Other factors affecting weight change were weight gained during pregnancy, mother's age, and marital status. Older women were less likely than younger women to return to their pre-pregnancy weights. Finally, unlike married women, single mothers had a pattern of weight gain rather than weight loss. Only by following the same women over time were the researchers able to observe these differences. Unfortunately, the methods used to assess diet were relatively crude and did not give a picture of energy intakes at intervals less than 6 months.
More research is needed among women from different racial, ethnic, and socioeconomic backgrounds.
Janney, C. A., D. Zhang, and MF Sowers. Lactation and weight retention. Genetics and the Birth Weight Gap between Whites and African Americans Poverty, smoking, inadequate prenatal care, very young or old maternal age, and black race are all well-documented risk factors for low birth weight. Although rates of low birth weight decrease as the number of risk factors goes down, improvement occurs more rapidly among whites than African Americans. The persistence of a gap in birth weights has led some researchers to speculate that the effect of race on birth weight is genetic.