Sociocultural and behavioral influences on weight gain during pregnancy.

Studies have consistently identified a positive association between prenatal weight gain and birth weight. Much less, however, is known about factors that may influence women to gain weight within currently recommended ranges. The importance of this issue is suggested by recent reports indicating that only 30-40% of women actually gain weight within these ranges. This paper examines demographic, sociocultural, and behavioral factors that are associated with, and may influence risk of, low prenatal weight gain among adult women with low and normal body mass indexes. Available data suggest that these factors include ethnicity, socioeconomic status, age, education, pregnancy intendedness or wantedness, prenatal advice, and psychosocial characteristics such as attitude toward weight gain, social support, depression, stress, anxiety, and self-efficacy. Potential theoretical models for these associations include biological, behavioral, and mixed pathways. The design of targeted intervention studies will depend on further identification and characterization of sociocultural and behavioral risk factors that, along with reproductive and nutritional characteristics, may predict which women are most likely to have inadequate prenatal weight gain.

Low prenatal weight gain among adult WIC participants delivering term singleton infants: variation by maternal and program participation characteristics.

OBJECTIVE: To determine the association of maternal and prenatal WIC program participation characteristics with low prenatal weight gain among adult women delivering liveborn, singleton infants at term. METHODS: WIC program data for 19,017 Black and White Alabama women delivering in 1994 were linked with birth certificate files to examine the association of anthropometric, demographic, reproductive, hematologic, behavioral and program participation characteristics with low prenatal weight gain. RESULTS: One third (31.0%) had low prenatal weight gain as defined by the Institute of Medicine. The incidence of low weight gain was increased among women who had < 12 years of education, were single, Black, anemic, had low or normal prepregnancy body mass index (BMI), increased parity, interpregnancy intervals < or = 24 months, used tobacco or alcohol, or entered prenatal care or WIC programs after the first trimester. After adjusting for selected maternal characteristics, the adjusted odds ratios (AOR) for low weight gain were increased with short interpregnancy intervals (AOR 1.21 to 2.20); tobacco use (AOR 1.16 to 1.40), anemia (AOR 1.20 to 1.25), and second trimester entry into prenatal care (AOR 1.14 to 1.20); the size of the AORs and 95% confidence intervals varied by BMI and racial subgroup. CONCLUSIONS: The results of this study suggest that WIC interventions targeting low prenatal weight gain be focused on risk factors present not only during pregnancy, but during the pre- and interconceptional periods as well. Interventions should target low BMI, tobacco use, and anemia, and include attention to nutrition screening and risk reduction among women in postpartum and family planning clinic settings.

Prenatal weight gain within upper and lower recommended ranges: effect on birth weight of black and white infants.

OBJECTIVE: To that end examine differences in birth weight among the term infants of black and white women with weight gains in the upper or lower half of recommended ranges. METHODS: Birth weight (mean, low [at or below 2500 gl, and suboptimal [2501-2999 g]) among term infants of 2219 black and 3966 white low-income women was compared with maternal prenatal weight gain classified according to four categories: below, within the lower or upper halves, and above the recommended ranges for pregravid body mass index (BMI) category (low, normal, high). RESULTS: Adjusted mean birth weights among the infants of women with prenatal weight gain in the upper versus lower half of the recommended ranges were higher among white women with normal BMI (3307 g upper half, 3199 g lower half, P = .001) but not among black women with normal BMI (3180 g upper half, 3105 g lower half, not significant). Logistic regression analyses revealed that prenatal weight gain in the upper compared with the lower half of the recommended ranges was associated with a decreased adjusted odds ratio (OR) for low (but not suboptimal) birth weight among the infants of white women (OR 0.4, 95% confidence intervals [CI] 0.2,0.9) but not of black women (OR 1.2; 95% CI 0.4,3.3). CONCLUSION: These preliminary observations do not provide support for the presence of ethnic group-specific recommendations within guidelines for prenatal weight gain.

Low prenatal weight gain among low-income women: what are the risk factors?

