Effects of birth weight of alcohol and caffeine consumption during pregnancy

The aim of this study was to investigate the effect of alcohol and caffeine consumption on birth weight and the possible interaction of these substances with smoking. The sample included 628 women who were interviewed at their first visit to the maternity hospital of Roubaix, France, in 1985-1986. A significant reduction in birth weight was found to be associated with an average daily alcohol consumption of three drinks or more after gestational age, infant sex, maternal age, parity, weight, and height, and cigarette smoking had been controlled for. There was no interaction between smoking and alcohol consumption on birth weight, but a significant relation between alcohol consumption and birth weight was observed among nonsmokers as well as heavy smokers. The relation observed between caffeine and birth weight disappeared after adjustment for smoking. Our results indicate that alcohol reduces birth weight, but do not support the hypothesis of an interaction between smoking and alcohol consumption.     

The effect of smoking cessation during pregnancy on preterm delivery and low birthweight

BACKGROUND: Evidence exists that maternal cigarette smoking is associated with preterm birth. Our purpose was to investigate the relation between maternal smoking cessation at different points during pregnancy and the preterm delivery rate and low birthweight. METHODS: Data from the 1988 National Health Interview Survey were analyzed. The study included women who gave birth to children within 6 years of the 1988 interview date (N = 4876). Preterm delivery and infant low birthweight were the main outcome measures. These measures were compared with maternal smoking status during pregnancy. Logistic regression models were computed to control for maternal age at the time of birth, parity, race, and total family income. RESULTS: Women who did not smoke cigarettes during pregnancy were less likely to give birth prematurely (5.9% vs 8.2%, P = .003) or give birth to a low-birthweight baby (5.5% vs 8.9%, P < .001) than women who smoked at some time during the year before giving birth. A significant association existed between maternal smoking status and both preterm delivery and low birthweight. Compared with those who smoked beyond the first trimester, those who quit smoking within the first trimester had reductions in the proportion of preterm deliveries (6.7% vs 9.1%) and low birthweight infants (7.9% vs 9.6%). CONCLUSIONS: Low birthweight and preterm delivery are reduced in women who stop smoking in the first trimester of pregnancy.     

Smoking habits among pregnant women in Norway--suggestions for intervention

Multiple surveys have shown that approximately 35 percent of women in Norway are daily cigarette consumers during their pregnancies. Smoking is the single most important risk factor in pregnancy leading to excessive rates of low birth weight, prenatal neonatal and infant mortality, sudden infant death syndrome and learning problems in school. Norway provides a decent prenatal care program free of charge to all pregnant women. But efforts to reduce smoking have been inadequate. A multilevel strategy including a media campaign, the policy changes recommended in the Action Plan "Smokefree Norway by the year 2000" and a standardized intervention program using generally available resources is suggested as a possible way to reduce the problem throughout the country.     

The effects of platelet-derived growth factor-BB on healing of the rabbit medial collateral ligament. An in vivo study

Cigarette smoking poses significant risk to mother and infant during pregnancy and the postpartum period. Recruitment of pregnant smokers to intervention studies has often been reactive and has excluded certain subgroups of women, such as those who have recently quit smoking. In this study, we examined smoking patterns among a proactively recruited sample of women presenting to six urban community maternity clinics. The current report describes the patterns of smoking in this population of ethnoculturally diverse low-income urban pregnant women and examines differences across subgroups. The majority of the total sample in the current study reported that they had never smoked. Of the total, 30% reported having "ever" smoked and 16% were current smokers. Of the group of "ever" smokers, 18% quit greater than 12 months before pregnancy, 5% quit 0-12 months before pregnancy and 23% quit during this pregnancy. On the average, women who quit during pregnancy did so about 5 weeks after diagnosis. Of those women who continued to smoke during pregnancy, the average number of cigarettes smoked per day was 10 +/- 8. Differences were found in smoking patterns across the ethnocultural subgroups. Recruitment represents the first and one of the most important phases in intervening with pregnant women. Inclusion of both current smokers and recent self-quitters takes the fullest advantage of the window of opportunity to help women quit smoking and remain cigarette free for good.     

Does passive smoking in early pregnancy increase the risk of small-for-gestational-age infants?

