Premature Labour Flashcards
Define: rupture of membranes (ROM)
The amniotic sac has ruptured.
Define: spontaneous rupture of membranes (SROM)
The amniotic sac has ruptured spontaneously.
Define: prelabour rupture of membranes (PROM)
The amniotic sac has ruptured before the onset of labour.
Define: preterm prelabour rupture of membranes (P‑PROM)
Preterm prelabour rupture of membranes (P‑PROM): The amniotic sac has ruptured before the onset of labour and before 37 weeks gestation (preterm).
Define: prolonged rupture of membranes (also PROM)
The amniotic sac ruptures more than 18 hours before delivery.
What is prematurity?
Prematurity is defined as birth before 37 weeks gestation. The more premature the baby, the worse the outcomes.
At what week is non-viability considered?
Babies are considered 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. Babies born at 23 weeks have around a 10% chance of survival. From 24 weeks onwards, there is an increased chance of survival, and full resuscitation is offered.
How does The WHO classify prematurity?
The World Health Organisation classify prematurity as:
- Under 28 weeks: extreme preterm
- 28-32 weeks: very preterm
- 32-37 weeks: moderate to late preterm
How can preterm labour be prevented?
Vaginal progesterone and cervical cerclage.
Briefly describe the role of vaginal progesterone in preventing preterm labour
Progesterone can be given vaginally via gel or pessary as prophylaxis for preterm labour. Progesterone has a role in maintaining pregnancy and preventing labour by decreasing activity of the myometrium and preventing the cervix remodelling in preparation for delivery. This is offered to women with a cervical length less than 25mm on vaginal ultrasound between 16 and 24 weeks gestation.
Briefly describe the role of cervical cerclage in preventing preterm labour
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.
Cervical cerclage is offered to 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 may also be offered between 16 and 27 + 6 weeks when there is cervical dilatation without rupture of membranes, to prevent progression and premature delivery.
What is preterm prelabour rupture of membranes?
Preterm prelabour rupture of membranes is where the amniotic sac ruptures, releasing amniotic fluid, before the onset of labour and in a preterm pregnancy (under 37 weeks gestation).
Briefly describe the diagnosis of preterm prelabour rupture of membranes
Rupture of membranes can be diagnosed by speculum examination revealing pooling of amniotic fluid in the vagina. No tests are required.
Where there is doubt about the diagnosis, tests can be performed:
- Insulin-like growth factor-binding protein-1 (IGFBP-1) is a protein present in high concentrations in amniotic fluid, which can be 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
Briefly describe the management of preterm prelabour rupture of membranes
Prophylactic antibiotics should be given to prevent the development of chorioamnionitis. The NICE guidelines (2019) recommend erythromycin 250mg four times daily for ten days, or until labour is established if within ten days.
Induction of labour may be offered from 34 weeks to initiate the onset of labour.
What is preterm labour with intact membranes?
Preterm labour with intact membranes involves regular painful contraction and cervical dilatation, without rupture of the amniotic sac.