A two-part model for reference curve estimation subject to a limit of detection.

Reference curves are commonly used to identify individuals with extreme values of clinically relevant variables or stages of progression which depend naturally on age or maturation. Estimation of reference curves can be complicated by a technical limit of detection (LOD) that censors the measurement from the left, as is the case in our study of reproductive hormone levels in boys around the time of the onset of puberty. We discuss issues with common approaches to the LOD problem in the context of our pubertal hormone study, and propose a two-part model that addresses these issues. One part of the proposed model specifies the probability of a measurement exceeding the LOD as a function of age. The other part of the model specifies the conditional distribution of a measurement given that it exceeds the LOD, again as a function of age. Information from the two parts can be combined to estimate the identifiable portion (i.e. above the LOD) of a reference curve and to calculate the relative standing of a given measurement above the LOD. Unlike some common approaches to LOD problems, the two-part model is free of untestable assumptions involving unobservable quantities, flexible for modeling the observable data, and easy to implement with existing software. The method is illustrated with hormone data from the Third National Health and Nutrition Examination Survey.

Effect of breastfeeding on cognitive development of infants born small for gestational age.

UNLABELLED: Breastfeeding during infancy appears to result in enhanced cognitive development during childhood, but it is not known whether breastfeeding should be encouraged for infants born small for gestational age (SGA) whose growth might otherwise benefit from nutritional supplementation. To address this issue, duration of exclusive breastfeeding and cognitive development were evaluated prospectively for 220 term children born SGA and 299 term children born appropriate for gestational age (AGA). Cognitive development was assessed using the Bayley Scale of Infant Development at 13 mo and Wechsler Preschool and Primary Scales of Intelligence at 5 y of age. Infants born SGA were given supplemental foods significantly earlier than those born AGA. Growth of infants born SGA was not related to early nutritional supplementation. The salutary effect of exclusive breastfeeding on cognitive development was greater for children born SGA than for those born AGA. Based on a linear association between duration of exclusive breastfeeding and intelligence quotient (IQ), children born SGA and exclusively breastfed for 24 wk were predicted to have an 11-point IQ advantage over those breastfed for 12 wk, as opposed to a 3-point advantage for children born AGA with similar durations of breastfeeding. The IQ distribution of children born SGA and exclusively breastfed for more than 12 wk was not different from that of all children born AGA. CONCLUSION: Duration of exclusive breastfeeding has a significant impact on cognitive development without compromising growth among children born SGA. These data suggest that mothers should breastfeed exclusively for 24 wk to enhance cognitive development.

Are maternal and sonographic factors associated with the detection of a fetal echogenic cardiac focus?

OBJECTIVE: To evaluate the influence of maternal weight and the orientation of the fetal 4-chamber heart view on the detection of a fetal echogenic cardiac focus. METHODS: In this nested case-control study, 103 women undergoing anatomic surveys at 15 to 22 weeks between January 1, 1997, and June 15, 1999, were identified as having an echogenic cardiac focus via our computerized database. A control group was selected from among the same group of patients. Data were collected from the sonography reports, prenatal records, and sonographic images of 4-chamber heart views; maternal characteristics and sonographic details were recorded, including the orientation of the 4-chamber view (apical, basilar, and right and left lateral). RESULTS: Gravidas in the echogenic cardiac focus group were more likely to be of lower weight (68.0 +/- 14.4 versus 72.9 +/- 18.3 kg; P = .04), of lower body mass index (25.5 +/- 5.3 versus 27.3 +/- 6.2 kg/m2; P = .03), of younger age (24.4 +/- 6.5 versus 26.9 +/- 6.9 years; P = .01), and African American or Asian (37.9% versus 27.2% and 9.7% versus 2%; P = .01). Cases were scanned at earlier gestational ages (18.9 +/- 1.6 versus 19.5 +/- 1.7 weeks; P = .01). The focus group was more likely to have had an apical view of the fetal heart taken (80.8% versus 51.4%; P = .0001). Controls were more likely to have had a right lateral view taken (44.6% versus 20.8%; P = .002). No significant difference was found between groups in terms of any other maternal or sonographic variable studied. CONCLUSIONS: The echogenic cardiac focus group was more likely to have a lower body mass index and to be scanned with the apical fetal heart view. The orientation of the fetal 4-chamber heart view exerted the most statistically significant influence on detection rates for the echogenic cardiac focus, implying that the more technically facile the sonographic study, the more likely an echogenic cardiac focus will be found.

