Lecture 15 - Normal Birth

Question 1

Challenges in human parturition

Answer 1

quiescence, timing, activation, birth (fetal-neonatal adaptations) and involution (haemostasis, establishing lactation)

Question 2

Quiescence?

Answer 2

uterine muscle contractions poorly synchronised, low amplitude and frequency, progesterone @ Ca driven

Question 3

Anti-progesterone durg?

Answer 3

mifeprestone

Question 4

Gestation length determinants (timing)?

Answer 4

unknown - links to parity, race and age

Question 5

Activation involvments?

Answer 5

intact fetus, uterine stretch, fetal HPA axis, melatonin and circadian rhythms, upregulation of myometrium, abnormal membrane rupture

Question 6

Activation - upregualtion of myometrium?

Answer 6

increased CAPS, gap junctions, prostaglandin receptors and oxytocin receptors leading to co-ordinated contractions

Question 7

Contraction associated proteins

Answer 7

Actin and myosin (increased contractility), v gated Ca channels (increased myocyte excitability), gap junctions, multimers of cx43 (increased intercellular connectivity)

Question 8

Origin of prostaglandins in labour?

Answer 8

phospholipases release Archidonic acid from cell membranes

Question 9

Oxytocin in labour?

Answer 9

not essential, requires gap junction presence (like prostaglandins), induce and augment labour, prevent post-partum haemorrhage

Question 10

Cervix in labour?

Answer 10

softens and rippens, looser cell structure

Question 11

Membranes?

Answer 11

amnion and chorion, sit of PG production not essential in inducing labour but sufficient from PG release

Question 12

5 conditions for birth?

Answer 12

mature fetus, pelvic ligaments softened, uterus excitable w coordinated contractions, cervix soft and easily dilated, membranes possibly ruptured for mechanical benefits

Question 13

Stages of labour?

Answer 13

1st - until full dilation (10cm); 2nd - until birth of baby; 3rd - util delivery of placenta

Question 14

Active phase?

Answer 14

more than 4cm dilation, brakes are oof no stopping

Question 15

1sst stage?

Answer 15

contractions, cervical enfacement and dilation, either: spontaneus rupture of membranes (RM), rupture of membranes (ROM) or premature rupture of membranes (PROM)

Question 16

Feeling of pain?

Answer 16

25 cmH2O

Question 17

First breath proportions?

Answer 17

90% fine, 10% some assistance, 1% major resuscitation

Question 18

CVS adaptation at first breath?

Answer 18

closure of foramen ovale, ventilation output through lungs, reduction in pulmonary vascular resistance, reduction-closure of ductus arteriosus

Question 19

Birth thermogenesis?

Answer 19

vascualr brown fat, sympathetic nervous control, canmaintain 23 degrees in first hour, dry baby to prevent evaporation heat loss

Question 20

Involution?

Answer 20

placental separation, cleavage through decidua basalis, contractions to prevent PPH, increased uterine sensitivity to oxytocin