Dutch researchers have revealed that the short-term memory of a foetus begins functioning at 30 weeks after gestation.
The study, conducted by researchers at Maastricht University Medical Centre and the University Medical Centre St. Radboud, offers insights into foetal development and may help address and prevent abnormalities.
The researchers studied about 100 healthy pregnant Dutch women and their foetuses, measuring changes in how the foetus responds to repeated stimulation.
After receiving a number of stimuli, the foetus no longer responds to the stimulus as observed by ultrasonography and the stimulus is then accepted as "safe." This change in response is called "habituation."
In a second session, the foetus "remembers" the stimulus and the number of stimuli needed for the foetus to habituate is then much smaller.
Based on their research, the researchers found the presence of foetal short-term memory of 10 minutes at 30 weeks.
They determined this because a significantly lower number of stimuli was needed to reach habituation in a second session, which was performed 10 minutes after the first session.
They also found that 34-week-old foetuses could store information and retrieve it four weeks later.
Foetuses were tested at 30, 32, 34, and 36 weeks, and again at 38 weeks. The 34- and 36-week-old foetuses habituated much faster than the 38-week-old foetuses that had not been tested before.
This implies that these foetuses have a memory of at least 4 weeks-the interval between the test at 34 weeks and that at 38 weeks.
"A better understanding of the normal development of the foetal central nervous system will lead to more insight into abnormalities, allowing prevention or extra care in the first years of life and, as a consequence, fewer problems in later life," the authors said.
The study has been published in the July/August 2009 issue of the journal Child Development.