The amniotic sac and fluid play an important role in the labour process and usually remain intact until the end of labour. However, around 10% of women will experience their waters breaking before labour begins (Prelabour Rupture of Membranes - PROM). The standard approach to this situation is to induce labour by using prostaglandins and/or syntocinon (pitocin) to stimulate contractions. The term 'augmentation' is often used instead of 'induction' for this procedure. Women who choose to wait are told their baby is at increased risk of infection and they are encouraged to have IV antibiotics during labour.

The rush to start labour and get the baby out after the waters have broken is fairly new. When I first qualified in 2001, the standard hospital advice (UK) for a woman who rang to tell us her waters had broken (and all else was well) was: "If you're not in labour by [day of the week in 3 days time] ring us back." Over the following years, this reduced from 72 hours to 48 hours, then 24 hours, then 18 hours, then 12 hours and now 0 hours. You might assume that this change was based on some new evidence about the dangers involved in waiting for labour. You would be wrong. This post is mainly based on a couple of Cochrane Reviews [1; 2] because hospitals are supposed to base their policies/guidelines on research evidence. 

Please note that this post is not about preterm rupture of membranes (before 37 weeks).

The term 'rupture of membranes' simply means there is a tear/hole in the amniotic sac. Where the hole is will alter how the amniotic fluid leaks out. However, there is no such thing as a 'dry labour' because the baby and placenta keep making amniotic fluid all the way through labour.

Forewater leak: The woman will likely experience a big gush as the fluid between the baby's head and the cervix bursts. The baby's head will move down and plug the cervix, but fluid will keep trickling past their head and through the cervix. Further gushes of fluid can happen if the baby moves their head.

Hindwater leak: This is usually less dramatic than a forewater leak. The hole in the amniotic sac is behind the baby's head, so fluid has to leak out between the amniotic sac and the uterus, past the baby's head and forewaters and out of the vagina. The result is a slow leaking of fluid over time. The forewaters remain intact and function in the same way during labour.

Chorion / Amnion leak: This isn't actually a rupture of membranes at all and often results in a misdiagnosis...

Continue reading this article on Dr. Rachel Reed's website here.