OBJECTIVES: This study tested the hypothesis that women who deliver small-for-gestational-age infants are more often exposed to passive smoking at home or at work. METHODS: Among a 1-year cohort of nulliparous women in the city of Malm?, Sweden 872 (87.7%) women completed a questionnaire during their first prenatal visit. The study was carried out among women whose pregnancies resulted in a singleton live birth (n = 826), 6.7% of infants were classified as small for their gestational age. RESULTS: Passive smoking in early pregnancy was shown to double a woman's risk of delivering a small-for-gestational-age infant, independent of potential confounding factors such as age, height, weight, nationality, educational level, and the mother's own active smoking (odds ratio [OR] = 2.7). A stratified analysis indicated interactional effects of maternal smoking and passive smoking on relative small-for-gestational-age risk. CONCLUSIONS: Based on an attributable risk estimate, a considerable reduction in the incidence of small-for-gestational-age births could be reached if pregnant women were not exposed to passive smoking.     

Exposure of young infants to environmental tobacco smoke: breast-feeding among smoking mothers

OBJECTIVES: This study examined the degree to which breast-feeding and cigarette smoking by mothers and smoking by other household members contribute to the exposure of infants to the products of tobacco smoke. METHODS: The subjects were 330 mother-infant pairs derived from a cohort of 1000 pairs enrolled in a longitudinal study of the pulmonary effects of prenatal and postnatal smoking. The main outcome measure was corrected urinary cotinine levels. RESULTS: Urinary cotinine levels were 10-fold higher in breast-fed infants of smoking mothers than among bottle-fed infants of smoking mothers. Among infants of nonsmoking mothers, urine cotinine levels were significantly increased in infants living in homes with other smokers; in this group there was no significant difference between bottle-fed and breast-fed infants. Infants whose mothers smoked in the same room as the infant had only nonsignificant increases in cotinine levels compared with infants whose mothers restricted their smoking to other rooms. CONCLUSIONS: Breast-fed infants of smoking mothers have urine cotinine levels 10-fold higher than bottle-fed infants whose mothers smoke, suggesting that breast-feeding, rather than direct inhalation of environmental tobacco smoke, is the primary determinant of cotinine levels in infants whose mothers smoke.     

A comparison of two different systems for CD34+ selection of autologous or allogeneic PBSC collections

Narghile smoking, a common habit among women in many non-Western societies, is assumed by the public to be minimally harmful. This study aims at identifying the effect of smoking narghiles during pregnancy on the weight of the newborn and other pregnancy outcomes. Three groups of pregnant women were interviewed in several hospitals in Lebanon between 1993 and 1995: 106 who smoked narghiles during their pregnancy, 277 who smoked cigarettes, and 512 who did not smoke. The adjusted mean birth weight of babies born to women who smoked one or more narghiles a day during pregnancy and to women who started smoking in the first trimester was more than 100 g less than that of babies born to nonsmokers (p < 0.1). The adjusted odds ratio of having babies with low birth weight (<2,500 g) among the narghile smokers was 1.89 (95% confidence interval (CI) 0.67-5.38). The risk increased to 2.62 (95% CI 0.90-7.66) among those who started smoking narghiles in the first trimester. A stronger association and a dose-response relation were found among cigarette smokers. The association between narghile smoking and other pregnancy outcomes, especially Apgar score and respiratory distress, was also noticeable. Further research and a policy action to fight the misperception that narghile smoking is safe are both recommended.     

Changes in employee smoking behavior after implementation of restrictive smoking policies

How do restrictive smoking policies affect the smoking behavior of employees? At two federal hospitals, 2,700 employees completed written surveys after implementation of restrictive smoking policies. At one hospital, smokers reported less smoking at work (down 2.0 cigarettes a day at 6 months, 1.7 at 12) without compensatory smoking. At the other, no significant changes in smoking behavior were reported. However, at both hospitals, some baseline smokers quit smoking. At 6 months, 9% had quit at one hospital and 8% at the other. Analyses were done using these two studies and 17 published studies. In 11 of 11 studies, consumption at work decreased, and in 12 of 14, total daily consumption decreased. Regression analysis indicated that the number of smokers who quit smoking after policy implementation increases over time at rates exceeding those normally expected in the population. Smoking policies appear to effect a reduction in total cigarette consumption and an increase in the number of smokers who quit.     

