Rupture of membranes (ROM): The amniotic sac has ruptured.

Spontaneous rupture of membranes (SROM): The amniotic sac has ruptured spontaneously.

Prelabour rupture of membranes (PROM): The amniotic sac has ruptured before the onset of labour.

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.

Pre-term: Birth before 37 weeks gestation.

The World Health Organisation classify prematurity as:

• Under 28 weeks: extreme preterm
  • From 24 weeks onwards, there is an increased chance of survival, and full resuscitation is offered.
• 28 – 32 weeks: very preterm
• 32 – 37 weeks: moderate to late preterm

Risk factors for pre-term labour:

• Previous pre-term labour
• Previous cervical trauma
• Previous induced abortion
• Maternal infections (UTI, BV, Malaria, listeria)
• Multifetal pregnancies
• Short cervical length