The U.S. Department of Justice estimates that women offenders account for about 16 percent of the total corrections population (Bureau of Justice Statistics, 1999). Recent estimates show that the number of women under the jurisdiction of state or federal prison authorities increased 1.2 percent from year-end 2007, reaching 115,779 (available online at http://www.ojp.usdoj.gov/bjs/prisons.htm [accessed April 13, 2009]). Of women who are incarcerated, most are of child-bearing age and approximately 6 percent are pregnant (Bureau of Justice Statistics, 1994; Safyer and Richmond, 1995).
While there are no studies that have examined the direct effect of incarceration on GWG per se, several studies (Martin et al., 1997a, 1997b; Bell et al., 2004) have examined its effect on birth weight. Martin et al. (1997a) found that a higher number of pregnancy days spent incarcerated was found to be associated with higher infant birth weight. Furthermore, Martin et al. (1997b) also found that infant birth weights among women incarcerated during pregnancy were not significantly different from women never incarcerated; however, infant birth weights were significantly worse among women incarcerated at a time other than during pregnancy than among never-incarcerated women and women incarcerated during pregnancy, suggesting certain aspects of the prison environment, such as shelters and regular meals, may be protective particularly for high-risk pregnant women.
There is a lack of evidence on societal/institutional (media, culture/acculturation, health services, policy), environmental (altitude, exposures to environmental toxicants, disasters), and neighborhood determinants (access to healthy foods, opportunities for physical activities) of GWG.
Few of the studies reviewed considered the influence of the many possible determinants of GWG among women of different racial/ethnic and socioeconomic groups, or alternatively, adjusted for race/ethnicity or SES in their analyses.
There is insufficient evidence to evaluate the influences of psychological factors such as depression, stress, social support, or attitude toward GWG on actual GWG.
There remains a lack of information to relate dietary intake or physical activity to GWG even though they are primary determinants of weight gain in nonpregnant individuals.