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  • Print publication year: 2005
  • Online publication date: August 2009

8 - Management of threatened preterm labour



Preterm labour (PTL) is the onset of labour (regular uterine contractions and cervical effacement and dilatation) between the limit of viability and term. In practice, it is defined as labour between 20 and 37 completed weeks of gestation.

Clinical assessment

The history is notoriously unreliable in the diagnosis of PTL, as the only symptom (maternal perception of contraction frequency or strength) is a poor guide to the outcome. Approximately 50% of patients presenting with threatened PTL will deliver at term even without treatment (Lockwood et al. 1991). However, in a proportion of patients, temporal changes in symptoms within an individual are helpful in guiding management. Clinical examination, particularly palpation of the uterus is often unreliable in assessing contraction strength. Vaginal speculum examination is useful however, to determine cervical effacement, dilation and the presence of amniotic fluid. Digital vaginal examination should be avoided if the membranes are ruptured to reduce the risk of introducing infection.

Further history and examination should include determination of the gestational age and presenting part, and elicit symptoms or signs of chorioamnionitis, maternal medical conditions (diabetes, thyrotoxicosis, cardiac disease, hypertension), pregnancy specific disorders (pre-eclampsia) and possible precipitating conditions in the current pregnancy (abruption, placenta praevia, multiple pregnancy, ruptured membranes). Fetal condition and presentation should also be assessed (Table 8.1).


General investigations

Specific investigations will be directed by clinical symptoms and signs although urinalysis (to exclude infection) and a full blood count are indicated in the majority of women.

