Preterm labour & PPROM Flashcards
(32 cards)
Definition: Preterm birth
Birth before 37 weeks of pregnancy
- spontaneous
- iatrogenic: IOL or CS for maternal/fetal indications
Definition: Established preterm labour
Progressive effacement and dilatation of the cervix in the presence of regular painful contractions
Definition: Suspected/threatened preterm labour
Symptoms of preterm labour, but clinical assessment (speculum/digital VE) rules out established labour ie. no cervical change
Definition: PPROM
Preterm Prelabour Rupture Of Membrane: rupture membrane before 37+0W and after 24 weeks (point of viability) + not in established labour
Risk factors for preterm birth
- Previous preterm birth (strongest predictor for recurrence)
- Risk increases with increasing number of preterm births - Cervical trauma / surgery -> cervical insufficiency
- Cervical surgery e.g knife cone biopsy or LLETZ/LEEP for CIN (where volume of cervical tissue removed is directly associated with the risk of preterm birth)
- Previous termination of pregnancy in mid-trimester - Uterine abnormalities e.g. didelphys (double uterus)
- Social
- Smoking, alcohol, drugs
- Low socioeconomic background
- Increasing age
- Low pre pregnancy weight
- Short pregnancy interval
- Domestic violence
Causes of spontaneous preterm birth
- Too much pressure
- Multiple fetal gestation
- Polyhydramnions - Too weak
- Cervical trauma / surgery -> cervical insufficiency
- Cervical surgery e.g knife cone biopsy or LLETZ/LEEP for CIN (where volume of cervical tissue removed is directly associated with the risk of preterm birth)
- Previous termination of pregnancy in mid-trimester - Outside is better than inside
- Infection
- Abruption
- Pre-eclampsia
- IUGR
Clinical features of Preterm labour
Similar to normal labour but occurring before 37 weeks
Symptoms
- Menstrual-like cramping
- Lower back ache
- Painful regular uterine contraction
- Vaginal discharge: Bloody show
Abdominal PE
- Palpable contractions
- Tenderness
- Fundal height, lie, presentation
Speculum and VE
- Effacement and dilatation of the cervix
If preterm labour suspected, run investigations
- Predict likelihood of preterm delivery
- Actim partus
- Fetal Fibronectin test
- Transvaginal US of cervical length - Look for infection
- Vaginal swab (including GBS)
- UFEME, urine culture TRO UTI
Actim partus (rapid test kit)
- Simple cervical swab
- Detects phosphorylated insulin-like growth factor binding protein-1 (pIGFBP-1)
- Found in decidua
- Leaks into cervix when decidua and chorion detaches
- High negative predictive value (If negative, 98% chance that the patient will NOT deliver preterm)
Fetal Fibronectin test
- Simple cervical swab
- Glycoprotein found in amniotic fluid and placenta
- Disruption of the chorionic-decidual interface leads to detection of FFN in the cervicovaginal secretions
- High negative predictive value (If negative, 97% chance that the patient will NOT deliver preterm
Transvaginal US of cervical length
- Determines likelihood of birth within 48h in those >30 weeks
- Cervical length 15mm or less = initiate treatment
Management of preterm labour
General:
- Admit mother to labour ward
- Serial vaginal examination: assess cervical effacement + dilatation
- Rest mother in lateral decubitus position
- Monitor maternal vitals
- CTG monitoring of fetus
- Inform neonatal unit to standby for premature fetus
- Send routine bloods: FBC, GXM, PT/PTT, UECr
Specific
+/- Prophylactic abx
- Antenatal steroids
- MgSO4
- Tocolytics
- Decision on time and mode of delivery (vertex (NVD) vs breech (C-sect) presentation)
Prophylactic abx for preterm labour
Only if GBS +ve or unknown
- Give IV penicillin G during delivery (clindamycin if allergic)
Antenatal steroids in preterm labour
- Promotes fetal lung maturity
- Reduces risk of respiratory distress syndrome, intraventricular haemorrhage (major cause of cerebral palsy)
- Recommended to be given between 24 weeks to 34+6 weeks in women with established PTL, PPROM, planned preterm birth)
Types and dose of antenatal steroids that can be administered
Only 2 can pass through placenta and reach fetus:
a. 24mg IM Betamethasone in 2 divided doses: 12mg 24H apart
b. 24mg IM Dexamethasone in 2 divided doses: 12mg 24H apart OR 4 divided doses: 6mg 12H apart
Maximum effectiveness of antenatal steroids is achieved
Benefit begins 24h after initiation for 1st dose to 7th day of administration of the second dose
- if mother does not delivery within 7 days, cannot give to her again
Use of MgSO4 in preterm labour
Reduces cerebral palsy (neuroprotection)
given < 32 weeks
Indications of tocolysis
- Delay of birth by 48h is necessary to administer ANS
- Prolongs pregnancy by inhibiting uterine contractions - In utero transfer
*NOT used in PPROM - a/w increased risk of chorioamnionitis
Types of tocolytics used
- PO Nifedipine (most commonly used) (CCB)
- PO indomethacin (NSAIDs)
- SC/IV terbutaline (b2 agonist)
- IV salbutamol (b2 agonist)
- IV MgSO4
- IV Atosiban (oxytocin antagonist)
Symptoms of PPROM
- Typically gush of clear fluid/ Steady leak of fluid
- Sudden, unprovoked
- Foul-smelling discharge indicates chorioamnionitis
- Painless uterine contraction
- Bleeding
- Fetal movements +
Physical Examination for PPROM
Sterile Speculum examination to prevent risk of infection
- Amniotic fluid pooling in posterior fornix
- Coughing reveals leaking fluid from cervix
**Vaginal examination is C/I so as to prevent infection and stimulation of preterm labour, only done in certain circumstances
- Regular painful contraction (Possible preterm labour)
- Non-reassuring CTG status (Check for cord prolapse)
Diagnosis of PPROM
Maternal history followed by sterile speculum examination demonstrating liquor – ‘gold
standard’
If PPROM suspected, run investigations
- Confirm presence of amniotic fluid
- Amnicator
- Actim PROM - Look for infection
- Vaginal swabs, including GBS
- UFEME, urine culture TRO UTI - If PPROM confirmed, inflammatory markers used to monitor for chorioamnionitis
- FBC
- CRP
*don’t use ESR as ESR levels are always raised in pregnancy
Amnicator for PPROM
Nitrazine-based test for detection of amniotic fluid
- Normal vaginal pH: 4.5-6
- Amniotic fluid pH: 7-7.5
- Colour change from yellow to blue indicates possible presence of amniotic fluid
- False positives: blood or semen
