L5 Physiological Changes During Pregnancy Flashcards
What are some physiological changes that occur during pregnancy (X9)? Originally thought to be harmful and attempted to treat the symptoms.
- Increased organ weight
- Increased respiratory rate
- Increased urinary output
- Increased heart rate & stroke volume
- Increased blood volume & RBC
- Increased blood lipids
- Increased insulin resistance
- Increased BMR
- Relaxed GIT muscle tone
When and what is the maternal anabolic phase?
The building up of mother’s body to supply the increased needs of the fetus and infant.
0-20 weeks
When does 10% of fetal growth occur?
During the maternal anabolic phase.
When and what is the maternal catabolic phase?
20 weeks - birth
The delivering of stored energy & nutrients to grow the fetus.
When does 90% of fetal growth occur?
Maternal catabolic phase
What physiological changes occur in the anabolic phase (X4)?
- Increased blood volume, growth of maternal organs (uterus, liver, kidney)
- Increased fat, glycogen, nutrient stores (ie. zinc)
- Increased appetite, decreased exercise tolerance (due to hormones)
- Increased anabolic hormones (ie. insulin)
What physiological changes occur int the catabolic phase (X4)?
- Mobilization of mother’s stores
- Accelerated fasting metabolism
- Increased appetite and food intake (declines near term) and exercise tolerance
- Increased catabolic hormones (ie. glucagon > decreases insulin sensitivity)
What is the best predictor of a baby’d health at birth?
Birth weight
In underweight mothers, what is the total weight gain expected to be in pregnancy and how much in the 2nd, and 3rd trimester per week?
- 28-40 lbs (12.5-18 kg)
- 1 lb per week (0.5 kg)
In healthy weight mothers, what is the total weight gain expected to be in pregnancy and how much in the 2nd, and 3rd trimester per week?
25-35 lbs (11.5-16 kg)
1 lb per week (0.5 kg)
In overweight mothers, what is the total weight gain expected to be in pregnancy and how much in the 2nd, and 3rd trimester per week?
15-25 lbs. (7-11.5 kg)
0.6 lb. per week (0.3 kg per week)
In obese mothers, what is the total weight gain expected to be in pregnancy and how much in the 2nd, and 3rd trimester per week?
11-20 lbs (5-9 kg)
0.5 lbs per week (0.2 kg per week)
About 58% or 6.5kg much of maternal weight gain is from what?
Extra blood, fluids, protein, breasts, and energy stores?
About 42% or 6.5 kg of maternal what gain is from what?
Uterus, placenta, baby, amniotic fluid
Maternal weight gain doe snot establish causation of fetal weight gain. What are some factors that can contribute to a fetus’ weight gain (X3)?
Nutrient availability, placental transfer capacity, fetal growth factors, ect.
Is the overall energy balance positive or negative during pregnancy? By about how much throughout pregnancy?
Positive
80,000kcal (mostly in the 2nd and 3rd trimester)
What are the increased energy requirements used for?
- Increased maternal tissue (breast, uterine, placenta, fat)
- Fetal tissue
- Energy cost of metabolic needs of new tissue (increased BMR)
- Increased cost of physical activity.
What are the 3 possible adaptive responses to achieve positive energy balance in pregnancy?
- Increase intake
- Decreased energy expenditure
- Metabolic adaptations
How does the BMR change in healthy weight women?
BMR increases (particularly later)
How does the BMR change in underweight women?
BMR decreases (so not to compromise fetal growth)
How does the BMR change in overweight women?
A greater increase in BMR (about 20%) to offset further fat accumulation.
What are the increased energy recommendations during the second and 3rd trimester?
How many servings are recommended
2nd = 340 kcal/day
3rd = 452 kcal/day
2-3 servings per day
When is hCG secreted and what is it’s purpose? Does it effect the maternal metabolism?
Within days of implantation and maintains the corpus luteum.
Has little effect on the metabolism.
What is the role of hPL in maternal metabolism during pregnancy?
Effects CHO and lipid metabolism, and mediates insulin resistance (similar to GH).
What is the role of estrogen in maternal metabolism during pregnancy?
Influences reproductive organs increases binding hormones, and influences macronutrient and bone metabolism.
What is the role of progesterone in maternal metabolism?
Relaxes the smooth muscle especially in the GI and the urinary tract (takes urine longer to transit through the GI tract to increase absorption).
