Autism Spectrum Disorder (ASD) is the name given to a group of neurodevelopmental disorders diagnosed in early childhood. It is characterized by difficulties in social interaction, verbal and nonverbal communication, and by the presence of repetitive behaviors such as rocking and spinning; and presents lifelong challenges to affected individuals and their families.
While there are therapies, educational approaches and medications that can help with some symptoms, there is no cure at this time.
The cause of autism is unknown and so there are many theories as to what may bring it on. These range from prenatal exposures such as pollution, maternal infections, other toxins, as well as genetic factors and parental age.
A mother's influenza infection during any of the three trimesters of pregnancy was not associated with an increased risk of developing autism spectrum disorder.
The researchers examined the health records of over 196,000 children born between 2000 and 2010 who were covered by the Kaiser Permanente health care system in Northern California. They determined how many were diagnosed with ASD, and kept track of the mothers' influenza infections and influenza immunizations by trimester.
They also took into account other factors, such as the child's sex, year of conception, gestational age, size and weight; and they recorded the child's mother's age, education, race/ethnicity, and whether or not the mothers had gestational diabetes, high blood pressure, autoimmune disease, allergies or asthma.
Fourteen hundred mothers, less than ten percent, had contracted influenza over the course of the study; and over 45,000 — nearly 25 percent — received the influenza vaccine while they were pregnant. Thirty-one hundred children were diagnosed with autism during the study period.
The study results demonstrated that maternal influenza infection during any of the three trimesters of pregnancy was not associated with an increased risk of developing autism spectrum disorder. No matter if or when the mothers contracted the flu, their children did not have a higher incidence of ASD.
Children with ASD were more likely to be male and born at less than 37 weeks’ gestation; their mothers were more likely to be older at time of delivery and have a college or postgraduate education.
Mothers of children with ASD were more likely to have been diagnosed with asthma, autoimmune disease and hypertension before conception. Gestational diabetes developed more often in the mothers whose children later developed ASD.
The authors suggest that the current vaccination recommendations remain unchanged but call for more studies to determine the risks during the first trimester. CDC currently recommends that pregnant women get a flu shot during any trimester of their pregnancy to protect themselves and their newborn babies from flu.
The nasal spray flu vaccine is not recommended for use in pregnant women. Flu is more likely to cause severe illness in pregnant women than in women who are not pregnant, and pregnant women with flu also have a greater chance of serious problems, including premature labor and delivery.
The study is published in JAMA, The Journal of the American Medical Association.