According to Winckel, and practically all pediatricians agree with him, "the weight of a child, if taken regularly, is the best thermometer of its health; it easily expresses in terms of figures what the nursing child cannot express in words."[34]
The new-born child weighs from three to four kilograms; but oscillations in weight from 2,500 to 5,000 grams are considered normal. Some obstetricians have noted weights in new-born children that are enormous, true gigantism, which, however, while possible, are altogether exceptional; nine and even eleven kilograms.
The oscillations in weight of the child at birth, within normal limits, may have been determined by general biological factors, as for example the sex (the female child weighing less than the male), and the race (especially in regard to the stature of the parents): but the factors which influence the weight of the new-born child in a decisive manner are those regarding the hygiene of generation.
1. "The children which have the greater weight are those born of mothers between the ages of twenty-five and thirty." (Mathews Duncan.) Let us recall what we have said regarding stature; at the end of the twenty-fifth year, that is, at the end of the period of growth, man is admirably ripe for the function of reproduction; and we ought further to recall the views cited regarding the mortality of children conceived at this age which is so favourable to parenthood; and finally the note in regard to celebrated men, almost always begotten at this age.
2. "First-born children have in general a weight inferior to that of those born later (1,729 first-born children gave an average of 3,254 grams: while 1,727 born of the second or subsequent conceptions gave an average of 3,412 gr.)" (Ingerslevs). Let us remember that celebrated men are scarcely ever the first-born.
3. "Very short intervals between successive pregnancies interfere with this progression in weight; long intervals on the contrary do not interfere with it" (Wernicke). In other words, too frequent pregnancy is unfavourable to the result of the conception.
4. "Mothers who, at the birth of their first child weigh less than fifty-five kilograms and are under twenty years of age, have children of inferior weight, who are less predisposed to normal growth" (Schafer).
Let us recall what we have said regarding the form and the scanty weight in the case of macrosceles; and also in regard to the age of procreation in its relation to stature.
5. "Women who toil at wearisome work up to the final hour give birth to children inferior in weight to those born of mothers who have given themselves up to rest and quiet for some time before the expected birth" (Pinard).
All these considerations which refer to normal individuals, represent a series of hygienic laws regarding maternity, which may be summed up as follows: excellence in procreation belongs to those mothers who have already attained the age at which the individual organism has completed its development, and before it has entered upon its involutive period; the mother must herself have a normal weight; the pregnancies must be separated by long intervals; and during the last weeks of pregnancy it is necessary that the mother should have the opportunity of complete rest.