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Gestational weight gain by mothers and autism

Research now suggests that gaining gestational weight outside of the current recommended guidelines, including excessive and inadequate gestational weight gain, is associated with a higher risk for Autism Spectrum Disorder (ASD) in babies.

Published by the Obesity Society of America, the research indicates that more than half of pregnant women gain weight outside the recommended guidelines worldwide. 

America’s Centers for Disease Control and Prevention recommends women carrying one baby to gain between 25-35 pounds if they had normal weight pre-pregnancy. 

However, underweight women are recommended to gain between 28 and 40 pounds while those who were previously overweight should gain between 15 and 25 pounds while carrying one baby.  

The research also reveals that maternal weight status may influence the neurodevelopment of offspring.  

“A growing number of studies have investigated the relationship between maternal obesity and ASD in offspring. However, previous studies have mainly focused on maternal BMI at the first antenatal visit as a proxy of pre-pregnancy maternal weight status,” the research paper says.  

 The disorder is described as a neurodevelopmental disorder which commences from early childhood that is manifested by persistent social interaction deficits in parallel with repetitive and stereotypic activities. 

According to the research, the disorder is lifelong and affects an estimated 1 percent of people globally. Most of the children with autism spectrum disorder may not work full time or even live independently after they reach adulthood, which may bring substantial economic burden to their families, the health care system, and society. 

More Data 

To conduct the research, nine studies were identified, including 323,253 participants with 4,135 cases of ASD from five cohort studies and 1,462 cases and 3,265 controls from four case‐control studies.  

One study was conducted in Europe, four in North America, and the remaining four in Asia.  

Evidence from cohort studies indicates that both excessive and inadequate Gestational Weight Gain (GWG) was significantly associated with a higher risk for ASD in offspring. 

According to the finding, excessive GWG but not inadequate GWG was significantly associated with a higher risk for ASD. 

“The accumulated evidence has supported that gaining weight outside the recommended GWG is associated with a higher risk for ASD in offspring.” 

It has been suggested that gaining gestational weight outside the current recommended guidelines may play a critical role in triggering the manifestations of ASD phenotypes in predisposing individuals during the prenatal period.  

Although the underlying mechanisms by which GWG affects the neurodevelopment of offspring are still unclear, the research suggests that excessive GWG may induce disturbed blood leptin signaling in offspring, which may consequently lead to adverse neurobiological conditions.  

Leptin is a proinflammatory cytokine produced by adipose tissue and placenta, and its receptors are widely expressed in brain regions that are related to behavior regulation. 

A proper level of leptin has neurotrophic effects and it stimulates neuronal differentiation during fetal neurodevelopment. 

Previously, a positive correlation between GWG and blood leptin levels in pregnant women has been observed. 

Neonates whose mothers gained excessive GWG had significantly elevated leptin levels in their cord blood.  

In addition, a few cohorts and case‐control studies have found that leptin levels were associated with a higher risk for ASD.  

Therefore, the observed association between excessive GWG and ASD risk may be partially explained by the dysregulation of leptin signaling during the fetal neurodevelopment period.  

“These studies suggest that, compared with pre-pregnancy obesity, GWG may play more critical roles in the development of ASD in offspring or serve as a reliable indicator for this disorder.” 

The research was extracted from studies that examined the association between GWG and ASD risk in offspring and that were published before March 19, 2020 and were identified by PubMed and Embase databases.

Margaret Njuguna