Association between infant breastfeeding and overweight in young children.

CONTEXT: It has been suggested that breastfeeding is protective against children becoming overweight, and that there is a dose-dependent effect of its duration. OBJECTIVE: To determine whether breastfeeding and its duration are associated with a reduced risk of being overweight among young children in the United States. DESIGN AND SETTING: Data on infant feeding and child overweight status were taken from the third National Health and Nutrition Examination Survey (NHANES III), a cross-sectional health examination survey conducted from 1988-1994. SUBJECTS: Sample of 2685 US-born children between the ages of 3 and 5 years, with birth certificates, height and weight measures, and information on infant feeding. MAIN OUTCOME MEASURES: A body mass index (BMI) between the 85th and 94th percentile was considered at risk of overweight and a BMI in the 95th percentile or higher was considered being overweight. RESULTS: After adjusting for potential confounders, there was a reduced risk of being at risk of overweight for ever breastfed children (adjusted odds ratio [AOR], 0.63; 95% confidence interval [CI], 0.41-0.96) compared with those never breastfed. There was no reduced risk of being overweight (AOR, 0.84; 95% CI, 0.62-1.13). There was no clear dose-dependent effect of the duration of full breastfeeding on being at risk of overweight or overweight and no threshold effect. The strongest predictor of child overweight status was the mother's concurrent weight. The rate of children being overweight nearly tripled with maternal overweight status (BMI, 25.0-29.9 kg/m(2); AOR, 2.95; 95% CI, 1.35-6.42) and more than quadrupled with maternal obesity status (BMI >/=30.0 kg/m(2); AOR, 4.34; 95% CI, 2.50-7.54). CONCLUSIONS: There are inconsistent associations among breastfeeding, its duration, and the risk of being overweight in young children. Breastfeeding continues to be strongly recommended, but may not be as effective as moderating familial factors, such as dietary habits and physical activity, in preventing children from becoming overweight.

Etiology of third-trimester maternal hyperuricemia in nonpreeclamptic twin gestations.

OBJECTIVE: To determine whether the higher maternal serum uric acid levels observed in the third trimester of nonpreeclamptic twin gestations result from increased uric acid production or decreased renal excretion. METHODS: Thirty-four nonpreeclamptic subjects with twin gestations were analyzed, along with 34 singleton controls matched for age, ethnicity, prepregnancy weight, height, and gestational age. For each subject, a serum sample and 24-hour urine specimen were obtained in the third trimester. Serum and urine uric acid and creatinine levels were determined, as well as total 24-hour urine uric acid, uric acid clearance, creatinine clearance, fractional uric acid clearance, and net tubular uric acid absorption. RESULTS: The twin gestation group had significantly higher maternal serum uric acid levels (5.2 +/- 1.2 compared with 4.0 +/- 1.0 mg/dL, P <.001) and maternal serum creatinine levels (0.7 +/- 0.2 compared with 0.5 +/- 0.1 mg/dL, P <.001) than the paired singleton group. This was associated with greater 24-hour urine uric acid excretion (688.7 +/- 167.0 compared with 597.7 +/- 164.2 mg, P =.04) and 24-hour urine creatinine excretion (1268.4 +/- 249.9 compared with 1161.2 +/- 277.1 mg, P =.03) in the twin group. No differences were seen between the groups in uric acid clearance, creatinine clearance, fractional uric acid clearance, filtered uric acid load, or net uric acid absorption. CONCLUSION: The higher maternal serum uric acid levels observed in the third trimester of nonpreeclamptic twin gestations result in part from increased uric acid production, as reflected in the increased daily uric acid excretion.

