7- Normal pregnancy and labour (normal labour and delivery ) Flashcards
normal labour occurs between
37 and 42 weeks
Prostaglandins and labour
- Trigger specific effects in local tissues
- Stimulate contractions in uterine muscle
- Role in ripening of the cervix before delivery
Prostaglandin E2 can be used to induce labour in the form of a pessary
define labour
progressive effacement and dilatation of the cervix in the presence of regular uterine contractions
define delivery
expulsion of fetus and placenta
define show
cervical mucus plug
define SROM
spontaneous rupture of membrane, can precede labour
define ARM
artificial rupture of membrane
define gravidity
total number of pregnanies including present
define parity
the state of having given birth
describes the number of births >24 weeks or >500g
length of labour
- Nulliparous – slower
- Multiparous – quicker
stages of labour
- Latent
- First stage
- Second stage
- Third stage
latent stage of labour
- 0-3cm dilation of the cervix
- Progresses at around 0.5 cm an hour
- Irregular painful contractions
first stage of labour
- Regular (true) contractions (3-4 times every 10 mins)
- From 3-4 cm dilated until 10cm dilated (fully dilated)
Second stage
from 10cm dilation to when the baby is born
Third stage
from delivery of the baby until delivery of the placenta
Diagnosing onsent of labour
- Show (mucus plug from cervix)
- Rupture of membranes
- Regular, painful contractions
- Dilating cervix on examination
What occurs in the first stage of labour
- cervical dilation (opening)
- cervical effacement (thining)
- the show falls out
- three stages: latent, active and transition
progressive effacement and dilatation of the cervix
cause by prostaglandins
first stage- latent
Latent (not true first stage)
- 0-3cm dilation of the cervix
- Progresses at around 0.5 cm an hour
- Irregular painful contractions
first stage- active
Active (established first stage)
- 3-7cm dilation
- 1cm per hour
- Regular painful contractions
first stage- transition
- 7-10cm
-1cm per hour - Strong and regular contractions
braxton hick contractions
- Occasional irregular contractions of the uterus
- Occur during 2nd and 3rd trimester
- Not true contractions and do not induce labour
- Management : staying hydrate and relaxing
Second stage of labour: factors
Passage
Power
Passenger
power
strength of uterine contractions
- fundal dominance (coming from the top of the uterus)
passage
size and shape of the passageway, mainly the pelvis (can also be pelvic floor)
The pelvis: split into 3 diameters
dictates how the baby moves to fit through the holes
- pelvic inlet
- mid- cavity (widest)
- pelvic outlet (narrowest)
The birth canal
- soft tisses: lower uterine segment, cevrix, vagina, vulva, pelvic floor, perineum
causes of obstruction
- Pelvis: macrosomnic baby or small mother
- Brith canal: FGM and LETTZ
Passenger
The fetus
1) Size- esp head
2) Attitude- posture of the fetus
3) Lie – position of the fetus in relation to the mothers body
- Longitudinal lie- fetus is straight up and down
- Transverse lie- fetus is straight side to side
- Oblique- the fetus is at an angle
4) Presentation- the part of the fetus closest to the cervix
- Cephalic – head first
- Shoulder- shoulder first
- Breech position
Breech positions
- Complete breech (with hips and knees flex)
- Frank breech- with hips flexed and knees extended, bottom first
- Footling breech- with a foot hanging through the cervix
how to determine the presentation/ position of a baby
do a vaginal examinationa dn look for 2 fontanellels for landmarks
o Posterior fontanelle (Occiput)- V shape
o Anterior – diamond shape
why is the position of the head importnant
Degree of flexion or extension of head and positions makes a difference in the circumference of the head – smaller the easier
How can the baby help with being delivered
- Moulding of the fetal cranium
- The more moulded the larger the circumference
The mechanism of labour
- Engagement
- Flexion
- Descent
- Internal rotation
- Extension
- Restitution and External rotation
- Expulsion
Engagement
- Is when the baby is fixed in the pelvis
- On abdominal exam you can only feel 2/5s of the babies head (due to being in the pelvis)
flexion
- Baby’s chin on chest
- Ideally in transverse position
descent
Baby moves further into the pelvis
Obstetricians describe the position of the baby’s head in relation to the mother’s ischial spines during the descent phase. Descent is measured in centimetres, from:
* -5: when the baby is high up at around the pelvic inlet
* 0: when the head is at the ischial spines (this is when the head is “engaged”)
* +5: when the fetal head has descended further out
internal rotation
- Anticlockwise rotation so the occiput (back of the head) is anterior
extension
neck extends under the symphysis pubis
Restitution and external
- Where the shoulder align with the head
monitoring in labour
x2
the mother
the baby
maternal monitoring
- Low risk- midwifery driven
- High risk- obstetrician driven
bladder care and
- If epidural in/out catheter (or indwelling if unable to void) catheter- Full bladder may obstruct head
maternal position in labour
If women lying on back the uterus will be pressing on the great vessels, reducing blood flow, which can cause maternal and therefore foetal hypotension
perineum
check for trauma after delivery
fetal monitoring
- Low risk- intermittent monitoring
- High risk- continuous monitoring (cardiotocogram CTG)
what is monitored for fetal wellbing
- fetal heart monitoring
- colour of liquor (if meconium is brown- sign of distress)
Partogram
A partogram or partograph is a composite graphical record of key data (maternal and fetal) during labour entered against time on a single sheet of paper. Relevant measurements might include statistics such as cervical dilation, fetal heart rate, duration of labour and vital signs.
