You may lovingly talk to and sing to your belly over the nine months that you are pregnant, trying to bond with your baby before he is even born. Research has shown us that these gestures are not just symbolic. Your baby can hear many sounds in the womb -- even identifying your voice -- and can see light. Around the third trimester, your baby can start to see bright lights through the womb and even react to them.
When Baby Can See
Your baby is rapidly developing throughout pregnancy, and the eyes start forming in the first trimester. However, your baby's eyes stay closed until around the 23rd or 25th week of pregnancy. After another five weeks, the baby's irises will start to contract in response to light. Your baby will open and close his eyes more frequently as a precursor to blinking and to sight outside the womb. Exposure to light can help develop your baby's sight.
What Baby Can See
The womb is a thick, protective home for your baby, so most light doesn't filter through. Light has to be very strong for baby to see it or respond to it. For example, doctors who have shined a light directly in the uterus reported the baby turning away from the light. If you shine a flashlight directly at your belly, it will appear as a soft glow, similar to the light you see when you are standing outside on a bright day and close your eyes. Babies don't start to see color well until about five months of age, so in the womb, light will appear as a soft glow.
Response to Light
If you shine a very bright light at your belly in the third trimester, your baby may turn or move. Light is stimulating, so the movement may be from excitement at seeing something new. Depending on the baby's position in the womb and how bright the light, baby's movement may be to get away from the light because of discomfort. Since the womb offers such a protective layer, the light would have to be very bright or close to your belly to have such an effect.
Effects of Light
A report in Medical Daily concluded that babies need light in the womb to develop healthy vision. The light stimulates the eyes, helping them to focus and vision to become stronger. However, too much light can be overstimulating and cause long-term changes to the brain. Consult with your doctor for guidance on how much light to shine on your belly and how frequently. Beware of shining fluorescent lights on your belly. They have been shown to cause headaches, eye strain and fatigue in adults, so they could distress your growing baby.