With and increase in the placenta size, there is also an increase in this hormone secretion?
hPL - human placental lactogen
At what point in the pregnancy is there a spike in the hCG secretion?
10th week
At what point in pregnancy does progesterone, hPL and estradiol peak?
End of pregnancy - about week 38-40.
What changes occur in early pregnancy around CHO metabolism?
Increased insulin secretion by hPL to increase the conversion of glucose to glycogen and fat for storage.
Insulin sensitivity is higher than in late pregnancy.
What changes occur in late pregnancy around CHO metabolism?
A maternal insulin resistance develops.
- Increased insulin secretion by hPL but decreased sensitivity of maternal tissues so there is less glucose taken up by the cells.
- Maternal tissues are fueled by non-glucose fuels (lipolysis). Hormonally mediated. Gestational diabetes is difficult to differentiate bc of insulin sensitivity.
- Increases glucose production (glycogen, glycerol)
What does the hPL hormone do in CHO metabolism?
Increases insulin secretion, decreases insulin sensitivity, increases hepatic glucose production (gluconeogenesis).
All to make sure there is more glucose for the fetus.
What is the CHO RDA for pregnant women and in non-pregnant women?
non-pregnant = 130 g/d pregnant = 175 g/d
About how many kcals are stored in the anabolic phase?
35,000 kcal
What happens to fat metabolism in early pregnancy?
*how is cholesterol used?
Estrogen, progesterone, and insulin favour fat deposition and inhibit lipolysis (insulin sensitivity is higher and encourages fat storage).
There is an increase in TG, f.a., cholesterol, and phospholipids.
*some cholesterol used by placenta for steroid synthesis and fetus for nerve and membrane. Fetus has own cholesterol production.
What are the levels (mmol/L) of cholesterol in the 1st, 2nd, and 3rd trimester?
5.78, 6.88, 8.14
What are the levels (mmol/L) of TG in the 1st, 2nd, and 3rd trimester?
1.19, 1.32, 2.58
What happens to fat metabolism in late pregnancy?
hPL favours maternal lipolysis and mobilization of fat stores.
There is an increase in fat oxidation as an energy source. Glucose and amino acids are conserved for fetus uptake.
There is also and increase in fetal uptake of f.a.
What is the increase in AI for essential fatty acids during pregnancy?
What are the recommendation for types of fats?
Linoleic acid: 12 g/d - 13 g/d
Linolenic acid: 1.1 g/d - 1.4 g/d
Get most fats from polyunsaturated, limit saturated fats, and eliminate trans fats
What are 2 essential f.a. that are important for fetal and neural and visual development?
AA and DHA
What is the recommendation for DHA/day for pregnant women?
about 200mg
What are some issues with with DHA?
There is a low conversion rate (about 5%) of linolenic acid to DHS. A good source is fish but needs to be limited in pregnancy becasue of heavy metal toxicity.
What is the recommended servings of fish for pregnant woman?
What are some types of recommended fish?
2-4 servings per week of fish or shellfish with low methyl mercury.
ie. Atlantic herring, mackerel, Alaskan Pollock, salmon, haddock, sardines, anchovies, shrimp, oysters, clams, scallops, canned light tuna
What happens to protein metabolism in pregnancy?
There is a gradual adaptation of protein metabolism with increased nitrogen retention in late pregnancy.
- decreased amino acid oxidation and urea synthesis & excretion, and an increased transfer of amino acids to the fetus
What is the protein RDA in non-pregnant and pregnant women?
non-pregnant = 0.8 g/kg/d pregnant = 1.1 g/kg/d (only recommended in the 2nd and 3rd trimester)
What is an RQ value?
A measurement of fuel utilization (CO2 produced/O2 consumed).
What is the RQ of a pregnant woman?
What would be the RQ for a woman are the end of pregnancy?
0.87
would it be less than that?
There is an increase in ____ for micro nutrients during pregnancy but not an increase in _____.
Need
Recommendations
What are the folate RDA for pregnant, and non-pregnant women?
UL?
Supplementation?
Non-pregnant RDA = 400 ug/day
Pregnant RDA = 600 ug/day
UL (synthetic folic acid only) = 1000 ug/day
Supplementation = 400 ug synthetic folic acid/d
Why is there an increased need for iron during pregnancy?
