Strictly speaking, preterm labour is the onset of regular painful contractions before 37 weeks. In practice, you can treat labour between 34 and 36 weeks as if it was at term, so that it is only labour before 34 weeks that needs managing differently. It may or may not be associated with rupture of the membranes.
The management of preterm labour is controversial. We think you should avoid tocolytics and steroids. Using them may lead you to think that you are doing something useful when you are not, and divert you away from the treatment of the cause of the premature labour, which may be antepartum haemorrhage, a urinary tract infection, or intrauterine growth retardation (IUGR), etc. In practice, when a mother does go into preterm labour there is little you can do about it. It often stops spontaneously, so that 70% of mothers are not delivered 48 hours later, and go into labour normally nearer term.
PRETERM LABOUR If a patient goes into labour before 34 completed weeks, find out if her membranes have ruptured, if necessary by the methods in Section 19.5. If they have ruptured, manage her as in that section. If they have not ruptured, manage her like this:
If she is in the active phase of labour (her cervix is [mt]3 cm), don't try to delay delivery.
If she is in the latent phase of labour (her cervix is [lt]3 cm) assess her contractions by palpation.
If she has regular contractions and her membranes are not ruptured, look for a possible cause, although you are unlikely to find one. Put her to bed, sedate her (give her pethidine 100 mg, or phenobarbitone 60 mg). Some obstetricians use tocolytics.
If her contractions are doubtful, consider other common and less common causes of pain. Urinary tract infection (17.6)? Constipation? This is sometimes the result of pica, eating quantities of earth, etc. Abruption (16.13)? Appendicitis (12.1)? Gut obstruction (10.3)? Other abdominal conditions (10.2)? Put her to bed and observe her for 24 hours.
WHEN SHE GOES INTO LABOUR her baby is at high risk, so, if she is a primip, make a liberal episiotomy, and control the delivery of his head with your hands. An episiotomy is usually unnecessary in a multip, because her perineum is no barrier, unless she has had a previous tear or an episiotomy. Handle him gently and keep him warm.