Stature, weight, and body mass among young US children born at term with appropriate birth weights.

OBJECTIVE: To describe weight, stature, and body mass index (BMI) changes occurring before the age of 7 years, which may influence the prevalence of overweight in adolescence and adulthood. METHODS: Regression models predicting height and weight at ages 2 months to 6. 75 years were based on the third National Health and Nutrition Examination Survey. Birth certificate data were used to adjust ethnic-specific models for birth weight for gestational age. RESULTS: Attained height is higher for non-Hispanic black children than for either non-Hispanic white or Mexican American children (P 85th percentile than either non-Hispanic white or black children (boys = 25.6%, SE = 2.7 compared with 14.1%, SE = 1.7 and 16.5%, SE = 1.7, respectively; girls = 21.9%, SE = 3.6 compared with 13.0%, SE = 1.7 and 13.7%, SE = 2.2, respectively). For non-Hispanic whites and Mexican Americans and for non-Hispanic black boys, BMI decreased slightly between ages 2 and 6.75 years; BMI for non-Hispanic black girls did not. CONCLUSION: Size differences before the age of 7 years may influence later ethnic-specific overweight prevalence, independent of prenatal influences.

Early infant feeding and growth status of US-born infants and children aged 4-71 mo: analyses from the third National Health and Nutrition Examination Survey, 1988-1994.

BACKGROUND: There is controversy over what growth references to use in evaluating breast-fed infants and concern about whether never-breast-fed infants are at risk of overweight in childhood. OBJECTIVE: The objective of this study was to determine whether infants who are exclusively breast-fed for 4 mo differ in average size from infants who are fed in other ways and whether such differences persist through age 5 y. DESIGN: Data from the third National Health and Nutrition Examination Survey (NHANES III) were linked to birth certificates of US-born infants and children. Feeding groups were defined on the basis of feeding patterns over the first 4 mo of life: exclusively breast-fed for 4 mo, partially breast-fed, breast-fed for <4 mo, and never breast-fed. Growth status, indexed as internally derived z scores (SD units) for weight, length (height), weight-for-length (height), midupper arm circumference, and triceps skinfold thickness, was compared among feeding groups. RESULTS: The final sample consisted of 5594 non-Hispanic white, non-Hispanic black, and Mexican American infants and children aged 4-71 mo. Of these, 21% were exclusively breast-fed for 4 mo, 10% were partially breast-fed, 24% were breast-fed for <4 mo, and 45% were never breast-fed. At 8-11 mo, infants who were exclusively breast-fed for4 mo had adjusted mean z scores for weight (-0.21; -0.2 kg), weight-for-length (-0.27), and midupper arm circumference (-0.15) that differed significantly from zero (P < 0. 05). By 12-23 mo, the differences had dissipated; there were no significant differences subsequent to 5 y. Triceps skinfold thickness was not related to early infant feeding. CONCLUSION: Infants who were exclusively breast-fed for 4 mo weighed less at 8-11 mo than did infants who were fed in other ways, but there were few other significant differences in growth status through age 5 y associated with early infant feeding.

Does light pressure effleurage reduce pain and anxiety associated with genetic amniocentesis? A randomized clinical trial.

OBJECTIVE: To determine if light pressure effleurage (leg rubbing) during genetic amniocentesis reduces procedure-related pain and anxiety. METHODS: Two hundred women with singleton gestations undergoing genetic amniocentesis between 15-22 weeks recorded their level of anticipated pain and anxiety on a 10-cm linear visual analog scale prior to the amniocentesis. Subjects were then randomized to receive effleurage or no effleurage by the assisting nurse during the procedure. Subjects were blinded to the effleurage nature of the study. Following the amniocentesis, subjects repeated the pain and anxiety scoring. RESULTS: The two groups were similar with respect to subject and procedure characteristics, as well as anticipated pain or anxiety prior to amniocentesis. Postamniocentesis pain and anxiety scoring were similar in the two groups. The mean effleurage acceptance score was 8.3 +/- 1.8 (out of 10), and 90.2% of subjects reported that they would want effleurage with future amniocenteses. CONCLUSIONS: Although well accepted by women, light pressure effleurage during genetic amniocentesis does not reduce procedure-related pain or anxiety.

