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2 Descriptive Epidemiology and Trends
Pages 25-70

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From page 25... ... The committee also evaluated trends since 1990 in postpartum weight retention. The committee then examined trends since 1990 in key weight-related sociodemographic maternal characteristics and pregnancy outcomes (i.e., characteristics and outcomes known to be associated with prepregnancy BMI and/or GWG) Read the entire page →
From page 26... ... Underweight 3.9 2.7 -- a Normal weight 47.8 37.3 23.4 Overweight 24.4 27.7 25.7 Class I obese 13.3 15.8 23.7 Class II obese 7.3 9.7 12.2 Class III obese -- a 6.8 13.3 obesity among American women of childbearing age (Flegal et al., 1998; Mokdad et al., 1999; IOM, 2005; Kim et al., 2007) Read the entire page →
From page 27... ... Underweight 7.1 5.1 4.6 Normal weight 64.9 58.3 44.2 Overweight 16.8 18.2 23.9 Class I obese 6.9 10.6 14.8 Class II obese 3.0 5.2 7.1 Class III obese 1.4 2.6 5.4 Age 35-44 (%) Underweight 3.8 3.3 2.1 Normal weight 55.7 46.8 37.3 Overweight 23.2 24.2 27.1 Class I obese 10.2 14.2 17.1 Class II obese 4.8 7.0 8.6 Class III obese -- a 4.4 7.9 NOTE: Underweight, < 18.5 kg/m2; normal, 18.5 to < 25.0 kg/m2; overweight, 25.0 to < 30.0 kg/m2; class I obese, 30.0 to < 35.0 kg/m2; class II obese, 35.0 to < 40 kg/m2; class III obese, ≥ 40 kg/m2. Read the entire page →
From page 28... ... recommended the use of BMI to classify maternal prepregnancy weight. The four prepregnancy BMI categories used in that report were selected to be consistent with 90 percent, 120 percent, and 135 percent of the 1959 Metropolitan Life Insurance Company's ideal weight-for-height standards -- the standard most Underweight Normal Weight Overweight Obese Total 2002-2003 1998 1993-1994 White 2002-2003 1998 1993-1994 Black 2002-2003 1998 1993-94 0 10 20 30 40 50 60 70 80 90 100 Percent of Women in Total Population FIGURE 2-1 Trends in the distribution of BMIa from 1993 to 2003 among prepregnant U.S. Read the entire page →
From page 29... ... report called for collection of national data on GWG, prepregnancy height, and weight for proper surveillance, today there are still no nationally representative data with which to study trends in GWG in the United States. The committee used three sets of data for its evaluation of GWG: birth certificate, PRAMS, and Pregnancy Nutrition Surveillance System (PNSS) Read the entire page →
From page 30... ... Unfortunately, the standard birth certificate lacks data on maternal prepregnancy weight and height. Thus, data from this source cannot provide information about GWG relative to prepregnant BMI category. Read the entire page →
From page 31... ... Weight Gain Relative to Prepregnancy BMI Unfortunately, the standard birth certificate lacks data on maternal prepregnancy weight and height. Thus, data from this source cannot pro Read the entire page →
From page 32... ... PNSS Recalled at the Measured at the Recalled at the Measured at Low-income women in prenatal visit or prenatal visit or postpartum visit WIC postpartum 26 states postpartum visit postpartum visit recertification visit IFPS II Recalled in the Recalled in the Recalled in the Recalled at 3, 6, 9, Nationally distributed postpartum period postpartum period postpartum period and 12 months consumer opinion panel NOTE: IFPS II = Infant Feeding Practices Study II; PNSS = Pregnancy Nutrition Surveillance System; WIC = Special Supplemental Nutrition Program for Women, Infants, and Children. Read the entire page →
From page 33... ... birth certificate, and by 2006, 19 states were using the revised birth certificate. At present, the two large surveillance systems collecting data on GWG and prepregnancy BMI in the United States, PRAMS and PNSS, permit identification of trends in recommended weight gains, although neither system is nationally representative. Read the entire page →
From page 34... ... SOURCE: CDC, 2008a. 20 < 20 yrs 20-34 yrs 15 ≥ 35 yrs Percent 10 5 0 Total Non-Hispanic Non-Hispanic Hispanic White Black Population Group FIGURE 2-5 Percentage of women in the United States who gained less than 15 pounds during pregnancy by age and race or ethnicity of the mother, 2005. Read the entire page →
