preterm birth

Question 1

what is preterm labour

Answer 1

term = labour before <37 weeks

very preterm = <32 weeks

prematurity is an abnormality - it is a failure of uterine quiescence
- a failure of the uterus to keep the baby in until the right time
(more than just dates)

Question 2

cost of preterm birth

Answer 2

• neonatal complications
• long term health problems
• individual and family cost
• societal cost
• neonatal enchephalopathy
• handicup potential e.g. cerebral palsy, sight, hearing, resp, behaviour

Question 3

causes of preterm

Answer 3

• endocrine maturation ‘stress’
• intrauterine haemorrhage
• intrauterine infection
• intrauterine stretch
  - membrane disruption
  - myometrial distention

(flowchart in book)

Question 4

failure of quiescence

Answer 4

functional levels of P4 and interaction with receptors is disturbed and uterus goes into labour
- inflammation is the most potent cause

Question 5

preterm activation problems

Answer 5

• uterine stretch-growth
• fetal HPA axis (stress)
• up-regulation of myometrium
• problems in cervix

Question 6

function of cervix

Answer 6

physical barrier against baby

barrier for ascending organisms

Question 7

cervical ripening

Answer 7

• active process
• inflammation like process
• infiltration of leukocytes
• increase in cytokines
• increase in MMPs
• independent of uterine activity

Question 8

what are triggers to upset peace

Answer 8

• infection
• stretch
  membrane disruption
  myometrial distension
• tissue damage esp cervix
• placentation
  growth of fetus
  hormone-P4
  PG release
  poor attachment-bleeding

Question 9

release of PG

Answer 9

• final common pathway in activation phase

phospholipases release arachidonic acid from cell membranes

Question 10

causes of PG release

Answer 10

• increase myometrial contractility
• lead to cervix changes
• associated with membrane rupture

Question 11

problems of preterm birth

Answer 11

• immature fetus
• often malpresentation e.g. breech
• often maternal comorbidities
• often have complicated C sections
• risks of recurrence
• may have poor outcomes

Question 12

limits of survival

Answer 12

lung development

- inability to undertake gas exchange

Question 13

who is at risk of prematurity

Answer 13

• previous history of PTB
• smoking
• multiple pregnancy e.g. twins
• maternal age
• obstetric history
• no prenatal care
• short cervical lengths

Question 14

fetal fibronectin

Answer 14

biomarker

• protein that sits between chorion and decidua
• high in early pregnancy and late pregnancy

measure it and if its high when it shouldn’t be you know something is wrong

Question 15

treatment given to abnormal pathological activation (with preterm labour)

Answer 15

tocolysis

steroids

MagSO4

Question 16

tocolysis

Answer 16

supresses preterm labour

Ca2+ channel blocker e.g. nifedipine

Question 17

steriods

Answer 17

antenatal corticosteroids

• prevents death from respiratory distress and reduce premature bleeding in the brain and infection in gut wall
  e. g. betamethasone

Question 18

magnesium sulphate

Answer 18

if baby is under 30 weeks can give IV infusion to mother

• reduces risk of cerebral palsy

Question 19

prevention strategies

Answer 19

• reduce smoking
• cervical cerclage
• drug therapies
• preterm birth clinics

Question 20

options - strategies

Answer 20

risk assessment and action
- social, smoking, prior PTB

P4

Cervix length measured

Ca2+ for preeclampsia

Question 21

progesterone therapy

Answer 21

• doesnt work for everyone or twins
• efficacious in prior spontaneous PTB
• efficacious in short Cx
• not effective if Cx <10mm
• role of P4 some benefits
• injection may be unsafe or ineffective
• not effective when women is contracting

Question 22

improving outcomes

Answer 22

• risk selection-history taking
• stop smoking
• assess maternal health risks for early delivery
• in patients at risk asess Cx length (use P4 for short)

use steriods and MagSO4 if delivery likely