American College of Obstetricians and Gynecologists (ACOG). (2002) ACOG Committee Opinion: Antenatal corticosteroid therapy for fetal maturation. Obstet. Gynecol. 99, 871–3.
American College of Obstetricians and Gynecologists (ACOG).(2003) ACOG Committee in Practice Bulletins – Obstetrics. Practice Bulletin no 43 – Management of Preterm labour. Obstet. Gynecol. 101, 1039–48.
Banks, B. A., Cnaan, A., Morgan, M. al. (1999) Multiple courses of antenatal corticosteroids and outcome of premature neonates. Am. J. Obstet. Gynecol. 181, 709–17.
Bottoms, S. (1995) Delivery of the premature infant. Clin. Obstet. Gynaecol. 38, 780–9.
Crowley, P., (2002) Prophylactic corticosteroids for preterm birth (Cochrane Review). In The Cochrane Library, Issue 4. Oxford: Update Software.
Crowther, C. A., (2002) Phenobarbital prior to preterm birth (Cochrane review). In The Cochrane Library, Issue 4. Oxford: Update software.
Crowther, C. A., and Harding, J. (2003) Repeat doses of prenatal corticosteroids for women at risk of preterm birth for preventing neonatal respiratory disease (Cochrane Review) In The Cochrane Library, Issue 3. Oxford. Update software.
Crowther, C. A., Alfirevic, Z. and Haslam, R. R. (2002) Antenatal thyrotropin-releasing hormone (TRH) prior to preterm delivery (Cochrane review). In The Cochrane Library, Issue 4. Oxford: Update software.
Druzin, M. L., Fox, A., Kogut, E. and Carlson, C. (1985) The relationship of the non-stress test to gestational age. Am. J. Obstet. Gynecol. 153, 386–9
Duckitt, K. and Thornton, S. (2003) Nitric oxide donors for the treatment of preterm labour (Cochrane Review). In The Cochrane Library, Issue 1. Oxford: Update Software.
Fejgin, M. D., Delpino, M. L. and Bidiwala, K. S. (1994) Isolated small bowel perforation following intrauterine treatment with indomethacin. Am. J. Perinatol. 11, 295–6.
Fuchs, A. R., Fuchs, F., Husslein, P. and Soloff, M. S. (1984) Oxytocin receptors in the human uterus during pregnancy and parturition. Am. J. Obstet. Gynecol. 150, 734–41.
Grant, A. and Glazener, C. M. A. (2002) Elective caesarean section versus expectant management for delivery of the small baby (Cochrane Review). In The Cochrane Library, Issue 4. Oxford: Update Software.
Grant, A., Penn, Z. J. and Steer, P. J. (1996) Elective or selective caesarean section for the small baby? A systematic review of the controlled trials. BJOG 103, 1197–200.
Groom, K. M., Shennan, A. H., Jones, B. A., Seed, P. and Bennett, P. (2003) TOCOX – a randomised double-blind placebo-controlled trial of rofecoxib (a cox-2 specific PG inhibitor) for the prevention of preterm delivery in high-risk women. J. Obstet. Gynaecol 23, S19.
Gyetvai, K., Hannah, M. E., Hodnett, E. D. and Ohlsson, A. (1999) Tocolytics for preterm labour: a systematic review. Obstet. Gynecol. 94, 869–77.
Hannah, M. E., Hannah, W. J., Hewson, S. al. (2000) Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial. Term Breech Trial Collaborative Group. Lancet 356, 1375–83.
Honest, H., Bachmann, L. M., Gupta, J. K., Kleijnen, J. and Khan, K. S. (2002) Accuracy of cervico-vaginal fetal fibronectin test in predicting risk of spontaneous preterm birth: systematic review. BMJ 325, 301–11.
Kenyon, S. L., Taylor, D. J. and Tarnow-Mordi, W.; ORACLE Collaborative Group (2001a) Broad-spectrum antibiotics for preterm, prelabour rupture of membranes: the ORACLE I randomised trial. Lancet 357, 979–88.
Kenyon, S. L., Taylor, D. J. and Tarnow-Mordi, W.; ORACLE Collaborative Group (2001b) Broad-spectrum antibiotics for spontaneous PTL: the ORACLE II randomised trial. Lancet 357 989–94.
Kierse, M. J. N. C., Grant, A. and King, J. F. (1989) Preterm labour. In Chalmers, I., Enkin, M. and Kierse, M. J. N. C., eds., Effective Care in Pregnancy and Childbirth. Oxford: Oxford University Press, pp. 694–745.
King, J. and Flenady, V. (2003) Prophylactic antibiotics for inhibiting preterm labour with intact membranes (Cochrane Review). In The Cochrane Library, Issue 3. Oxford: Update Software.
King, J. F., Flenady, V. J., Papatsonis, D. N. M., Dekker, G. A. and Carbonne, B. (2002) Calcium channel blockers for inhibiting preterm labour (Cochrane Review). In The Cochrane Library, Issue 4. Oxford: Update Software.
Kirshon, B., Moise, K. J., Mari, G. and Willis, R. (1991) Long-term indomethacin therapy decreases fetal urine output and results in oligohydramnios. Am. J. Perinatol. 8, 86–8.
Leitich, H., Brunbauer, M., Kaider, A., Egarter, C. and Husslein, P. (1999) Cervical length and dilatation of the internal cervical os detected by vaginal ultrasonography as markers for preterm delivery: A systematic review. Am. J. Obstet. Gynecol. 181, 1465–72.
