Treatment of preterm labour. A review of the therapeutic options.

Preterm delivery accounts for a major proportion of perinatal deaths. The cause of preterm labour is usually not known, but in most instances, maintaining the fetus in utero appears to be preferred to allowing preterm delivery. Numerous pharmacological agents have been utilised to inhibit preterm labour, but none has proven to be ideal. Currently, the beta-adrenoceptor stimulants such as ritodrine, terbutaline, isoxsuprine, salbutamol and fenoterol provide the best combination of safety and efficacy. However, because of their potential adverse effects, adequate maternal and fetal surveillance needs to be maintained throughout their administration. Magnesium sulphate, although probably not as effective as other labour-inhibiting drugs, is an appropriate choice when the beta-adrenoceptor stimulants are either contraindicated or poorly tolerated. Other drugs such as the prostaglandin inhibitors, diazoxide or the calcium antagonists are also potent labour-inhibitors, but further controlled studies are required to evaluate the risks associated with their use. Ethanol has been supplanted by the beta-adrenoceptor stimulants and is unlikely to be used in the future.