BACKGROUND: Although a large body of evidence suggests that prenatal weight gain is an important determinant of fetal growth, 23 to 38 percent of nonobese women have low prenatal weight gain. Determination of potential risk factors for low gain is essential to develop targeted intervention programs. This study examined the association of maternal sociodemographic, lifestyle, and reproductive characteristics with the actual occurrence of low gain among 536 black and 270 white low-income, nonobese women. METHODS: Sociodemographic, pregnancy wantedness, reproductive, and anthropometric data were obtained by interview during the first prenatal visit. A 72-item questionnaire, administered at 24 to 26 weeks' gestation, assessed residential and household characteristics, housing characteristics, income, transportation, physical activity, employment, and institutional support. Variables associated with low gain in bivariate analyses were included in logistic regression analysis to determine the adjusted odds ratios for low gain. RESULTS: Three characteristics were associated with increased adjusted odds ratios for low prenatal weight gain among black women: having a mistimed or unwanted pregnancy, caring for more than one preschool child at home, and not using own car for errands. One characteristic, working more than 40 hours per week when employed, was associated with low gain among white women. CONCLUSION: Although these preliminary findings require additional confirmation, they suggest that a variety of sociodemographic and lifestyle features deserve investigations that target the identification and characterization of risk factors for low prenatal weight gain.

Low pregravid body mass index as a risk factor for preterm birth: variation by ethnic group.

OBJECTIVE: To examine the association between pregravid body mass index (BMI) and preterm delivery among black, white, and Hispanic women. METHODS: Preterm deliveries among 12,459 women (43.2% black, 39.3% white, and 17.5% Hispanic) enrolled in a large multicenter trial of preterm birth prevention were examined by pregravid BMI category (very low, less than 16.5; low, 16.5-19.7; normal, 19.8-26.0; high, greater than 26) and by pathway (all, early, late, spontaneous preterm labor, and premature rupture of membranes [PROM]). RESULTS: More than one-fifth of both black (20.1%) and white (28.6%) women had low pregravid BMIs (less than 19.8), whereas only 11.7% of Hispanic women were under-weight. The overall prevalence of preterm delivery (gestational age less than 37 completed weeks) was 8.1% (10.3% in black, 7.3% in white, and 4.8% in Hispanic women). Among black and white women, bivariate analysis revealed an inverse linear association between pregravid BMI and the prevalence of all preterm deliveries (P < or = .001) and between pregravid BMI and the prevalence of late (33-36 weeks' gestation) preterm deliveries (P < .001). No such associations were observed for early (20-32 weeks' gestation) preterm delivery or among Hispanic women. Pregravid BMI was also associated inversely with spontaneous preterm labor among both black (P < or = .01) and white (P < .001) women, but not among Hispanic women. Logistic regression analysis (adjusting for the effects of maternal age, education, smoking, parity, previous preterm delivery, birth interval, and height) revealed that among black and white women, very low and low pregravid BMIs were associated with increased adjusted odds ratios for late (but not early) preterm delivery and for spontaneous preterm labor (but not PROM). CONCLUSIONS: These observations suggest that low pregravid BMI is associated with an increase in the prevalence of late preterm delivery and of spontaneous preterm labor among black and white, but not Hispanic, women.

Abbreviated scale for the assessment of psychosocial status in pregnancy: development and evaluation.

BACKGROUND: Data from five existing psychosocial scales were used to develop an abbreviated scale for the assessment of psychosocial status during pregnancy. METHODS: Scales were self-administered by 842 black and 381 white low-income multiparous women at risk for poor pregnancy outcome. Trait anxiety (Speilberger), self-esteem (Rosenberg), mastery (Pearlin), and depression (CES-D) were assessed at 24-26 weeks' gestation; subjective stress (Schar) was assessed at 30-32 weeks' gestation. The 59 pooled items were examined for redundancy and the discernment of primary factors using principal factor analysis. Regression analysis was used to determine if the resulting abbreviated scale (28 items) would provide information similar to that obtained with the 59 item pool (full scale) in predicting gestational age (GA), birth weight (BW), fetal growth restriction (FGR), and preterm delivery (PTD). RESULTS: The abbreviated scale was highly correlated (r = 0.97) with the 59-item pool and the six factors isolated were generally compatible with the major characteristics assessed by the five original scales. The distribution of FGR and PTD by scale quartile was similar for the abbreviated and the combined scales. Logistic regression analysis of scores for all women revealed that poor (high) scores on both the full (p = 0.0151) and the abbreviated scales (p = 0.0131) were positively associated with FGR, but not with PTD. In linear regression analysis poor (high) scores on both the full (p = 0.0024) and the abbreviated scale (p = 0.0019) were negatively related to BW, but not to GA. When data for black and white women were examined separately, the two scales provided comparable information. CONCLUSIONS: The abbreviated psychosocial scale provided information similar to that obtained with 59 pooled items in predicting GA, BW, FGR, and PTD.

Medical, psychosocial, and behavioral risk factors do not explain the increased risk for low birth weight among black women.

