| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
ORIGINAL RESEARCH |
From the Divisions of Reproductive Health and Nutrition and Physical Activity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, the Maternal and Child Health Bureau, Health Resources and Services Administration, Rockville, Maryland, and the School of Public Health, University of Illinois at Chicago, Chicago, Illinois.
Address reprint requests to: Laura A. Schieve, PhD Centers for Disease Control and Prevention Division of Reproductive Health Mailstop K-34 4770 Buford Highway, NE Atlanta, GA 30341 E-mail: LJS9{at}cdc.gov
 |
Abstract |
|---|
Top
 Abstract Materials and MethodsResultsDiscussionReferences |
|---|
Methods: Subjects were 3511 mother-infant pairs from the 1988 National Maternal and Infant Health Survey. Prenatal weight measured between 14 and 28 weeks’ gestation was used to calculate rate of pregnancy weight gain for each woman. Weight gain (lb/week) was categorized as low (under 0.5), average (0.5–1.5), or high (above 1.5). Prepregnancy BMI was calculated as weight divided by height in (kg/m2) and categorized as low (under 19.8), average (19.8–26.0), and high (above 26). Delivery before 37 weeks’ gestation was considered preterm. Associations between BMI, weight gain, and preterm delivery were examined before and after exclusion of medically indicated preterm deliveries and pregnancies complicated by maternal medical conditions potentially related to weight gain or fetal growth restriction. Associations were expressed as odds ratios (OR) adjusted for several potential confounding factors.
Results: Women with low pregnancy weight gain were at increased risk of preterm delivery. The magnitude of risk varied according to a woman’s prepregnancy BMI. After all exclusions and adjustments for confounders, ORs, and 95% confidence intervals (CI) for low pregnancy weight gain were 6.7 (1.1, 40.6) for underweight women, 3.6 (1.6, 8.0) for average-weight women, and 1.6 (0.7, 3.5) for overweight women compared with average-weight women with average pregnancy weight gain.
Conclusions: Low weight gain in pregnancy was associated with increased risk of preterm delivery, particularly if women were underweight or of average weight before pregnancy.
Disorders related to shortened gestation are among the leading causes of perinatal mortality in the United States.1 Previous studies documented associations between preterm delivery and low prepregnancy body mass index (BMI)2–5 and a low rate of weight gain during pregnancy.2–11 Some studies reported that the preterm association was strongest among women with both risk factors.2,4,6 Studies that examined pattern of weight gain found the association between weight gain and preterm delivery to be strongest for low weight gain during the latter half of pregnancy.4,7,8 Some studies also reported an association between a high rate of pregnancy weight gain and preterm delivery.2,4
The nature of the association between prepregnancy BMI, pregnancy weight gain, and preterm delivery remains undetermined. Although prepregnancy BMI has genetic as well as nutritional components, a low BMI might be a general marker for minimal tissue nutrient reserves.12 Additionally, women with a low BMI might have less capacity for fluid expansion during pregnancy. Pregnancy weight gain is multifaceted, including increases in maternal fat and nutrient stores, growth of breast and uterine tissues, increases in plasma volume, and weight gain directly resulting from the products of conception.12 Thus, the relationship between pregnancy weight gain and preterm delivery could be explained by direct or indirect factors, including energy and nutrient intake; physical activity; maternal pregnancy complications that might influence fluid retention and weight gain, such as hypertension and diabetes; or the contribution of fetal growth and weight to the total pregnancy weight gain. Previous studies have been limited in their ability to disentangle those components of prepregnancy weight and pregnancy weight gain and how each might relate to preterm delivery. Such information would be useful in guiding strategies to prevent preterm delivery.
Previous studies also had methodologic limitations, such as small samples, that sometimes impeded simultaneous evaluation of prepregnancy BMI and weight gain, and lack of information on confounding factors, particularly maternal medical complications. Many studies relied on prepregnancy BMI and weight at delivery to calculate weight gain per week, a method that might overestimate risk, because weight gain is generally not uniform throughout pregnancy, but is somewhat lower during the first trimester. Thus, total weight gain among women with pregnancies that end in preterm delivery disproportionately include the lower first-trimester weight gains compared with pregnancies that end at term.