From page 35... ... For obese women, average weight gains were well 40 Underweight Overweight 35 Normal Weight Obese 30 Weight Gain (lb) 25 20 15 10 5 0 All Women White Black Hispanic Population Group FIGURE 2-6 Mean gestational weight gain by BMI category and race or ethnicity, Pregnancy Risk Assessment Monitoring System, 2002-2003. Read the entire page →
From page 36... ... Among women in all BMI categories, no more than 50 percent of women gained within the recommended range. Data Obtained from PNSS The only other large U.S. Read the entire page →
From page 37... ... . Non-Hispanic black women and Hispanic women had similar rates of low weight gain and were more likely than non-Hispanic white women to gain less than the recommended levels. Read the entire page →
From page 38... ... 38 IOM 100% 90% 23.2% 24.7% 27.9% 27.8% 26.9% 29.0% 29.4% 29.8% 30.2% 29.6% 28.9% 80% 39.6% 40.8% 43.8% 44.1% 45.5% 45.7% 46.3% 46.2% 45.9% 46.4% 46.3% 70% 60% 35.8% 36.3% 38.4% 41.4% 40.0% 40.9% 50% 40.1% 40.2% 40.1% 40.4% 40.2% 26.9% 26.5% 26.6% 27.2% 27.0% 28.5% 40% 26.9% 26.8% 26.9% 28.2% 28.1% 30% pinpoint size 20% 41.0% 39.0% 33.7% 31.8% 33.5% 32.7% 31.0% 30.5% 30.0% 30.3% 30.7% 31.2% 29.6% 29.6% 27.3% 27.3% 27.4% 26.8% 27.0% 27.2% 25.5% 25.3% Figure 2-8 left-hand half.eps 10% set landscape on spread in 2 parts 0% 0 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Underweight Normal weight because reduction to 1 page would reduce the type to Read the entire page →
From page 39... ... Sharma, CDC, Atlanta, Georgia, December 2008; CDC, Pregnancy Nutrition Surveillance System. Available online at http://www.cdc.gov/PEDNSS/pnss_tables/pdf/national_table20.pdf [accessed February 12, 2009] Read the entire page →
From page 40... ... POSTPARTUM WEIGHT RETENTION Studies of population trends in maternal postpartum weight retention build upon and extend the data required to assess the adequacy of GWG (i.e., whether women are gaining weight during pregnancy within the IOM [1990] recommended ranges; see Table 2-2) Read the entire page →
From page 41... ... Unfortunately, data on maternal postpartum weights are not widely available, particularly for times later in the year after birth; this is different than during pregnancy, when maternal weight is monitored and routinely recorded in the clinical record. The committee used two sets of data for its evaluation of postpartum weight retention: PNSS, which was described earlier in the discussion on GWG trends, and the Infant Feeding Practices Study II (IFPS II) Read the entire page →
From page 42... ... . In all BMI categories and at each postpartum visit, mean postpartum weight retention and the percentage of women retaining > 20 and > 10 pounds increased as GWG category increased (Figure 2-12) Read the entire page →
From page 43... ... > 20 lbs. Underweight Normal Weight 80 80 60 60 40 40 Percent 20 20 0 0 IOM IOM IOM IOM IOM IOM W B H W B H 80 Overweight 80 Obese 60 60 40 Percent 40 20 20 0 0 IOM IOM IOM IOM IOM IOM W B H W B H FIGURE 2-11 Percentage of women retaining more thanFigure 2-11.eps 10 pounds and more than 20 pounds at > 24 weeks postpartum (mean 30.6 weeks postpartum) Read the entire page →
From page 44... ... 20 20 15 15 10 10 5 5 0 0 0 10 20 30 40 50 60 0 10 20 30 40 50 60 -5 -5 -10 -10 -15 -15 -20 -20 Weeks Postpartum Weeks Postpartum FIGURE 2-12 Mean postpartum weight retention by weight gain category (IOM, 1990) and prepregnancy BMI category across four postpartum visits in the IFPS II study. Read the entire page →
From page 45... ... However, postpartum weight retention remains a problem for a large proportion of mothers, even at 1 year after birth. These data also show that obese women who gained within or below the recommended ranges experienced a net loss in weight from their prepregnancy weight. Read the entire page →