OBJECTIVE: Our purpose was to determine whether various demographic, behavioral, housing, psychosocial, or medical characteristics explain the difference in pregnancy outcome between black and white women. STUDY DESIGN: A sample of 1491 multiparous women with singleton pregnancies, 69% of whom were black and 31% of whom were white and who enrolled for care between Oct. 1, 1985, and March 30, 1988, participated in the study. The frequencies of various demographic, medical environmental, and psychosocial risk factors among black and white women were determined. The outcome measures were birth weight, gestational age, fetal growth restriction, preterm delivery and low birth weight. RESULTS: White infants were heavier and born later than black infants. The white women in this sample smoked more cigarettes, moved more frequently, and had worse psychosocial scores. The black women had lower incomes, were less likely to be married, and had more hypertension, anemia, and diabetes. Besides race, only maternal height, weight, blood pressure, diabetes, and smoking had a consistent impact on outcome and did not explain the difference in outcome between the two groups. CONCLUSION: In this low-income population, many of the risk factors for low birth weight were more common among white women than black women. Nevertheless, black women had more infants born preterm, with growth restriction, and with low birth weight than did white women. The various maternal characteristics studied did not explain these differences.

Prenatal weight gain patterns and birth weight among nonobese black and white women.

OBJECTIVE: To examine the association between prenatal weight gain patterns and birth weight, using Institute of Medicine (IOM) guidelines. METHODS: Data from a prospective follow-up study of risk factors for fetal growth restriction were used to examine the impact of low weight gain on mean birth weight. A total of 415 nonobese (body mass index [BMI] less than 26) black (n = 275) and white (n = 140) women who delivered at term were included in this analysis. Linear regression analysis was used to examine the impact of low first-trimester gain (less than 2.3 kg with low BMI [less than 19.8]; less than 1.6 kg with normal BMI [19.8-26.0]) and low second- and third-trimester rates of gain (less than 0.38 kg/week with low BMI; less than 0.37 kg/week with normal BMI) on mean birth weight while controlling for selected sociodemographic and reproductive variables. RESULTS: Patterns with low gain in the first and second or in the second and third trimesters were associated with significant decreases in mean birth weight, ranging from 206 to 265 g; low gain in only the first or third trimester was not associated with a significant decrease in mean in birth weight. The impact of low gain on mean birth weight varied by ethnic group. CONCLUSION: These observations suggest that inadequate patterns of prenatal weight gain, defined by IOM guidelines, are associated with decreased birth weight, particularly when the patterns involve low second-trimester gain.

Serum ferritin: a predictor of early spontaneous preterm delivery.

OBJECTIVE: To identify biochemical indices for iron and protein nutriture as well as acute-phase reactants as predictors of preterm delivery. METHODS: In this nested case-control study, serum samples were obtained at about 24 weeks' gestation from 94 indigent multiparas. These cases were defined based on having a spontaneous delivery of 32 weeks or less (n = 31) with two control groups, one delivering spontaneously at 33-36 weeks (n = 32) and the other delivering spontaneously at 37 weeks or more (n = 31). The concentrations of iron, ferritin, transferrin, transferrin saturation, and transferrin receptor were measured as indices of iron status. The concentrations of acute-phase reactants, including C-reactive protein, alpha-2-macroglobulin, beta-2-microglobulin and ceruloplasmin, were also measured, along with albumin, prealbumin, retinol-binding protein, copper, and zinc. RESULTS: Serum ferritin concentrations were negatively correlated with gestational age at birth (P = .034). For subjects having serum ferritin levels above the median compared with those below, the odds ratio of having an early spontaneous preterm delivery was 2.99 (95% confidence interval 1.13-7.89). The other indices, including iron status and the acute-phase reactants, were not significantly associated with gestational age at birth. CONCLUSION: Elevated serum ferritin levels during the second trimester are predictive of early spontaneous preterm delivery, possibly because these reflect an acute-phase reaction to subclinical infections that are closely associated with premature delivery.

Relationship of psychosocial status to low prenatal weight gain among nonobese black and white women delivering at term.

OBJECTIVE: To examine the association of six indices of psychosocial well-being with low prenatal weight gain. METHODS: Scales assessing depression, trait anxiety, stress, mastery, self-esteem, and social support were self-administered at mid-pregnancy to 536 black and 270 white low-income, nonobese, multiparous women who subsequently delivered at term. All women had one or more risk factors for fetal growth restriction. The association of individual scale scores with prenatal weight gain values below current Institute of Medicine guidelines was examined while controlling for sociodemographic and reproductive variables, and for time between last weight observation and delivery. RESULTS: None of the scales were associated with low gain among black women. Among white women, poor scores (worst quartile) on four of the scales were associated with increased adjusted odds ratios for low gain, including 2.5 for high trait anxiety, 3.0 for increased levels of depression, 3.9 for low mastery, and 7.2 for low self-esteem. When scale scores and weight gain were examined as continuous variables, poor scores on five of the six scales were associated with lower weight gain values among white women (scores on the stress scale were the exception). CONCLUSION: These data suggest an important role for psychosocial factors in the etiology of low prenatal weight gain among white women but show no such role for black women. Along with reports of wide inter-individual variability in the energy costs of pregnancy, these data also suggest that attempts to manipulate pregnancy weight gain through dietary means will meet with variable success until psychosocial and other factors affecting prenatal energy intake and/or utilization are further delineated.

