In wealthy countries a majority of children are born with the use of pain relieving drugs. In wealthy countries drug addiction is increasing.
Bring these two facts together and you will wonder why thousands of researchers are not trying to confirm (or invalidate) the conclusions of the studies by B Jacobson and his team in Sweden about the relationship between opiate or amphetamine addiction in adult offspring of mothers given pain medication during their births ( BMJ, 1990;301:1067-70). These researchers studied the birth records of 200 opiate addicts born in Stockholm between 1945 and 1966. The control group consisted only of siblings of drug addicts, also born in Stockholm during the same period to reduce possible bias caused by such factors as socio economic levels.
The main finding is that in the study group a higher proportion of mothers received opiates (morphine or pethidine) or barbiturates, or both, during labor and delivery. If the drugs have been administered more than 10 hours before delivery there is no significant difference between the two groups. The risks are increased when the drugs have been administered several times. Furthermore, the mothers in the study group had received nitrous oxide for longer periods and more often during delivery than had those in the control group. Possible confounding factors such as surgical intervention and birth weight were taken into account.
This report was preceded by a study by the same group, this time focusing on amphetamine addiction (Acta Obstet Scand, 1988; 67: 677-82). Stockholm is particular in that there are about 3,000 addicts using exclusively amphetamine for only 400 using exclusively opiates.
The main conclusion of this study is that nitrous oxide administration during delivery is an essential risk factor for eventual amphetamine addiction in offspring and that the risks of addiction are proportional to the duration of nitrous oxide exposure. Duration of nitrous oxide analgesia was tested in competition with 12 potential confounding factors, such as birth weight, duration of labour, surgical intervention and administration of other drugs, such as opiates. When nitrous oxide has been given for four and a half hours or more, the risk that the infant will become addicted is 5.6 times higher than if the gas has been given less than 15 minutes.
Jacobson got into this work by chance. He is a professor of medical engineering. While programming computers he accidentally found a relationship between traumatic birth and self destructive behaviour later in life. Birth record data were gathered for 281 unambiguous cases of suicide among victims born in Stockholm after 1940, and who died there between 1978 and 1984. Comparison with 2901 people in the control group showed that suicides involving asphyxiation were closely associated with asphyxia at birth, while suicides by violent mechanical means were associated with mechanical birth trauma.
These findings are still more significant if they are compared with the conclusions of research done in Rhode Island in America by Lee Salk and colleagues about adolescent suicides (The Lancet, 16 March 1985). The prenatal and neonatal records of 52 infants who subsequently committed suicide between the ages of 12 and 20 were reviewed and compared with two matched control groups. Forty six risk factors were investigated. One of the most significant findings is that respiratory distress for more than one hour at birth is a specific factor for committing suicide when adolescent. The authors of the report suggest a link between the dramatic increase in suicides rates among teenagers and the fact that more and more infants can survive thanks to modern methods of resuscitation.
The work of Jacobson gives insight into the probably long term effects of drugs which were commonly used in Sweden between 1945 and 1966. This leads one to wonder about the long term effects of the extensive use of drugs employed today.
For those who are not familiar with medical statistics, let's recall that ll of these computerized studies can only establish correlations and detect risk factors. Correlation means that the association between two facts is more frequent than if it occurred by chance. Statisticians have methods of evaluating the interference of confounding factors that is to say, of bias, before introducing the concept of risk factors. However, it is always possible to miss a confounding factor. In other words, correlation and risk factors do not mean cause and effect. Moreover, statisticians have at their disposal means to determine how significant a correlation is.
For obvious reasons, there is still a lack of scientific studies regarding the possible long term effects of new procedures such as epidural anaesthesia. The effects of epidurals on the behaviour of the baby over the first month following birth have been traced by using the "neonatal behavioural assessment scale" of American researcher T B Brazelton. A significant dose effect was found (Developmental Medicine and Child Neurology, 1992; 34: 1072-80). If ewes are given epidurals in early labour, they fail to show interest in their lambs (Physiology and Behaviour, 1987; 40: 463-72).
The reports about the probable long term effects of drugs used in the period around birth are not surprising. Brain receptors reorganize themselves during precise stages of development, and in particular in the perinatal period and at puberty. This is probably the case of oxytocin receptors, opiate receptors, benzodiazepine gaba receptors, insulin receptors, etc.
In the scientific context of the 1990s, it is increasingly easy to understand that there are no innocent drugs. Midwives and doctors who use nitrous oxide should know that this gas influences neurotransmission directly at opioid receptors.
Extracted from Primal Health Research, a quarterly newsletter pub lished by the Primal Health Research Centre (59 Roderick Road, London NW3 2NP lb12 ($18 US per year). Editor Dr Michel Odent is author of many books including Primal Health.