Completeness of ascertainment of prenatal smoking using birth certificates and confidential questionnaires: variations by maternal attributes and infant birth weight. PRAMS Working Group. Pregnancy Risk Assessment Monitoring System

Birth certificate data frequently are used to monitor the prevalence of smoking during pregnancy. The authors used a two-sample capture-recapture method to estimate the completeness of ascertainment of prenatal smoking on birth certificates and on confidential questionnaires in six US states. Completeness of ascertainment was also examined according to maternal attributes and infant birth weight. The samples included white women who delivered a live infant between 1993 and 1995 in one of six states (Alabama, Alaska, Georgia, Maine, South Carolina, or West Virginia) and who responded to a questionnaire mailed to them 2-6 months postpartum as part of the Pregnancy Risk Assessment Monitoring System. State-specific sample sizes ranged from 2,647 to 4,795. The completeness of ascertainment ranged from 70.6% to 82.0% using birth certificates and from 86.2% to 90.3% using confidential questionnaires. In all six states, the birth certificates' completeness of ascertainment varied by maternal education and infant birth weight, and the questionnaires' completeness varied by maternal age. Both birth certificates and questionnaires underestimated the true extent of smoking during pregnancy among these white women. Differential reporting by birth weights recorded on birth certificates would result in an overestimated association between low birth weight and prenatal smoking.     

Human immunodeficiency virus and resistance]

CONTEXT: Racial differences in tobacco-related diseases are not fully explained by cigarette-smoking behavior. Despite smoking fewer cigarettes per day, blacks have higher levels of serum cotinine, the proximate metabolite of nicotine. OBJECTIVE: To compare the rates of metabolism and the daily intake of nicotine in black smokers and white smokers. DESIGN: Participants received simultaneous infusions of deuterium-labeled nicotine and cotinine. Urine was collected for determination of total clearance of nicotine and cotinine, fractional conversion of nicotine to cotinine, and cotinine elimination rate. Using cotinine levels during ad libitum smoking and clearance data, the daily intake of nicotine from smoking was estimated. SETTING: Metabolic ward of a university-affiliated public hospital. PARTICIPANTS: A total of 40 black and 39 white smokers, average consumption of 14 and 14.7 cigarettes per day, respectively, of similar age (mean, 32.5 and 32.3 years, respectively) and body weight (mean, 73.3 and 68.8 kg, respectively). MAIN OUTCOME MEASURES: Clearance (renal and nonrenal), half-life, and volume of distribution of nicotine and cotinine and the calculated daily intake of nicotine. RESULTS: The total and nonrenal clearances of nicotine were not significantly different, respectively, in blacks (17.7 and 17.2 mL x min(-1) x kg(-1)) compared with whites (19.6 and 18.9 mL x min(-1) x kg(-1)) (P=.11 and .20). However, the total and nonrenal clearances of cotinine were significantly lower, respectively, in blacks (0.56 and 0.47 mL x min(-1) x kg(-1)) than in whites (0.68 vs 0.61 mL x min(-1) x kg(-1); P=.009 for each comparison). The nicotine intake per cigarette was 30% greater in blacks compared with whites (1.41 vs 1.09 mg per cigarette, respectively; P=.02). Volume of distribution did not differ for the 2 groups, but cotinine half-life was higher in blacks than in whites (1064 vs 950 minutes, respectively; P = .07). CONCLUSIONS: Higher levels of cotinine per cigarette smoked by blacks compared with whites can be explained by both slower clearance of cotinine and higher intake of nicotine per cigarette in blacks. Greater nicotine and therefore greater tobacco smoke intake per cigarette could, in part, explain some of the ethnic differences in smoking-related disease risks.     

Architecture. HOTELIA, an innovative concept

This article focuses on adolescent pregnancy and birth issues in the US. Although the birth rate among adolescents aged 10-19 years in New Jersey declined to 9609 infants per year in 1994, a decline of 7% from 1990, there remain concerns about the welfare of the mother and fetal development. Adolescent birth rates in New Jersey are higher for Black youths compared to White youths (100/1000 births vs. 25.4/1000). During 1990-94, births to girls aged 10-14 years increased from 241 to 284. There are many reasons for teenage pregnancy: abuse or coercion, peer pressure, misinformation, defiant behavior, person whims, and need for success through pregnancy. Pregnant teens frequently do not receive adequate prenatal care, maintain good nutrition, and/or refrain from unhealthy habits such as cigarette smoking, alcohol drinking, and/or drug use. The lack of prenatal care until late pregnancy may be due to lack of health insurance coverage or money for transportation. Teenagers have higher rates of premature births. Fetal development may be impaired due to lack of a proper maternal diet with a sufficient amount of folic acid, iron and protein, or food intake. Teenagers have twice the rate of spina bifida. Girls need to know the facts about the risk of premature birth and low birth weight associated with their cigarette smoking during pregnancy. Girls should be asked to reduce smoking to 3-5 cigarettes per week by the next visit and to stop entirely by the following visit. Teenagers need reinforcement in adopting the right eating patterns and curbing undesirable habits. Prenatal care should be comprehensive. The evidence suggests that fetal development is hampered by the competition for resources between the mother and fetus. Health care professionals must provide contraceptives and education; most hope that the repetitive cycle of repeat pregnancy and poverty does not continue.     

