Pregancy/Labour

Question 1

What are the timelines of pregancy (mother/child/placenta)-summary

Answer 1

mother-changes alltrhough out
Child-Embryo, fetus (before 13 weeks)-viability after 26, term near the end
1st trimester-13weeks-most things go wrong there
2nd-26weeks is earliest baby could come out

placental-COMPLEX-but mostly in the 1st half

Question 2

What are the changes that occur in the mothers body during pregancncy

Answer 2

first 22 weeks-very hard to tell mother is pregnant-belly barely shows
Increase in girth at abdomen, change in spine angle

Short list of things that are altered and which term most likely to start
short list-increase weight (3rd), inc blood volume (2nd), lower BP (2nd), 
altered brain (1st), hormones (1st) appetite (1st), fluid balance (2nd), emotional (1st), joints (3rd), immune system-(1st)

first 2 trimerster-little risk on mother
but delivery can be bad

Question 3

How do maternal hormones changes during pregancy?

Answer 3

First 10 weeks-peak of HCG-human coryonic gonadotrophin-produced by placenta–starts rising before even end of period. Lower levels during rest of pregancy
In very early pregnancy-peak similar to ovulation
Long linear rise of progesterone, oestrogens and placental lactogen (nearly 100X levels of ovulation)

Question 4

What is conceptus, embryo, fetus and infant?

Answer 4

Conceptus-everything resulting from fertilised egg-baby, placenta, fetal membrane, umbilical chorn
(the timing-in obstetricians-from last day of period that didnt happen. For biologist-from feritlisation. usually 2 weeks off (pregnancy 2 week later))

blastrocyst before embryo
Embryo-baby before its clearly human (usually head, spinal chorn-red liver for RBC, no limbs/bones (5-6 weeks)
fetus-baby for rest of pregancy (3months)-limbs, chods, - all primary features are here-> grow a lot after
Infant-less precise-normally after delivery

Question 5

What are the carnigie stages of development?

Answer 5

Stages that count the features of the embryo as they appear untill they become fetus’
23 stages

Question 6

How is pregancy time usually counted?

Answer 6

(the timing-in obstetricians-from last day of period that didnt happen. For biologist-from feritlisation. usually 2 weeks off (pregnancy 2 week later))
usually will not matter, except for very early delivery-if way to early might not want to ressucitate because of bad QOL later

Question 7

Are human embryos different from other species?

Answer 7

Not really-ressemble each other
some species are longer, larger, or have yolk (chick)-but very similar

can use them as model structures-stop ethical issues of researching on development-but still need to be careful (like timing issues-human on the long side-deer are close, elephants higher (whales 1/2 of elephants-> not size issue)
Closer to humans is usual sheep

Question 8

When are CNS, Eyes, heart, ear, teeth, brain vulnerable in embryos?

Answer 8

CNS-up to 3 weeks
eye, up to heart-4/5
ears, teeth, plate, ear-up to 6-9)
brain-nearly always vulerable

Question 9

What is the placenta?

Answer 9

Look like 20cm disc-with umbilical chord (transfer nutriens back and forth), lots of vein systems, and made of simili-gyri and sulci (called Cotyledon, with gaps fillied with maternal tissue)-
Has foetal membrane around (where amniotic fluid is)
co

Size and number of Cotyledon does not matter to baby development

anchors the baby

Question 10

What is inside a Cotyledon?

Answer 10

Branched structure-placental villous tree
Central stem with blood vessels and many splitting branches (bronchi like)-large surface area
the ciruclations of motehr/child do not come in contact
Maternal blood arrives in the branches, and are carried towards stem
Stem combine to become veins are arteries
arteries seen in blue because arrive deoxygenated, no nutrients
Veins are what bring the nutrients back in (similar to lungs)

Very large surface area (11m2), and intimate contact between baby and mother-immune relations, etc

Question 11

Whata re the function of placenta?

Answer 11

-Seperation-make sure bloods dont contact,
-exchange-oxygen, etc,
-biosynthesis-very active-makes nearly all pregancy hormones,
-immunoregulation-what reduces mother immune/gives immune previledge (produce Ag that says theyre HUMAN but thats all-not who they belong to-never varies)
connection-dug

Question 12

How does the placenta develop?

Answer 12

Single layer of cell in blastocyst- proliferation, then branching (then just gets more and more branched)
Branches get longer and more complex (looks like a weeping willow)

Question 13

Is the contact bwteen mother and placenta vary?