Using data from the 1988 National Maternal and Infant Health Survey, we explored associations with prepregnancy BMI and pregnancy weight gain and preterm delivery, with consideration for the underlying mechanism(s). For a portion of women included in that database, provider medical records were available and included weights measured at prenatal visits, which allowed us to calculate the rate of pregnancy weight gain from 14 to 28 weeks’ gestation, a more accurate method of estimating rate of weight gain than in previous studies. With those data we could also examine associations between low and high rates of weight gain and preterm delivery among women of varying prepregnancy BMIs. The medical record data also allowed us to examine associations after dividing preterm delivery into etiologic subgroups and restricting the sample based on maternal medical complications and fetal growth restriction (FGR).
|
Materials and Methods |
|---|
|
Top
AbstractMaterials and MethodsResultsDiscussionReferences |
|---|
Initially, 13,417 live births were sampled and the mothers of the infants were mailed a 35-page questionnaire; 9953 questionnaires were returned, 9296 with a signed permission page allowing us to contact hospitals and prenatal care providers. Of those births, 9216 occurred in a hospital, and responses from the delivery hospital were available for 6995. (Information from one or more prenatal care providers was obtained for 4913 of the 6995 births.) Hospital of delivery and prenatal care data were abstracted from medical records.
For the current analysis we selected singleton births delivered between 28 and 43 weeks’ gestation (n = 5931). We required that data be available for three or more prenatal weight measurements between 14 and 28 weeks’ gestation (n = 3595) and that the interval between the first and last weight measurement was at least 4 weeks (n = 3582). We used the measured prenatal weights to calculate a rate of pregnancy weight gain for each woman, from linear regression models. To minimize effects of data entry or recording errors we excluded seven women for whom weight gain per week was more than +5.0 lb or less than -2.5 lb. We excluded 64 women for whom data were missing for prepregnancy weight or height. Our final sample included 3511 mother-infant pairs.
Our final sample was comparable to the original sample of National Maternal and Infant Health Survey respondents (n = 9953) with regard to distributions of prepregnancy BMI, age, parity, education, and prenatal smoking. However, our final sample had a lower proportion of nonwhite women (23% versus 30%), unmarried women (20% versus 28%), and preterm deliveries (6.7% versus 8.7%) than in the original sample. Inclusion in the final sample was dependent upon prenatal care use, so those differences were in the direction expected.
For each woman, we fit a regression model using prenatal weight (y) and gestational age (x) data from 14 to 28 weeks’ gestation to calculate her rate of pregnancy weight gain during that period. Our choice of 14 to 28 weeks was based on prior studies that showed that pregnancy weight gain is typically low during the first trimester, increases linearly beginning around week 14, and then slows late in the third trimester.12,14 That pattern was consistent with our data; examination of the mean measured weight gain at each week of gestation showed a linear increase between 14 and 28 weeks that continued to approximately week 36 (Figure 1
). Also, analysis of residuals from the regression models suggested that a linear assumption was appropriate for this analysis. Finally, we were interested in the 14 to 28 weeks’ interval because first-trimester weight gain has been shown to have little association with preterm delivery in previous studies4,7,8 and truncating weight gain at 28 weeks’ gestation provided comparability in the prenatal weight gain rates between women who delivered at term or preterm after 28 weeks. Rate of pregnancy weight gain that was derived from regression models correlated well with total and trimester-specific weight gains.
