How long does antenatal steroid injection take to work for preterm labour?

Preterm labour means labour may begin before the pregnancy has reached term. Corticosteroids are offered when early birth is a concern because they help the baby's lungs prepare for breathing outside the womb. They are not a painkiller, do not guarantee that labour will stop and do not replace assessment of the cervix, contractions, fetal heart rate or possible infection.

Contact your maternity unit as soon as you notice regular tightening, pelvic pressure, period-like cramps, backache or a change in vaginal discharge. Follow the team's instructions about coming in, monitoring and medicines. If injections are advised, attend each planned dose unless the team tells you otherwise. Keep track of contractions and tell staff about fluid leakage, bleeding, fever or reduced fetal movement.

Get urgent maternity assessment for suspected labour, leaking fluid, vaginal bleeding, severe constant abdominal pain, fever or reduced fetal movement. Do not wait to see whether the steroid takes effect. The timing of birth depends on your condition and your baby's wellbeing, and the team may need to act promptly.

Ask what the injections are expected to do in your situation, when the next dose is due and how labour and fetal wellbeing will be monitored. Ask which changes mean you should call immediately, even after treatment starts.