Defined as birth before 37 weeks gestation

Definitions

The WHO classify prematurity as:

• Under 28 weeks: extreme preterm
• 28 – 32 weeks: very preterm
• 32 – 37 weeks: moderate to late preterm

Aetiology

Risk factors

• 2 preterm deliveries increases the risk of another premature baby by 70%

• Abnormally shaped uterus increases the risk of giving birth early by 19%
• Women are 9 times more likely to give birth early if they have a multiple pregnancy
• Interval of < 6 months between pregnancies
• Conceiving through IVF
• Smoking, drinking alcohol, using illicit drugs
• Poor nutrition, some chronic conditions (high BP, diabetes), multiple miscarriages or abortions

Management (before birth)

Delaying birth

• There is a dramatic improvement in prognosis with each additional week of gestation, particularly in very premature babies
• In women with a history of preterm birth or an ultrasound demonstrating a cervical length of 25mm or less before 24 weeks gestation there are two options of trying to delay birth:
  • Prophylactic vaginal progesterone: putting a progesterone suppository in the vagina to discourage labour
  • Prophylactic cervical cerclage: putting a suture in the cervix to hold it closed

Improving outcomes