Cocaine use can increase cigarette smoking: Evidence from laboratory and naturalistic settings.

Two studies examined the effects of cocaine use on cigarette smoking. Study 1 was conducted with 10 healthy volunteers under controlled laboratory conditions. Participants received double-blind doses of intranasal cocaine HCI (100 mg) or placebo in separate sessions, with each being followed by a 3-hr period of monitored cigarette smoking. Latency to the first cigarette and the mean interval between cigarettes was significantly shorter and the total number of cigarettes smoked was greater after cocaine than placebo administration. Study 2 was conducted by using urine specimens from 9 ambulatory cocaine-dependent patients. Urine cotinine (nicotine metabolite) levels on days when urinalysis testing indicated recent cocaine use were compared with levels on days when urinalysis testing indicated no recent use. Cotinine levels were significantly higher on cocaine-positive days, indicating that cocaine use was associated with greater cigarette smoking. Overall results provide evidence that acute cocaine administration can increase cigarette smoking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Desire and efforts to quit smoking among cigarette smokers in Wisconsin

This research studied the desire and attempts of cigarette smokers in Wisconsin to quit smoking. Data were based on the 1993 Wisconsin Division of Health's Behavioral Risk Factor Surveillance System (BRFSS). Among the 23% of respondents who were current smokers, 79% said they wanted to quit smoking and 60% said they had quit smoking for a day or more in the preceding year. High rates of wanting to quit and having tried to quit were found in all demographic subgroups of smokers studied. Compared to lighter smokers, heavy cigarette smokers (20 or more cigarettes per day) were less likely to have tried quitting in the past year, but were almost as likely to want to quit. These results demonstrate the great demand for smoking cessation services among smokers in Wisconsin and support for efforts to increase the use and effectiveness of these interventions.     

Tobacco and cancer in Turkey

Although the smoking epidemic is decreasing steadily in other parts of the world, it continues to spread at an accelerated rate in underdeveloped and developing countries. Turkey, among other developing countries, faces the increasing threat of tobacco-related cancers, particularly lung cancer, which is the leading cause of cancer death in both sexes. We investigated the relationship between cigarette consumption and the relative mortality rates due to lung cancer in men and women between 1965 and 1992. We found a parallelism between the increasing total and per capita cigarette consumption and the rising relative mortality from lung cancer in both sexes. Total per capita cigarette consumption rose from 1230 cigarettes per year in 1985 to 1495 in 1991, and the per capita yearly cigarette consumption over the age of 15 increased from 1850 in 1965 to 2600 in 1992. During the same period, the relative mortality from lung cancer increased from 25 to 40% in men and from 11 to 16% in women. The tar, nicotine, and carbon monoxide determinations of locally produced and imported cigarettes suggested that the high tar and carbon monoxide content of most locally produced cigarettes smoked over many years could also be a contributory factor to the increased mortality rates due to lung cancer. Only two brands of locally produced cigarettes contained lower than 12 mg of tar per cigarette as allowed in European community states, whereas half of the imported brands of cigarettes met this standard. Four of the six imported brands of cigarettes contained higher tar and carbon monoxide compared with the same brands sold in England. These findings indicate that urgent measures are necessary not only to ban all activities promoting the sale of cigarettes but also to establish standards for both national and foreign brands of cigarettes while making a greater effort to reduce active and passive smoking in the Turkish population.     

