Intrapartum Care: Labour Flashcards
Define labour
The onset of regular and painful contractions associated with cervical dilation and descent of the presenting part.
When does labour and delivery normally occur?
Between 37 and 42 weeks gestation.
What are the 3 stages of labour?
1) 1st stage: from the onset of labour (true contractions) until 10cm cervical dilatation
2) 2nd stage: from 10cm cervical dilatation until delivery of the baby
3) 3rd stage: from delivery of the baby until delivery of the placenta
describe stage 1 of labour
from the onset of true labour to when the cervix is fully dilated (10cm)
describe stage 2 of labour
from full dilation (10cm) to delivery of the fetus
Describe stage 3 of labour
from delivery of fetus to when the placenta and membranes have been completely delivered
Describe monitoring steps in labour
1) FHR monitored every 15min (or continuously via CTG)
2) Contractions assessed every 30min
3) Maternal pulse rate assessed every 60min
4) Maternal BP and temp should be checked every 4 hours
5) VE should be offered every 4 hours to check progression of labour
6) Maternal urine should be checked for ketones and protein every 4 hours
How often should foetal heart rate be monitored in labour?
every 15min (or continuously via CTG)
How often should contractions be assessed in labour?
Every 30 mins
How often should maternal HR be assessed in labour?
Every 60 mins
How often should maternal BP & temp be assessed in labour?
every 4 hours
How often should vaginal exam be offered in labour to check progression?
Every 4 hours
How often should maternal urine be checked in labour?
Every 4 hours: for ketones and protein
How long does stage 1 of labour typically last in a primigravida?
10-16 hours
What happens in 1st stage of labour?
1) cervical dilation (opening up)
2) cervical effacement (getting thinner)
3) mucus plug in cervix ( which prevents bacteria from entering the uterus during pregnancy) falls out and creates space for baby to pass through
What are the 3 phases of stage 1 of labour?
1) Latent phase
2) Active phase
3) Transition phase
Describe the latent phase of stage 1 of labour
1) From 0 to 3cm dilation of cervix (progresses at around 0.5cm per hour)
2) Irregular contractions
Describe rate of progression of dilation of cervix in latent phase of stage 1 of labour
0.5cm per hour
Describe the active phase of stage 1 of labour
1) 3cm to 7cm dilation of the cervix (progresses at around 1cm per hour)
2) Regular contractions
Describe rate of progression of dilation of cervix in active phase of stage 1 of labour
1cm per hour
Describe the transition phase of stage 1 of labour
1) From 7cm to 10cm dilation of cervix (1cm per hour)
2) Strong & regular contractions
How does baby’s head typically a) enter pelvis and b) deliver?
a) occipito-lateral position
b) occipito-anterior position
What is a vertex presentation in delivery?
The ideal position for a fetus to be in for a vaginal delivery.
It means the fetus is head down, headfirst and facing your spine with its chin tucked to its chest.
What % of babies are vertex at delivery?
90%
What are braxton hicks contractions?
1) Occasional irregular contractions of the uterus.
2) Women can experience temporary and irregular tightening or mild cramping in the abdomen.
When do braxton hicks contractions usually occur?
2nd and 3rd trimester
Do Braxton-Hicks contractions indicate the onset of labour?
NO - these are not true contractions.
They do not progress or become regular.
What can help reduce braxton-hicks contractions?
Staying hydrated and relaxing
What are the 4 signs of labour?
1) Show (mucus plus from cervix)
2) Rupture of membrane (not always)
3) Regular, painful contractions
4) Dilating cervix on examination
Latent 1st stage vs established 1st stage of labour?
Latent: when there is both
1) Painful contractions
2) Changes to the cervix, with effacement and dilation up to 4cm
Established: when there is both
1) Regular, painful contractions
2) Dilatation of the cervix from 4cm onwards
Define rupture of membranes (ROM)
The amniotic sac has ruptured.
Define spontaneous rupture of membranes (SROM)
The amniotic sac has ruptured spontaneously.
Define prelabour rupture of membranes (PROM)
The amniotic sac has ruptured before the onset of labour.
Define preterm prelabour rupture of membranes (P‑PROM)
The amniotic sac has ruptured before the onset of labour AND before 37 weeks gestation (preterm).
Define prolonged rupture of membranes (also PROM)
The amniotic sac ruptures more than 18 hours before delivery.
Define prematurity
Birth <37 weeks gestation
Before what date are premature babies considred non-viable?
<23 weeks gestation
Generally, from 23 to 24 weeks, resuscitation is not considered in babies that do not show signs of life.
Survival chance of babies born at 23 weeks?