what parameters are included on partogram
- Foetal heart rate
- Dilation and descent of baby
- Contractions
- Drugs and IV fluids
- Blood pressure and pulse
- Urine
o Protein
o Acetone
o Glucose - Temp
normal progression of labour
Ideally a women would progress (cervical dilatation) 1 cm every hour
- Yellow = normal progress
- Purple = stop line (to show if a labour is progressing too slowly and an intervention needs doing)
the thrid stage
- From the completed birth of the baby to the delivery of the placenta
- Physiological management
or - Active management
physiological management of labour
Placenta is delivered by maternal effort without medications or cord traction
active management of labour
- Midwife or doctor assist in delivery of the placenta
- Oxytocin and controlled cord traction
- Shortens and reduces risk of bleeding
- Haemorrhage of delay of >60 mins should prompt active management
what does active management entail
- Intramuscular oxytocin -> helps uterus contract and expel placenta
- Careful traction applied to umbilical cord to guide placenta out of uterus and vagina
when can induction of labour be offered
between 41 and 42 weeks
when may induction of labour be indicated in a women who is not overdue
- Prelabour rupture of membranes
- Fetal growth restriction
- Pre-eclampsia
- Obstetric cholestasis
- Existing diabetes
- Intrauterine fetal death
*
which score is used to determine whether to induce labour
Bishops score
Fetal station (scored 0 – 3)
Cervical position (scored 0 – 2)
Cervical dilatation (scored 0 – 3)
Cervical effacement (scored 0 – 3)
Cervical consistency (scored 0 – 2)
A score of 8 or more predicts a successful induction of labour. A score below this suggests cervical ripening may be required to prepare the cervix.
options for induction of labour
- membrane sweep
- vaginal prostaglands
- cervical ripening balloon
- articfudual ruptuee of membrane with oxytocin infusion
- oral mifepristone (anti-progesterone) plus misoprostol
membrane sweep for IOL
used from 40 weeks gestation
- involves a finger into the cervix to stimulat ethe cervix and begins the prcoess of labour
- should produce onset of labour within 48 hours
Vaginal prostaglandin E2 (dinoprostone) for IOL
involves inserting a gel, tablet (Prostin) or pessary (Propess) into the vagina. The pessary is similar to a tampon, and slowly releases local prostaglandins over 24 hours. This stimulates the cervix and uterus to cause the onset of labour. This is usually done in the hospital setting so that the woman can be monitored before being allowed home to await the full onset of labour.
Cervical ripening balloon (CRB) for IOL
is a silicone balloon that is inserted into the cervix and gently inflated to dilate the cervix. This is used as an alternative where vaginal prostaglandins are not preferred, usually in women with a previous caesarean section, where vaginal prostaglandins have failed or multiparous women (para ≥ 3).
Artificial rupture of membranes with an oxytocin infusion
can also be used to induce labour, although this would only be used where there are reasons not to use vaginal prostaglandins. It can be used to progress the induction of labour after vaginal prostaglandins have been used.
when are oral mifepristone plus misoprostol used to induce labour
where intrauterine fetal death has occurred.
monitoring induction of labour
complication of induction opf labour
Uterine hyperstimulation
Uterine hyperstimulation
where the contraction of the uterus is prolonged and frequent, causing fetal distress and compromise.
The two criteria often given are:
- Individual uterine contractions lasting more than 2 minutes in duration
- More than five uterine contractions every 10 minutes
uterine hyperstimulation can lead to
- Fetal compromise, with hypoxia and acidosis
- Emergency caesarean section
- Uterine rupture - esp if previous VBAC