From page 46... ... SOCIODEMOGRAPHIC CHARACTERISTICS OF MOTHERS The committee examined trends since 1990 in several weight-related sociodemographic and lifestyle characteristics of pregnant women, in an effort to identify trends related to GWG and to provide information that may be helpful in developing interventions aimed at increasing the number of women that gain within the recommended ranges. Sociodemographic Trends Since 1990 there have been several changes in the sociodemographic characteristics of women, as shown in Table 2-5: • Between 1990 and 2005, there was an increase in the racial and ethnic diversity of U.S. Read the entire page →
From page 47... ... . Dietary Practices Dietary intake No comprehensive national data are available on dietary intake practices of pregnant women. Read the entire page →
From page 48... ... No other nationally representative data on dietary intake among pregnant women or women of childbearing age are available. Among the population as a whole ages 19-39 years, total energy intake increased by 18 percent (1,856 to 2,198 kilocalories [kcal] Read the entire page →
From page 49... ... provide recommended levels of physical activity and emphasize that inactivity has adverse health consequences. Data from the BRFSS indicate that although the proportion of women of childbearing age who reported no recreational physical activity decreased between 1994 Read the entire page →
From page 50... ... . Physical activity increased with education, from 37 percent among women who did not 35 30 25 Percent 20 18-29 30-39 15 40-49 10 1994 1996 1998 2000 2002 2004 Year FIGURE 2-15 Trends in leisure-time physical inactivity for women of childbearing age, United States, 1994-2004. Read the entire page →
From page 51... ... Although nationally representative data specific to women during and after pregnancy are not available, data for U.S. women of childbearing age illustrate striking increases in the prevalence of major depression from 1991-1992 to 2001-2002 in the total population and among white and black women (Figure 2-17) Read the entire page →
From page 52... ... PREGNANCY OUTCOMES RELATED TO GESTATIONAL WEIGHT GAIN The following describes trends since 1990 in known GWG-related pregnancy outcomes, including gestational diabetes, preeclampsia and gestational hypertension, cesarean delivery, maternal mortality, birth weight, preterm birth, breastfeeding, and childhood obesity. Gestational Diabetes Data from birth certificates collected nationally illustrate that there has been a striking increase in the prevalence of diabetes in pregnancy in each Read the entire page →
From page 53... ... . The authors noted that clinical diagnostic criteria, revised in the 1990s, may have simultaneously caused an exaggerated rise in the rate of gestational hypertension and an attenuated increase in the rate 100 1990 2000 2005 90 80 70 Per 1,000 60 50 40 30 20 10 0 All Ages Less than 20 20-29 30-39 40 and over Years FIGURE 2-18 Diabetes rates by age of mother: United States, 1990, 2000, and 2005. Read the entire page →
From page 54... ... They concluded that the small but consistent elevation in the rate of preeclampsia is a conservative estimate of the true population-level change. Cesarean Delivery The rate of total cesarean deliveries in the United States increased almost fivefold between 1970 and 1988 and then declined to 20.7 percent in 1996 (Figure 2-20) Read the entire page →
From page 55... ... birth certificates since 2003 will allow future researchers to more clearly understand relationships between maternal prepregnancy BMI, GWG, and cesarean deliveries in the United States. Maternal Mortality The crude maternal mortality rate (deaths per 100,000) Read the entire page →
From page 56... ... 50 Black 45 Deaths per 1,000 Live Births All Races 40 White 35 30 25 20 15 10 5 0 1950 1960 1970 1980 1990 2000 2004 Year FIGURE 2-21 Infant mortality rates in the United States, 1950 through 2004, by race. Figure 2-21.eps SOURCE: NCHS, 2007b. Read the entire page →
From page 57... ... Other possible explanations for these trends in birth weight include a greater prevalence of older mothers, who tend to have more complications of pregnancy, as well as increased use of assisted reproductive technology and obstetrical procedures, including labor induction and elective cesarean deliveries. Rates for low birth weight and very low birth weight increased in the United States between 1990 and 2005, when the overall rate of low birth weight among singletons was 6.41 percent and the overall rate of very low birth weight was 1.14 percent. Read the entire page →
