Obs And Gynae Flashcards
(191 cards)
Which hormones are actively involved in transforming a pregnancy into the labour phase?
Progesterone levels decrease and oxytocin increases which increase uterine contractions
Prostaglandin levels increase which lead to cervical ripening and increase uterine contractions
Oestrogen and relaxin also contribute to this
When is a foetus considered mature?
Maintain an independent existence outside the uterus
Breathe / maintain oxygenation
Feed / Maintain blood sugars
Maintain body temperature
When is a foetus considered viable?
Can survive extra-uterine
Usually 23-24 weeks depending on neonatal intensive care facilities
When is a foetus considered term?
Gestational age
37 completed weeks till 42 weeks
When is a foetus considered pre term?
Earlier than 37 completed weeks and after accepted age of viability (23-24 weeks)
When is a foetus considered post mature?
After 42 weeks
What processes have to occur in the process of parturition?
Cervical ripening / effacement
Cervical dilatation
Uterine contractions
Foetal membrane rupture
What is cervical effacement?
Cervix shortens and thins
What is a bloody show?
Mucus plug loosened and released from cervix as it starts to efface
What is the latent phase of labour?
Once cervix effacement starts to dilation of 4cm and regular contractions have begun
What factors contribute to cervical ripening?
Cyclooxygenase-2
Prostaglandin E2 (PGE2) and F2-alpha
Hyaluronic acid
Chemotaxis for leukocytes, causes increased collagen degradation
Stimulation of interleukin (IL)–8 release
Activity of matrix metalloproteinases 2 and 9
Cervical collagenase and elastase
Why can infection or inflammation lead to pre term labour?
Cytokines: interleukins 1 and 6 released as inflammatory response can trigger the process of cervical ripening and uterine contractions as they lead to the production of prostaglandins E2 and F2a
What are indications for inducing labour using prostaglandins?
Prolonged pregnancy
Pre labour rupture of membranes
Concerns about health of mother: pre eclampsia
Concerns about health of baby: poor growth
What can be used to induce labour?
Prostaglandin E2
Propess and cervidil: controlled release vaginal insert
Prostin and glandin: vaginal suppositories
What are the names of the foetal membranes?
Chorion: outermost membrane, contributes to placenta formation
Amnion: when first formed, closely covers embryo, fills with amniotic fluid to become protective sac
What cellular changes occur to allow growth of the uterus?
Smooth muscle hyperplasia and hypertrophy
When is the first trimester?
0-12 weeks
When is the second trimester?
13-28 weeks
When is the third trimester?
29-40 weeks
What are the layers of the uterus?
Endometrium: highly vascular mucosa, stratum functionalis (shed during menstruation), stratum basalis (permanent, gives rise to new functionalis after each cycle)
Myometrium: three layers of muscle
Perimetrium/serosa: visceral peritoneum
What happens to the Myometrium prior to parturition?
Increased expression of contraction-associated proteins,
including oxytocin receptors, connexin-43, and prostaglandin F2alpha receptors
Down-regulation of the nitric oxide (NO) pathway and other
vasorelaxing peptides
What happens to the myometrium during labour?
Prostaglandins and oxytocin act in synergy to trigger contractility through an increase in intracellular Ca2+ concentration
What percentage of deliveries are pre term?
7-10%
What factors could cause pre term labour?
Increasing maternal age, stress (domestic abuse)
Pre term rupture of membranes: infection, smoking, drug use, previous PROM, polyhydramnios, multiple gestation, amniocentesis, poor nutrition, cervical insufficiency, low SES, underweight
Pre term contractions
Cervical insufficiency: previous cervical biopsy, uterine abnormalities, trauma to cervix