Module 2: Pregnancy III

Question 1

when does embryogenesis occur?

Answer 1

0 to 8 weeks gestation
first 2 months of pregnancy

Question 2

embryogenesis overview

Answer 2

Egg is fertilized → zygote is formed (within 24 hours of fertilization) → cleavage
woman might not know she is pregnant yet

Question 3

embryogenesis stages in order

Answer 3

1. cleavage
2. blastulation
3. implantation
4. gastrulation
5. neurulation

• growth and development of the fetus
• 0 to 8 weeks

Question 4

embryogenesis stage 1: cleavage

Answer 4

zygote cleaved into 2 blastomeres

Question 5

embryogenesis stage 2: blastulation

Answer 5

morula divides to form blastocyte (has inner cell mass)

Question 6

embryogenesis stage 3: implantation

Answer 6

6-7 days after fertilization
blastocyte penetrates endometrium
we begin to have a difference between inner cell mass and trophectoderm

Question 7

embryogenesis stage 4: gastrulation

Answer 7

embryo forms blastula (layer of epithelial cells) which reorganizes into gastrula

Question 8

embryogenesis stage 5: neurulation

Answer 8

neural plate turns into neural tube

this will later form brain and spinal cord (CNS)
This allows for organogenesis
Tissues begin differentiated, we get different cell types
Folate is key in neurulation

Question 9

week 4 major step

Answer 9

heart does “practice beatings” (no heartbeat is heard yet)
The practice/testing happens so if things are not working correctly the pregnancy can self-terminate

Question 10

week 5

Answer 10

Week 5: we see more organ systems (still no heartbeat on ultrasound)

Question 11

which stage has more growth, fetal or embryo?

Answer 11

fetal stage

Question 12

at what week is embryo considered a fetus

Answer 12

week 9

Question 13

when does fetal development occur?

Answer 13

8 to 38/40 weeks gestation

Question 14

why does water decrease in fetus from 30 to 40 weeks

Answer 14

increase in fat and protein mass
More deposition of lean body mass, muscles grow and develop
Fat mass is very important to neonatal period
Babies with not enough fat mass end up in the NICU to control their body temperature

Question 15

fetal development characteristics

Answer 15

We see increases in weight with each phase of pregnancy
We see primitive sperm or egg cells
After midway through pregnancy we see calcification of skeleton
Towards end of pregnancy we see deposition of many nutrients
Growth declines a bit near term

Question 16

critical periods of development

Answer 16

finite periods during development in which certain events occur that will have irreversible effects on later developmental stages

Question 17

key critical periods in fetus

Answer 17

during early embryonic period and embryogenesis (much more than fetal period)

Question 18

critical periods of development overview

Answer 18

Differentiation: cellular acquisition of one or more characteristics or functions different from that of the original cell
We make a lot of cells, and then get rid of the ones we don’t need
We want to start with too many rather than two few

Question 19

maternal factors that influence fetal growth

Answer 19

1. micronutrient availability
   - vitamin D
   - antioxidants
2. inflammation and oxidative stress
3. vasoconstriction
4. hormone activity
   - thyroid
   - glucocorticoids
5. metabolic function

Question 20

placental factors that influence fetal growth

Answer 20

1. implantation
2. growth
   - mitochondrial function
   - epigenetic regulation
3. nutrient transfer
   - transporters
   - oxygen gradient
4. hormone activity
   - placental hormones
   - regulation of hormone transfer

Question 21

fetal growth factors

Answer 21

1. epigenetics
2. organ toxicity
3. hormone activity

Question 22

consequences of inadequate nutrition during fetal development

Answer 22

small for gestational age (SGA)
large for gestational age (LGA)
intrauterine growth restriction (IUGR)

Question 23

small for gestational age (SGA)

Answer 23

newborn weight is <10th percentile for gestational age
dSGA: Normal head size, smaller body and limbs
Proportionally SGA (pSGA): long-term risk factors

Question 24

large for gestation age (LGA)

Answer 24

weight for gestational age exceeds the 90th percentile for gestational age or birthweight >4500g

Question 25

variations in fetal growth are linked to

Answer 25

Energy, nutrient, and oxygen availability
Conditions that interfere with genetically programmed growth and development
Insulin-like growth factor (IGF-1) is the main fetal growth stimulator

Question 26

What effects do preterm birth have on growth and development?

