Low Birth Weight and Premature Births Affect Child's IQ Later in Life, Study Says

Babies born premature or five weeks earlier than their estimated due date and those with low birth weight may have lower IQs later in life.

A statistical analysis published in the journal JAMA Pediatrics, " Association of Very Preterm Birth or Very Low Birth Weight With Intelligence in Adulthood", suggests that young adults born at 32 weeks gestation or less and weighing approximately 5 pounds -- the minimum weight for a healthy newborn -- had 12 points lower IQ test scores than full term babies or those who had higher birth weights.

Premature Births Explained

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Babies undergo crucial developmental stages during the final weeks and months of pregnancy. Preterm or premature births are described as babies born before 37 weeks of pregnancy. According to the Centers for Disease Control and Prevention (CDC), the earlier a baby is born before the due date, the higher the risks of serious disability or even death.

In 2018, 17 percent of infant deaths were due to preterm births and low birth weight. Babies who survive tend to have breathing issues, intestinal problems, or bleeding in their brains. Long term problems for premature births include developmental delay and low school performance.

The number of premature birth rates have significantly decreased from 22007-2014, according to the CDC. It says the numbers are due to the decline of teens and young women giving birth. However, the rate of preterm birth rose in 2019, with one in every 10 babies born too early in the US.

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Effects of Premature Births on Young Adults IQ

The statistical analysis suggests that a baby's health at birth may influence her or his cognitive function and intelligence later in life. Dieter Wolke of the Warwick Medical School and co-author of the study told UPI by email that modern obstetric and neonatal care for most preterm births result in cognitive abilities within the normal range.

Babies born very prematurely, however, tend to experience more cognitive challenges in their development, Wolke said. The study shows that roughly 2 percent of babies born worldwide are "very" preterm, roughly at 32 weeks gestation or less.

In the US, 37 weeks to 40 weeks of gestation is the norm, with survival rates at 95 percent or more, based on estimates by the CDC.

For the analysis, researchers compiled data from 13 studies that included 2,000 adults born very prematurely or had very low birth weights. Most of the adults included in the statistical analysis underwent intelligence testing in their 20s or were assessed between the ages 18-30.

Although studies utilized various tests for the IQ evaluation, the average scores of babies born preterm or had a lower birth weight on average were at 20 percent, or 12 points lower than babies born at normal weight and gestation. An IQ score between 95-100 is considered to be the average.

Wolke said that in order to improve the long-term health of very premature births, improvements to obstetric and neonatal care must be prioritized to reduce neonatal complications and long-term cognitive effects. Families must be supported by counseling by the neonatal unit, with continued support even after discharge and pre-school years, he added.