Pre-term Birth Flashcards
Definition of Pre-term labour
The occurrence of regular uterine activity which produces either cervical effacement or dilation prior to 37 weeks gestation
Incidence of Pre-term labour
6-7% in the UK –> 2-3% are Iatrogenic deliveries
1-2% are very pre-term (before 32 weeks)
Mortality of pre-term birth
Perinatal mortality is dependent on gestational age
Exponentially increases with increasing prematurity
Also significant risk of lifelong disability
Causes of preterm delivery (3,3,1)
Spontaneous labour --> 30-50% Multiple pregnancy --> 10-30% Premature ROM --> 5-40% Hypertensive disorders --> 10% IUGR --> 5% APH --> 10% Other --> 10%
Risk factors for pre-term birth (3,4,2,4)
Age (>35), Primeip, IVF, maternal illness, ethnicity (black), weight gain, bacteriuria, HTN, smoking, multiple pregnancy, APH, fetal abnormalities,cervical incompetence
Causes of Iatrogenic prematurity
When a patient is induced early on purpose
Pre-eclampsia (42.5%), Fetal distress (26.7%)
IGUR (10%), Abruption (6.7%), Fetal death (6.7%)
Other - placenta previa, maternal medical disorders
Short term complications of prematurity (7)
Neonatal death, Morbidity due to precipitating factor
Respiratory distress syndrome, Cardiovascular (PDA etc), Immune failure, necrotising entercolitis, intraventricular haemorrhage, retinopathy of prematurity, birth trauma
Long term complications of prematurity
Cerebral Palsy, Visual Problems, Poor respiratory function and ongoing breathing problems, poor cognitive and behavioural function
How can we predict preterm labour?
Past Obstetric Hx, scoring systems (POH or social status), Using home uterine monitoring, Cervical Length (V. good indication if IL-6, IL8, fFN
Cervicovaginal fetal fibronectin
An extracellular matrix protein produced by chorionic cells which is an adhesive binding the membranes to the uterine wall –> structurally altered at the end of pregnancy to make it less adhesive –>should not be present in the vagina between 22-36 weeks. only have negative predictive value
Role of the cervix in preventing ascending infection
Acts as a barrier both physically and because mucus has antibacterial properties
breach of this barrier leads to inflammatory processes which further weaken the barrier and can lead to preterm labour
Diagnosis of preterm labour
Regular contractions
pPROM
Cervical dilation or effacement
Treatment of pre-term labour
Drugs to stop contractions (tocolysis): oxytocin receptor antagonists, Beta-mimics, NO donors, CCB, MgSO4, NSAIDs
Also steroids, antibiotics, progestogens, cervical cerclage
Contraindications for tocolysis
Should not be used in cardiac disease or eclampsia
Intrauterine infection or death
APH or placenta previa
Benefits of steroids
Reduce neonatal death
Respiratory distress syndrome
Necrotising enterocolitis
Periventricular haemorrhage
Antibiotics in pre-term labour
Some evidence for giving augmentin or erythromycin in preterm labour with intact membranes
Treatment of BV in early labour is controversial
If SROM give Erythromycin (or penicillin if group B strep) as co-amox increases the risk of NEC while gentamicin is associated with auditory and vestibular damage.
Cervical cerclage
A strong stitch being placed in and around the cervix between 12-14 weeks to prevent cervical incompetence and miscarriage
Chorioamnionitis
Ascending infection - risk is increased by SROM and each vaginal exam. Will cause maternal fever, uterine tenderness if PROM. May have purulent discharge, if severe it can lead to vasculitis of umbilical vessels. Treat with delivery, broad spec abx for the mother. Increases the risk of cerebral palsy and periventricular leukomalacia.
Braxton Hick contractions
Prodromal labour are sporadic uterine contractions which sometimes start around six weeks into a pregnancy. Not usually felt until the 2nd or 3rd trimester. Will be infrequent, irregular and only mild cramping (1-2mins). Can be improved by hydration, breathing, lying on the left side, urination or moving.
