Changes in Body Weight in Pregnancy.

Abstract

Some 10 years ago, the senior author began a study of certain phases of the metabolism in normal pregnancy as a basis for a later comprehensive investigation of the toxaemias incident to this condition. Many of the measurements could demonstrate their real significance only if presented as relative values or changes, using convenient and easily ascertained biometric magnitudes as bases of reference. A case in point is the so-called basal metabolic rate, all of the usual prediction criteria involving some expression of the body weight in the formula used. A review of the literature disclosed a paucity of dependable recent observations of weight changes, and the few older records were incomplete. Single measurements on isolated cases are of little worth. Only continuous studies, both ante- and post-partum, on the same individual, are significant. This involved the continued cooperation on the part of the individual patient. In the present study the work has been carried out on this basis.

For the purposes of the entire investigation, subjects were drawn from 2 independent sources, group “A” from a prenatal out-patient service, supplemented by a few private cases, groups “B” and “C” from inmates of 2 nursing homes for unmarried mothers. The living conditions of the 2 major divisions thus represent the extremes of possible practice.

Normal, healthy individuals were selected initially and only those retained who maintained this condition throughout the period of study. Considerably more than 200 individuals were at least partially studied to yield the 77 that form the basis of this report.

The present paper will be devoted to the record of weight changes. Weights were taken at a uniform hour in the early morning, after emptying the bladder, with the patient nude and in a post-absorptive state (i. e. at least 12 hours after the last meal).