancy outcomes and reccommendations should be a weight range for all pregnant women and should be monitored

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15
Q

Where are some considerations for weight gain?

A

subsets of populations
* adolescents
* multiple pregnancy

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16
Q

What is the risk of low or excessive gestational weight gain on fetus/infant?

A

low or high birth weight

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17
Q

What is the risk low or excessive gestational weight gain on the mother?

A
  • nutritional status
  • gestational diabetes
  • pre-enclampsia
  • complications during pregnancy
  • post-partum weight retention
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18
Q

What is the association vs. causation of maternal weight gain and infant weight gain?

A

Association between maternal weight gain and infant birth weight does NOT mean that maternal weight gain CAUSES fetal weight gain
* Fetal weight gain is compilation of many different factors – nutrient availability, placental transfer capacity, fetal growth factors, etc.

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19
Q

What is the overall energy balance during pregnancy?

A

positive energy balance of 80,000 kcal over the course of pregnancy

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20
Q

What is energy required for?

A
  1. Increases in maternal tissue: breast tissue, uterine muscles, placenta, fat stores
  2. Fetal tissues
  3. Increased BMR to meet new energy “cost” of metabolic needs of new tissue
  4. Increased cost of physical activity: carrying more
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21
Q

What are the adaptive responces to achieve positive energy balance?

A
  1. Increased intake
  2. Decreased energy expenditure
  3. Metabolic adaptations
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22
Q

Energy balance in pregnancy for healthy weight women

A

BMR increases throughout pregnancy (particularly later)

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23
Q

Energy balance in pregnancy for underweight women

A

decreased BMR
* may allow continuation of pregnancy, but compromise fetal growth

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24
Q

Energy balance in pregnancy for overweight/obese women

A

Greater increase in BMR (about 20%) to offset further fat accumulation

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25
Q

Kcal recommendations during 2nd and 3rd trimesters

A

Additional servings: 2-3/day
* 2nd: 340 kcal/d
* 3rd: 452 kcal/d

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26
Q

How is appropriate intake monitored?

A

Weight gain during pregnancy

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27
Q

What hormones play a key role in pregnancy?

A
  • human chorionic gonadotrophin (hCG)
  • human placental lactogen (hPL)
  • estrogens
  • progesterone
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28
Q

Role of hCG?

A

human chorionic gonadotrophin
* secreted within days of implantation
* maintains corpus luteum
* little effect on metabolism

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29
Q

Role of hPL

A

human placental lactogen
* effects on carbohydrate and lipid metabolism
* mediates insulin resistance
* fetal/placental growth factor?
* only around when there is the placenta

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30
Q

Role of estrogens

A
  • influences reproductive organs, ↑binding hormones
  • influence macronutrient and bone metabolism
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31
Q

Role of progesterone

A
  • relaxes smooth muscle (GI, urinary tract)
  • Results in some of the exercise intolerance as it acts on muscles and bones
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32
Q

How do hCG, hPL, estrogen and progesterone change throughout pregnancy?

A
  • hCG rises rapidly to 10 weeks then rapidly declones
  • hPL, estrogen and progesterone rise throughout
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33
Q

What is the CHO metabolism in early pregnancy?

A

mediated through estrogen and progesterone
* enhanced insulin secretion
* glucose → glycogen synthesis and fat storage

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34
Q

What is the purpose of the CHO changes?

A

To maintain availability of glucose for the fetu
* fetal energy use is preferentially glucose

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35
Q

How does hPL mediate CHO metabolism?

A
  • insulin secretion
  • insulin sensitivity
  • hepatic glucose production
36
Q

Describe CHO metabolism later in pregnancy

A

maternal insulin resistance
* ↑ insulin secretion, but decreased sensitivity of maternal peripheral tissues so less glucose uptake by tissues
* glucose production (glycogen, glycerol)

37
Q

What does the mother use for fuel later in pregnancy?

A

fatty acids
* hormonally mediated preferential use of non- glucose fuels (lipolysis) by maternal peripheral tissues

38
Q

How does the RDA change for CHO with pregnancy?

A

Increased RDA (minimum amount) from 130 g/d to 175g/d with the extra 45 going toward the infant

39
Q

Why should pregnant women consume regular small CHO meals?

A

Regular small CHO meals are important because pregnant women reach fasting levels faster which may result in ketone production which may be toxic to babe.

40
Q

How much fat gets stored in the anabolic phase?

