19.3 Preterm labour

Strictly speaking, preterm labour is the onset of regular painful contractions <37 weeks. In practice, you can treat labour between 34–36 weeks as if it was at term, so that it is only labour <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. 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, 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 and treat accordingly (23.4).

If the membranes have not ruptured, and she is in the active phase of labour (her cervix is >3 cm), don’t try to delay delivery.

If she is in the latent phase of labour (her cervix is <3 cm) assess her contractions by palpation.

If she has regular contractions, look for a possible cause, although you are unlikely to find one. Put her to bed, sedate her (give her pethidine 100mg, or phenobarbitone 60mg).

If her contractions are doubtful, consider other common and less common causes of pain. Urinary tract infection (21.5)? Constipation (12.15)? This is sometimes the result of pica. Abruption (20.11)? Appendicitis (14.1)? Gut obstruction (12.2)? 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 primipara, make a liberal episiotomy and control the delivery of his head with your hands. An episiotomy is usually unnecessary in a multipara, because her perineum is no barrier, unless she has had a previous tear or an episiotomy. Handle him gently and keep him warm.