Prenatal care has drastically changed in the last 100 years. Up until 75 years ago, nearly 66 percent of U.S. women had a home birth with no painkillers. The practice of modern obstetrics included a trend toward hospital births. Much of the first issues in obstetrics was the debate over analgesics used during childbirth and the effort to find something safe for both the mother and the child.¹

Nurses played an active role in starting prenatal care programs before hospital births became the norm and data demonstrated prenatal care reduced infant mortality. Routine evaluation for blood pressure, urine and weight were included in prenatal care visits. Since then, screenings have been added for other maternal risk factors and indicators of abnormal fetal development.²

By the 1980s prenatal care primarily focused on prompt treatment of complications rather than promotion and prevention.³ While the current pattern for prenatal visits usually begins in the first trimester, researchers are now investigating the effectiveness of preconception care.

Care before conception includes advising women on steps they may take to help prevent illness and promote health of mother and baby. One such study published in JAMA Psychiatry looked at the association of prenatal vitamins with the risk of autism in families who already had a child diagnosed with autism spectrum disorder (ASD).⁴

Autism and Genetics

Autism encompasses a broad range of conditions characterized by challenges with social skills, communication and repetitive behaviors. Autism is a spectrum disorder, meaning the symptoms can be classified in terms of their position on a scale.

According to Autism Speaks,⁵ there is not just one type of autism but many subtypes influenced by a combination of genetic and environmental factors. Each individual has a distinct set of strengths and challenges affecting how they learn, think and problem-solve.

In some cases, people with ASD require significant support, while others can live independently and hold high-functioning positions. Several factors are thought to influence the development of the condition, including gastrointestinal disorders.

In most children symptoms of ASD appear by age 2 or 3, although symptoms of associated developmental delays may appear even earlier. Since the 1970s, when researchers discovered pairs of identical twins often shared ASD, they have known the condition has a genetic component.⁶

Through years of investigation to find the genetic culprit, researchers have unearthed a variety of different genetic changes. Still, scientists agree that at this time there is no such thing as an autism gene. However, there are several genetic conditions highly associated with autism, including Fragile X and Retts syndrome. Boys appear to have a greater risk of developing autism than girls.

Scientists have also found that girls with autism have more DNA mutations than boys with the condition. These and other results suggest girls may somehow be more resistant to mutations and need a larger genetic change to exhibit symptoms.⁷

Prenatal Vitamins May Reduce Risk of Autism Spectrum Disorder

If one identical twin has autism, there’s an 80 percent chance the other twin will as well. Fraternal twins have a 40 percent chance of sharing autism, which is close to the predisposition found in other studies for recurring siblings to demonstrate symptoms of ASD.

In one study, researchers enrolled 463 pregnant women and found a 24 percent familial recurrence risk for ASD.⁸ More recently, researchers followed 241 families and found 32.7 percent of children developed autism without prenatal vitamin intervention.⁹

Researchers wanted to know whether maternal use of prenatal vitamins might reduce the risk of autism in siblings of children who suffered ASD. In this sample of families, recruited at the MIND Institute from the University of California, Davis (UCD), younger siblings were born between December 1, 2006, and June 30, 2015.

Final clinical assessments of the children were completed within six months of their third birthday and moms reported use of prenatal vitamins during their pregnancy in telephone interviews. According to the researchers, while most mothers reported taking prenatal vitamins during the pregnancy, only 87 (36.1 percent) took prenatal vitamins in the six months prior to pregnancy.¹⁰

In this last group, only 14 percent of children were diagnosed with ASD, compared to 32 percent of children whose mothers did not take prenatal vitamins during preconception. Mothers who reported taking prenatal vitamins during the first month were also less likely to have children with ASD, compared to mothers who reported not taking prenatal vitamins at all.¹¹

The researchers concluded prenatal vitamins during the first month may reduce ASD, but additional research is needed to confirm the results and to analyze the impact dosage has on the development of ASD. Dr. Pankhuree Vandana, child psychiatrist and medical director of the Autism Center at Nationwide Children’s Hospital, who was not involved in the research, believes this was an important study.¹²

Children born to mothers taking prenatal vitamins scored higher in cognitive scores and had less severe symptoms if they were ultimately diagnosed with ASD. The reduction in risk for ASD seemed to be greater in moms whose prenatal vitamins had higher doses of iron and folic acid, which suggested there may be a partial dose effect.¹³