A

fat storage is ~35,000 kcal to 20 weeks

41
Q

Describe fat metabolism during early pregnancy

A

Anabolic: Estrogen, progesterone and insulin favour fat deposition and inhibit lipolysis
* ↑ levels of triglycerides, fatty acids, cholesterol, phospholipids
* some cholesterol used by placenta for steroid synthesis and fetus for nerve and membrane

42
Q

How do cholesterol and triglyceride levels change during pregnancy?

A

both rise from non-pregnancy and throughout

43
Q

Describe fat metabolism in late pregnancy

A

Catabolic: hPL favours maternal lipolysis and mobilization of fat stores
* fat oxidation as an energy source conserves glucose and amino acids for fetus
* fetal uptake of fatty acids also occurs

44
Q

What fatty acids are important for fetal development?

A
  • linoleic acid
  • 𝝰-linolenic acid
45
Q

What are the fat recommendations for pregnancy

A

Recommendations for total fat and types of fat not different from non-pregnancy but small increases in AI for LA and ALA
* LA: 12 g/d to 13 g/d
* ALA: 1.1 g/d to 1.4 g/d

46
Q

What are the important LA and ALA essential fatty acids?

A

AA and DHA important fatty acids for optimal fetal neural and visual development

47
Q

When are AA and DHA transferred to fetus?

A

preferentially transferred to fetus later gestation
* concentration in serum will be higher in fetus than in the mom

48
Q

What is the issue with DHA?

A
  • Conversion of linolenic to DHA is low (~5%)
  • Good source of DHA is fish but need to be warry for mercury
49
Q

Reccomendation of DHA/d

A

Pregnant women should aim for ~200mg DHA/day
* Recommendation is 2-4 servings per week of fish or shellfish with low risk of methyl mercury contamination

50
Q

What are the fish to avoid?

A

Atlantic herring and mackeral, Alaskan pollock, salmon, haddock, sardines, anchovies, shrimp, oysters, clams, scallops, canned light tuna

51
Q

Describe protein metabolism during pregnancy

A

Gradual adaptation of protein metabolism with increased nitrogen retention in late pregnancy so more protein synthesis
* ↓ amino acid oxidation
* ↓ urea synthesis & excretion - ↑excretion of other N wastes (due to ↑GFR)
* transfer of amino acids to fetus

52
Q

What are the reccomended changes in protein RDA?

A

mostly changes in the 2nd and 3rd trimester to 1.1 g/kg/d (71 g/d)
* from 0.8 g/kg/d (46 g/d)

53
Q

What is RQ?

A

Respiratory qoutient used as a measurement of fuel utilization - CO2 produced/O2 consumed

54
Q

What would the RQ of a pregnant woman (including the fetus) be at the end of pregnancy?

A

higher
* Maternal and fetal because a lot more glucose being used. Even though she is relying on lipids she is conserving more glucose for baby and that supersedes.

55
Q

How do the micronutrient needs change during pregnancy?

A

All micronutrients are important during pregnancy and fetal development
Increased need for micronutrients but not an increase in recommendations for all

56
Q

What are key micronutrients to consider during pregnancy?

A
  • folate
  • iron
  • vitamin D
  • Calcium
  • Vitamin A
57
Q

Folate reccomendations

A

Pregnancy RDA is 600µg/d of which 400µg synthetic folic acid/d and the other 200µg from food
* non-pregnant is 400µg/d
* UL of folic acid is 1000µg/d

58
Q

What is the need for iron in pregnancy?

A

An average of ~1065mg during pregnancy needed (with variation in each component) with increased utilization:
* 500 mg to increase RBC mass
* 315 mg for fetal/placental use
* in addition to 250 mg for basal loss (non- menstruating adult women)

59
Q

How is iron status assessed?

A

Physiological increase in plasma volume as well as RBC means hemoglobin concentrations changes throughout pregnancy with hemodilution effect mostly 10-20 weeks
* >110 g/l during 1st and 3rd trimesters
* >105 g/l during the 2nd trimester (maximum volume increase)

60
Q

Maternal risks of iron deficiency during pregnancy

A
  • fatigue, decreased work performance, impaired resistance to infections
  • poor tolerance to blood loss
61
Q

Fetal risks to iron deficiency during pregnancy

A
  • 2-3 x ↑ risk of preterm delivery/low birth weight
  • lower intelligence, language, gross motor, attention tests (5 years)
  • low iron stores to fetus, risk of iron deficiency anemia
62
Q

Problems with iron supplementation

A
  • The larger the dose, the less the absorption
  • Less absorption when taken with food, or other supplements
  • Increasing absorption as pregnancy progresses
63
Q

interpret the graph

A

The greater the dose if iron the less absorption but the small percentage of a higher dose may still be better