Employment-related stress and preterm delivery: a contextual examination.

Studies of employment-related stress as a risk factor for preterm delivery suggest that contextual factors unrelated to occupation, as well as work-related characteristics, must be examined in assessing this relationship. In this study, the relationship of work and contextual characteristics--assessed at midpregnancy and including scores on an occupational fatigue index--to preterm delivery was examined among 943 black and 425 white low-income multiparous women who were at risk for a poor pregnancy outcome. At 24 to 26 weeks gestational age, a 77-item questionnaire was self-administered to obtain detailed information on sociodemographic and contextual characteristics, home physical activities, and occupational characteristics. Questions in the occupational section of the questionnaire included most of those previously used by Mamelle and coworkers in 1984 and 1987 to construct an occupational fatigue index. The overall preterm delivery rate for black women was 14.0 percent and for white women, 9.6 percent. No relationships were observed between age, education, or marital status and preterm delivery, or between work status, hours per week, transportation, travel time, reliability of child care, or home physical activity and preterm delivery for either black women or white women. Black (but not white) women who continued to work at midpregnancy and who reported being able to take rest breaks when they felt tired had a lower preterm delivery rate (10.4 percent versus 21.9 percent; P = 0.031) compared with those who could or did not. Generally, scores for individual sources and levels of occupational fatigue, as well as total occupational fatigue index scores, were unrelated to preterm delivery in this relatively homogeneous group of low income high-risk women.

Prenatal weight gain patterns and spontaneous preterm birth among nonobese black and white women.

OBJECTIVE: To examine the relationship between prenatal weight gain and spontaneous preterm delivery, using the Institute of Medicine (IOM) guidelines. METHODS: Nonobese low-income black (677 subjects) and white (338) women were grouped by ethnicity and prepregnancy body mass index (BMI) as low (less than 19.8) or normal (19.8-26.0). The relationship of total gain (first trimester) and weekly rate of gain (second and third trimester) to spontaneous preterm delivery was determined while controlling for sociodemographic and reproductive variables as well as for time between last weight observation and delivery. RESULTS: For all women combined, the mean (+/- standard deviation) weight gain during the first trimester was 2.48 +/- 3.36 kg, and the mean rate of gain during the second and third trimesters was 0.49 +/- 0.21 and 0.45 +/- 0.28 kg/week, respectively. Low first- or second-trimester weight gain was not associated with increased adjusted odds ratios (OR) for spontaneous preterm delivery. Third-trimester rates of gain below the lower limit of the IOM-recommended range (less than 0.38 kg/week with low BMI, less than 0.37 kg/week with normal BMI) were associated with increased preterm delivery among all women (OR 2.46, 95% confidence interval [CI] 1.53-3.92), all black women (OR 1.98, 95% CI 1.16-3.41), and all white women (OR 4.05, 95% CI 1.41-11.66). CONCLUSION: These observations suggest that a low third-trimester rate of weight gain, defined using IOM guidelines, is associated with an increased risk of spontaneous preterm delivery among nonobese black and white women.

Prenatal weight gain, term birth weight, and fetal growth retardation among high-risk multiparous black and white women.

OBJECTIVE: To examine the association of prenatal weight gain below, within, and above the Institute of Medicine guidelines with birth weight and fetal growth restriction (FGR) among low-income, high-risk black and white women. METHODS: Eight hundred three black and 365 white women were grouped by pregravid body mass index (BMI): low (below 19.8), normal (19.8-26), high (above 26-29), and very high (above 29). The impact of maternal weight gain on birth weight and race-specific FGR was determined while controlling for sociodemographic and reproductive variables and for time between last weight observation and delivery. RESULTS: One-third of both black and white women failed to achieve the Institute of Medicine minimum recommended gain for pregravid BMI. More women with low BMI gained less than the recommended weight as compared with those having normal, high, or very high BMI. Nonobese black women (BMI 29 or below) delivered fewer infants with FGR as weight gain increased from below the recommended range (17.9% FGR) to within (10.3% FGR) or above (3.8% FGR) the range; corresponding data for nonobese white women were 20.9, 19.1, and 10.5% FGR, respectively. Obese black women (BMI above 29) also delivered fewer infants with FGR (4.2%) when they exceeded the minimum gain (6 kg) than did white women (11.8%). When analysis of covariance was used to adjust mean birth weight, black women in each pregravid BMI category delivered increasingly larger infants (P < or = .01 for each category) as they met or exceeded the guidelines; among white women this trend was attenuated. CONCLUSION: These observations support the Institute of Medicine suggestion that black women strive for prenatal weight gain at the upper end of the recommended range for pregravid BMI.

