Most obstetric anaesthetists presuppose that regional analgesia has made a contribution to the safe conduct of obstetric anaesthesia and analgesia and would like to believe that efforts to increase the use of regional blockade has reduced the risks of obstetric pain relief. Proving this is not easy.
Mortality in Obstetric Anaesthesia and Analgesia
Despite many deficiencies in data collection we know that maternal mortality is declining. In the 1600's, one woman in every 44 died in childbirth. In the 1930's maternal mortality was 670:100,000 births. In the 1980's it had fallen to 9.6: 100,000. In the 1990's in Australia it is 6.7:100,000 births, a 100-fold reduction in 60 years.
Regrettably, the contribution of anaesthesia to the maternal death rate, as a percentage, has risen. This is because, in most countries, total anaesthetic-related maternal deaths have remained relatively constant whilst there has been a dramatic fall in the numbers of maternal deaths due to the three great killers: sepsis, haemorrhage and toxaemia.
Because of deficiencies in the denominator of national databases we are still unable to say with confidence what numbers of pregnant women undergo general anaesthesia and what numbers undergo regional anaesthesia in childbirth.
In national maternal mortality reports of the USA, Britain and Australia, it is apparent that the number of maternal deaths from general anaesthesia-related causes outnumber those from regional analgesia causes. However, because of the denominator deficiencies we are still unable to say with certainty that regional blockade is safer than general anaesthesia.
Morbidity in Obstetric Anaesthesia and Analgesia
Prospective collection of morbidity data has not been undertaken on a large enough scale to enable one to reliably comment on the relative morbidities of general and regional anaesthesia techniques.
The significance of morbidity depends on the point of view of the observer. The mother as an observer may well have a different perspective of post-anaesthesia morbidity when compared to the anaesthetist. The data are just not available to allow us to form a conclusion about the safety of both techniques, either from the point of view of the mother or the anaesthetist. Most anaesthetists would feel that permanent morbidity associated with general anaesthesia is relatively rare. The incidence of permanent neurological sequelae after epidural anaesthesia appears to be in the range of 1:15,000 to 1:100,000 epidurals (1). It must be remembered that permanent neurological sequelae have been reported in childbirth when regional blocks have not been used.
Better collection of procedural, morbidity and mortality data in the age of the microchip will allow us to provide an answer to our question. At present we don't have the solution.