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How common is it for membranes to rupture before term?
It is fairly common in the sense that it affects about 8 per cent of all pregnancies. Overall, 10 per cent of all pregnancies will be affected by membranes rupturing before labour. The difference (2 per cent) is accounted for by rupture at term but before the onset of labour.
What is the difference between membranes rupturing before term and before labour?
If membranes rupture before the onset of labour then this is termed "pre-labour rupture of membranes", regardless of the gestation. If this occurs before thirty-seven weeks of gestation, then it is further qualified by the term "preterm pre-labour rupture of membranes" (PPROM). The significance is in the prematurity in the latter case.
When should membranes ideally rupture?
Amniotic fluid membranes (or "waters", in popular terms) should stay intact until the onset of labour. The waters will go at any stage of labour. This may be spontaneous or they may be artificially ruptured (if this is seen to be useful or necessary). This is what happens in 90 per cent of all pregnancies.
What does "premature rupture of membranes" mean?
This has been mentioned here in case it is a term that has been used by your midwife or doctor. It is in fact an old term which is both inaccurate and misleading. The original meaning of the term was a situation where waters broke before the onset of labour, even at term. This, as you can see, can create confusion. It is a term that has been largely abandoned but old habits die hard and old medical habits probably die hardest. You may therefore encounter somebody using it. In this text, we shall stick with the currently used terms, i.e. preterm rupture of membranes and pre-labour rupture of membranes, which are self-descriptive.
What happens when membranes rupture before labour?
You will notice a gush or trickle of fluid from the vagina. It is usually clear and feels warm. It can be - and often is - confused with urine incontinence, especially when it is only a trickle. The tendency is for the leak to continue and it is normally increased by actions such as laughing, coughing or sneezing. There is usually no pain.
What do you need to do when the waters break?
Regardless of the gestation, the mother should be seen in a maternity unit promptly. One of the not infrequent statements that obstetricians and midwives hear with a sinking heart is, "Oh, I have been wet for the last three days or so." This, quite frankly, is irresponsible on the part of the mother. The plan of management needs to be put in place immediately after any pre-labour rupture of membranes, regardless of whether it is term or preterm.
Why should one worry about the waters breaking if the pregnancy is already at term?
There are immediate concerns such as cord complications. Pre-labour rupture of membranes could be complicated by prolapse of the cord, which may then be compressed, effectively cutting off the blood supply to the fetus. By the time the mother is alerted by, let's say, loss of fetal movements, it is really too late.
Delayed complications of pre-labour rupture of membranes at term include infection, especially if labour is delayed for a number of days. The baby may be born in poor health and could suffer from severe pneumonia or other serious forms of infection as a result.
Most obstetric units operate a policy of inducing labour after twenty-four hours if it has not happened spontaneously. Even those units which observe a more conservative policy will take measures to exclude infection or to monitor for any signs of this, so that timely appropriate action can be taken.