Lecture 6 - Maternal Nutrition During Pregnancy Flashcards
pregnancy is considered a what state
anabolic state
during pregnancy, hormonal changes alter nutrient metabolism to support :
- fetal growth and development
- reproductive tissue accretion
- maternal homeostasis
what happens to basal energy expenditure (BEE) during pregnancy
increase over the non pregnant state due to added metabolism of uterus and fetus increased work of the maternal heart and lungs
what happens to the thermic effect of food during pregnancy
remains unchanged
what happens to the energy cost of physical activity during pregnancy
energy cost remains the same
what is equivalent to total energy expenditure
- basal energy expenditure
- thermic effect of food
- physical activity
what is the recommended energy intake during the first trimester of pregnancy
extra energy not required
what is the recommended energy intake during the second trimester of pregnancy
1,400kJ/day added to estimated energy requirement of non pregnant women
what is the recommended energy intake during the third trimester of pregnancy
1,900kJ/day added to estimated energy requirement of non pregnant women
what are linoleic (18:2n-6, LA) and a-linolenic acid (18:3n-3, LNA) and what are they used to make
essential fatty acids omega 3 and omega 6, used to make LCPUFA’s
what is desaturation of LCPUFAs
inserting of double bonds into the fatty acid chain
what are LCPUFAs
long chain polyunsaturated fatty acids
what is elongation of LCPUFAs
adding two carbon atoms onto the carboxyl end of the fatty acid chain
what is desaturation of LCPUFAs catalysed by
desaturase enzyme
what is elongation of LCPUFAs facilitated by
elongase enzyme
what are LCPUFAs essential for
for normal fetal development, particularly neural and visual function
endogenous synthesis of AA is far more effective than …
DHA
what is DHA (LCPUFAs)
a critical component of cell membranes, especially in the brain and retina
what is AA (LCPUFAs)
both a membrane component and a precursor to potent signalling molecules, the prostaglandins and leukotrienes (mediate inflammatory response)
how does n-3 fatty acid deposition in the developing fetal brain and retina occur
initially occurs fairly slowly and then rapidly accumulates during the last trimester
why is the fetus dependent on placental supply for both LCPUFAs and essential fatty acids
the fetus has active desaturases but limited ability to make LCPUFAs
what influences the cord blood concentrations of LCPUFAs
maternal diet
in NZ most of us get enough of what essential fatty acid but we get less of what one
most of us get enough of linoleic acid (omega 6) but we get less of a-linoleic acid (omega 3)
a rich supply of n-3 fatty acids during pregnancy is associated with what
reduced incidence of low birth weight
higher DHA and / or EPA intake during pregnancy increases
increases gestational age and heavier infants (better healthy weight)
why do maternal and fetal fatty acid requirements during pregnancy depend on maternal genetic variation in LCPUFA synthesis
because it was found FADS (homozygous minor allele) had shorter pregnancies and lighter infants
a meta-analysis found that omega-3 intake during pregnancy reduced risk of
peanut and egg allergy
what is monomethylmercury
occurs naturally in the environment and in industrial pollution accumulating in streams and seas
monomethylmercury is taken up by what
taken up by aquatic organisms and concentrated in fish
what fish have higher concentrations of monomethylmercury
higher concentrations in longer living fish such as shark, ray, swordfish etc
tuna for canning is often lower in monomethylmercury why ?
the fish are often smaller
an estimated 40% of the mercury that eventually finds its way into fish originates with …..
