and of higher parity than non-obese subjects. The obese subjects also had higher rates of chronic hypertension, diabetes, and inadequate GWG. Prysak et al. (1995), in a retrospective comparison of pregnancy characteristics between older (≥ 35 years old) and younger (25-29 years old) nulliparous women, found that the older women had significantly lower mean GWG than the younger women. In addition, obesity was significantly greater in the older compared to the younger women.
Endres et al. (1987) evaluated nutrient intake, prepregnancy weight, and GWG in pregnant women enrolled in the WIC program who were over 35 years of age versus adolescents aged 15-18 years. The investigators calculated prepregnancy BMI for both groups and found more than 50 percent of the older women were identified as obese prior to pregnancy. The study found no significant difference in total nutrient intake between the groups (neither met the Recommended Dietary Allowances [RDAs]), but the younger women had higher mean energy intakes (p = 0.006) and greater cumulative GWG in the third trimester (9.5 kg versus 7.6 kg) than the older women. In sum, several studies reported higher prepregnancy BMI and lower GWG among older women, compared to their younger counterparts. The contributions of GWG to birth outcomes, postpartum weight retention, and subsequent overweight/obesity among older women remain unclear.
Table 4-1 summarizes reports from the past three decades on GWG by age and racial/ethnic group.
Few studies have examined racial/ethnic differences in GWG, and even fewer studies have considered the influence of the many possible determinants of GWG among different racial/ethnic groups or alternatively, adjusted for race/ethnicity in their analyses. Caulfield et al. (1996), for example, found that among 2,617 black and 1,253 white women delivering at a university hospital during 1987-1989 only 28.2 and 32.5 percent of black and white women, respectively, gained within the ranges recommended by IOM (1990).
Black women are at increased risk for gaining less weight than recommended, when controlled for maternal prepregnancy BMI, height, parity, education, smoking, hypertension, duration of pregnancy, and fetal sex. Chu et al. (2009) assessed the amount of GWG among 52,988 underweight, normal weight, overweight, and obese U.S. women who delivered a singleton, full-term infant in 2004-2005 using Pregnancy Risk Assessment Monitoring System (PRAMS) data (2004-2005). They found that black women were significantly more likely than white women to gain less than 15 pounds, but less likely than white women to gain more than 34 pounds.