According to a new study in the journal Child Development, researchers have found short-term memory in fetuses as early as 30 weeks. The report looked at 100 pregnant women and measured how the fetus responds to repeated stimulation . They used ultrasound to watch. After the same stimulus was applied over and over, the fetus no longer responded – the theory is that it learned that the stimulus is safe. Repeating this process later on during the same session, the fetus was found to stop responding after fewer numbers of stimuli – it remembered that the stimulus was safe. For older fetuses, this demonstration of memory could be extended to sessions weeks apart. While 30-week fetuses had memories that lasted at least 10 minutes, 34-week fetuses had memories that lasted at least 4 weeks.
This is a fascinating report because it demonstrates pain perception months before birth. It makes sense because vital organs are functioning at these early stages of development. In addition, there is memory at this early time as well.