As pregnancy progresses, fetal urine makes up an increasingly larger proportion of the amniotic fluid that surrounds the baby. This dynamic process is made possible by the placenta which passes excess urine into the mother's blood stream, where it travels to her kidneys and is excreted as extra urine. It may surprise you that the fetus can survive without kidneys. This is because the placenta takes over that function until the baby is born. My daughter literally wears her baby in a sling everywhere she goes.
Studies show that baby-wearing is good for the baby, and it makes life easier for the mother.
Carried infants cry less, have fewer colicky episodes and seem more content. The next time you visit your granddaughter, carry her in the sling and see what happens. You might be pleasantly surprised. Many of these children come from orphanages or other institutional settings where they may not have received adequate medical care. He can't answer personally, but your question may appear in a future edition of The Baby Beat.