normal birth Flashcards

1
Q

define parturition

A

the process of giving birth

  • expelling the fetus, placenta and membranes from the uterus
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2
Q

challenges in human parturition

A

Quiescence - of uterus with growth, distension, pressure

timing - for safe birth

activation - stimulation of uterine musculature changes in genital tract

birth - fetal-neonatal adaptations

involution - haemostasis, establishing lactation

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3
Q

physiological processes

A
  1. quiescence
  2. activation
  3. stimulation
  4. involution
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4
Q

anatomical changes leading to pregnancy

A

uterus - upper and lower segments

cervical changes = ripening

softening shortening effacement

membrane rapture

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5
Q

uterine quiescence

A

uterine muscle contractions poorly synchronised

low amplitude and frequency

painless

cervix remains firm and closed

hormone responsible = P4 (form corpus luteum and placenta)

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6
Q

mifepristone

A

drugs which blocks P4 a and b

can be used to induce labour later on in pregnancy

(progesterone is normally a muscle relaxant)

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7
Q

factors that may determine gestation length

A
  • parity
  • age
  • genetics-maternal and paternal
  • race-ethnicity
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8
Q

activation

A

timing - 37-42 weeks

activation involves fetal genome

  • uterine stretch-growth (twins earlier)
  • fetal HPA axis
  • membrane ruptures
  • upregulation of myometrium
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9
Q

activation: up-regulation of myometrium in labour

A

increased PG receptors
increased oxytoxin receptors
increase in CAPS (gap junctions connexin 43)

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10
Q

contraction associated proteins

A

increase myometrial contractility
= actin myosin

increase myocyte excitability ion channels
= Ca2+ voltage, regulated

increase intercellular connectivity gap junctions
= connexin 43

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11
Q

PGs and labour

A

final stage of labour is an inflammatory event through PG

- potent inducer of labour

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12
Q

action of PG in labour

A

increase myometrial contractility

lead to cervix changes

associated with membrane rupture

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13
Q

cervical ripening

A

firm hard cervix gets remodelled by numerous cytokines causing extracellular matrix to breakdown and soften. leads to opening of the cervix

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14
Q

cervical ripening

A

firm hard cervix gets remodelled by numerous cytokines causing extracellular matrix to breakdown and soften. Leads to opening of the cervix

can happen preterm = infection

term = P4 decrease, E2 increase

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15
Q

membranes

A

amnion and chorion

  • site of PG production
  • rupture not essential for labour
  • method of inducing labour
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16
Q

major changes to the uterus during parturition and success for labour

A
  • increased coupling
  • increased ion channels
  • increased receptors
  • decreased NO

causes

  • increased conductivity and excitability
  • decreased relaxation

=reinforcement of contractions

17
Q

major changes to the cervix during parturition and success for labour

A
  • increased inflammatory response
  • increased collagenolysis

causes
- increased ripening

= dilatation

18
Q

major changes to the fetal membranes during parturition and success for labour

A
  • increased ECM degradation

causes
- decreased tissue integrity

= rupture

19
Q

stages of labour

A

1st = until full dilatation (10cms)

2nd = full dilatation until birth of baby

3rd = from birth of baby until delivery of the placenta

20
Q

partogram

A

graphical description of labour

  • looks at progress of labour
  • women having first baby have a slower labour than 2nd +
  • time against cervical dilatation
21
Q

1st stage of labour

A

contractions

cervical effacement and dilatation

descent of presenting part

intrauterine pressure increases (about 25mmHg pain felt)

22
Q

CVS adaptation in neonate

A
  • closure of foramen ovale
  • 100% of right ventricle CO has to go through lungs therefore needs to be a rapid reduction in pulmonary vascular resistance (to allow blood to go through lungs)
  • reduction-closure ductus aretiosus (pulmonary to aorta)
23
Q

things needing to happen at birth

A

establishing continuous breathing

thermogenesis

intermittent nutrition

cardiovascular adaptations

24
Q

involution

A
  • placental seperation
  • cleavage through decidua basalis
  • contractions to prevent postpartum haemorrhage
  • increased uterine sensitivity to oxytocin
25
Q

P4 effect of labour

A

pregnancy hormones such as P4 put the brakes on myometrium

26
Q

normal term labour

A
  • inflammatory response
  • multiple steps in a cascade
  • requires interplay between fetoplacental unit and myometrium