Flashcards in Lecture 15 - Normal Birth Deck (20):
Challenges in human parturition
quiescence, timing, activation, birth (fetal-neonatal adaptations) and involution (haemostasis, establishing lactation)
uterine muscle contractions poorly synchronised, low amplitude and frequency, progesterone @ Ca driven
Gestation length determinants (timing)?
unknown - links to parity, race and age
intact fetus, uterine stretch, fetal HPA axis, melatonin and circadian rhythms, upregulation of myometrium, abnormal membrane rupture
Activation - upregualtion of myometrium?
increased CAPS, gap junctions, prostaglandin receptors and oxytocin receptors leading to co-ordinated contractions
Contraction associated proteins
Actin and myosin (increased contractility), v gated Ca channels (increased myocyte excitability), gap junctions, multimers of cx43 (increased intercellular connectivity)
Origin of prostaglandins in labour?
phospholipases release Archidonic acid from cell membranes
Oxytocin in labour?
not essential, requires gap junction presence (like prostaglandins), induce and augment labour, prevent post-partum haemorrhage
Cervix in labour?
softens and rippens, looser cell structure
amnion and chorion, sit of PG production not essential in inducing labour but sufficient from PG release
5 conditions for birth?
mature fetus, pelvic ligaments softened, uterus excitable w coordinated contractions, cervix soft and easily dilated, membranes possibly ruptured for mechanical benefits
Stages of labour?
1st - until full dilation (10cm); 2nd - until birth of baby; 3rd - util delivery of placenta
more than 4cm dilation, brakes are oof no stopping
contractions, cervical enfacement and dilation, either: spontaneus rupture of membranes (RM), rupture of membranes (ROM) or premature rupture of membranes (PROM)
Feeling of pain?
First breath proportions?
90% fine, 10% some assistance, 1% major resuscitation
CVS adaptation at first breath?
closure of foramen ovale, ventilation output through lungs, reduction in pulmonary vascular resistance, reduction-closure of ductus arteriosus
vascualr brown fat, sympathetic nervous control, canmaintain 23 degrees in first hour, dry baby to prevent evaporation heat loss