Growth and fatness at three to six years of age of children born small- or large-for-gestational age.

OBJECTIVE: To compare young children 3 to 6 years of age who were born small-for-gestational age (SGA; <10th percentile for gestational age) or large-for-gestational age (LGA; >/=90th percentile) with those who were born appropriate-for-gestational age (10th-89th percentile) to determine whether there are differences in growth and fatness in early childhood associated with birth weight status. DESIGN AND METHODS: National sample of 3192 US-born non-Hispanic white, non-Hispanic black, and Mexican-American children 3 to 6 years of age (36-83 months) examined in the third National Health and Nutrition Examination Survey and for whom birth certificates were obtained. On the birth certificates, length of gestation from the mother's last menstrual period was examined for completeness, validity, and whether the pattern of missing (n = 141) and invalid data (n = 147) on gestation was random. Gestation was considered invalid when >44 weeks, or when at gestations of

Birth weight for gestational age of Mexican American infants born in the United States.

OBJECTIVE: To develop a reference for birth weight for gestational age to identify Mexican American infants born in the United States who are small or large for gestational age. METHODS: Reference percentiles were developed for Mexican American and non-Hispanic white births, using national vital statistics from 1992-1994 for Mexican Americans (n = 1,197,916) and 1994 for non-Hispanic whites (n = 2,238,457). Birth weights and gestation from the last menstrual period were taken from birth certificates. Smoothed curves were fit, using unweighted fourth-degree polynomial equations, for the tenth, 50th, and 90th percentiles by gender and parity. RESULTS: Mexican American infants were heavier than non-Hispanic white infants between 30 and 37 weeks' gestation for all parities and both genders. However, at term there was consistent crossover. Non-Hispanic white infants were heavier at or after 37 through 42 weeks' gestation, whereas the growth of Mexican American infants appeared to slow. Beginning at 37 weeks, the differences in weights of infants of primiparas increased to more than 100 g by 40 weeks; the differences were only slightly less for infants of multiparas. CONCLUSION: Given differences in distribution of birth weights for gestational age between Mexican Americans and non-Hispanic whites, the ability to recognize fetal growth restriction (FGR) or excessive growth is questionable. These data provide a reference for Mexican Americans for clinical use and for future studies in identifying infants at risk for FGR or overgrowth.

Growth of infants and young children born small or large for gestational age: findings from the Third National Health and Nutrition Examination Survey.

OBJECTIVES: To compare the growth profiles of infants and young children born small for gestational age (SGA, < 10th percentile birth weight for gestation) or large for gestational age (LGA, > or =90th percentile) with those appropriate for gestational age, and to document the expected growth patterns through early childhood based on national health examination survey data. SAMPLE: Infants and children, 2 to 47 months of age, who were born in the United States and examined using the Third National Health and Nutrition Examination Survey (1988-1994). MAIN OUTCOME MEASURES: Measurements of growth status based on normalized distributions (z scores or standard deviation units [SDUs] for weight, length, and head circumference. RESULTS: Prevalence rates were as follows: SGA infants, 8.6%; appropriate for gestational age infants, 80.9%; and LGA infants, 10.5%. Infants who were SGA appeared to catch up in weight in the first 6 months, but thereafter maintained a deficit of about -0.75 SDUs compared with infants who were appropriate for gestational age. The weight status of LGA infants remained at about +0.50 SDUs through 47 months of age. Length and head circumference were also associated with birth weight status, averaging over -0.60 SDUs for SGA infants and +0.43 SDUs for LGA infants. CONCLUSIONS: Birth weight status is related to growth rates in infancy and early childhood, which underscores the importance of considering child growth relative to birth status when using growth charts. Small for gestational age infants remain shorter and lighter and have smaller head circumferences, while LGA infants grow longer and heavier and have larger head circumferences.