10%
At how many weeks gestation is there an increased chance of survival and full resuscitation is offered in premature babies?
24 weeks onwards
Prematurity can be classified into a) extreme preterm, b) very preterm, c) moderate to late preterm
What are the dates for each?
a) Under 28 weeks: extreme preterm
b) 28 – 32 weeks: very preterm
c) 32 – 37 weeks: moderate to late preterm
Via what 2 mechanisms can be used for prophylaxis of preterm labour?
1) vaginal progesterone
2) cervical cerclage
How can vaginal progesterone be given in the prophylaxis of preterm labour?
Via gel or pessart
Role of progesterone in prophylaxis of preterm labour?
Progesterone has a role in maintaining pregnancy and preventing labour by decreasing activity of the myometrium and preventing the cervix remodelling in preparation for delivery.
Who is vaginal progesterone offered to for the prophylaxis of preterm labour?
Women with a cervical length less than 25mm on vaginal US who are <24 weeks gestation.
What is cervical cerclage?
Involves putting a stitch in the cervix to add support and keep it closed.
This involves a spinal or general anaesthetic.
The stitch is removed when the woman goes into labour or reaches term.
Who is cervical cerclage offered to for the prophylaxis of preterm labour?
Women with cervical length of <25mm on vaginal US between 16 and 24 weeks gestation who have had previous premature birth or cervical trauma (e.g. colposcopy and cone biopsy).
Investigation for assessing cervical length in pregnancy?
Vaginal US
What length is a ‘short cervix’?
<25mm
Potential complications of a short cervix?
increases the risk of preterm labor and premature birth.
What is a “rescue” cervical cerclage? When is it offered?
May be offered between 16 and 27+6 weeks gestation where there is cervical dilatation without rupture of membranes, to prevent progression and premature delivery.
What are the 2 main classifications of premature membrane rupture?
1) Prelabour rupture of membranes (PROM)
2) Pre-term prelabour rupture of membranes (P-PROM)
Define prelabour rupture of membranes (PROM)
The rupture of fetal membranes at least 1 hour prior to the onset of labour, at >/=37 weeks gestation.
Define pre-term prelabour rupture of membranes (P-PROM)
the rupture of fetal membranes occurring at <37 weeks gestation.
What do the fetal membranes consist of?
The chorion & amnion.
What are the foetal membranes strengthened by?
Collagen - under normal circumstances, membranes become weaker at term in preparation for labour.
What 3 factors can contribute to the early weakening and rupture of fetal membranes?
1) Early activation of normal physiological processes: higher than normal levels of apoptotic markers and MMPs in the amniotic fluid (ie. breakdown of collage by enzymes)
2) Infection: inflammatory markers e.g. cytokines contribute to the weakening of fetal membranes.
3) Genetic predisposition
Risk factors associated with PROM and P-PROM?
1) Smoking: especially <28 weeks gestation
2) Previous PROM/pre-term deliverty
3) Vaginal bleeding during pregnancy
4) Lower genital tract infection
5) Invasive procedures e.g. amniocentesis.
6) Polyhydramnios
7) Multiple pregnancy
8) Cervical insufficiency
Typical history of in prelabour rupture of membranes?
1) ‘Broken water’: painless popping sensation, followed by a gush of watery fluid leaking from the vagina.
2) Symptoms can be non-specific:
a) gradual leakage of watery fluid from the vagina and damp underwear/pad
b) a change in the colour or consistency of vaginal discharge.
How can a rupture of membranes be diagnosed?
By sterile speculum examination.
1) Look for pooling of amniotic fluid in posterior vaginal fornix (after draining from cervix).
2) Asking the woman to cough during the examination can cause amniotic fluid to be expelled.
3) A lack of normal vaginal discharge (‘washed clean’) can be suggestive of rupture of membranes
Why is digital exam contraindication in PROM/PPROM (until the woman is in active labour)?
risk of infection - this can reduce the time between rupture of membranes and onset of labour (latency)
Position of women for speculum exam in PROM/PPROM?
The woman should be laid on an examination couch for at least 30 minutes –> will allow pooling of any leaking amniotic fluid in the top of the vagina.
When is a speculum not required in PROM/PPROM?
if amniotic fluid is seen draining from the vagina.
Differentials for PROM/PPROM?
1) urinary incontinence
2) normal vaginal secretions of pregnancy
3) increased sweat/moisture around perineum
4) increased cervical discharge (e.g. with infection)
5) vesicovaginal fistula
6) loss of mucus plug
Where there is doubt about the diagnosis of rupture of membranes, what 2 tests can be performed?
