Analgesia for labour

Regional analgesia is the method of choice. Good analgesia prevents hypertensive episodes associated with contraction pain. Well-conducted epidural or combined epidural-spinal analgesia may be beneficial to the compromised fetus by improving uteroplacental perfusion. A combination of low-dose local anaesthetic and opioid may be given by continuous epidural infusion or intermittent boluses, and this can be supplemented as necessary should instrumental or operative delivery be required. A pre-epidural platelet count should be performed (if trends suggest that platelet numbers are decreasing significantly, a platelet count should be repeated immediately before epidural injection is commenced). Current opinion suggest that a platelet count of at least 80 x 109/l is advisable before instituting central neural blockade, although any stated lower safe limit is entirely arbitrary, and the relative risks and benefits of regional analgesia and anaesthesia must be considered for each patient. Several studies have confirmed that if the platelet count is at least 100 x 109/l there is no need to perform further coagulation studies. In some centres thromboelastography or similar techniques have been used to indicate the status of coagulation and fibrinolytic, but these are not widely available. Bleeding time has been suggested as a clinical tool for assessment of coagulation, but a normal range for bleeding time has not been established in pregnancy and there is considerable inter- and intraobserver variability in its measurement, so this is rarely used.

If epidural analgesia is contraindicated, it is important to control the blood pressure by using appropriate agents (hydralazine, nifedipine, labetalol) and to provide alternative analgesia. Patient-controlled intravenous opioids offer the mother the psychological benefit of being in control of her analgesia and are more predictable than intramuscular opioids.

Transcutaneous electrical nerve stimulation, Entonox and non-pharmacological methods of analgesia are not suitable for the pre-eclamptic mother in established labour. They do not provide reliable analgesia and increase the likelihood of general anaesthesia being used if emergency Caesarean section is required.

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