Muscularity and fatness of infants and young children born small- or large-for-gestational-age.

OBJECTIVE: There is growing interest in the extent to which body composition, both short- and long-term, differs in infants and children born at the extremes of birth weight. This is because a growing number of studies have linked low birth weight and fetal growth restriction to the chronic diseases in adulthood that often are obesity-related, and there is also evidence to suggest that heavy infants may be at increased risk for obesity in later life, again with the attendant obesity-related chronic diseases. Our objective was to compare anthropometric indices of body composition of infants and young children born small-for-gestational-age (SGA, <10th percentile) or large-for-gestational age (LGA, >/=90th percentile) with those of normal birth weight status (appropriate-for-gestational-age, AGA) in a US sample. DESIGN: National sample of US-born non-Hispanic white, non-Hispanic black, and Mexican-American infants and young children, 2 to 47 months of age, examined in the third National Health and Nutrition Examination Survey (NHANES III, 1988-1994), for whom birth certificates were obtained. The primary outcomes were normalized anthropometric indices (z scores or standard deviation units [SDU]) of nutritional status and body composition (mid-upper arm circumference, triceps and subscapular skinfolds, mid-upper arm muscle and mid-upper arm fat areas (UFA), and the arm fat index). The outcomes thus were scaled to permit comparison across chronologic ages. RESULTS: The prevalence of SGA was 8.6%, appropriate-for-gestational-age 80.9%, and LGA 10.5%. From ages 2 to 47 months, for infants and young children born SGA, there was a persistent overall deficit in muscularity (mid-upper arm circumference and mid-upper arm muscle area) of approximately -0.50 SDU, but less of a deficit in fatness, particularly at the youngest ages. For infants and young children born LGA, there was a surfeit in muscularity of approximately 0.45 SDU, with less of a surfeit in fatness, particularly at the youngest ages. Across all ages, the mean UFA showed a statistically significant deficit for SGA children (-0.27 +/- 0.10 SDU) and surfeit for LGA children (0.24 +/- 0.08 SDU). At individual ages for UFA and at individual and all ages combined for skinfold thicknesses, there were no significant differences in level of subcutaneous fatness in the three birth-weight-for-gestational-age groups. There was a tendency in the first year for the arm fat index (% arm fat) to be significantly higher for SGA infants, but the effect did not persist after the first year. CONCLUSION: SGA infants remain smaller and LGA infants larger in size through early childhood, but the discrepancies in weight are primarily attributable to differences in lean body mass (muscularity). Fatness is less affected. Thus, based on the fatness indicators used, at any given weight for infants and children 2 to 47 months of age, percent body fat appears to be relatively higher for children who were SGA at birth and lower in those who were LGA at birth. These differences in body composition for SGA infants support the evidence documenting a link between disturbances in intrauterine growth and chronic disease associated with subsequent adiposity in adulthood.

Social factors predicting postpartum choice of Norplant among African-American and non-Hispanic white adolescents.