Answer 13

Yes-about 8 weeks in
Provision of blood via spiral ateries (in endometrium)-placentar cytotrphoblast infiltrate the vascular endothelium and remove SMC –as baby grows, need to allow for vessels to be very wide, and provide more nutrients

Cytotrophoblasts also cut off blood supply to placenta in the early pregnancy–this is because ROS would damage babies-low oxygen environement

Question 14

What is the role of Cytotrophoblasts

Answer 14

Provision of blood via spiral ateries (in endometrium)-placentar cytotrphoblast infiltrate the vascular endothelium and remove SMC –as baby grows, need to allow for vessels to be very wide, and provide more nutrients

Cytotrophoblasts also cut off blood supply to placenta in the early pregnancy–this is because ROS would damage babies-low oxygen environement

Question 15

What happens if the the placetna mal develops?

Answer 15

Not anchor-miscarriage (late first timerster/second)

Pre-eclampsia, fetal growth restriction

Question 16

Epidiemology of labour and delivery?

Answer 16

Misscarriage (under 23weeks0-350000
Most are delivered by labour
175000 elective ceasarian
baby head is side of hand and body size of a forearm

preterm-80000-
cant really stop labour when it starts
Or medical emegencies where babies would be better be out

Question 17

What is the defintion of labour?

Answer 17

Coordinated uteral contraction-start at fundus towards cervix

cervical rineping-from firm becomes soft and flexible
Effacement-moves sideways to allow a baby to place

Question 18

What are the stages of labour?

Answer 18

Idendent of gestational age
Cervical ripeding/effacement
Coordinate myometrial contraction
Rupture of fetal membrane
delivery of infant, then placenta

8 weeks before-latent stages-early contraction
labour 12-48h-> increase in 3 phases increases contraction
Phase 1-any many hours
phase 2-hours
phase 3-30mins
usually faster in second baby

wrong way up-can delay things even more

Question 19

what initates labour?

Answer 19

human-unsure-cant do studies

estrogens? Low progesterone? CRH? oxytocin

Question 20

What happens during cervical ripening and effacement?

Answer 20

Change from  rigid to flexible
Remodelling (loss) of ECM
recruitment of leukocyte
inflammatory process-prostaglandins, IL8
large part of NFKB-> feedforwards mechanism-maybe why labour is so hard to stop

Question 21

What happens during myometrial contraction?

Answer 21

Fundal dominance,
inflammatory style cascade again
large part of NFKB

Question 22

What happens during rupture of fetal membranes?

Answer 22

inflammatory process in fetal membrane
PGs, interleukins
large part of NFKB

Question 23

What is the role of inflammation in labour?

Answer 23

Seems like initating factors upregulate NFKB-this leads to large upregulation of inflamm genes all over the uterus and initiation of labour-> PGs, ILs, cytokines
Feedforward of the cytokines of NFKB that drives this forward evem more

Almost all pro-labour genes have NFKB binding domain
Modification of theses sites lead to loss of expression->loss of labour

So infections are also linked with pre-term labour too

Question 24

What is the role of Prostaglandins in inducing labour?

Answer 24

tissues in utero-constitutive PGE2 synthesis-already producing maximum PGE2
even before labour officially starts-> and labour does follow this constitive

Using PAF and CRH to induce PGE2 in models have produced labour

CRH (the one that produced ACTH in Pit) sharp rise 3weeks before labour
COX2 also (PG producer)
PAF also rises

Question 25

What is platelet activating factor?

Answer 25

PAF-part of lung surfactant
Produced by maturing lung in immediate run up to birth
levels in amniotic fluids increase near term
fetal signal of maturity (maybe?)
stimulates COX2, PGE, IL1B

still candidate initator of term

Question 26

Describe hypothesis of endocrine control of labour?

Answer 26

CRH produced by placenta goes to baby pit glands-> produce cortisol
Cortisol on placenta has FEEDFORWARD action-drives up CRH very high
CAF also produced by lungs
Together produce PG and IL

adrenal makes DHEAS precursor that help produce factors in placenta that induces labour
many factors that affect that can impact labour

STILL HYPTHESIS

Question 27

What is the role of progesterone in labour?

Answer 27

NECESSARY to sustain pregancy
But levels stay high even after placenta is delivered

During preg, lot of ProgReceptor in tissue
Blocks NFKB action and does it things
at the end of pregnancy-PR downregulation->not inhbiting NFKB-> suddently acts and cause labour
called functional progesterone withdrawal

Question 28

Why is birth so dangerous>

Answer 28

Uterus needs to contract to block the spiral arteries that after placenta left, are feeding directly into uterus
theyve lost a lot of their SMC so need uterus to contract to stop these

drugs can induce this contraction which is good
Midwife study placenta to be sure its all there and not staying in the mother where it might stop contract from fully closing the arteries