Birth & The Autism Epidemic - (Inc. Australian Study)
Exclusive Interview with Michel Odent: The Autism Epidemic
Among the readers of Midwifery Today are mothers of autistic children. Many of them are seeking explanations about the current autism epidemic. Some are ready to transform themselves into amateur epidemiologists and to design their own surveys. Before supporting one of these surveys, Jan Tritten requested the point of view of Dr. Michel Odent, the founder of the Primal Health Research Centre in London, UK. Primal Health Research is a developing branch of epidemiology. It includes all studies exploring correlations between what happened during the "primal period" (fetal life, perinatal period, year following birth) and what will happen later on in life in terms of health, behavior and personality traits.
JT: Midwifery Today is considering supporting a survey of parents of autistic children to try to interpret what is leading to the current epidemic of autism (and autistic spectrum disorders). The intent of the survey is to consider possible risk factors such as prenatal pollution, exposure to ultrasounds during fetal life, obstetrical procedures during the perinatal period and vaccinations. Do you consider such a survey promising?
MO: I am skeptical about the value of such a retrospective study, which will reach too few families to accurately evaluate the risks of autism. Explore the primal health research database www.birthworks.org/primalhealth and select keywords such as "autism", "vaccination" and "ultrasound scans": You'll find dozens of huge published studies that address these issues. An accumulation of data suggests that the timing of the gene-environment interactions is different for autism than for schizophrenia. Several authoritative studies indicate the paramount importance of what happened at birth in the genesis of the autistic spectrum disorders.
Perinatal Period Risks. Among the recent large and authoritative studies of autism from a Primal Health Research perspective, the Australian one will convince anyone that the main risk factors occur in the perinatal period (Glasson, E.J., et al. 2004. Perinatal factors and the development of autism: a population study. Arch Gen Psychiatry 61(6): 618–27). The birth records of 465 subjects born in Western Australia between 1980 and 1995 and diagnosed with an autism spectrum disorder by 1999 were compared with those of 481 siblings and of 1313 controls. No differences in gestational age at birth (including the proportion of premature infants), weight for gestational age, head circumference or length were observed between cases and control subjects. Pre-eclampsia did not appear as a risk factor. These negative findings lend more importance to perinatal factors. Compared with their siblings, individuals with autism were more likely to have had induced births, to have experienced fetal distress and to have been born with low Apgar scores. Compared with control subjects, they were more likely to have been born after induction and by elective or emergency c-section.
The largest study ever published about the perinatal risk factors for autism was published in July 2002.(Hultman, C., P. Sparen and S. Cnattingius. 2002. Perinatal risk factors for infantile autism. Epidemiology 13: 417–23) The researchers had at their disposal the recorded data from the Swedish nationwide Birth Register regarding all Swedish children born during a period of 20 years (from 1974 until 1993). They also had at their disposal data regarding 408 children (321 boys and 87 girls) diagnosed as autistic after being discharged from a hospital from 1987 through 1994 (diagnosis according to ICD-9 code 299A). Five matched controls were selected for each case, resulting in a control sample of 2040 infants. The risk of autism was significantly associated with caesarean delivery and a 5-minute Apgar score below 7. Unfortunately the variable "labour induction" could not be taken into account, because it did not appear in the National Birth Register until 1991 (personal correspondence with one of the authors).
A recent report from Israel also found no prenatal differences between autistic children and controls, but the rates of birth complications were higher among the autistic population. In addition, we must consider data indicating that perinatal factors may play a lesser role in autism in "high-functioning" individuals compared with studies of autism associated with severe retardation, as well as data suggesting that anesthesia during labour is a risk factor for the development of dyskinesia among autistic children. Although the risk factors for autism seem to occur mostly in the perinatal period, we must keep in mind the association of autism with fetal valproate syndrome (a rare congenital disorder caused by exposure of the fetus to valproic acid during the first three months of pregnancy), thalidomide embryopathy (a syndrome related to in utero exposure to thalidomide) and Mobius sequence (disorder linked to first-trimester exposure to misoprostol).