PURPOSE: This study was designed to determine the factors associated with Norplant choice for postpartum teens. METHODS: A total of 151 teenagers, ages 12-20 years, who delivered at the Medical Center of Delaware from July to December 1992, were offered insertion of Norplant within 48 h postpartum. A structured interview was conducted in the postpartum period after nondirective counseling sessions including a physical demonstration using anatomical models of various contraceptive methods. Student's t-tests, chi-square, and multivariate analyses were used. RESULTS: Eighty-six teenagers were African-American (mean age = 17.3 +/- 1.9 years) and 65 non-Hispanic white (NHW) (mean age = 18.3 +/- 1.5 years). The NHW teenagers were older (p < 0.001); the African-American teenagers were more likely to have Medicaid (49% vs. 14%; p < 0.001) and to have one or more friends who use Norplant (62% vs. 34%; p < 0.001). In multivariate analyses, NHW teenagers were more likely to choose Norplant if they had discussed their choice with a parent or guardian [adjusted odds ratio (AOR) = 14.6, 95% confidence interval (CI), 2.12-100.57]; had Medicaid funding (AOR = 12.1; 95% (CI), 10.6-91.34); and had any friends who used Norplant (AOR = 6.3; 95% (CI), 1.38-28.40). However, for African-American teenagers, the strongest predictor for choice of Norplant was number of prior children delivered. After two deliveries, there was a better than four-fold likelihood (AOR = 4.8; 95% (CI), 1.47-15.94) that African-American teenagers would choose Norplant. For the African-American teenagers, parental discussion, Medicaid status, and friends' use of Norplant were not as important as family size, but far greater percentages of the African-American teenagers had access to Medicaid funding and peers who used Norplant. CONCLUSIONS: NHW and African-American teenagers choose Norplant for different reasons. Lack of funding may have been a barrier to choosing Norplant. Discussions with parents and friends have a positive influence on choosing Norplant for NHW teenagers. African-American teenagers were more likely than NHW to have Medicaid coverage, and more frequently choose Norplant if the current birth was their third child.

PIP: 151 youths, aged 12-20 years, who delivered at the Medical Center of Delaware from July to December 1992, were offered insertion of Norplant within 48 hours postpartum. These young women were subsequently interviewed to determine which factors are associated with choosing to accept or not accept Norplant. 86 Black teenagers of mean age 17.3 years and 65 non-Hispanic Whites of mean age 18.3 years participated. The White teenagers were significantly older, 49% of Blacks and 14% of Whites had Medicaid, and 62% of Blacks and 34% of Whites had one or more friends who use Norplant. In multivariate analyses, the White teens were more likely to choose Norplant if they had discussed their choice with a parent or guardian, if they received Medicaid funding, and if they had any friends who used Norplant. The strongest predictor for choice of Norplant among Black teens was the number of prior children delivered. After 2 deliveries, there was an almost 5-fold likelihood that Black teenagers would choose Norplant. For the Black teens, parental discussion, Medicaid status, and friends' use of Norplant were not as important as family size, but larger proportions of the Black teens had access to Medicaid funding and peers who used Norplant.

Young maternal age and preterm labor.

PURPOSE: The relationship among young age, biologic immaturity (as indexed by low gynecologic age), and the causes of preterm delivery (idiopathic preterm labor [PTL], premature rupture of the membranes [PROM], and medical indications) were investigated among 605 primigravidas from the Camden Study. METHODS: The sample consisted of 366 young adolescents < 16 years at the time of their last menstrual period (LMP) and 239 older women, 18-29 years at LMP (controls). The young adolescents were significantly shorter, thinner, had younger ages at menarche, and over a third (36.3%) were of low gynecologic age, i.e., their chronologic age was 2 or fewer years more than their age at menarche. RESULTS: Adjusting for ethnicity, cigarettes smoked/day, weight gain rate, height, fetal sex, gestational diabetes mellitus, and pregnancy-induced hypertension, young adolescents overall had a nearly 75% increased risk of PTL (adjusted odds ratio [AOR] = 1.74, 95% confidence interval [95% CI]: 1.07-2.84), and preterm delivery with PTL (AOR = 2.08, 95% CI: 1.08-4.00). There was a modest decreased risk of preterm delivery among young gravidas attributable to other causes, such as PROM or medical indications (AOR = 0.70, 95% CI: 0.28-1.75). This increased risk of PTL and preterm delivery with PTL was principally attributable to biologic immaturity. Young age with low gynecologic age was associated with a twofold risk of PTL (AOR = 2.15, 95% CI: 1.19-3.89) and preterm delivery with PTL (AOR = 2.64, 95% CI: 1.23-5.65), while the risk associated with young age and higher gynecologic age was only increased moderately. CONCLUSIONS: Young adolescents, and especially those of low gynecologic age, appear prone to PTL and are at increased risk for preterm delivery through this pathway.

