Body weight in parous women.

MATERNITY is commonly believed to be an important contributory cause of increased weight in women. Sheldon (1949) provided circumstantial evidence from the histories of obese parous women, and further support was given by the conclusion of Thomson and Hytten (1961) that about 30% of the average weight gained during pregnancy is due to an increase of body fat. Yet Thomson and Billewicz (1965) showed from cross-sectional data that parity added little to the tendency of weight to increase with age, though 'increasing parity does give rise to a minority of unusually heavy women'. Lowe and Gibson (1955) had previously concluded, also from a cross-sectional study, that marriage, but not parity, added to the effect of age, while the Joint Clothing Council Ltd. (1957) found no clear effect of either marital status or parity. Though all investigators agree that weight tends to increase with age, an independent effect of parity must still be regarded as uncertain. Investigation is complicated by the fact that the average weights of women have tended to increase during recent years (Thomson, Billewicz, and Holliday, 1967). In this paper, the effects of age, parity and other factors on body weight are reported on the basis of longitudinal data derived from women who were weighed during their first and subsequent pregnancies.