Premature Rupture of the Membranes
Premature rupture of the membranes (PROM) is when the sac of water surrounding the baby breaks and the liquor leaks out. This can happen either at the end of pregnancy, or earlier on well before the due date. When it happens near the end (after 37 weeks, or term) it is known as PROM - it is still deemed premature as labour contractions haven't started.
Should I be Induced?
There is much debate as to what to do when PROM happens at term. Some believe that labour should start within 24 hours or the risk of infection outweighs the risks of induction of labour.
Others feel that the risk of infection remains low for the next 72 hours and waiting gives the benefit of avoiding the 'cascade of intervention' that may occur with induction of labour - by this time, most women will have gone into labour, anyway. In either case, the risk to the baby is very small and either way to go is reasonable.
Preterm PROM (before 37 weeks) is much more likely to lead to problems and this will be discussed in more detail.
Have My Waters Actually Gone?
This may sound a stupid question, but it is not always immediately obvious if this is the case. There are two bags of water in the pelvis, the other, of course, being the bladder, and its not at all unusual for women to leak urine at some time during pregnancy. If there is an ongoing leak, particularly after having been lying flat for some time (suggesting pooling of fluid in the vagina) and it smells sweet, then it may be liquor. There is no foolproof way of telling and if there is any doubt, a doctor or midwife should be consulted for an examination.
An examination will involve feeling your abdomen (to see if it feels like there's less water around the baby) and a speculum examination - like when you have a smear test done. The cervix is visualised and you'll be asked to cough. If the waters have gone, a gush of water is often seen coming out of the cervix.
Some doctors use Amni-stix or nitrizine sticks, which change colour when dipped into liquor. These are not 100% accurate and can be falsely positive in the presence of bleeding, with some vaginal infections or if you've had unprotected sex recently. Swabs are also taken to check for the presence of infection.
They Have Gone - What Now?
Once it is confirmed that your waters have gone, your obstetrician will discuss with you the plan until delivery. There is no simple definition of what is the right thing to do, and it will depend very much on exactly how far on the pregnancy is and if there are any signs to suggest the presence of infection.
Infection is the main risk to the continuing pregnancy once PROM is confirmed. The amniotic membranes and liquor represent a formidable barrier to infection, and now bacteria may work their way from the lower genital tract into the womb, causing infection around the baby.
The other main risk to the baby is that of prematurity, should she be born now. Prematurely born babies face several problems, the most severe of which can be breathing difficulties, as the lungs are not adequately developed. All the babe's systems are immature and premature infants face many weeks on a special care unit depending on the age at which they are born.
On the whole, the risks of prematurity are the greater of the two, as long as there's no obvious signs of infection - such as a fever, tenderness over the womb, or even pus-stained liquor. Once infection sets in, the balance of risk is almost always in the other direction and delivery would be expedited - often labour starts itself because of infection, sometimes induction is needed.
How Long Until Labour Starts Naturally?
At the end of pregnancy when the waters go, about 80% of women will start contracting within 24 hours. The earlier PROM occurs, the longer is the latency period until contractions begin. At 30 to 32 weeks, the average is about one week, and at 25-26 weeks, it is two weeks with half having delivered after the first week.
Can the Membranes 'Reseal'?
Sometimes there can be an ongoing loss of water, but the pregnancy lasts until term. 'Resealing' of the membranes is also possible: one study found this to happen in three of 31 women (9.7%) with PROM at less than 26 weeks and five of 189 (2.6%) at 26 to 34 weeks. So, it does happen, but is unusual.
Further Treatments: Steroids & Stopping Labour
Studies have looked at trying to stop labour when it starts after the waters have gone, but there is no real benefit in terms of significant prolongation of the pregnancy. Steroid injections are prescribed (usually in pregnancies before 34 weeks) to help mature the baby's lungs. They aren't the type of steroids that make you muscular, but they stimulate the babe's lungs to prepare for breathing air. Should you not go on to deliver, this doesn't do any harm, so there are really no draw backs to having them.
Sometimes drugs are used to stop labour to allow the steroid course to be completed; this normally takes about 24 to 36 hours. Also,labour may be stopped while mum is transferred to a hospital able to manage a premature infant.
Looking for the Development of Infection
In the time between the PROM being diagnosed and labor starting, there seems to be little consensus on where women should be managed. Many doctors prefer women to remain as hospital inpatients during this time. This allows a regular check on temperature, pulse rate and development of womb tenderness which may indicate infection. Twice weekly blood tests looking for signs of a response to infection and weekly vaginal swabs are often instigated.
Increasingly, however, doctors are beginning to feel that the risks of infection with PROM have been previously overstated, and many are now happy for women to be managed at home after an initial period in the hospital. Daily temperature checks are helpful and the other investigations mentioned above can be done in the clinic.
Will My Baby Survive and be Healthy if Born Early?
This is something that a doctor from the neonatal unit will be able to discuss. Survival rates vary in different parts of the world and in different units.
In the UK, when delivery occurs after 30 weeks gestation, the outlook for the baby is very good, all other things being equal. Between 28 to 30 weeks there is still a good chance of a normal outcome, although some infants will run into problems. An infant delivering at 24 to 25 weeks can be expected to have a difficult time on a neonatal unit, and unfortunately many do not survive. Every day between 25 and 28 weeks is important and chance of survival without long-term problems gradually improves. These are, of course, gross generalisations, and individual factors will apply.
What About Very Early Membrane Rupture?
At 20 to 23 weeks, survival is unfortunately poor (20% to 25%) and there is a high incidence of handicap in those who do live. PROM before 20 weeks gestation is associated with significant risk of infection and survival chance is negligible, and usually then with significant handicap. Some elect termination of pregnancy in this case to protect the mother from what can sometimes be an overwhelming infection. Unfortunately there is no therapy available to replace the fluid or, at present, to plug the hole in the membranes.
However, survival is not impossible. Some women have had their liquor break prior to 20 weeks and gone on to give birth to babies that, after much time in intensive care, have developed into healthy babies. This is not the common outcome, though. If you find yourself in this situation, discuss with your doctor what the best course of action is for you.
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