Pregnancy and birth Flashcards
Describe the factors involved in the initiation of labour
Think about mechanical and hormonal/hormone like stimulation
Multifactorial (hormonal and mechanical)
- fetal hypothalamus triggered , maternal post-pituitary release oxytocin, decidua (fetus) releases prostaglandins
Uterine contracetions created by
- Raised oestrogens= pro labour hormone
- Reduction in progesterones = pro-pregnancy hormone
- Release of oxytocin by mothers neurohypophysis
- Prostaglandins from the decidua
- Mechanical stimulation of the uterus and cervix caused by overstretching and pressure from the PP
How do you diagnose labour?
- Regular pattern of uterine contractions (3/4 every 10 minutes)
- Waters breaking? (can happen any term, even after birth)
Consider the stages of labour
Outline what happens during the latent phase
- Lasts hours to days
- Contractions (enough to cause restless sleep)
- Effacement of cervix (due to muscle memory this occurs faster in parituous women)
- Intensity of contractions vary (e.g. terrible period pains)
Consider the stages of labour
Outline what happens during the active/1st stage of labour
How would you manage it?
What do you want to ensure about the fetal head?
- Painful regular contractions
- Cervical effacement
- Dilation of the cervix of 4cm or more
Vaginal examinations to check cervical dilation. Average is 0.5cm/hour
Descent of the fetal head in relation to the ischial spines
- progress measured by dilation and descent of the fetal head (in relation to the pelvic brim and the ischial spines)
Consider the stages of labour
Outline what happens during the 2nd stage of labour
- From full dilatation to the delivery of the baby
Describe the pelvic inlet
- The brim is oval except where the promonotory projects
- The anteroposterior diameter is 12cm
Describe the pelvic outlet
Diamond shaped with 3 diameters
- Anteroposterior ( as the coccyx is deflected backwards, this is the space available during birth)
- Oblique
- Transverse
Describe the ideal fetal position
How would you check this?
Describe another fetal position
Suboccipitobregmatic in OA position (9.5cm)
Can feel posterior fontanelle
- y shaped intersection of 3 sutures
- closes at 6-8 weeks
Anterior fontanelle (bregma)
- diamond shaped intersection of 4 sutures
- 2x3cms
- closes at 18 months
State the diameters of the fetal skull
Suboccipitobregmatic (9.5cm) = OA position
Occipitofrontal (11cm) = OP position
Supraoccipitomental (13.5)= brow
Submentalbregmatic (9.5)= face
Outline the mechanism of birth
- Head at pelvic brim in OT position
- Flexion of neck (subocciptobregmatic)
- Head descends and engages
- Head reaches pelvic floor - rotates to OA position
- Head delivers by extension
- Head ‘restitutes’ (comes in line with shoulders)
- Shoulders rotate into anterior/posterior diameter of pelvis
- Anterior shoulder delivered by lateral flexion from downward pressure on babys head
- Posterior shoulder by upward lateral flexion
Consider the stages of labour
Outline what happens during the 3rd stage of labour
What two management options are there?
Delivery of placenta
Normal estimated blood loss (300-500mls)
Inspection of placenta to ensure completion (if any is left it can cause post partum haemorrhage or infection)
- should have 2 membrane and chord (2 arteries and 2 veins)
Active management
- IM Oxytocin given into maternal thigh causing sustained uterine contraction, aids delivery of the placenta and contraction of the placental bed, decreases risk of PPH
OR Physiological management
- Mother naturally expels the placenta and membranes with contractions
Why is it important to monitor the fetud during labour?
How is it done?
To detect fetal hypoxia and deliver baby if needed
Screening the fetal HR by intermittent auscultation by Pinard or Sonicaid; cardiotograph (CTG); fetal blood sampling (FBS)
- Every 15 minutes before and after a contraction during the 1st stage, every 5 minutes in 2nd stage
ANY ABNORMALITY RECORDED RESULTS IN CTG
How does a cardiotograph (CTG) work?
Continuous print out of fetal HR and contractions
- abdomincal ultrasound detects cardiac movements and therefore HR
- a clip is applied to the fetal scalp (FSE) which detects the R-R wave of the fetal ECG
Discuss the efficacy of the CTG and why it is important to also use FBS
How does FBS work?
Contraindications?
CTG is highly sensitive but poorly specific (eg. if abnormal only a few babies are actually hypoxic)
- Use of CTG results in a 4fold increase in c section for fetal distress therefore need to check the CTG findings with FBS
Stab on the fetal scalp, blood collected via a glass pipette and pH and base excess testing
Infections (HIV, Hep B), fetal blood disorder, prematurity (under 32 weeks)