64
Q

Average iron needs in 3rd trimester

A

5.6mg/d absorbed iron
* 0.9 mg/d absorbed iron for basal lost
* 2.0mg/d absorbed iron for fetus/placenta
* 2.7mg/d absorbed iron for RBC expansion

65
Q

DRIs for iron during pregnancy

A
  • EAR: 22 mg/d = 5.5 mg absorbed
  • RDA: 27 mg/d = 6.75 mg absorbed iron
66
Q

Recommendations for iron supplement

A

Health Canada recommends supplementation of 16-20 mg iron throughout pregnancy
* higher amounts if maternal iron deficiency present

67
Q

Role of Calcium and vitamin D

A

Maintenance of maternal bones and skeletal development of fetus

68
Q

DRI reccomendations for Calcium and vitamin D

A

RDAs and same as for non-pregnant
* Calcium: 1000 mg/d (enhanced absorption, taken from maternal bones but quickly replaced)
* Vitamin D: 600 IU/d (15 µg/d)

69
Q

What is the supplement recommendation for vitamin D?

A

Canadian Paediatric Society: consideration
of 2000IU supplement during pregnancy

70
Q

Vitamin A DRIs during pregnancy

A

RDA pregnancy 770 ug RAE/d
* Vitamin A deficiency a concern in developing countries; in developed countries Vitamin A toxicity is a concern
* Beta-carotene safer source of vitamin A

71
Q

What are the 2007 food guidelines for pregnant women?

A

+ 2-3 servings from any group
* Vegetables & Fruit: 7-8 servings
* Grain Products: 6-7 servings
* Milk & Alternatives: 2 servings
* Meat & Alternatives: 2 servings

72
Q

What should a supplement contain?

A

Supplement containing 0.4 mg folic acid and 16-20 mg of iron is recommended

73
Q

Caffeine recommendations

A

Maximum 300mg/d
* 250ml coffee: 40-180mg,
* 250 mL tea: 10-110mg
* 355ml Cola drink: 30-60mg
* 56g dark chocolate: 50mg

74
Q

artificial sweetener reccomendations

A
  • Aspartame, acesulfame-potassium, sucralose, saccaharin and stevia considered safe (usually found in nutrient poor foods though)
  • Cyclamates not recommended
75
Q

Recommendations of herbal productions

A
  • Safety of many herbal products unknown
  • Generally considered safe in moderation: ginger, peppermint leaf, orange peel, rose hip, red raspberry leaf
76
Q

considerations with vegetarianism during pregnancy

A

A healthy pregnancy can be supported by a vegetarian diet but takes more pre-planning and careful though into nutrients at risk
* adequate energy and weight gain
* protein and iron intake
* B12 supplementation may be required

77
Q

Why is weight loss not reccomended during pregnancy?

A
  • limits nutrient availability
  • promotes ketone formation which may reduced fetal growth and impaired cognitive function
78
Q

What occurs with accelerated fasting metabolism during pregnancy?

A

ketone formation and low blood glucose occurs more quickly
* Important to have regular small CHO snacks

79
Q

What are common cravings and aversions?

A
  • cravings are dairy and sweets → encourage consumption of food from the food groups (not “other foods”)
  • aversions are alcohol, caffeine, meats so may need to consume other protein/iron rich foods
80
Q

Foods to avoid during pregnancy

A

General principles of food safety and avoidance of raw food that may causes food borne illness
* Listeriosis, toxoplasmosis, salmonella, E. coli

81
Q

Benefits of regular physical activity during pregnancy

A
  • maintenance of fitness
  • promotion of appropriate weight gain
  • provide strength for labour
  • may also help prevent gestational diabetes and pregnancy induced hypertension
82
Q

physical activity considerations for pregnant women

A
  • Ensure adequate energy and fluid intake
  • Some limitations to type of activity → avoid over-exertion and high risk activity
83
Q

What hormone might result in intolerance to PA at the start of pregnancy?

A

progesterone

84
Q

What screening tool is used to determine PA readiness during pregnancy?

A

PAR-med-X for Pregnancy
* Contraindications
* Guidelines for exercise based on ‘FITT’
* Heart Rate Ranges

85
Q

What are the FITT guidelines?

A

Found on PARmed-X
* frequency
* intensity
* time
* type of activity

86
Q

What are the heart ranges based on for the PAR-med-X?

A

Based on age, fitness level or BMI