According to ancient Indian medical literature, quoting from a textbook on the study of Obstetrics:
" in the eighth month, all the parts of the foetal body becomes restless and full of oja, the element of vitality; an exchange of oja takes place from the mother to the foetus and vice-versa. So, the mother becomes blanched and flushed alternately. In this month the oja is very volatile. The mother should be properly nourished in this month. This is a very important month rather a critical period in the life of the pregnant woman."
"The oja, is strictly, to be termed as the very life itself. In the eighth month, it has a constant movement from mother to foetus. So, if a woman delivers when the oja is in the body of the foetus, the child will live and the mother will expire; and if it is vice versa, the child will die, and the mother survives."
"This phenomenon is generally known to the Hindu ladies. When they happen to know that a woman has delivered during the eighth month, they at once question if the mother and child are alive; and they rarely expect the child to live. "
"This rare phenomenon is not all known ... in the west ".
extract from the book by Dr. Chidambaram Pillai (varmam.com)
P.S. I am only a student, quoting from my understanding of this ancient knowledge, which information is to be digested at reader's discretion