|
Maternal prepregnancy BMI was calculated as weight (kg) divided by height (m2). Height was reported in feet and inches on the maternal questionnaire; prepregnancy weight was recorded in pounds on maternal and provider questionnaires. Data from the maternal questionnaire were self-reported. Data from provider records were also assumed to be primarily self-reported by women during their first prenatal visits. When calculating BMI, we gave preference to prepregnancy weight reported by providers (n = 3074) because of the shorter recall interval. In cases in which providers had not reported prepregnancy weight, data from the maternal questionnaire were used (n = 437). Prepregnancy BMI was categorized as low (<19.8 kg/m2), average (19.8–26.0 kg/m2), or high (>26 kg/m2), according to classifications used by the Institute of Medicine for defining appropriate weight gain during pregnancy.12
We defined preterm delivery as that before 37 completed weeks’ gestation. Gestational age was based on last menstrual period (LMP). We did not evaluate preterm deliveries before 28 weeks’ gestation. We further classified preterm deliveries as spontaneous or medically indicated. We used birth data from hospitals and care providers to determine the circumstances surrounding delivery. We evaluated whether pregnancies had been complicated by one or more antenatal medical conditions, including diabetes (pre-existing and gestational), hypertension, polyhydramnios, and first- or second-trimester anemia. Data pertaining to diabetes and polyhydramnios were based on reports from medical care providers. Hypertension was defined as two or more antenatal systolic blood pressure readings of 140 mmHg or more, or two or more antenatal diastolic readings of 90 mmHg or more. Anemia was defined by established Centers for Disease Control and Prevention criteria, ie, hemoglobin less than 11.0 and less than 10.5 g/dL in the first and second trimesters, respectively.15 When hematocrit rather than hemoglobin was given, we used definitions of less than 33.0% and less than 32.0% in the first and second trimesters, respectively. Because third-trimester anemia might reflect physiologic shifts in plasma and blood cell volume, we considered only first- and second-trimester anemia in this analysis, as we were interested in anemia as a potential marker for iron deficiency. We assessed whether pregnancies were complicated by FGR, defined as birth weight less than the tenth percentile of birth weight distribution of a United States reference population stratified by gender and gestational age at delivery.16
Several factors were analyzed as confounding variables, including maternal age at delivery, self-identified race or ethnicity, maternal education, parity, marital status, and smoking during pregnancy. We assessed distribution of maternal demographic, behavioral, and pregnancy-related factors by preterm delivery status. We also assessed mean pregnancy weight gain and percentage distribution of pregnancy weight gain according to women’s prepregnancy BMIs. Comparisons between groups were based on 
2 tests for differences in percentage distribution and t tests for differences in means.
We calculated risk of preterm delivery according to women’s prepregnancy BMIs and rates of pregnancy weight gain. Prepregnancy BMI and pregnancy weight gain were combined into a single, nine-category variable. For each BMI and weight gain category, we also calculated the odds of preterm delivery relative to women in the average BMI-average weight gain category. We repeated those analyses after excluding medically indicated preterm deliveries and pregnancies complicated by diabetes, hypertension, polyhydramnios, first- or second-trimester anemia, or FGR. We also computed adjusted odds ratios (OR) from multivariable logistic regression models that included the confounding variables listed above. Analyses were done using sample weights with SUDAAN software (Research Triangle Institute, Research Triangle Park, NC), which calculated variance estimates appropriate for the sampling design of this study.
|
Results |
|---|
|
Top
AbstractMaterials and MethodsResultsDiscussionReferences |
|---|
). Women who delivered preterm were also more likely to have had a pregnancy complicated by hypertension or polyhydramnios. Maternal age, parity, smoking during pregnancy, diabetes during pregnancy, first- and second-trimester anemia, and FGR did not vary significantly between preterm and term deliveries, although differences between groups were in the expected direction.
|
). Women with a low prepregnancy BMI gained an average of 1.2 lb/week, and only 4% of these women gained less than 0.5 lb/week. Conversely, women with a high BMI gained an average of 0.9 lb/week and 23% gained less than 0.5 lb/week.
|
). Compared with that group, the risk of pre-term delivery was markedly higher for two groups: women with low prepregnancy BMI and low weight gain (14.0% preterm risk), and women with average prepregnancy BMI and low weight gain (19.6%). Pre-term risk was also higher among women with a high prepregnancy BMI and low or average weight gain (9.3% and 9.0%, respectively). Lower risk (2.4%) was noted for women with a high BMI and high weight gain.
