[David O McKay]
In the absence of President Grant, who is attending to duties in Los Angeles, I am requested to give such information as advisable in regard to the questions you ask in your letter of January 11th.
All that we feel justified in saying is that the health of a mother demands that there be a reasonable space between the birth of babies, and this should be accomplished in a proper manner with mutual understanding between the husband and wife. Due consideration and regard for the health of the wife should prompt the husband to refrain from intimate relations with her for at least three months after the birth of a child.
I would advise that you consult a responsible physician in regard to this and let him advise you relative to the necessity of preserving your health and strength, that your life may be pronged to take care of the children with whom God has blessed you.
[David O. McKay, Letter to Mrs. Jesse Gale, as quoted in Minutes of the Apostles of The Church of Jesus Christ of Latter-day Saints, 1910-1951, Privately Published, Salt Lake City, Utah 2010]