Lockwood, C. J. (1997) Calcium channel blockers in the management of preterm labour. Lancet 350, 1339–40.
Lockwood, C. J., Senyei, A. E., Dische, M. R. (1991) Fetal fibronectin in cervical and vaginal secretions as a predictor of preterm delivery. N. Engl. J. Med. 325, 669–74.
Lumley, J. (2003) Method of delivery for the preterm infant. BJOG 110, 88–92.
MacLennan, F. M., Thomson, M. A., Rankin, R., Terry, P. B. and Adey, G. D. (1985) Fatal pulmonary oedema associated with the use of ritodrine in pregnancy. A case report. BJOG 92, 703–5.
Matsuda, Y., Maeda, Y., Ito, al. (1997) Effect of magnesium sulfate treatment on neonatal bone abnormalities. Gynec. Obstet. Invest. 44, 82–8.
Mittendorf, R., Covert, R., Boman, al. (1997) Is tocolytic magnesium sulphate associated with increased total paediatric mortality?Lancet 350, 1517–18.
Moutquin, J. M., Sherman, D., Cohen, al. (2000) Double-blind, randomized, controlled trial of atosiban and ritodrine in the treatment of preterm labour: a multicenter effectiveness and safety study. Am. J. Obstet. Gynecol. 182, 1191–9.
Norton, M. E., Merrill, J., Cooper, B. A., Kuller, J. A. and Clyman, R. I. (1993) Neonatal complications after the administration of indomethacin for preterm labour. N. Engl. J. Med. 329, 1602–7.
Olatunbosun, O. A., al-Nuaim, L. and Turnell, R. W. (1995) Emergency cerclage compared with bed rest for advanced cervical dilatation in pregnancy. Int. Surg. 80, 170–4.
Papatsonis, D. N., Geijn, H. P., Ader, H. al. (1997) Nifedipine and ritodrine in the management of preterm labour: a randomized multicenter trial. Obstet. Gynecol. 90 230–4.
Peruzzi, L., Gianoglio, B., Porcellini, M. G. and Coppo, R. (1999) Neonatal end-stage renal failure associated with maternal ingestion of cyclo-oxygenase-type-1 selective inhibitor nimesulide as tocolytic. Lancet 354, 1615.
Royal College of Obstetricians and Gynaecologists (RCOG). (2002) Tocolytic Drugs for Women in Preterm Labour RCOG Guideline 1B
Romero, R., Sibai, B. M., Sanchez-Ramos, al. (2000) An oxytocin receptor antagonist (atosiban) in the treatment of preterm labour: A randomised, double-blind, placebo-controlled trial with tocolytic rescue. Am. J. Obstet. Gynecol. 182, 1173–83.
Sakamoto, C. (1998) Roles of COX-1 and COX-2 in gastrointestinal pathophysiology. J. Gastroenterol. 33, 618–24.
Sawdy, R., Slater, D., Fisk, N., Edmonds, D. K. and Bennett, P. (1997) Use of a cyclo-oxygenase type-2-selective non-steroidal anti-inflammatory agent to prevent preterm delivery. Lancet 350, 265–6.
Sawdy, R. J., Lye, S., Fisk, N. M. and Bennett, P. R. (2003) A double-blind randomized study of fetal side effects during and after the short-term maternal administration of indomethacin, sulindac, and nimesulide for the treatment of preterm labour. Am. J. Obstet. Gynecol. 188, 1046–51.
Smith, G. N., Walker, M. C. and McGrath, M. J. (1999) Randomised, double blind, placebo controlled pilot study assessing nitroglycerin as a tocolytic. BJOG 106, 736–9.
Smolders-de Haas, H., Neuvel, J., Schmand, al. (1990) Physical development and medical history of children who were treated antenatally with corticosteroids to prevent respiratory distress syndrome: a 10 to 12 year follow-up. Paediatrics 86, 65–70.
Souter, D., Harding, J., McCowan, al. (1998) Antenatal indomethacin- adverse fetal effects confirmed. Aust. N. Z. J. Obstet. Gynecol. 38, 11–16.
Stan, C., Boulvain, M., Hirsbrunner-Amagbaly, P. and Pfister, R. (2002) Hydration for treatment of preterm labour (Cochrane Review). In The Cochrane Library, Issue 4. Oxford: Update Software.
Takahashi, K., Diamond, F., Bieniarz, J., Jen, H. and Burd, L. (1980) Uterine contractility and oxytocin. Sensitivity in preterm, term, and posterm pregnancy. Am. J. Obstet. Gynecol. 136, 774–9.
Hof, M. and Crane, J. (2001) Ultrasound cervical assessment in predicting preterm birth. J. Soc. Obstet. Gynecol. Can. 23, 418–21.
Iddekinge, B., Gobetz, L., Seaward, P. G. and Hofmeyr, G. J. (1991) Pulmonary oedema after hexoprenaline administration in preterm labour. A report of 4 cases. S. Afr. Med. J. 79, 620–2.
Vermillon, S. T., Scardo, J. A., Lashus, A. G. and Wiles, H. B. (1997) The effect of indomethacin tocorysis on fetal ductus arteriosus constriction with advancing gestational age. Am. J. Obstet. Gynecol. 177, 256–9.
Walfisch, A., Hallak, M. and Mazor, M. (2001) Multiple courses of antenatal steroids: risks and benefits. Obstet. Gynecol. 98, 491–7.
Whitelaw, A. and Thoresen, M. (2000) Antenatal steroids and the developing brain. Arch. Dis. Child. Fetal Neonatal Ed. 83 F154–7.