Premature labour

• Prematurity is defined as birth before 37 weeks gestation. The more premature the baby, the worse the outcomes.

  Babies are considered non-viable below 23 weeks gestation
• Prophylaxis of preterm labour:

  • Vaginal progesterone - decreases activity of the myometrium and prevents cervical remodelling - offered to women with a cervical length less than 25mm between 16 and 24 weeks
  • Cervical cerclage - stitch in the cervix to add support and keep it closed - offered to women with cervical length less than 25mm between 16 and 24 weeks, who have has a previous premature birth or cervical trauma
• Preterm labour with intact membranes:

  • Regular painful contraction and cervical dilation, without rupture of the amniotic sac
  • Less than 30 weeks gestation, clinical assessment alone is enough to offer management of preterm labour.
  • More than 30 weeks gestation, a transvaginal ultrasound can be used to assess the cervical length. When the cervical length on ultrasound is less than 15mm, management of preterm labour can be offered. A cervical length of more than 15mm indicates preterm labour is unlikely.
• Management of preterm labour with rupture of membranes:

  • Foetal monitoring with CTG
  • Tocolysis with nifedipine - calcium channel blocker that stops uterine contractions
  • Maternal corticosteroids - offered before 36 weeks to develop foetal lungs and reduce respiratory distress syndrome
  • IV magnesium sulphate - given before 34 weeks gestation to protect the foetal brain - reduces risk and severity of cerebral palsy
  • Delayed cord clamping - can increase the circulating blood volume and haemoglobin in the baby at birth
• Mothers need close monitoring for magnesium toxicity at least four hourly. This involves close monitoring of observations, as well as tendon reflexes (usually patella reflex). Key signs of toxicity are:

  • Reduced respiratory rate
  • Reduced blood pressure
  • Absent reflexes