|
Adjustment for potential confounding factors did not substantially impact those findings (Table 4). Elevated ORs were observed for the low BMI-low weight gain and the average BMI-low weight gain groups. An elevated OR also was noted for the high BMI-low weight gain group, but it did not reach statistical significance. A protective effect was noted for the high BMI-high weight gain group.
|
|
Discussion |
|---|
|
Top
AbstractMaterials and MethodsResultsDiscussionReferences |
|---|
We evaluated several hypotheses regarding the mechanism by which pregnancy weight gain might relate to preterm delivery. First, we assessed preterm etiology and medical complications that might affect pregnancy weight gain, including diabetes, hypertension, and polyhydramnios. Gestational diabetes generally has been associated with lower pregnancy weight gain,14,17 and pre-existing diabetes has been associated with high pregnancy weight gain.18 Hypertension also has been related to low and high pregnancy weight gains.14,19,20 Polyhydramnios also might lead to pregnancy weight gain. We repeated our analysis after limiting our sample to spontaneous preterm deliveries and excluding women with one of the aforementioned complications. Associations originally found between low pregnancy weight gain and preterm delivery persisted. Thus, low pregnancy weight gain does not appear to be merely a marker for those complications.
We also repeated our analysis after excluding pregnancies in which the fetus was born growth restricted. The association between weight gain and preterm delivery persisted, suggesting that low pregnancy weight gain is not simply an indication of slower fetal growth among preterm infants.
We did not have data to fully evaluate maternal nutrition, but we did consider first- and second-trimester anemia as a general indicator of iron deficiency. Maternal anemia, particularly that caused by iron deficiency, has been associated with preterm delivery.21,22 Excluding pregnancies complicated by that condition did not affect our findings substantially. In the fully excluded sample, the associations between low pregnancy weight gain and preterm delivery appeared to be even stronger. Finally, the results were not confounded by several sociodemographic and behavioral factors previously found to be related to both weight gain and preterm delivery, including age, race or ethnicity, parity, marital status, education, and smoking during pregnancy.
The role of maternal nutrition in the causal pathway for preterm delivery requires further consideration. Although human studies of energy and dietary intake are not conclusive for the role of nutrition in preterm delivery,23 Frentzen et al5 found increased ketonuria, a possible indicator of recent nutrient deficiency, among women presenting with preterm contractions at 32 weeks, compared with control subjects. Animal studies have shown an increase in uterine prostaglandin metabolites in response to fasting with subsequent decreases in plasma glucose.24,25 Micronutrient undernutrition also might play a role. Although we were able to assess antepartum anemia and address potential iron deficiency anemia, zinc deficiency also has been associated with low pregnancy weight gain26 and preterm delivery26 and merits further study.
A surprising finding in this analysis was the low risk of preterm delivery among overweight or obese women with excessive pregnancy weight gain. The protective effect in that subgroup remained after excluding maternal complications and controlling for potential confounding factors. Other studies that assessed high pregnancy weight gain and preterm delivery found no association11 or increased risk.2,4 We cannot explain the discrepancy between our study and the previous ones. Only two previous studies assessed prepregnancy BMI. One of those studies found increased risk from high weight gain only among average-weight women.4 The other study found an association between high weight gain (over 1.2 lb/week) and preterm delivery among all BMI groups; however, the absolute risks for preterm delivery decreased as BMI increased.2 The populations in those two studies were drawn from clinics that served low-income women. Our study population was based on a nationally representative sample that was further restricted to women with at least three prenatal weight measurements between 14 and 28 weeks’ gestation. It is possible that high pregnancy weight gain represents an unknown high-risk factor in low-income populations. The low risk observed in our high BMI-high weight gain group should also be interpreted cautiously because there might be underlying differences between this group and the reference population that could not be assessed in our analysis. High pregnancy weight gain, particularly among overweight women, is associated with other adverse outcomes, such as macrosomia12 and maternal weight retention,27 and thus is not advised.
