What stage does the fetus begin to open and close its eyes?

The stage when the fetus begins to open and close its eyes is around 28 weeks of gestation. At this point in fetal development, significant neurological maturation occurs, and the eyes are fully formed. The opening and closing of the eyes indicate developing neural connections and increased responsiveness to external stimuli.

This developmental milestone is part of a broader set of changes occurring during the third trimester, where the fetus becomes more active and begins to exhibit behaviors similar to a newborn. While the fetus may detect light and respond to certain auditory stimuli earlier, the physical ability to open and close the eyes typically manifests around 28 weeks.