[Systemic analgesia during labour.].

Systemic analgesia is used in obstetrics to alleviate the pain in labour and to prevent adverse effects on the fetus due to maternal pain and stress and subsequent complications such as prolonged labour. To supplement psychological support tranquillizers such as diazepam are useful in allaying anxiety and increasing patients' acceptance of labour. Possible side-effects include neonatal hypothermia and poor muscle tone of the newborn when large doses are given. When pain is more severe opioids should be administered, since less potent analgesics cannot provide adequate pain relief in obstetrics. The most important side effect of opioids is the dose-related respiratory depression, which can be harmful to the neonate. Therefore, large doses (>150 mg pethidine) should be avoided. However, even moderate doses (100 mg pethidine) may adversely affect infant neurobehaviour. Thus, in many cases adequate pain relief afforded to parturients by systemic analgesia may result in altered adaptive functions of the newborn. This makes it reasonable to consider alternative methods, including epidural anaesthesia, which is highly effective and fairly unproblematic. Drug administration in the management of labour pain can be recommended if only small doses are needed and in parturients who refuse regional anaesthesia or for whom it is contraindicated or not available.