Premature Labour Flashcards
Rupture of membranes (ROM)
The amniotic sac has ruptured
Spontaneous rupture of membranes (SROM)
The amniotic sac has ruptured spontaneously
Preterm prelabour rupture of membranes (P‑PROM)
The amniotic sac has ruptured before the onset of labour and before 37 weeks gestation (preterm)
Prolonged rupture of membranes (also PROM)
The amniotic sac ruptures more than 18 hours before delivery
Prematurity
Prematurity is defined as birth before 37 weeks gestation
When are babies non viable
Below 23 weeks gestation.
Generally, from 23 to 24 weeks, resuscitation is not considered in babies that do not show signs of life.
Classification of prematurity
Under 28 weeks: extreme preterm
28 – 32 weeks: very preterm
32 – 37 weeks: moderate to late preterm
Prophylaxis of Preterm Labour
Vaginal progesterone
Cervical cerclage
Vaginal Progesterone
Progesterone maintains the pregnancy and prevents labour by decreasing activity of the myometrium and prevents the cervix remodelling in preparation for delivery
Who is offered vaginal progesterone
Women with a cervical length less than 25mm on vaginal ultrasound between 16 and 24 weeks gestation
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 offered cervical cerclage
Women with a cervical length less than 25mm on vaginal ultrasound between 16 and 24 weeks gestation, who have had a previous premature birth or cervical trauma (e.g. colposcopy and cone biopsy)
Rescue cervical cerclage
Offered between 16 and 27 + 6 weeks when there is cervical dilatation without rupture of membranes, to prevent progression and premature delivery
How to diagnose preterm prelabour rupture of membranes
Speculum examination revealing pooling of amniotic fluid in the vagina
When there is doubt about a preterm prelabour rupture of membranes on speculum
Insulin-like growth factor-binding protein-1 (IGFBP-1) - tested on vaginal fluid if there is doubt about rupture of membranes
Placental alpha-microglobin-1 (PAMG-1) is a similar alternative to IGFBP-1
Management of preterm prelabour rupture of membranes
Prophylactic antibiotics given to prevent the development of chorioamnionitis.
Induction of labour may be offered from 34 weeks to initiate the onset of labour
Which prophylactic antibiotics are given in preterm prelabour rupture of membranes
Erythromycin 250mg qds for ten days, or until labour is established if within ten days
Preterm Labour with Intact Membranes
Preterm labour with intact membranes involves regular painful contraction and cervical dilatation, without rupture of the amniotic sac
How to diagnose preterm labour with intact membranes
Speculum examination - cervical dilatation.
Less than 30 weeks gestation - clinical assessment alone enough to offer management of preterm labour
More than 30 weeks gestation - a transvaginal ultrasound to assess the cervical length.
- cervical length less than 15mm - management of preterm labour offered.
- cervical length of more than 15mm - preterm labour is unlikely
Fetal fibronectin is an alternative test to vaginal ultrasound.
Fetal fibronectin
Fetal fibronectin - “glue” between the chorion and the uterus, and is found in the vagina during labour.
A result of less than 50 ng/ml is considered negative, and indicates that preterm labour is unlikely
Management of preterm labour
Fetal monitoring (CTG or intermittent auscultation)
Tocolysis with nifedipine: calcium channel blocker that suppresses labour
Maternal corticosteroids: can be offered before 35 weeks gestation to stimulate surfactant production
IV magnesium sulphate: can be given before 34 weeks gestation and helps protect the baby’s brain
Delayed cord clamping or cord milking: can increase the circulating blood volume and haemoglobin in the baby at birth
Tocolysis
Nifedipine to stop uterine contractions
Used between 24 and 33 + 6 weeks
Atosiban - oxytocin receptor antagonist that can be used as an alternative
Antenatal Steroids
Used in women with suspected preterm labour of babies less than 36 weeks gestation
Two doses of intramuscular betamethasone, 24 hours apart.
Magnesium Sulfate
IV magnesium sulfate protect the fetal brain during premature delivery.
Reduces the risk and severity of cerebral palsy
Given within 24 hours of delivery of preterm babies of less than 34 weeks gestation.
It is given as a bolus, followed by an infusion for up to 24 hours or until birth
Monitoring for magnesium sulphate
Monitor for magnesium toxicity at least 4 hourly
Close monitoring of observations + tendon reflexes (usually patella reflex).
Signs of magnesium toxicity
Reduced RR
Reduced BP
Absent reflexes
