Preterm labour & PPROM Flashcards
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
Actim PROM for PPROM
Similar to actim partus
PPROM management
Similar to PTL
Except
+Abx: Erythromycin for 10D after PPROM reduces the risk of chorioamnionitis
- tocolysis (no need)
Monitor for chorioamnionitis
- Clinical assessment of vital signs
- Maternal blood tests (WBC, CRP)
- Fetal heart rate
When to deliver in PPROM?
Expectant management until 37W, in discussion with mommy and ongoing clinical assessment
Exclusion criteria from expectant management in PPROM
- Active labour
- Chorioamnionitis
- Concerns about fetal wellbeing
- Monochorionic multiple pregnancy
- Hypertensive disorder
- Other contraindications to continuing pregnancy
Complications of PPROM
- Chorioamnionitis
- ascending infection -> chorioamnionitis ->
fetal/neonatal infection
- strict indication for delivery regardless of gestation - Placental abruption
- Cord prolapse
- Preterm baby
- Fetal demise
Prevention of preterm birth / PPROM in future pregnancies
- Next pregnancy manage in preterm birth clinic
- Target modifiable risk factors e.g. smoking
- Screen and treat for infection: UTI, STI, BV
- Cervical length screening with serial TVUS
- Monitor from 16-24weeks for women with previous preterm birth, PPROM or previous 2nd trimester miscarriage
- Short cervix = cervical length < 25mm before GA 24 weeks - Vaginal progesterone suppository
- Cervical cerclage
Cervical cerclage
Insertion of suture in the cervix to prevent preterm labour
- Vaginal / trans-abdominal approach
- Elective or emergency
(rescue cerclage)
- Vaginal cerclage usually removed around 36W because mommy can go into labour after that and if cerclage is still present, it can lead to cervical tear and heavy bleeding
Worrying sign seen in transvaginal cervical length U/S
Funneling
- means labour is impending
- cervix length is shortening
