and Mott (1988) found in a cohort of 6,015 primiparous women that not desiring a pregnancy was not a significant predictor of very low prenatal weight gain. Several large population-based surveys have not found an association between GWG and planned pregnancy (Kost et al., 1998; Wells et al., 2006).

The actual number of migrant farm workers currently in the United States in not known, but estimates are that at least 3-5 million migrant and seasonal workers come to the United States each year (CDC, 1997). Further, approximately 16 percent of migrant workers are women. Data about GWG among migrant women in four states was obtained through the Pregnancy Nutrition Surveillance System (PNSS). Analysis of the data collected showed that about 52 percent of migrant women gained less than the range recommended by the IOM (1990) compared to 32 percent of non-migrant women. Mean weight gain was also lower for migrant women (22.9 pounds) compared to nonmigrant women (29.7 pounds). However, even though migrant women had lower GWG than nonmigrant women, the prevalence for adverse birth outcomes (low birth weight, very low birth weight, preterm birth, and small-for-gestational age) was similar for both groups (CDC, 1997). Similarly, Reed et al. (2005) found that migrant women had higher rates of pregnancy-related risk factors but lower rates of adverse birth outcomes compared to nonmigrant women.

The committee was unable to identify studies that specifically examined GWG among women in military service. Several studies found women in active-duty experience greater stress but less job control, as well as higher rates of depression, compared to a parity-matched control group of dependent military wives (Magann and Nolan, 1991; O’Boyle et al., 2005), but it is unclear how these factors might influence GWG. One study surveyed pregnant women with deployed partners (Haas and Pazdernik, 2006). Women whose partners were deployed showed a greater tendency to deliver a large infant and reported more stress and changed eating habits, compared to women whose partners were not deployed; however, the results were not statistically significant. No difference was seen in the gestational age at delivery, percentage with vaginal delivery, average number of children at home, self-reported stress, or reported GWG.