From page 58... ... Live Births 14 13 12 11 10 9 8 7 6 5 1990 1992 1994 1996 1998 2000 2002 2004 Year FIGURE 2-24 Trends in low birth weight of live-born singleton infants in the United States from 1990 through 2005, by race and ethnic background. NOTE: Low birth weight is defined as less than 2,500 g. Read the entire page →
From page 59... ... . TABLE 2-6 Estimates of SGA by Sex, Race or Ethnicity, and Year: United States 1990 1995 2000 2005 Males Total 10.5 10.5 10.2 10.7 Non-Hispanic white 8.7 8.8 8.4 8.7 Non-Hispanic black 17.1 16.9 16.3 16.8 Hispanic 10.7 10.6 10.4 10.7 White 9.1 9.2 8.9 9.3 Black 17.0 16.8 16.2 16.5 American Indian/Alaska Native 9.9 9.7 9.4 9.8 Asian/Pacific Islander 14.0 14.4 13.9 14.5 Females Total 10.7 10.5 10.1 10.5 Non-Hispanic white 9.0 8.9 8.4 8.8 Non-Hispanic black 17.3 16.9 16.2 16.7 Hispanic 10.4 10.2 9.8 10.1 White 9.3 9.2 8.7 9.1 Black 17.2 16.8 16.1 16.3 American Indian/Alaska Native 9.3 9.5 9.0 9.3 Asian/Pacific Islander 13.2 13.7 13.2 13.6 NOTE: Singleton births only. Read the entire page →
From page 60... ... The preterm birth rate for singleton gestations increased 13 percent from 1990 to 2005, again with late preterm births accounting for a majority of the increase. An increase in the rates of cesarean deliveries and induced births contributes to but does not completely explain this trend in late preterm births (March of Dimes, available online at http://www. Read the entire page →
From page 61... ... SOURCE: NCHS, 2007a. Figure 2-25.eps Non-Hispanic White Non-Hispanic Black Hispanic 20 18 16 Percent of Live Births Preterm 14 12 10 8 6 4 2 0 1990 1992 1994 1996 1998 2000 2002 2004 FIGURE 2-26 Trends in preterm live births in the United States by race, 1990 to 2005. Read the entire page →
From page 62... ... . Recent data from the National Immunization Survey, a population-based survey conducted by the CDC, showed that these rates continued to rise from 2000 to 2004. Read the entire page →
From page 63... ... . Non-Hispanic black adolescents have a dramatically greater prevalence of overweight compared to nonHispanic whites; Mexican American girls also have somewhat higher rates (Table 2-8) Read the entire page →
From page 64... ... among children and adolescents, United States, collected from 1963-2004, and reported from 1965-2006. SOURCES: Ogden et al., 2006, 2008. Read the entire page →
From page 65... ... . Action Recommendations Action Recommendation 2-1: The committee recommends that the Depart ment of Health and Human Services conduct routine surveillance of GWG and postpartum weight retention on a nationally representative sample of women and report the results by prepregnancy BMI (includ Read the entire page →
From page 66... ... Action Recommendation 2-2: The committee recommends that all states adopt the revised version of the birth certificate, which includes fields for maternal prepregnancy weight, height, weight at delivery, and ges tational age at the last measured weight. In addition, all states should strive for 100 percent completion of these fields on birth certificates and collaborate to share data, thereby allowing a complete national picture as well as regional snapshots. Read the entire page →
From page 67... ... 2007. Prevalence of regular physical activity among adults -- United States, 2001 and 2005. Read the entire page →
From page 68... ... 2005. Correlates of physical activity among pregnant women in the United States. Read the entire page →
From page 69... ... 2008. Secular trends in the rates of pre eclampsia, eclampsia, and gestational hypertension, United States, 1987-2004. Read the entire page →

From page 25...

... The committee also evaluated trends since 1990 in postpartum weight retention. The committee then examined trends since 1990 in key weight-related sociodemographic maternal characteristics and pregnancy outcomes (i.e., characteristics and outcomes known to be associated with prepregnancy BMI and/or GWG)

2 Descriptive Epidemiology and Trends Pages 25-70

2 Descriptive Epidemiology and Trends
Pages 25-70