This study had a number of strengths, including use of a nationally representative sampling base; serial weight gain data to model rate of weight gain; ability to limit weight gain of interest to 14–28 weeks, which provided comparability between preterm and term deliveries; and availability of data on preterm etiology and antenatal maternal complications. The study must be interpreted in the context of several limitations. A large proportion of original respondents were excluded by our strict study criteria, which might have affected generalizability; however, our sample remained comparable to the original respondents on several key variables. We have no indication that our selection criteria differentially excluded subjects based on relative comparisons between BMI, weight gain, and pre-term delivery. Gestational age estimates for this study were based on LMP, a concern because that method of calculating gestational age has been shown to be biased toward underestimation of gestational age among pre-term deliveries.28 One study that evaluated the association between low weight gain and preterm delivery using LMP and early ultrasound gestational age estimates reported comparable results of a positive association with both estimates.10 The current study considered deliveries before 37 weeks’ gestation to be preterm, a method that categorized moderate and severe cases of preterm delivery together. Although sample size limited our ability to analyze very preterm deliveries, we repeated our analysis after defining preterm as deliveries before 34 weeks’ gestation and found comparable results (data not shown). The National Maternal and Infant Health Survey is based on births from more than 10 years ago, so our study population might have differed from more recent birth cohorts with respect to weight gain patterns and other factors that might have been affected by secular changes in clinical practice. However, we have no reason to question the validity of relative comparisons presented here.
Preterm delivery, and the associated morbidity and mortality, is an important public health problem in the United States. This study shows that a low pregnancy weight gain is associated with an increased risk for preterm delivery, particularly if a woman was underweight or average weight before pregnancy. Although we were not able to define the exact mechanism for this association, the strong associations that persisted after limiting the sample to a select group of apparently healthy mother-infant pairs and after adjustment for many key potential confounding factors, lends support to the legitimacy of this association. Further study of maternal nutrition and weight gain composition in relation to preterm delivery is needed. However, the findings presented here indicate that prenatal care providers should consider women with low pregnancy weight gains at increased risk for preterm delivery.
|
Footnotes |
|---|
Received November 12, 1999. Received in revised form February 17, 2000. Accepted March 16, 2000.
|
References |
|---|
|
Top
AbstractMaterials and MethodsResultsDiscussionReferences |
|---|
2. Schieve LA, Cogswell ME, Scanlon KS. Maternal weight gain and preterm delivery: Differential effects by body mass index. Epidemiology 1999;10:141–7.[Medline]
3. Kramer MS, Coates AL, Michoud MC, Dagenais S, Hamilton EF, Papageorgiou A. Maternal anthropometry and idiopathic preterm labor. Obstet Gynecol 1995;86:744–8.[Abstract]
4. Siega-Riz AM, Adair LS, Hobel CJ. Institute of Medicine maternal weight gain recommendations and pregnancy outcome in a predominantly Hispanic population. Obstet Gynecol 1994;84:565–73.[Medline]
5. Frentzen BH, Johnson JWC, Simpson S. Nutrition and hydration: Relationship to preterm myometrial contractility. Obstet Gynecol 1987;70:887–91.[Medline]
6. Spinillo A, Capuzzo E, Piazzi G, Ferrari A, Morales V, Mario M. Risk for spontaneous preterm delivery by combined body mass index and gestational weight gain patterns. Acta Obstet Gynecol Scand 1998;77:32–6.[Medline]
7. Hickey CA, Cliver SP, McNeal SF, Hoffman HJ, Goldenberg RL. Prenatal weight gain patterns and spontaneous preterm birth among nonobese black and white women. Obstet Gynecol 1995; 85:909–14.[Abstract]
8. Hediger ML, Scholl TO, Belsky DH, Ances IG, Salmon RW. Patterns of weight gain in adolescent pregnancy: Effects on birth weight and preterm delivery. Obstet Gynecol 1989;74:6–12.
