Preterm prelabour rupture of membranes (PPROM): waters breaking early

Your baby is surrounded by amniotic fluid held in a membrane bag. Normally the waters break shortly before or during labour. The RCOG says PPROM is when this happens before labour at less than 37 weeks. Tommy's adds that it can, but does not always, trigger early labour and that if it happens you need medical help straight away. The RCOG leaflet applies to waters breaking between 24 and 37 completed weeks and says that before 24 weeks you should have a discussion with your healthcare professional about your individual circumstances.

The RCOG says it is not always known why it happens but may be because of infections, placental problems or other causes. Tommy's says it is usually not caused by anything you did or did not do in pregnancy, and lists possible causes including placental problems, pressure within the sac, inflammation or infection and a collection of blood beneath the sac. Risk factors listed include a previous PPROM, vaginal bleeding after 12 weeks, invasive procedures such as amniocentesis, a short cervix, smoking, a differently shaped womb, a low BMI, connective tissue disorders and a multiple pregnancy.

The RCOG says you may notice a gush of fluid or feel damp, and the amount can vary from a trickle to a gush. Tommy's describes a mild popping sensation followed by a trickle or gush that you cannot stop, unlike urine. The RCOG notes that leaking urine is common in pregnancy, but if you think your waters may have broken you should contact your healthcare professional and go to the hospital straight away.

Wear a pad rather than a tampon, so the midwife or doctor can check the amount and colour of the fluid. Do not wait to see whether it settles.

The RCOG says the check-up includes a discussion about the fluid loss and your pregnancy, a check of your general health including temperature, pulse and blood pressure, and a check of the baby's heartbeat. PPROM is best diagnosed by a vaginal examination with a sterile speculum, with your consent, to see whether the leaking fluid is amniotic fluid; a swab test of the fluid may help if it is still unclear, and an ultrasound to estimate the fluid around the baby is sometimes helpful.

Tommy's says that if the test is negative it is unlikely that your waters have broken and you should be able to go home but should return if symptoms recur. The RCOG adds that if only a little fluid is leaking it can be hard to confirm, and if you continue to leak you should go back.

Infection is a key concern. The RCOG says the membranes form a protective barrier and, once broken, infection can reach the uterus (chorioamnionitis), which can cause early labour or lead to you or your baby developing sepsis. Signs include a raised temperature, an unusual or unpleasant-smelling discharge, a fast pulse and lower abdominal pain, and the baby's heart rate may be faster than normal. If infection is suspected the baby may need to be born straight away.

Other points from the RCOG and Tommy's: about half of women go into labour within a week, babies born early have increased risk of breathing, feeding and infection problems and may need a neonatal unit, and rarer complications include cord prolapse, placental abruption and, with very early PPROM before 24 weeks, poor lung development (pulmonary hypoplasia). The RCOG is clear that, sometimes, a baby may not survive, with risk higher if waters break very early or birth is very early. Your team will discuss likely outcomes for your gestation.

The RCOG and Tommy's say it is not possible to replace the fluid or repair the hole, and you may continue to leak for the rest of the pregnancy because fluid keeps being made. Treatments that may be offered to reduce risk are listed below. Whether they apply to you depends on your gestation and situation; they are always prescribed by your clinical team, and you should not start or stop any medicine without their advice.

• A course of antibiotics to reduce the risk of infection reaching the womb; the RCOG says this can also help delay labour.

• A course of steroid injections to help the baby's development and reduce problems from being born early.

• Magnesium sulfate, offered if the baby is at risk of being born very early, which can reduce the risk of cerebral palsy (Tommy's says if you are in labour or having a planned birth within 24 hours).

• Intravenous antibiotics if you are in preterm labour, to reduce the risk of early-onset group B strep infection.

You will usually be advised to stay in hospital for a few days after your waters break so that you and your baby can be closely monitored, with regular temperature, pulse and blood pressure, blood tests for infection and baby heart-rate checks. The RCOG says your healthcare professional will discuss going home if you are well and not thought to be at higher risk of early birth, with check-ups usually once or twice weekly.

The RCOG says to contact your healthcare professional and return to hospital immediately for a raised temperature, flu-like symptoms, vaginal bleeding, greenish or smelly leaking fluid, contractions or cramping pain, abdominal or back pain, or if the baby is not moving as normal. Tommy's gives over 37.5 as the temperature threshold. If you feel very unwell, collapse, or have heavy bleeding, call 999.

The RCOG says that if you and your baby are well with no signs of infection you may be advised to wait until 37 weeks, because continuing reduces the risks of being born preterm. If you are known to carry group B strep you may be advised to give birth from 34 weeks. NICE guideline NG207 on inducing labour says that with PPROM before 34+0 weeks induction should not be carried out unless there are additional reasons such as infection or fetal compromise, that between 34+0 and 37+0 weeks the options of expectant management until 37+0 weeks or induction are discussed, and that if you have a positive group B strep test, immediate induction or caesarean birth should be offered.

The RCOG says vaginal birth is often possible after PPROM, depending on when labour starts, the baby's position and your circumstances. It says that after PPROM or preterm birth you are at an increased risk of preterm birth in future pregnancies and will be advised to be under a specialist team. Emotional support should be offered, and organisations such as Little Heartbeats, Group B Strep Support, Sands and the UK Sepsis Trust are signposted. Policies on timing differ between hospitals and UK nations.