How babies are born knowing the difference between day and night
Before a baby sees its first sunrise, it is already receiving signals about day and night. Melatonin, a hormone released mainly at night, can pass from the mother through the placenta. The placenta supplies the developing fetus with oxygen and nutrients.
<p>Before a baby sees its first sunrise, it is already receiving signals about day and night. Melatonin, a hormone released mainly at night, can pass from the mother through the placenta. The placenta supplies the developing fetus with oxygen and nutrients.</p>