Pregancy/Labour Flashcards
What are the timelines of pregancy (mother/child/placenta)-summary
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
What are the changes that occur in the mothers body during pregancncy
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
How do maternal hormones changes during pregancy?
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)
What is conceptus, embryo, fetus and infant?
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
What are the carnigie stages of development?
Stages that count the features of the embryo as they appear untill they become fetus’
23 stages
How is pregancy time usually counted?
(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
Are human embryos different from other species?
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
When are CNS, Eyes, heart, ear, teeth, brain vulnerable in embryos?
CNS-up to 3 weeks
eye, up to heart-4/5
ears, teeth, plate, ear-up to 6-9)
brain-nearly always vulerable
What is the placenta?
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
What is inside a Cotyledon?
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
Whata re the function of placenta?
-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
How does the placenta develop?
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)
Is the contact bwteen mother and placenta vary?
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
What is the role of Cytotrophoblasts
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
What happens if the the placetna mal develops?
Not anchor-miscarriage (late first timerster/second)
Pre-eclampsia, fetal growth restriction
Epidiemology of labour and delivery?
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
What is the defintion of labour?
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
What are the stages of labour?
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
what initates labour?
human-unsure-cant do studies
estrogens? Low progesterone? CRH? oxytocin
What happens during cervical ripening and effacement?
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
What happens during myometrial contraction?
Fundal dominance,
inflammatory style cascade again
large part of NFKB
What happens during rupture of fetal membranes?
inflammatory process in fetal membrane
PGs, interleukins
large part of NFKB
What is the role of inflammation in labour?
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
What is the role of Prostaglandins in inducing labour?
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