Health behavior and outcomes in sequential pregnancies of black and white adolescents.

OBJECTIVE: To examine the relationships among parity, preterm delivery, fetal growth retardation, and prenatal care utilization in first and second adolescent pregnancies. DESIGN: A longitudinal, retrospective study in which obstetric, behavioral, and sociodemographic data were used to examine birth outcomes of 737 low-income black (80%) and white (20%) teenagers delivering first and second singleton infants at 20 or more weeks' gestation. SETTING: Public health clinics in Jefferson County, Alabama, between January 1983 and February 1990. MAIN OUTCOME MEASURES: Mean birth weight, preterm delivery, fetal growth retardation, Apgar scores, and perinatal mortality. MAIN RESULTS: In their second pregnancies, adolescents presented 2.8 weeks later for care (P = .0001) and made fewer total clinic visits. Mean infant birth weight increased by 91 g (P = .0005). This increase was significantly associated with an increase in maternal prepregnancy body mass index. The rate of fetal growth retardation decreased (P = .0001) and the rate of preterm delivery increased (P < .02) in the second pregnancy. The rate of recurrence of fetal growth retardation was 13% and the rate of preterm delivery was 46%. CONCLUSIONS: Poorer utilization of prenatal care and high risk for recurrence of adverse outcomes are characteristic of adolescents' second pregnancies and should be considered in teenage pregnancy intervention programs.

Maternal weight status and term birth weight in first and second adolescent pregnancies.

The relationship of maternal weight status to birth weight was evaluated retrospectively for the first and second pregnancies of 72 younger (age 12-15 years at first conception) and 80 older (age 16-19 years at first conception) low-income adolescents (76% black, 24% white). Mean birth weight increased during the second pregnancies of both groups (277 g and 132 g, respectively). Multiple regression analysis (controlling for potentially confounding variables) indicated a positive relationship between second and third trimester rate of maternal weight gain (kg/week) and birth weight for younger adolescents during their second pregnancy (p = 0.014), and for older adolescents during their first pregnancy (p = 0.047). Mean birth weight increased with each increase in maternal weight-for-height (W/H) category near term from the lowest (< 100% of standard) to the highest (> or = 140% of standard), for both age groups during both pregnancies. Multiple regression analysis indicated that among older adolescents birth weight increased 4.2 +/- 2.0 g (X +/- SE) for each 1% increase in maternal W/H near term in their first pregnancy (p = 0.038) and 7.1 +/- 1.8 g for each 1% increase in maternal W/H near term in their second pregnancy (p = 0.0003). Among younger adolescents these relationships, while in the same direction, were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Maternal weight gain in low-income black and Hispanic women: evaluation by use of weight-for-height near term.

This study determined the prevalence of low maternal weight gain among a target group of low-income black and Hispanic women and compared weight-for-height near term with total weight gain during pregnancy as an index of birth-weight classification. One-third (30.8%) of 325 women had weights near term less than 120% of their standard pregravid weight-for-height; there was little variation by ethnic group. After adjusting for gestational age as a covariate of birth weight (P = 0.0001), maternal weight-for-height near term (P = 0.0010), ethnicity (P " 0.0068), and parity (P = 0.0083) significantly influenced birth weight. Women with near-term weights greater than or equal to 120% of their standard pregravid weight-for-height delivered infants with higher birth weights (P = 0.001). Comparison of weight-for-height near term with total weight gain as an index of birth-weight classification (less than or greater than or equal to 3000 g) revealed that the two methods differ in terms of sensitivity and specificity with variation in pregravid weight.

Maternal phenylketonuria: case management as a preventive approach to a chronic condition affecting pregnancy.

Women with PKU are at extremely high risk for bearing children with multiple congenital anomalies and mental retardation. PKU related psychoeducational and psychosocial issues can impact reproductive decision making and the ability to resume and/or maintain a restricted phenylalanine diet prior to and during pregnancy. Intensive case management may provide a preventive approach to the current "crisis" in the management of maternal phenylketonuria, as well as facilitate ongoing diet therapy during adolescence and adulthood.