Test fluid for:
1) Insulin-like growth factor-binding protein-1 (IGFBP-1): Actim-PROM (Medix Biochemica)
2) Placental alpha-microglobin-1 (PAMG-1): Amnisure (QiaGen)
What is insulin-like growth factor-binding protein-1 (IGFBP-1)?
A protein present in high concentrations in amniotic fluid (100 – 1000 times the concentration of maternal serum).
This can be tested on vaginal fluid if there is doubt about rupture of membranes.
What is Placental alpha microglobulin-1 (PAMG-1)?
Present in the blood, amniotic fluid (in large conc) and cervico-vaginal discharge of pregnant women (in low concentrations with membranes intact).
Describe levels of IGFBP-1 and PAMG-1 in fluid tested in rupture of membranes?
High in fluid tested
US is not routinely used to aid diagnosis of rupture of membranes but may facilitate diagnosis in cases where it remains unclear.
What US result would indicate membrane rupture?
Reduced levels of amniotic fluid within the uterus
In all cases of premature membrane rupture, what test should be done?
High vaginal swab
Purpose of high vaginal swab in cases of premature membrane rupture?
1) Look for Group B Streptococcus (GBS) which would indicate antibiotics in labour
2) Give information as to a potential cause for PPROM (bacterial vaginosis is commonly implicated).
Impact of rupture of fetal membranes?
Rupture of the fetal membranes releases amniotic fluid - acts to stimulate uterus.
The vast majority of women with rupture of membranes will fall in to labour within 24-48 hour - very little that can be done to halt this.
If labour doesn’t start, it is important to consider the risks and benefits of expectant management versus induction of labour (IOL) when formulating an appropriate management plan for women with PROM:
What should always be given in PROM/PPROOM if <36 weeks gestation?
Prophylactic Abx to prevent the development of chorioamnionitis –> erhythromycin 250mg 4x daily for 10 days OR until labour is established if within 10 days
Abx of choice in PROM/PPROM for preventing the development of chorioamnionitis?
Erythromycin
Following PPROM, after how many weeks gestation is induction of labour considered?
> 34 weeks
In PRROM >36 weeks gestation, if labour does not start, how soon should induction of labour be considered?
24-48 hours: the risk of infection outweighs any benefit of the fetus remaining in utero.
Why is induction of labour considered >34 weeks gestation?
because the risk of infection outweighs any benefit of the fetus remaining in utero.
Management of PROM/PPROM >36 weeks gestation?
1) Monitor for signs of clinical chorioamnionitis.
2) Clindamycin/penicillin during labour if GBS isolated.
3) Watch and wait for 24 hours (60% of women go into labour naturally), or consider induction of labour.
4) IOL and delivery recommended if greater than 24 hours (but women can wait up to 96 hours – beyond this is their choice after counselling)
Management of PROM/PPROM 34-36 weeks gestation?
1) Prophylactic erythromycin 250 mg QDS for 10 days.
2) Monitor for signs of clinical chorioamnionitis, and advise patient to avoid sexual intercourse (can increase risk of ascending infection).
3) Clindamycin/penicillin during labour if GBS isolated.
4) Corticosteroids if between 34 and 34+6 weeks gestation.
5) IOL and delivery recommended.
Management of PROM/PPROM 24-33 weeks gestation?
1) Prophylactic Erythromycin 250 mg QDS for 10 days.
2) Monitor for signs of clinical chorioamnionitis, and advise patient to avoid sexual intercourse.
3) Corticosteroids (as less than 34+6).
4) Aim expectant management until 34 weeks.
What should parents be advised to avoid in PROM/PPROM?
Sexual intercourse - can increase risk of chorioamnionitis due to ascending infection
What does the outcome of PROM generally correlate with?
Gestational age of fetus.
The majority of women at term will enter spontaneous labour within 24 hours after membrane rupture, but there is a greater latency period the younger the gestational age.
Complications associated with an increased latency period?
1) Chorioamnionitis
2) Oligohydramnios: particularly significant if the gestational age is less than 24 weeks, as it greatly increases the risk of lung hypoplasia.
3) Neonatal death
4) Placental abruption
5) Umbilical cord prolapse
What is chorioamnionitis?
Inflammation of the fetal membranes, due to infection.
The risk increases the longer the membranes remain ruptured and baby undelivered.
What does oligohydramnios increase the risk of if gestational age is <24 weeks?
lung hypoplasia.
What is oligohydramnios?
Oligohydramnios is when you have low amniotic fluid during pregnancy.
What is preterm labour with intact membranes?
Involves regular painful contraction and cervical dilatation, without rupture of the amniotic sac.