PIP: The relationship between young maternal age and preterm delivery was investigated in a subsample of 605 primigravidas enrolled in the Camden (New Jersey, US) Study. Included were 366 adolescents under 16 years of age (cases) and 239 women 18-29 years of age (controls). 36.3% of young mothers had a low gynecological age (i.e., their chronological age was 2 or fewer years more than their age at menarche). After adjustment for ethnicity, cigarette smoking, weight gain rate, height, fetal sex, gestational diabetes mellitus, and pregnancy-induced hypertension, the odds ratio (OR) of preterm labor among young adolescents was 1.74 (95% confidence interval (CI), 1.07-2.84) and that of preterm delivery was 2.08 (95% CI, 1.08-4.00). There was a modest decreased risk of preterm delivery attributable to other causes (e.g., premature rupture of the membranes) among the youngest women (OR, 0.70; 95% CI, 0.28-1.75). Young age with low gynecological age was associated with a 2.15 OR (95% CI, 1.19-3.89) of preterm labor and a 2.64 OR (95% CI, 1.23-5.65) of preterm delivery with preterm labor. The risk associated with young age and higher gynecological age was increased only moderately. These findings suggest that it is the biological immaturity often associated with young age, rather than young maternal age per se, that increases the risks of adolescent pregnancy. The association between low gynecological age and preterm labor is presumed to reflect an irritability of the adolescent uterus, a sensitivity to dehydration, and/or an altered hormonal milieu that promotes maternal development at the expense of fetal well-being.

Use of multivitamin/mineral prenatal supplements: influence on the outcome of pregnancy.

The objective of this study was to examine the association of prenatal multivitamin/mineral supplement use during the first and second trimesters of pregnancy by low income, urban women in the Camden Study (1985-1995, n = 1,430) and preterm delivery (< 37 completed weeks) and infant low birth weight (< 2,500 g). Prenatal supplement use was corroborated by assay of circulating micronutrients at entry to care (no differences) and week 28 gestation (increased concentrations of folate and ferritin for supplement users). Compared with women who entered care during the first or second trimester but did not use prenatal supplements, supplement use starting in the first or second trimester was associated with approximately a twofold reduction in risk of preterm delivery. After controlling for potential confounding variables, risk of very preterm delivery (< 33 weeks' gestation) was reduced more than fourfold for first trimester users and approximately twofold when use dated from the second trimester. Infant low birth weight and very low birth weight (< 1,500 g) risks were also reduced. Risk of low birth weight was reduced approximately twofold with supplement use during the first and second trimester. Diminution in risk was greater for very low birth weight infants, amounting to a sevenfold reduction in risk of very low birth weight with first trimester supplementation and a greater than sixfold reduction when supplement use started in the second trimester. Thus, in low income, urban women, use of prenatal multivitamin/mineral supplements may have the potential to diminish infant morbidity and mortality.

Gestational age and infant size at birth are associated with dietary sugar intake among pregnant adolescents.

