There are three epochs of a child's life during which the mother's influence is supreme: The middle period of the three is that of lactation, and it is followed by a time of varying extent, lasting usually till the child goes to school, while it is preceded by an antenatal epoch of at least nine months' duration. It is with the last named of the series only that I am here concerned; but it may make for lucidity if I indicate briefly the kind of influence which a mother exerts during the other two periods, both of which are distinguished from the third by the fact that they are postnatal. I will call the three epochs in their order: 1, Antenatal; 2, lactational. and, 3, postlactational.
The postlactational period of influence extends from the time of weaning, which may, perhaps, be stated roughly as occurring at the ninth month of
BALLANTYNE JW. INFLUENCE OF THE MOTHER'S HEALTH IN PREGNANCY ON HER UNBORN CHILD.. JAMA. 1907;XLVIII(17):1418-1420. doi:10.1001/jama.1907.25220430030001g