1
Q
What are the main functions of the placenta
A
- provides oxygen and nutrients and
- removes carbon dioxide and wastes to and from fetus
- produces hormones to promote the pregnancy
2
Q
when does the placenta begin to form?
A
at implantation and by day 17 the maternal-placenta-embryonic circulation is on place for when the fetal heart starts to beat
3
Q
what does the placenta act as?
A
its a barrier - blood cannot pass through but other substances can that can harm the developing fetus
4
Q
what are the 2 protein hormones the placenta secretes?
A
- human chorionic gonadotropin (hCG) and human chorionic somatomammotropin (hCS)
5
Q
what are the 2 steroid hormones the placenta secretes
A
- estrogen and progesterone
6
Q
what are the metabolic functions of the placenta
A
respiration, nutrition, excretion, and storage
7
Q
how many veins and arteries does the umbilical cord have
A
one vein to bring blood to fetus and 2 arteries to bring wastes back to mom
8
Q
what surrounds the umbilical vein and arteries
A
Whartons jelly
9
Q
what are the 2 fetal membranes
A
- chorion and amnion
- form at time of implantation
10
Q
how does the chorion develop
A
- develops first from trophoblasts
- little hair like projections called chorionic villi burrowing into the decidua basalis (uterine lining)
11
Q
what is the amnion
A
- inner cell membrane
- smooth membrane lies closer to the embryo and develops into the cover for the umbilical cord
12
Q
how does the ‘bag of waters’ form
A
- when the chorion and amnion merge together to form the fetal sac containing amniotic fluid and the developing fetus
- protects against infections
13
Q
when does amniotic fluid start to produce
A
- around 10-12 weeks when the fetuses kidneys function
14
Q
how much amniotic fluid is normal at term
A
- 700-800ml
15
Q
oligohydramnios
A
- less than 300ml by term
- associated with fetal renal anomalies and growth restriction
16
Q
polyhydramnios
A
2L or more
- associated with neural tube defects, GI, fetal anomalies
17
Q
how is amniotic fluid measured
A
- ultrasound
- measuring the depth of pockets of fluid surrounding the fetus
18
Q
what colour is normal amniotic fluid
A
- pale, straw-like, certain door that is foul, and contains dissolved solids
19
Q
what is the amniotic fluids important functions:
A
- maintains constant temp
- equalizes pressure (feats, placenta, umbilical cord)
- protects from infection
- allows freedom of movement
- provides fluid
- repository for fetal waste
- aids in effacement, dilation of cervix
20
Q
Human chorionic gonadotrophin function
A
- preserves function of corpus lutes, ensures continued supply of estrogen and progesterone needed to maintain pregnancy
21
Q
Human placental lactogen
A
- stimulates metabolism for nutrients for fetal growth
- transports glucose across placental membrane
- stimulates breast development
22
Q
progesterone
A
- maintains endometrium
- decreases contractility of uterus
- stimulates development of breast alveoli and maternal metabolism
23
Q
estrogen
A
- stimulates uterine growth and blood flow
- proliferation of breast glandular tissue
24
Q
what does fetal growth refer to
A
- increasing in number of fetal cells in early pregnancy and then increase in cell size in later pregnancy
25
fetal development refers to
- functional and structural changes that occur in fetal organ systems
- development starts at the head (cephalocaudal)
- differentiation of the cells and tissues
- organization of cells and tissues into organ systems
- cell growth
26
how to determine gestational age
- last menstraul period
- pregnancy tests
- ultrasound
27
organogenesis
- organs and structures form and begin to function within 18 weeks
28
how is fetal growth measured
- by measuring symphysis fundal height (SFH), at 20 weeks is when SFH should be 20cm and should follow that curve until term
29
when does fetal growth happen the most?
- development mostly occurs within the first 18weeks and after that is when the fetus focuses more on growing (400g-3400g at 40 weeks) - average of 120-220g a week
30
what fetal development occurs at 0-2 weeks
- ovum (pre embryonic)
- conception to implantation when fertilized egg differentiates into different specialized cells
31
what fetal development occurs at 2-8 weeks
- embryonic
- embryo is starting to turn into a fetus
- organogenesis occurs, heart beats, has large head and distinct arms/legs and joints
32
fetal development at 9-40 weeks
- fetal
- week 14 placenta is fully formed
- fetal organs continue to mature
- significant increase in weight
33
what are the 5 features of fetal circulation:
- oxygen needs are low
- placenta is organ for gas exchange
- fetal brain and heart get highest O2 needs
- lungs are hypo perfused and fluid filled
- right-to-left shunting (foramen ovale, and ductus arteriosus)
34
fetal oxygen needs are low due to:
respirations, thermoregulation, digestion are done with placenta
- arterial pO2 is 30mmHg (relative hypoxemia)
- keeps pulmonary vasoconstricted - lungs hypo perfused and ductus Art. patent
35
how does the fetal circulation divert blood with highest oxygen content to the brain and heart?
- ductus arteriosus and foramen ovale
36
describe right to left shunting in the fetal circulation
- blood enters ductus venousus and inferior vena cava, blood is then shunted right to left via foreman ovale from right to left atrium (high pulmonary pressure to low pressure), blood that stays in right atrium and flows to pulmonary artery is then shunted through ductus arteriosus into low pressure aorta
37
what is a teratogen
- substance or exposure that causes abnormal development
38
TORCH
- toxoplasmosis
- Other
- Rubella
- Cytomegalovirus
- Herpes
39
what is considered a toxoplasmosis and what can it do to the developing fetus
- parasite transmitted through raw/undercooked meat/seafood, drinking unpasteurized milk, contaminated soil, cat faces
- prevent by using gloves, hand washing
- infant develops chorioretinitis, cognitive and developmental impairment, hearing loss
40
Examples of 'Other'
- syphillis, varicella, Hep virus, HIV
41
what happens to the baby with syphilis?
- deformities to growing fetus
- all women should be screened
42
Varicella
- in early pregnancy, limb hypoplasia, fetal death, damage to CNS, eye abnormalities
43
Hep virus
- neonates are given immunoglobulin at birth if parents are positive
- not considered teratogenic
44
HIV
- biggest threat to infants
- given antiretroviral treatment during pregnancy
- not considered teratogenic
45
what does Rubella do to fetuses
- lower the gestational age the greater risk the fetus is in
- recommend moms take rubella vaccine and wait a month before trying
46
cytomegalovirus (CMV)
- miscarriage, stillbirth, congenital cytomegalic disease
- most common congenital viral infections in America
- at birth: rash, petechiae, jaundice, hepatosplenomegaly, IUGR, microcephaly, chorioretinitis, intracerebral calficications
47
Herpes
- very rare
- transmission occurs during birth
-
48
what is the most common pathological origin of FGR
placental dysfunction
49
what are the risks with FGR
- stillbirth, neonatal mortality, morbidity
50
how to diagnose the type of FGR is by:
- fetal weight for gestational age and topple velocimetry
51
what are some short term benefits of preconception care include:
- reduce number of preterm births
- decrease number of unintended pregnancies
- lower risk of genetic disorders/environmental exposures
- reduce maternal/neonatal mortality
- improve maternal/child health outcomes
NSPN 7100
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