Nutrition and Pregnancy Flashcards
significant increase in DNA content (cell number) before birth (undernourished children had decreased increase), levels off after birth; Protein content (cell size) continually increases before and after birth
Human brain
Liver increases throughout life, Kidney increases after birth but stops at about 3-4 months
Tissue DNA content (cell size)
->only carbohydrate transported across the placenta by facilitated diffusion
(concentration greater on the mother’s size)
Glucose
- > transported as acetyl CoA and free FA across the placenta
- > species differences in ease of transport
-> in humans the main source of this for fetuses is glucose
Fat
-> cross by pinocytosis
(small section of maternal cells is swallowed into vacuole and released into cell on fetal side)
-> the rate is inversely proportional to square root of MW for:
~albumin
~fibrinogen
~gamma-globulins
~transferrin
-> GH, insulin and TSH DO NOT cross (protects)
-> fetus gets 10-15% of daily requirement from drinking amniotic fluid
(fetuses with swallowing difficulties suffer growth retardation)
Proteins
> cross by active transport
- > concentration is highest on fetal side
- > only L type cross, NOT D
AA
more surface area causes increased weight of fetuses -> obese mothers have highest placental weight
Placental size
the fattest fetus at birth of all species
Humans
first the mother increases levels, fetus will increase levels after a delay then exponentially
Fat
5g more protein, 0.8MJ more energy 30mg more of ascorbic acid, 700mg more of calcium, 3 more mg of iron
Daily dietary requirements for pregnancy in 3rd trimester
actually need more than during pregnancy of protein and energy (same for ascorbic acid, calcium and iron)
Lactation
optimal BMI for conceiving children
20-26
key to pregnancy nutrition -> basic principles during pregnancy are the same -> it is likely to provide the micronutrients needed, it should include enough portions of fruits and vegetables
Eating a balanced diet
no increase in the first trimester -> 300 increase per day in 2nd and 3rd trimester, increase should come from nutrient dense foods -> need for increase depends on physical activity, age and weight
Calories
most of the energy will come from this source, mostly complex starch -> whole grain foods are good because they are high in B vitamins and high in trace minerals such as zinc, selenium, chromium, magnesium
Carbohydrates
required for hyperplasia and hypertrophy of maternal tissues and to meet fetal needs
- > intake for pregnancy is about 70 g/day
- > greatest demand during the last half of pregnancy when the fetal growth is greatest
Protein
essential fatty acids are important for infant growth, especially omega 3 and omega 6 FAs (DHA) -> seafood is good source of protein and iron and omega 3 which helps baby’s brain development
Fat
women should not consume these fish because of potential damage to baby’s developing nervous system -> swordfish, shark, king mackerel, tilefish
Mercury
deficiency can cause neural tube defects
Folic acid
deficiency can cause anemia and hemorrhage
Iron
deficiency can cause cretinism
Iodine
deficiency can cause anemia and low birth weight
Zinc
deficiency can cause neonatal hypocalcemia, poor infant bone formation
Vitamin D
deficiency can cause hemorrhage
Vitamin K
deficiency can cause anemia, anencephaly, low birth weight
Copper
caused by incomplete development of the brain and spinal cord and/or their protective covering -> spina bifida is most common (also anencephaly and encephaloceles) -> no cures
Neural tube defects
spine fails to close properly during first few weeks of pregnancy causing damage to the nerves and spinal cord -> severe cases can result in full or partial paralysis and other problems such as hydrocephalus, bowel and bladder problems and learning disabilities
Spina bifida
strong evidence that this supplement will prevent NTD’s -> need 400 micrograms/day for all woman in childbearing age,
- > 1000 micro g/day in pregnant women (MAX),
- > 4mg/day in women with history of Neural tube defect deliveries
- > should take supplement 1 month prior to conception and during first trimester
Folic acid
needed during pregnancy due to increased maternal blood volume -> good stores before pregnancy protect against deficiency anemias (increases risk of preterm delivery and low birth weight) -> a 30mg supplement/day is recommended during the 2nd and 3rd trimester (about twice normal)
Iron
- > increased need can be met through changes in metabolism during pregnancy
- > resulting in increased absorption and release from bones
- > appears to be replaced after pregnancy in women who have adequate intake of this and vitamin D
Calcium
1.4 to 2.2kg weight gain
1st trimester
0.5kg weight gain per week
2nd and 3rd trimester
11-14kg (distributed)
- > 5 for fetus/placenta/amniotic fluid, -> 1 for uterus,
- > 2 for increased blood volume,
- > 1.5 to breast tissue
- > 1.5-2.5 maternal fat stores
Average weight gain during pregnancy
underweight = 13-18Kg normal = 11-14, overweight = 9-11, obese = at least 7, twins = 16-21kg
Recommended weight gain
metabolic rate drops if low maternal nutrition -> mothers become more efficient at metabolizing fat (don’t have a lot to use in malnourished areas)
Fetal growth is protected against malnutrition
carries risks such as gestational diabetes and high blood pressure (however, pregnancy is no time for dieting)
Excess weight
not necessary during pregnancy as long as a balanced diet is maintained -> except for maybe iron, folate, vitamin D + DHA
BUT note: Vit D supplement recommendation for pregnant and gen. pop is the same
Nutritional supplements
mix cereals with legumes to get extra proteins -> may be need for supplements, especially iron, vitamin B12 and vitamin D
Vegetarian Diets
significant increase in stillbirths, premature babies, neonatal deaths, low birth weight babies and a significant decrease in mean birth weight all together (but still average more than 2.5kg -> incredible capacity of mother to protect fetus from malnutrition)
During famine
varies in response to energy intake -> additional adaptations in Gambian women = reduced diet induced thermogenesis and reduced activity (decreased basal metabolic rate in the mother’s tissues)
Energy cost of pregnancy
adjusts to protect the fetus when food is in short supply -> long term consequences?
Maternal metabolism
will only be effective if there are situations compromising fetal growth (ex. malaria) -> will significantly help undernourished with hemoglobin levels and birth weight -> extra energy is beneficial but extra protein can have negative effects
Food supplement
