What are the factors that trigger labour?
This may surprise many people but the truth, is we do not know how labour is triggered!
What is known - and this is incomplete - is the fact that prostaglandins (which are natural chemicals) play a crucial role in the initiation of labour.
What triggers the release of prostaglandins at the crucial moment is not clearly known. To date, it is practically impossible to predict precisely when labour is going to start.
Why is it that some women go into labour prematurely every time and others go into labour at various stages of pregnancy each time?
For the same reason as above, nobody can answer this question succinctly, at least not yet. The intricate mechanism of labour onset remains largely a mystery.
Where are the prostaglandins produced?
Mainly in the uterine muscle, the lining of the uterus and the fetal membranes.
There is what is described as spurious labour or false labour. What does this mean?
Normally, in late pregnancy, the uterus tends to go into mild painless contractions, on and off. These are known as Braxton-Hicks contractions. If these contractions become painful, the woman may erroneously assume that she is in labour. Sometimes there is an unrelated but concomitant low backache, which reinforces the impression of being in labour. Vaginal examination will reveal that there is no evidence of labour.
Spurious labour can be quite distressing and can continue for several days before the onset of true labour.
How is spurious labour managed?
No specific treatment is required. The doctors and midwives will explain the situation patiently to the mother-to-be. Painkillers may be prescribed, to take the edge off the pain. A mixture of light domestic activities, long warm baths and plenty of rest will help to alleviate the discomfort. Labour will eventually start.
What is "head engagement" and what is its significance?
What engagement means is that most of the baby's head has descended into the mother's pelvic cavity and only a small part can be felt abdominally (or not at all). The significance varies. If there are known potential problems - such as a uterine abnormality, pelvic abnormality or a pelvic mass - lack of engagement in late pregnancy (beyond 38 weeks) or at the onset of labour may signify potential problems. The same may be the case if the fetus has been noted to be very large.
The attending midwife or obstetrician may then re-evaluate the planned method of delivery and if there are other strong indicators of potential problems in labour, then the relevant advice will be given.
It is, however, very unusual to advise against labour or vaginal delivery simply on the basis of head engagement or lack of it.
Is ‘early’ engagement of the head of any significance regarding labour onset?
Not really. It may be reassuring to have the head engaging early but this does not guarantee a successful vaginal delivery. When everything is normal, early or late head engagement does not make any difference. In fact, in women of African descent, engagement before the onset of labour is unusual, except in a first pregnancy, when it is slightly more common.