Vaccinations. In regard to a link between autism and vaccinations, a study involving all children born in Denmark from January 1991 through December 1998 (more than half a million children) will convince anyone that the main negative effect of the MMR (measles, mumps, rubella vaccination) fuss has been to divert the attention (and probably money) from the study of risk factors that might explain the current autism epidemic.(Madsen, K.M. et al. 2002. A population-based study of measles, mumps, and rubella vaccination and autism. N Engl J Med 347(19): 1474–75) An accumulation of data suggests that the significant risk factors occur before the age at which babies receive MMR, which is usually given at 12 months or after.
The hypothesis that mercury associated with certain vaccines is a risk factor is not supported by a study involving all children born in Denmark from January 1990 until December 1996 (nearly half a million).(Hviid, A, et al. 2003. Association between thimerosal-containing vaccine and autism. JAMA 290(13): 1763–66) The risk of autism and other autistic-spectrum disorders was the same among children vaccinated with thimerosal-containing vaccine and children vaccinated with thimerosal-free vaccine.
Ultrasound Scans. Although prospective studies found effects of exposure to ultrasounds during fetal life on average birth weight and handedness, none of them found effects on intellectual performance and therefore (probably) on the risks of autism.
I think that many people express opinions, theories and hypotheses (that lead to small surveys) without being aware of huge valuable studies published in authoritative medical or scientific journals. These studies can be easily explored on the primal health research database (it is more time consuming to feed it!).
JT: Taking into account the studies already included in your database, can you imagine some fruitful avenues for research in the near future?
MO: We have many reasons to suspect a link between "autism epidemic" and "labour induction epidemic." The first reason is that in all studies that took into account independently the variable "labour induction," it appeared as a risk factor. Labour induction should be explicitly taken into consideration by epidemiologists, because it can be associated either with birth by the vaginal route (with or without intervention such as forceps), or with cesarean birth.
Another reason is that the epidemic of autism and the epidemic of induction seem to have developed side by side in Western countries and in China. Bai, from the Association of Rehabilitation for Children with Autism of Wuhan City, estimates that the number of children with autism is growing at an annual rate of 20 percent in that country, higher than the world average of 14 percent (http://news.xinhuanet.com/english/20...nt_1759576.htm). Let us recall that the rate of inductions is growing fast in China, since the Chinese are autonomous for synthesizing misoprostol.
A third reason is that the results of recent studies suggest that children with autistic disorder show alterations in their oxytocin system. The first clues came from a study of mid-day blood samples from 29 autistic and 30 age-matched normal children, all prepubertal.(Modahl, C., et al. Plasma oxytocin levels in autistic children. 1998. Biol Psychiatry (4): 270–77) The autistic group appeared to have significantly lower blood oxytocin levels than the normal group. Oxytocin increased with age in the normal but not in the autistic children. These results inspired an in-depth inquiry into the oxytocin system of autistic children.
In recent years oxytocin has been shown to appear in the brain in several forms. The nonapeptide oxytocin (OT) and the "C-terminal extended peptides" are described together as OT-X. The OT-X represent intermediates of oxytocin synthesis that accumulate due to an incomplete processing mechanism.
Twenty-eight male children, diagnosed with autistic disorder, were compared with 31 age-matched control children with no psychiatric disorders: A decrease in blood OT, an increase in OT-X and an increase in the ratio of OT-X/OT were seen in the autistic sample, compared with control subjects.(Green, L., et al. 2001. Oxytocin and autistic disorder: alterations in peptides forms. Biol Psychiatry 50 (8): 609–13) In other words autistic children show alterations in the oxytocin system: there are deficits in the synthesis of oxytocin.
We are learning that, among humans, the period surrounding birth is a period of dramatic reorganization of central oxytocin binding. Artificial induction of labour creates situations that undoubtedly interfere with the development and the reorganization of the oxytocin system in such a critical period. This fact alone is a reason for further epidemiological studies focusing on labour induction as a possible risk factor. It would be useful to know also how autistic children release oxytocin. Oxytocin is more effective when released rhythmically, in a succession of fast pulsations. Today it is possible to measure the rhythmicity "the pulsatility" of oxytocin release. In other words, the time has come to study autism as an "impaired capacity to love."
Editor's Note: Oxytocin is a hormone released by the posterior pituitary gland. Its mechanical effects, particularly its stimulating effects on uterine contractions during labour, have been known for a long time. Recently we learned that oxytocin also has important behavioral effects. Today we are in a position to summarize the results of dozens of studies by claiming that oxytocin is the typical hormone of love: Whichever facet of love one considers, oxytocin is involved.
