obsteterics Flashcards
(110 cards)
Effacement
Starts in the fundus (pacemaker)
Retraction/shortening of muscle fibres in cervix, that build in amplitude as labour progresses
Fetus forced down-pressure on cervix
effacement leads to …
dilation
fully dilated at 10cm
mechanical factors that affect active labour 3ps
Powers - the degree of force expelling the fetus
primigravida women and induced = poor uterine contractions
Passage
Bony pelvis - inlet, mid cavity, outlet
Ischia spine - used to assess decent (station)
Soft tissues - cervical dilation, vagina and perineum need to be overcome in second stage
macrosomnia, inadequate pelivs (to small)
Passenger - the diameters of the fetal head
malpresentation (breach)
pan relief in labour - opiates
examples
fetal SE
Pethidine/morphine
Side effects Fetal
Respiratory depression
Diminishes breast-seeking, breast-feeding behaviours
pan relief in labour - opiates
examples
maternal SE
Pethidine/morphine
Side effects-maternal
Euphoria & dysphoria
Nausea/vomiting
Longer 1st and 2nd stage labour
epidural maternal SE
Side effects-maternal Increase length 1st & 2nd stage Need for more oxytocin (synctocinon) Increase incidence malpositon Increase instrumental rate
epidural fetal SE
Tachycardia due to maternal temp
Diminishes breast feeding behaviours
1st stage of labour - latent phase
painful, irregular contractions
cervix effaces - becomes shorter and softer
then dilates to 4cm
1st stage of labour - establishment phase
regular contractions
dilation from 4cm increasing 0.5cm/h
asses contractions strength, frequency every 30mins
asses maternal BP temp and pulse
2nd stage of labour - passive stage
complete cervical dilation (10cm)
until head reaches pelvic floor and desire to push experienced (but no pushing)
completes rotation and flexion. Lasts a few mins.
2nd stage of labour - active stage
Regular, frequent contractions
Progressive
Role of oxytocin
mechanism of labour / passage of fetus through birth canal (8)
Engagement - head enters pelvis in occipito-transverse (OT) position.
Descent and flexion - head descends and flexes as the cervix dilates.
Internal Rotation - head internally rotates 90 degrees, baby in OA position (all during early 2nd stage)
Rotation complete, further descent
Crowning - perineum distends
Extension and delivery
Restitution - head rotates 90 degrees to the same position in which it entered the pelvis to enable delivery of the shoulders (aligns its head with the shoulders)
Internal rotation - shoulders rotation from a transverse position to an anterior-posterior position
lateral flexion
3rd stage of labour
delivery of placenta
Check placenta and membranes complete
delayed cord clamping - improves iron status and reduces prevalence of neonatal anaemia
active - oxytocin by IM injection to reduce the risk of PPH
low birth weight values
<2500gm at birth regardless of GA
LBW: <2500gm
VLBW: <1500gm
ELBW: <1000gm
prematurity risk factors
anterpartum haemorrhage unkown multiple pregnancys chorioamnionitis anaemia (iron def)
primary prevention of pre term birth
Reducing population risk Effective interventions not demonstrable yet Smoking and STD prevention Prevention of multiple pregnancy Planned pregnancy Variable work schedules Physical and sexual activity advice Cervical assessment at 20-26 weeks
diagnosis of labour
Persistent uterine activity / contractions AND change in cervical dilatation and/or effacement
screening of pre term labour
Transvaginal cervical ultrasound - cervical length
fetal fibronectin
Extracellular matrix protein found in choriodecidual interface. Abnormal finding in cervicovaginal fluid after 20 wks may indicate disruption of attachment of membranes to decidua
management of pre term labour
corticosteroids (betamethosone) - for fetal surfactant production, close patent ductus
nifedipine can suppress labour, allows time for surfactant to work
magnesium sulfate - neuroprotective
chronic hypertension definition
Hypertension diagnosed
Before pregnancy
Before the 20th week of gestation
During pregnancy and not resolved postpartum
Gestational Hypertension definition
New HT after 20 wks gestation Systolic >140 Diastolic>90 No or little proteinuria 25% develop pre-eclampsia
pre-eclampsia definition
hypertension and proteinuria in pregnancy
New HT after 20th week (earlier with trophoblastic disease)
eclampsia definition
pre-eclampsia and tonic clonic seizures
pre-eclampsia diagnosis
Gestational Hypertension Systolic >140 Diastolic>90 Proteinuria ≥ 0.3g protein /24hr ≥ +2 on urine dip specimen sudden weight gain odema