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Are there any maternal habits that might predispose to preterm labour?
Yes. Smoking and drug abuse increase the risk of preterm labour.
Anybody who has threatened preterm labour or has had actual preterm labour and delivery in a previous pregnancy and is using either should be strongly advised to quit. Of course, those patients who are abusing heroin are not asked to stop during pregnancy but are switched to a safer and better-controlled drug - methadone.
Cocaine increases the risk of placental abruption, which is associated with preterm labour and a very high rate of fetal loss.
Is there any risk of recurrence of preterm labour?
Yes. A previous preterm labour should be regarded as a risk factor for preterm labour. If the factor that predisposed to preterm labour in the first instance is unidentified, then the risk of recurrence is considered to be substantial.
One preterm delivery raises the individual woman's risk of another preterm birth to around 15% (the general risk is 10%) Some experts now recommend regular (weekly or fortnightly) vaginal swabs from about twenty-four weeks of gestation for women at risk in order to detect any low grade asymptomatic genital tract infections. These are considered to be legitimate risk factors. This may be done if there is a history of previous preterm labour and an absence of any identifiable risk factor. There is really no solid scientific evidence that this strategy is of benefit.
Is there anything that can be done to influence things in preterm labour?
It depends on the gestation and other factors present, as will be discussed below.
If the preterm labour occurs after 34 weeks, most experts agree that there is no need to interfere. Assessment of the labour and maternal and fetal conditions will be made. Labour will be allowed to proceed, unless there are obstetric contraindications (for labour or vaginal delivery), when delivery may be made by caesarean section.
If the preterm labour is before 34 weeks, efforts may be made to stop or - more realistically - postpone labour, to achieve a few more valuable days or, if lucky, weeks.
Can labour be induced?
In some units, preterm labour in the ‘grey’ phase of 34 – 37 weeks is managed actively. That is, if labour does not ensue spontaneously in a couple of days or so, the mother is offered an induction of labour. If she is not suitable for a vaginal delivery, a caesarean section is offered. More often than not, conservative expectant management is adopted to allow for spontaneous labour to ensue as it does sooner or later.When waters have not ruptured and the baby is fine, there is little justification to intervene if the pregnancy gestation is less than 37 weeks.
What do doctors use to stop or postpone labour?
There are a number of medications that can be used to suppress contractions and therefore stop labour. These are not always successful and have a number of side-effects. There is evidence, albeit weak, that any one of them can prolong pregnancy for a maximum of forty-eight hours.
In fact, most experts agree that if the pregnancy continues for more than a few days, it would have done so anyway, with or without the medication. It is, however, very important to understand that the 48 hours or so that may be gained as a result of using these drugs could be extremely crucial for the baby's prospects, once he or she is born. This is explained further below.
How can 24 or more hours gained by suppressing labour help a baby that is going to be born prematurely?
One of the most feared problems of prematurity is lung immaturity. After about 24 weeks of gestation, an administration of steroids - usually in the form of two injections, 12 or 24 hours apart - significantly improves the functional capacity of the baby's lungs, thus improving its chances of survival and the chances of survival without handicap.