Autism Spectrum Disorder (ASD) encompasses a range of conditions that most commonly affect males and are characterized by lifelong neurodevelopmental derangements manifesting as deficiencies in social interaction, verbal and nonverbal communication, and dysfunctional interests and behavioral pattern that range from social isolation, delayed speech, and repetitious movement, to Asperger’s syndrome, characterized by higher levels of cognition and social behavior. It result from a complex interaction between genetics, the environment, and a host of maternal risk factors. While a genetics-linked etiology is appealing, , of the more than 100 genes that have been associated with ASD (as well as ADHD and others), none, alone or in combination, appear to be directly causative. Nor has any synergistic environmental factor been identified. Over a period of less than 2 decades, the incidence of diagnosed (ASD) has increased from about 1:2000 to greater than 1;50, and the incidence continues to increase year by year. But ASD is not the only developmental disability increasing . Since 2010, there has been a 33 percent increase over the preceding decade in developmental disabilities of all types including ASD, attention-deficit/hyperactivity disorder (ADHD) and other development delays. The question arises as to whether this dramatic change is due increased awareness of ASD leading to over-testing and over-diagnosis and/or whether it represents a true epidemiologic phenomenon.
- Infertility and ASD: It is a fact that those of us who are actively involved in medically promoting reproduction are commonly confronted by prospective parents who are concerned that their age and reproductive performance could be associated with an increased risk that their offspring could be affected by ASD….While it is as yet not possible to establish a clear relationship between infertility, its treatments, and ASD, this is still a subject of heated debate. Factors such as the effects of fertility medications, fertility procedures performed and a relationship to the cause of the infertility and hormonal factors linked to fetal testosterone have all been cited as possible contributing factors to the occurrence of ASD in patients seeking infertility treatment. Of interest is the emergence of evidence to suggest a possible etiologic role of the immune system in ASD . A relatively recent large study analyzed the birth records of 2.5 million children born in Sweden between 1982 and 2007, and after correcting for confounding variables, found there to be a very small increase in the incidence risk of intellectual impairment in the resulting children (about 4% of IVF children had physical or mental problems at birth compared with 3% of those conceived A naturally) but no link between in vitro fertilization (IVF) and ASD. This having been said, the study was somewhat flawed in the fact that the IVF births reported dated back more than 30 years when IVF technology was still in its infancy. Overall, the main message was a positive and reassuring one for patients undergoing IVF treatment
- Obstetrical History and ASD: It is believed that that 70% of ASD cases result from “adverse” perinatal events such as fetal distress and prolonged head compression during labor. ASD is far more prevalent in the offspring of older women and obese , those with diabetes and women who experienced premature labor , intrauterine growth restriction , placental insufficiency , and pregnancy-induced complications. It should come as no surprise that the performance of Elective Cesarean section (conducted prior to labor), is protective. Notwithstanding this, it is also factual that the majority of ASD cases, cannot be traced back to intrapartum fetal monitoring evidence of perinatal asphyxia . Nor do the vast majority of babies asphyxiated at birth, subsequently develop ASD. ASD is also more common in first born babies.
Gender and ASD: ASD is more common in male offspring. The mother’s age: The incidence of ASD increases with advancing age of the mother In fact, women over age 40Y are 51% more likely than women aged 25-29 to have a child with ASD. The father’s age: A relatively recent study published in the magazine, “Nature” suggests that the risk of ASD increases as the age of the father progresses. When the man is over 50, the incidence doubles. It is about time that men start to realize that it is not only women that should be worried about unduly putting off parenting. Hopefully, it will also prompt physicians to recommend to their married male patients that they begin considering their “reproductive options” sooner rather than later and that the topic be taught in medical school. Genetics/Epigenetics and ASD: With identical twins, when one has ASD, the other is about 90% likely to also be so affected. In non-identical twins, the concordance rate is twenty times lower. This points strongly to a genetic link. There is new evidence that defects in epigenetic regulatory genes and in certain gene regions on chromosomes might play a role in the development of autism. About 10% of ASD cases have definite links to genetic disorders such as Fragile X, neurofibromatosis and tuberous sclerosis which can often (although not easily) be detected through meticulous parental clinical history taking and can be diagnosed pre- and postnatal using genetic testing, ultrasound examination and by sophisticated chromosomal and DNA testing. Predicting/Diagnosing/Preventing ASD: It is as yet not possible to diagnose ASD through preimplantation genetic diagnosis (PGD) or through prenatal testing. However, recent advances in fetal heart rate offer hope for the emergence of hitherto unrecognized heart rate patterns that might point to neuro-regulatory cerebral changes that could identify babies at subsequent risk of developing ADS, thereby allowing for earlier delivery and escape from the adverse intrauterine environment. .