Autism spectrum disorders (ASD) refer to a group of neurodevelopmental disorders that affect communication, social interaction, and behavior. These disorders are usually diagnosed in early childhood, with symptoms appearing before the age of 3.

While the exact causes of ASD are not yet known, research has linked certain risk factors, including genetic factors, environmental factors, and pregnancy-related factors. One of the pregnancy-related factors that have received increasing attention in recent years is pregnancy spacing.

What is Pregnancy Spacing?

Pregnancy spacing refers to the interval between consecutive pregnancies.

The World Health Organization (WHO) recommends an inter-pregnancy interval of at least 2 years, as shorter intervals have been associated with increased maternal and neonatal risks. These risks include prematurity, low birth weight, small size for gestational age, stillbirth, and maternal morbidity and mortality.

Longer intervals, on the other hand, have been associated with decreased fertility and increased risks of genetic abnormalities and other complications.

What Does Research Say About Pregnancy Spacing and Autism?

Recent studies have suggested that there may be a link between pregnancy spacing and the risk of having a child with ASD.

A study published in JAMA Pediatrics in 2019 analyzed data from over 45,000 children and found that children who were conceived less than 12 months or more than 60 months after a previous birth had a higher risk of ASD than children conceived at 36-59 months after a previous birth. The study also found that the risk was highest when the inter-pregnancy interval was less than 6 months.

Another study published in Autism Research in 2020 analyzed data from over 7 million births in California and found a similar pattern.

Children who were conceived less than 12 months or more than 84 months after a previous birth had a higher risk of ASD than children conceived at 24-35 months after a previous birth. The study also found that the risk was highest for mothers who were older than 35 years of age and had short inter-pregnancy intervals.

What Could Explain the Link?

The exact mechanisms behind the link between pregnancy spacing and ASD are not yet clear, but researchers have proposed several hypotheses.

One hypothesis is that short inter-pregnancy intervals may deplete maternal nutrient stores and increase the risk of micronutrient deficiencies, which have been associated with ASD. Another hypothesis is that short inter-pregnancy intervals may increase maternal stress, which has also been linked to ASD.

Yet another hypothesis is that short inter-pregnancy intervals may increase the likelihood of genetic mutations or epigenetic changes that affect brain development and contribute to ASD.

What are the Implications?

The findings of these studies have important implications for family planning and public health.

Women and couples who are planning to have a child should consider the optimal inter-pregnancy interval not only for maternal and neonatal health but also for the potential risk of ASD. Healthcare providers should also be aware of the potential link between pregnancy spacing and ASD and advise their patients accordingly.

Finally, policymakers should promote public awareness of the importance of optimal pregnancy spacing and provide support and resources for women and families to achieve it.

Conclusion

Autism spectrum disorders (ASD) are complex disorders that affect a growing number of children worldwide. While the exact causes of ASD are not yet known, research has identified several risk factors, including pregnancy spacing.

Recent studies have suggested that children conceived less than 12 months or more than 60 months after a previous birth have a higher risk of ASD than children conceived at 36-59 months after a previous birth. The mechanisms behind this link are not yet clear, but could involve maternal nutrient depletion, maternal stress, or genetic mutations or epigenetic changes.

These findings have important implications for family planning, healthcare, and public policy, and highlight the need for further research to better understand the link between pregnancy spacing and ASD.