Answer 26

<37 weeks
11.4% of infants born in the US in 2013 were preterm
Greater risk of death, neurological problems, and congenital malformations
Born without adequate stores of nutrition
Infants born preterm are at risk for death, neurological problems, congenital malformations, and chronic health problems

Question 27

preterm birth risk factors

Answer 27

Multivitamin supplements or folate intake decrease risk
One to three fish meals per week are protective
Underweight and obesity increase risk
Elevated blood lipids increase risk

Question 28

What effects do birth weight have on growth and development?

Answer 28

Desirable birth weight: 3500-4500 g (seven pounds and twelve ounces to ten pounds)
Less likely to develop heart and lung diseases, diabetes, and hypertension
Reduces infant mortality and morbidity

Question 29

what are the only nutrients we don’t need more of in pregnancy?

Answer 29

Vit D and calcium
BUT, many women are deficient so we must make sure they meet normal levels
if not, vit D and caclium can be leached from bones

Question 30

folate deficiency can lead to

Answer 30

neural tube defects

Question 31

folate and neural tube defects

Answer 31

*When neural tube doesn’t close, you end up with neural tube defects
Anencephaly: open brain and lack of skull vault
Encephalocele: herniation of the meninges (and brain)
Spina bifida occulta: closed asymptomatic NTD in which some of the vertebrae are not completely closed

Question 32

folate

Answer 32

Involved in DNA replication
Gene expression
Amino acid metabolism
Recommended intake:
RDA for women of child bearing age 400 mcg/day
RDA for pregnancy is 600 mcg/day
Upper limit is 1000 mcg/day

Question 33

iodine

Answer 33

Neurocognitive development
Recommended intake:
RDA for women of child bearing age and pregnancy is 220 mcg
Upper limit is 1110 mcg

Question 34

choline

Answer 34

Replenish maternal stores
Development of brain and spinal cord
Recommended intake:
RDA for women of child bearing age and pregnancy is 450g

Question 35

iron needs during pregnancy

Answer 35

ron: need increases substantially
300 mg for fetus and placenta
250 mg lost at delivery → need to make sure we have this stored
450 mg for increased red blood cell mass

Question 36

anemia in pregnancy

Answer 36

~23% of pregnant women in developed countries
1 in 10 US pregnancies; 1 in 4 during 3rd trimester
Common causes: increased demands, change in dietary patterns, poor nutrition
Consequences: compromised growth, cognitive function, and immunity
Mortality in mothers and babies
Pre-term birth

Question 37

iron function

Answer 37

Fetal hemoglobin has “gamma” which has an increased affinity for oxygen so it will favor it more during the prenatal period (aka in the womb). Adult hemoglobin has the “beta” which has decreased affinity for hemoglobin and is lower in the prenatal period but gets higher in the postnatal period after the baby is born since the fetus takes up so much of the oxygen.

Iron can compromise growth, cognitive function, and immunity and leads to mortality and pre-term birth. Need more during pregnancy because of fetal/placental needs and increased RBC mass.

Question 38

iugr

Answer 38

relationship of size and gestational age

Question 39

What is preterm? What are some of the consequences?

Answer 39

< 37 weeks

Greater risk of death, neurological problems, and congenital malformations – also means born without adequate stores of nutrients

Question 40

What is preterm? What are some of the consequences?

Answer 40

< 37 weeks

Greater risk of death, neurological problems, and congenital malformations – also means born without adequate stores of nutrients

Question 41

What are the effects of alcohol use during each trimester?

Answer 41

First trimester
Reduce cell growth: in CNS
Second trimester
Higher risk of miscarriage (in absence of alcohol, miscarriage rate decreases in second trimester)
Third trimester
Long-term neurological effects
Birth defects

Question 42

Describe the characteristic features of fetal alcohol syndrome:

Answer 42

Most severe
Abnormal facial features
Growth problems
CNS abnormalities
Problems with social skills, learning, memory, attention span, communication, vision, or hearing

Question 43

Describe the characteristic features of fetal alcohol syndrome:

Answer 43

Most severe
Abnormal facial features
Growth problems
CNS abnormalities
Problems with social skills, learning, memory, attention span, communication, vision, or hearing

Question 44

issue with alcohol

Answer 44

Alcohol can cross the placenta. The fetus will have reduced ADH capacity, which increases the harmful effects of alcohol on the fetus. This leads to birth defects, intellectual disability, and developmental disorders.