9. Scholl TO, Hediger ML, Salmon RW, Belsky DH, Ances IG. Influence of prepregnant body mass and weight gain for gestation on spontaneous preterm delivery and duration of gestation during adolescent pregnancy. Am J Hum Biol 1989;1:657–64.
10. Abrams B, Newman V, Key T, Parker J. Maternal weight gain and preterm delivery. Obstet Gynecol 1989;74:577–83.
11. Van den Berg BJ, Oechsli FW. Prematurity. In: Bracken MB, ed. Perinatal epidemiology. New York: Oxford University Press, 1984, 69–85.
12. Institute of Medicine. Nutrition during pregnancy. Part I. Weight gain. Washington, DC: National Academy Press, 1990.
13. Sanderson M, Placek PJ, Keppel KG. The 1988 National Maternal and Infant Health Survey: Design, content, and data availability. Birth 1991;18:26–32.[Medline]
14. Abrams B, Carmichael S, Selvin S. Factors associated with the pattern of maternal weight gain during pregnancy. Obstet Gynecol 1995;86:170–6.[Abstract]
15. Centers for Disease Control and Prevention. Recommendations to prevent and control iron deficiency in the United States. MMWR Morb Mortal Wkly Rep 1998;47(No. RR-3):1–28.[Medline]
16. Alexander GR, Himes JH, Kaufman RB, Mor J, Kogan M. A United States national reference for fetal growth. Obstet Gynecol 1996;98: 163–8.
17. Catalano PM, Roman NM, Tyzbir ED, Merritt AO, Driscoll P, Amini SB. Weight gain in women with gestational diabetes. Obstet Gynecol 1993;81:523–8.
18. Peterson CM, Jovanovic-Peterson L, Mills JL, Conley MR, Knopp RH, Reed GF, et al. The diabetes in early pregnancy study: Changes in cholesterol, triglycerides, body weight, and blood pressure. Am J Obstet Gynecol 1992;166:513–8.[Medline]
19. Shepard MJ, Hellenbrand KG, Bracken MB. Proportional weight gain and complications of pregnancy, labor, and delivery in healthy women of normal prepregnant stature. Am J Obstet Gynecol 1986;155:947–54.[Medline]
20. Tompkins WT, Wiehl DG, Mitchell RM. The underweight patient as an increased obstetric hazard. Am J Obstet Gynecol 1955;69: 114–24.
21. Scholl TO, Hediger ML, Fischer RL, Shearer JW. Anemia vs. iron deficiency: Increased risk of preterm delivery in a prospective study. Am J Clin Nutr 1992;55:985–8.
22. Klebanoff MA, Shiono PH, Selby JV, Trachtenberg AI, Graubard BI. Anemia and spontaneous preterm delivery. Am J Obstet Gynecol 1991;164:59–63.[Medline]
23. Kramer MS. Effects of energy and protein intakes on pregnancy outcome: An overview of the research evidence from controlled clinical trials. Am J Clin Nutr 1993;58:627–35.
24. Silver M, Fowden AL. Uterine prostaglandin F metabolite production in relation to glucose availability in late pregnancy and a possible influence of diet on time of delivery in the mare. J Reprod Fert 1982;32(Suppl):511–9.
25. Fowden AL, Silver M. The effect of the nutritional state on uterine prostaglandin F metabolite concentrations in the pregnant ewe during late gestation. Q J Exp Physiol 1983;68:337–49.
26. Scholl TO, Hediger ML, Schall JI, Fischer RL, Khoo CS. Low zinc intake during pregnancy: Its association with preterm and very preterm delivery. Am J Epidemiol 1993;137:1115–24.
27. Keppel KG, Taffel SM. Pregnancy-related weight gain and retention: Implications of the 1990 Institute of Medicine guidelines. Am J Public Health 1993;83:1100–3.