The objective of this study was explore the relationship between pregnancy outcomes and dietary sugar intake by pregnant adolescents. From two urban, prenatal clinics in the City of Camden, NJ, a cohort of 594 nondiabetic, pregnant adolescents, aged 13-19 y, who delivered live, singleton newborns between 1985 and 1990, was recruited and followed through pregnancy. Registered dietitians collected up to three 24-h recalls during pregnancy. The adolescents were categorized according to total sugar in their diets, with those in the top 10th percentile defined as high sugar consumers (> or = 206 g, n = 60) and the remainder as reference consumers (< 206 g). Primary outcome measures were birth of small-for-gestational-age infants and gestational age. The cohort was 61% black, 30% Hispanic (Puerto Rican) and 9% white. The adjusted odds ratio was 2.01 (95% confidence interval 1.05-7.53) for the delivery of a small-for-gestational-age infant for adolescents consuming high sugar diets, regardless of their ethnicity. In addition, gestational age at delivery was -1.69 +/- 0.62 wk (beta +/- SE) shorter among Puerto Rican adolescents consuming high sugar diets (P = 0.007) compared with all reference sugar consumers and white adolescents consuming high sugar diets. Black adolescents consuming high sugar diets did not exhibit a shortening of gestation. Thus, adolescents consuming high sugar diets are at increased risk for delivering small-for-gestational-age infants, and for delivering infants earlier if they are of Puerto Rican ethnicity.

Implications of the Camden Study of adolescent pregnancy: interactions among maternal growth, nutritional status, and body composition.

One of the principal goals of the Camden Study over the past decade has been to document the extent to which pregnancy during adolescence is affected by continued maternal growth. Findings from the Camden Study relating to the other main goal, the effects of maternal growth during pregnancy on the outcome of pregnancy (maternal-fetal competition), are reviewed elsewhere. Contrary to widely held beliefs, we have found that there is considerable growth in late adolescence for girls, and, in particular, continued development of weight (> 1 kg/year) and increases in subcutaneous fatness at central sites. Thus, when pregnancy occurs during this final phase of adolescent growth, the normal growth processes may be exacerbated. That is, the adolescent potential for weight gain (as fat) may be exploited. Along with others, we have documented that adolescent pregnancy is associated with larger gestational weight gains. Using methods sufficiently sensitive to detect maternal growth prospectively, we also found that the larger-than-average total weight gains among adolescents appear attributable primarily to the growing adolescent gravidas and reflect their continued accrual of subcutaneous fat and increased risk for weight retention. Excessive gestational weight gain, as is more common among growing adolescent gravidas, appears to exacerbate the accumulation of fat at central sites. Aside from the consequences to the outcome of pregnancy, adolescents who begin their childbearing early while still growing themselves, such as those we have followed in the Camden Study over the past decade, may be at particularly increased risk for overweight and obesity. Further, the excessive deposition of subcutaneous fat at central body sites, as we have documented for adolescent pregnancy, will often in later life presage the development of cardiovascular disease, noninsulin-dependent diabetes mellitus (NIDDM), and hypertension. Thus, far from being benign, pregnancy during adolescence, particularly when the adolescent is herself still growing, may contribute to long-term risk for obesity-related diseases and diminish the quality of life.

Pregnancy in early adolescence: are there obstetric risks?

The purpose of this study was to determine if early adolescence imparts a significant obstetric risk in young primiparas relative to adult primiparas. The records of 239 young primiparas (< 16 years) and 148 older primiparas (18-29 years) were reviewed for demographic information, antepartum complications, mode of delivery, length of labor, episiotomy, lacerations, birthweight, and length of gestation. The young adolescents were shorter, had an earlier age at menarche, a lower pregravid body mass index, and a higher gestational weight gain. The young teens were less likely to smoke cigarettes but were more likely to be Medicaid recipients. The incidence of most antenatal complications (chronic hypertension, pregnancy-induced hypertension, placental abruption, placenta previa, premature rupture of the membranes, urinary tract infections, and anemia) were similar between the two groups. Preterm labor and contracted pelvis were more common among the young adolescent, while gestational diabetes was less common. The young primiparas were significantly (P < .05) less likely to have a Cesarean delivery and to lacerate with vaginal delivery. The length of labor and its stages were similar, as were overall birthweight and length of gestation. Thus, obstetric concerns regarding pregnancy in early adolescence may be unfounded. With the exception of an increased risk for preterm labor, it appears that pregnancy, labor, and delivery do not pose inordinate obstetric and medical risk to the very young adolescent primipara.