MedicalHypotheses: Autism spectrum disorder (ASD) is a group of developmental 
disabilities that include full syndrome autism, Asperger’s syndrome, and
 other pervasive developmental disorders. The identified prevalence of 
ASD has increased in a short time period across multiple studies causing
 some to conclude that it has reached epidemic proportions in the U.S. Many
 possible explanations for the rise in numbers of individuals diagnosed 
with ASD have been offered and yet, causes and contributing factors for 
ASD are inadequately understood. Current evidence suggests that both 
genetics and environment play a part in causing ASD.
One possible 
risk factor for the increase in prevalence has been profoundly 
overlooked in the existing biomedical and epidemiologic literature. As 
the prevalence of ASD has risen in the last sixty years, so has the 
prevalence of the usage of the oral contraceptives and other modern 
hormonal delivery methods. In 1960 about one million American women were
 using oral contraceptives, today close to 11 million women in the U.S. 
use oral contraceptives. Eighty-two percent of sexually active women in 
the U.S. have used oral contraceptives at some point during their 
reproductive years. Thus, the growth in use of 
progesterone/estrogen-based contraceptives in the United State has 
reached near-ubiquitous levels among women in the child-bearing age 
range.
The suppression of ovulation produced by 
estrogen–progesterone is an indisputable abnormality. It is logical to 
consider the outcome of the ovum that would have been normally released 
from the ovary during ovulation. To date there is no comprehensive 
research into the potential neurodevelopmental effects of oral 
contraceptive use on progeny. The issue has been only sparsely 
considered in the biomedical literature. This article hypothesizes that 
the compounds, estrogen and progesterone, used in oral contraceptives 
modify the condition of the oocyte and give rise to a potent risk factor
 that helps explain the recent increase in the prevalence of ASD’s.
This
 hypothesis does not propose to delineate the cause of autism. Rather, 
it attempts to explain the recent dramatic increase in prevalence and 
point the way for further study that will lead to causal examination.