The Food and Drug Administration warned, Dec. 14, that repeated or long term use of general anesthesia or sedation drugs for children, who are younger than three years old or pregnant women, who are in their third trimester could affect the child's developing brain.

The warning is the result of a comprehensive analysis of the most recent research in the field, according to the agency.

Anesthesia And Brain Development In Infants

FDA issued a drug safety communication to inform people who are medical care providers, as well as parents of young children and future parents that there are serious risks associated with using these types of drugs on a long term basis. More than three hours at a time is too much, according to the same FDA recommendation.

"We recognize that in many cases these exposures may be medically necessary," noted Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research.

The lab research shows that the effects of repeated exposure to these drugs involve widespread loss of nerve cells, which can be further translated into long-term issues, such as difficulties in learning and effects on behavior.

Among the research conducted on children, some results suggested that animals had the same cognitive reactions when exposed to anesthetics, especially in the cases of long exposure during early childhood.

"It is unclear whether any negative effects seen in children's learning or behavior were due to the drugs or to other factors, such as the underlying medical condition that led to the need for the surgery or procedure," also noted the FDA recommendation.

Effects of Anesthesia - Largely Correlated To Patient's Age

In addition to the FDA guidelines, the largest study ever performed on the effects of local and general anesthesia on babies, published in May 2016, suggested that exposure to an hour of general anesthesia during surgery is not more damaging to the infants' brains than local anesthesia at two years of age.

However, a limitation of that research was caused by the fact that it is extraordinarily difficult to examine long term cognitive effects in such young children.

We can't conclude they're both safe. But there's no reason to think the spinal anesthetic would be unsafe because all of the animal data shows that it is okay," noted Andrew Davidson, lead author of that research.

However, as people age, the effects of anesthetics are not as dramatic. Another research suggested that there is no correlation whatsoever between being anesthetized after the age of 40 and any type of cognitive impairment.

"The bottom line of our study is that we did not find an association between exposure to anesthesia for surgery and the development of mild cognitive [mental] impairment in these patients," explained Dr. David Warner, senior author of the research.