What is the role of steroid injections in pre-term membrane rupture?
Any woman who has had an episode of threatened or real premature labour will probably know that steroid injections are offered, as is generally described, to "help mature the baby's lungs".
It is important to know that the problem that we try to correct using steroids is not the same as the one created by lack or deficiency of water.
Lack of water impairs structural development of the lungs and therefore there is insufficient lung tissue development in such a situation. Steroids are meant to stimulate lung tissue to produce a chemical which facilitates normal lung function. It therefore means that, for the steroids to be useful, there has to be a sufficient amount of lung tissue there in the first place. Steroids facilitate lung function and not lung development.
There is firm evidence that progesterone supplementation in case of threatened pre-term labour (or where there is history suggestive of increased risk of pre-term delivery) can help avert or at least postpone preterm delivery buying valuable time for the baby to stay in the womb. However, studies have shown that the same isn’t the case with pre-term membrane rupture. When this happens, there appears to be no benefit from administering progesterone. In fact there is some suggestion that this may even do harm. Its use in cases of pre-term membrane rupture is therefore not recommended.
What should a mother-to-be expect, faced with such a complication?
The primary aim of the doctors is to evaluate the situation and explore the possibility of a favourable outcome. They will then give thorough counseling to the prospective parents. It is very important to be honest. In cases where preterm rupture of membranes occurs before twenty-six weeks- of gestation, the chances of the baby surviving intact are probably less than 40%.
Even for those who survive, well over half will have some degree of handicap. Prematurity is the main problem. For gestation of over 27 weeks, the outlook is more favourable, but prematurity and its complications can still cause considerable havoc.
After 31 weeks of gestation, the outlook is good and nine out of ten babies survive without problems.
What is the standard advice in preterm rupture of membranes?
There is no standard advice. Each case must be evaluated and managed individually. If, for instance, there is infection already involving the membranes, delivery will be made promptly, regardless of the gestation.
The method of delivery will also depend on the circumstances, even though the chances of having a caesarean section are increased considerably because of such potential problems as cord compression or fetal distress. Rupture of membranes in itself is not an indication for caesarean section.
What if the preterm rupture occurs rather late in pregnancy?
If membranes rupture between 34 and 37 weeks of gestation, worry about the baby's well-being has receded and many obstetricians will just wait for things to happen. This is on the proviso that both the mother and the baby are well.
This policy is adopted mostly because the alternative is to induce labour. This may not be easy, increasing the chance of an otherwise unnecessary caesarean section. In many cases labour will start within 24 to 48 hours.
If delivery was going to be by caesarean section anyway, for other reasons, and preterm rupture of membranes occurs, then delivery will be brought forward, because there is no conceivable benefit in waiting at this gestation. Steroids may still be given even after 34 weeks of gestation if there is concern that the baby may have breathing difficulties should delivery take place within the next 24-48 hours.
The conservative approach is not favoured by everybody, however. Some obstetricians start the process of induction of labour as soon as the mother is admitted with ruptured membranes at this gestation. Still others try to compromise by putting a limit to the waiting time. After this time has elapsed (without labour), induction of labour is commenced. All the facts are put to the mother-to-be, explaining the options and allowing her to make an informed decision on how she would like to proceed.