28. Kramer MS, McLean FH, Boyd ME, Usher RH. The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations. JAMA 1988;260:3306–8.[Abstract]
This article has been cited by other articles:
|
|
 |
|
  H. M. Salihu, O. Lynch, A. P. Alio, and J. Liu Obesity Subtypes and Risk of Spontaneous versus Medically Indicated Preterm Births in Singletons and Twins Am. J. Epidemiol., July 1, 2008; 168(1): 13 - 20. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. P Kleinman, E. Oken, J. S Radesky, J. W Rich-Edwards, K. E Peterson, and M. W Gillman How should gestational weight gain be assessed? A comparison of existing methods and a novel method, area under the weight gain curve Int. J. Epidemiol., December 1, 2007; 36(6): 1275 - 1282. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. R. DeVader, H. L. Neeley, T. D. Myles, and T. L. Leet Evaluation of Gestational Weight Gain Guidelines for Women With Normal Prepregnancy Body Mass Index Obstet. Gynecol., October 1, 2007; 110(4): 745 - 751. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. M. Catalano Management of Obesity in Pregnancy Obstet. Gynecol., February 1, 2007; 109(2): 419 - 433. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. C.S. Smith, I. Shah, J. P. Pell, J. A. Crossley, and R. Dobbie Maternal Obesity in Early Pregnancy and Risk of Spontaneous and Elective Preterm Deliveries: A Retrospective Cohort Study Am J Public Health, January 1, 2007; 97(1): 157 - 162. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. E. Stotland, A. B. Caughey, M. Lahiff, and B. Abrams Weight Gain and Spontaneous Preterm Birth: The Role of Race or Ethnicity and Previous Preterm Birth Obstet. Gynecol., December 1, 2006; 108(6): 1448 - 1455. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H C Wainwright My approach to performing a perinatal or neonatal autopsy. J. Clin. Pathol., July 1, 2006; 59(7): 673 - 680. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. N. Simhan and L. M. Bodnar Prepregnancy Body Mass Index, Vaginal Inflammation, and the Racial Disparity in Preterm Birth Am. J. Epidemiol., March 1, 2006; 163(5): 459 - 466. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. E. Stotland, J. S. Haas, P. Brawarsky, R. A. Jackson, E. Fuentes-Afflick, and G. J. Escobar Body Mass Index, Provider Advice, and Target Gestational Weight Gain Obstet. Gynecol., March 1, 2005; 105(3): 633 - 638. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Mustillo, N. Krieger, E. P. Gunderson, S. Sidney, H. McCreath, and C. I. Kiefe Self-Reported Experiences of Racial Discrimination and Black-White Differences in Preterm and Low-Birthweight Deliveries: The CARDIA Study Am J Public Health, December 1, 2004; 94(12): 2125 - 2131. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. LaMarca, A. Volpe, and C. Mantzoros Recombinant Human Leptin in Women with Hypothalamic Amenorrhea N. Engl. J. Med., November 25, 2004; 351(22): 2343 - 2343. [Full Text] [PDF]
|
|
|
|
 |
|
 E. Villamor, M. L. Dreyfuss, A. Baylin, G. Msamanga, and W. W. Fawzi Weight Loss During Pregnancy Is Associated with Adverse Pregnancy Outcomes among HIV-1 Infected Women J. Nutr., June 1, 2004; 134(6): 1424 - 1431. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. G. Ronnenberg, X. Wang, H. Xing, C. Chen, D. Chen, W. Guang, A. Guang, L. Wang, L. Ryan, and X. Xu Low Preconception Body Mass Index Is Associated with Birth Outcome in a Prospective Cohort of Chinese Women J. Nutr., November 1, 2003; 133(11): 3449 - 3455. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Neggers and R. L. Goldenberg Some Thoughts on Body Mass Index, Micronutrient Intakes and Pregnancy Outcome J. Nutr., May 1, 2003; 133(5): 1737S - 1740. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H C Shukla, P C Gupta, H C Mehta, and J R Hebert Descriptive epidemiology of body mass index of an urban adult population in western India J. Epidemiol. Community Health, November 1, 2002; 56(11): 876 - 880. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
