Why did so many ancient cultures show pregnant or nursing women?

Children were considered a blessing in ancient Egypt. Sons and daughters took care of their parents in their old age. They were often called "the staff of old age," that is, one upon whom the elderly parents could depend upon for support and care. The scribe Ani instructed that children repay the devotion of Egyptian mothers:

"Repay your mother for all her care. Give her as much bread as she needs, and carry her as she carried you, for you were a heavy burden to her. When you were finally born, she still carried you on her neck and for three years she suckled you and kept you clean."

It was also expected that the older son or child carry on the funerary provisioning of the parents after their death. Children had value in ancient Egypt. The Greeks, who were accustomed to leaving infants exposed to the elements, were stunned to observe that every baby born to Egyptian families were cared for and raised. This care was not easy. Many children died to infection and disease. There was a high rate of infant mortality, one death out of two or three births, but the number of children born to a family on average were four to six, some even having ten to fifteen.

oranienbaum, russia.