Preterm labour/ birth
- Normal gestation = 37-40/40
- Preterm = <37w
- Late prem = 34-36/40 (lungs more mature)
- Mod prem = 32-34/40
- Very prem = <32/40
- Extremely prem = <28/40
Also defined by bw
- Low <2500g
- Very low <1500g
- Extremely low <1000g
Definition
Labour - Regular (>4/h) painful contractions + cervical dilatation
Epidemiology
- 7%
Risks causing Prem
- Previous prem
- Multiple pregnancy (eg twins)
- PPROM
- Infection
- Antepartum haemorrhage (blood causes uterus to contract)
- Smoking
- Uterine abnormalities
- Previous cervical surg (cone bx, LLETZ) --> cervical incompetence
NOTE: 50% of Prem moms do not have any RF
Aetiology
- 70-80% spontaneous (prem labour 50%, PROM 30%)
- Antepartum haemorrhage (APH) - placenta abruption
- Infection (irritate uterus, contract)
- Pathological uterine distension (multiple gestation, cervical insuf)
- Activation of HPA axis
- 20% due interventions
Risks of Prem
- Resp distress
- Necrotising enterocolitis
- Cerebral palsy
- Retinopathy (hi O2 rx - resus)
Investigations
- Foetal fibronectin +ve is a screen for prem (50-60% chance of labour in next 1/52)
- If -ve, 95% chance no labour yet
- false positive if recent coitus/ bleeding
- Hi vagina swab
- Continuous CTG
- Amnisure (less specific than fFN)
- FBC, CRP
- Kleihauer (detect foetal blood cells in maternal blood - specific for placenta bleed not sensitive)
- Corticosteroids
- Birth in institution with resus capabilities
- Abx to mom only if PPROM (4h before delivery)
- MgSO4 (rx for preeclampsia - prevents seizures, dec rates of cerebral palsy)
Source
Dr Felicity Dukes 2014