coal burning power plants and chlorine production plants
maternal methylmercury exposure is directly related to :
related to fish consumption
what is the concern of methylmercury
neurotoxin, large amounts can damage the developing nervous system of the fetus and delay mental development
what is the recommendation for eating longer living fish during pregnancy
less than three to four times per week
what is the recommendation for eating fish such as shark, southern bluefin tuna and trout while pregnanct
only once a week or once a fortnight
what is the most common micronutrient deficiency during pregnancy
iron
why does iron intake need to increase during pregnancy
- expansion of our maternal red blood cells (because we are developing a temporary organ)
- fetal erythropoiesis
- allow for enough blood loess that will likely occur at delivery
what is the RDI of iron for pregnant women aged 14-50 years, and how much is this an increase compared to non pregnant women
27mg/day, 9mg increase
what is the upper limit of iron intake
45mg/day
low Hb indicative of moderate or severe anaemia has been associated with an increase risk of what for the infant
- low birth weight
- small gestational age
- preterm birth
- decreased infant iron stores
- consequent impaired cognition and growth of the child
low Hb indicative of moderate or severe anaemia has been associated with an increase risk of what for the mother
- severe anaemia may increase the risk of cardiac failure or death from peripartum hemorrhage
an estimated what % of pregnant women have anaemia globally
40%
what is peripartum
occurring during the last month of gestation or first few months after delivery
what is the WHO recommendation of iron supplementation in areas of the world where this is an issue in pregnancy (this doesn’t apply to NZ)
routine iron supplements of 60mg daily for pregnant women living in areas where malnutrition is prevalent
how does iron status screening work for pregnant women in NZ
iron status at booking (<20 weeks) and 26-28 weeks gestation
how to reduce the side effects of iron medication
- start with half the dose then gradually increase
- taking the supplement in divided doses with food
what is delayed ‘optimal’ cord clamping mean and what does it improve
means changing the time of cord clamping from immediately after delivery to 1-3 minutes after delivery, this improves iron status of the infant
how much blood will be transferred from the placenta to the infant at 1 minute after birth, and at 3 minutes
about 80ml, reaching 100ml at 3 minutes
iodine is essential for the production of what
production of thyroid hormones, required for regulating the babies metabolism, for normal growth and neurocognitive development of the fetus, infant and child
severe iodine deficiency causes
intellectual disabilties
what is the RDA for iodine in non pregnant women vs pregnant
150mcg/d
220mcg/d
recommended intakes of vitamin A increase by what in pregnancy
~10%
intakes of vitamin A above 10,000 IU per day increase risk of
fetal abnormalities
what is retinoic acid syndrome
collection of birth defects including crainofacial, cardiovascular, thymus dysfunction and microcephaly
vitamin D deficiency linked to maternal health outcomes such as
- gestational diabetes
- pre eclampsia
vitamin D deficiency linked to infant health outcomes such as
- low birth weight
- dental decay
- acute respiratory infections
what is listeria and what does it cause in healthy people and pregnant people
food borne bacteria : widely distributed yet does not cause symptoms in healthy individuals, but can cause listeriosis in pregnant women and newborn infants
what does listeriosis develop as a result of
infection with listeria monocytogenes, usually from a food
what symptoms does listeriosis cause
causes influenza type symptoms and can result in premature labour and reduced fetal movements
listeria can multiply over a wide range of temperatures from …
-1.5 to 50 degrees
what temperature should you heat foods to, to minimise the risk of listeria
70 degrees
foods that are considered unsafe in terms of listeria
- uncooked, smoked or ready to eat fish or seafood
- pate, hummus
- cold - pre cooked chicken
- ham and other chilled pre cooked meats
- pre prepared or stored salads
- raw unpasteurised milk
- soft serve ice creams
- soft cheeses
what is toxoplasmosis
a parasitic disease cause by toxoplasma gondii, can cause eye or brain damage in unborn babies
toxoplasmosis infection can come from :
- eating unwashed vegetables, undercooked meat or ready to eat meat
- drinking raw unpasteurised milk
- cross contamination of coming in contact with cats or their faeces
what symptoms do pregnant women usually show when they have toxoplasmosis
a pregnant women is often asymptomatic
alcohol readily passes the what and what does this mean
alcohol readily passes the placenta such that fetal blood alcohol levels will be similar to maternal blood alcohol levels
what are the key features of fetal alcohol syndrome (FAS)
- growth deficiency of prenatal onset
- central nervous system dysfunction
- a specific pattern of facial characteristics
what are the central nervous system dysfunction related to alcohol examples include
microcephaly
delayed development
hyperactivity
attention deficits
learning disabilities
intellectual deficits
fetal alcohol spectrum disorder includes
- full FAS
- alcohol related neurodevelopment disorder
- alcohol related birth defects
full FAS is generally only present when ….
with exposure of fetus to regular heavy alcohol intake, or to very high alcohol concentrations at critical periods
what does alcohol related neurodevelopment disorder include
difficulties with mathematical skills,
difficulties with memory or attention
poor school performance
and poor impulse control and / or judgement
alcohol related birth defects includes
problems with the heart, kidneys, bones and / or hearing
packaged alcohol containing more then 1.15% alcohol requires …
to have a “pregnancy warning label”