There is an increase in the utilization of iron - 500mg to increase RBC mass - 315 mg for fetal/placental use - basal loss of 250 mg (an average of about 1065 mg needed)
What are the normal amounts of iron in the 1st, 2nd, and 3rd trimester?
1st and 3rd = >110 g/l
2nd = >105 g/l
What are the maternal risks of iron deficiency in pregnancy?
Fatigue, decreased work performance, impaired resistance to infections, poor tolerance to blood loss.
What are the fetal risks of iron deficiency during pregnancy?
- 2-3 X increased risk of preterm delivery/low birth weight
- Lower intelligence, language, gross motor, attention tests (likely from deficiency in late pregnancy)
- Low iron stored to fetus, risk of iron deficiency anemia
Explain iron absorption during pregnancy.
The larger the dose = less absorption
Less absorption when taken with food or other supplements
Increasing absorption as pregnancy progresses
What is the EAR for iron in the third trimester?
Break down
- 0.9 mg/d for basal loss
- 2.0 mg/d for fetus/placenta
- 2.7 mg/d for RBC expansion
total = 5.6 mg/d
Based on a 25% abortion rate, what is the RDA and the EAR for pregnant women?
EAR = 22 mg/d = 5.5 mg absorbed RDA = 27 mg/d = 6.75 mg absorbed
What is the Health Canada recommendation for iron supplementation throughout pregnancy?
16-20mg
Why is calcium and vitamin D important for fetal development?
Maintenance of maternal bones and skeleton.
The RDA for calcium and vitamin D for pregnant and non-pregnant is the same. What are they?
Calcium = 1000 mg/d
Vitamin D = 600 IU/d (in northern latitudes 2000 IU supplementation is recommended).
Where is vitamin A deficiency a concern?
Deficiency is a concern in developing countries. Toxicity is a concern in underdeveloped countries.
What is the RDA for vitamin A during pregnancy?
What is the safest source of vitamin A?
770 ug RAE/d
Beta-carotene
How can a woman meet all of her micronutrient needs?
The recommended servings from the Canada Guide food groups plus 2-3 extra servings from any food group and a supplement containing 0.4 mg folic acid and 16-20 mg of iron. Veg and fruit - 7-8 servings Grains - 6-7 Milk & Alt. = 2 Meat & Alt = 2
What are some common questions about diet diet during pregnancy?
Can caffeine, artificial sweeteners, herbal products be consumed?
Can nutrient needs be obtained with a vegetarian diet?
If overweight of obese, is weight loss ok?
Do food cravings and aversions negatively affect nutritional intake?
What foods are not safe to eat during pregnancy?
Is exercise safe?
Can caffeine, artificial sweeteners, herbal products be consumed?
Caffeine is generally recommended to avoid but some is ok.
About 100mg with a MAX of 300mg/d
Artificial sweeteners are safe especially if they have diabetes. Mostly a concern bc it could be an indication of the types of foods they are eating.
Cyclamates NOT recommended.
Safety of many herbal products are unknown. The following are generally considered safe in moderation: ginger, peppermint leaf, orange peel, rose hip, red raspberry leaf
Can nutrient needs be obtained with a vegetarian diet?
Yes but must consider protein, and iron intake.
B12 supplementation may be required
If overweight of obese, is weight loss ok?
Weight loss is not recommended bc it limits nutrient availability, promotes ketone formation (growth and impaired cognitive function).
Fasting metabolism is accelerated during pregnancy - ketones and glucose occurs more quickly. Should not go more than 12 hours without meal or snack.
Do food cravings and aversions negatively affect nutritional intake?
Food consumption from the food groups is encouraged not from the “other” foods.
What foods are not safe to eat during pregnancy?
Foodborne illness is more likely to affect the fetus (listeriosis, toxoplasosis, salmonella, E. coli).
Generally recommend to avoid raw foods and follow food safe preparations. (ie. sushi, raw dough, some salad dressings, unpasteurized dairy.
Is exercise safe?
Has benefits:
- maintenance of fitness
- promotion of appropriate weight gain
- provide strength for labour
- may also help prevent gestational diabetes and hypertension
Should ensure adequate energy and fluid intake but avoid over-exertion and high risk activity.
What is a screening tool that a woman can do before exercising while pregnant?
PAR-med-X
- provides guidelines for frequency, intensity, time, type of activity
- heart rate ranges, based on age, fitness level or BMI