Identification of multiprotein complexes containing DNA replication factors by native immunoblotting of HeLa cell protein preparations with T-antigen-dependent SV40 DNA replication activity

Adequate prenatal care has been linked to improved birth outcomes in general populations but has not been assessed in HIV-infected women. We examined longitudinal claims files and vital statistics records for women in the New York State Medicaid HIV/AIDS data base delivering a singleton from 1985 through 1990. Adequacy of the self-reported number of prenatal visits was assessed by the Kessner index. In logistics models, we estimated the association of prenatal care, illicit drug use, and other maternal characteristics with three outcomes; low birth weight, preterm birth, and small-for-gestational-age. Of 2,254 singletons delivered by this HIV-infected cohort, 28% were low birth weight, 23% were preterm birth, and 20% were small for gestational age. Two-thirds had inadequate prenatal care. Non-drug users had 57 and 26% lower adjusted odds of low birth weight and preterm delivery than drug users. The adjusted odds of low birth weight and preterm birth for women with an adequate number of prenatal visits were, respectively, 48 and 21% lower than for women with inadequate care. Adequate prenatal care was also associated with a 43% reduction in the odds of small-for-gestational-age. An adequate number of prenatal visits by women in this HIV cohort was associated with a significant reduction in all three adverse birth outcomes, but most had inadequate prenatal care. These data support strengthening efforts to bring pregnant, HIV-infected women into care.     

Dose-dependent induction of IL-12 but not IL-10 from human keratinocytes after exposure to ultraviolet light A

OBJECTIVE: Our purpose was to assess the risk of ectopic pregnancy among women who smoke cigarettes. STUDY DESIGN: We used data from a case-control study of ectopic pregnancy conducted from October 1988 to August 1990 at an inner-city hospital in Georgia. Cases were 196 non-Hispanic black women with a surgically confirmed ectopic pregnancy. Controls were non-Hispanic black women who had delivered either a live or a stillborn infant weighing at least 500 gm (n = 882) or who were pregnant and seeking an induced abortion (n = 237). RESULTS: After we adjusted for parity, douching history, history of infertility, and age, the odds ratio for ectopic pregnancy was 1.9 (95% confidence interval 1.4 to 2.7) for women who smoked during the periconception period compared with women who did not smoke at that time. After stratification by the amount of daily smoking during the periconception period, the odds ratio rose from 1.6 (95% confidence interval 0.9 to 2.9) for women who smoked 1 to 5 cigarettes to 1.7 (95% confidence interval 1.1 to 2.8) for women who smoked 6 to 10 cigarettes to 2.3 (95% confidence interval 1.3 to 4.0) for women who smoked 11 to 20 cigarettes, and to 3.5 (95% confidence interval 1.4 to 8.6) for women who smoked >20 cigarettes per day. CONCLUSION: In this inner-city population, cigarette smoking was an independent, dose-related risk factor for ectopic pregnancy among black women. The public health and medical care communities should inform the public of this additional risk associated with cigarette smoking and intensify intervention strategies to reduce cigarette smoking among women of reproductive age.     

Effects of daily caffeine intake on smoking behavior in the natural environment.

The effects of changes in daily caffeine intake on cigarette smoking were investigated. Forty cigarette smokers consumed caffeine ad lib on a baseline day then consumed controlled multiple doses of caffeine (100 mg and 500 mg per day) for two-day trials. Smokers recorded the number of cigarettes consumed, and measurements of expired-air carbon monoxide and salivary cotinine concentration were obtained to estimate smoke and nicotine intake. Baseline caffeine intake averaged 449 mg per day, with wide variations among participants. The 5-fold change in caffeine dose on treatment days did not affect any measure of smoking behavior in these participants. Results suggest that daily caffeine intake has little influence on cigarette smoking in the natural environment. Coffee drinking and cigarette smoking are commonly associated behaviors, although the links between them are not yet understood. Results raise doubts that the influence of coffee drinking on smoking, if any, can be attributed to the effects of caffeine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

1988 National Maternal and Infant Health Survey: methods and response characteristics

OBJECTIVES: The 1988 National Maternal and Infant Health Survey (NMIHS) was conducted by the National Center for Health Statistics to study factors related to poor pregnancy outcome, such as adequacy of prenatal care; inadequate and excessive weight gain during pregnancy; maternal smoking, drinking, and drug use; and pregnancy and delivery complications. METHODS: The NMIHS is a nationally representative sample of 11,000 women who had live births, 4,000 who had late fetal deaths, and 6,000 who had infant deaths in 1988. Questionnaires were mailed to mothers based on information from certificates of live birth, reports of fetal death, and certificates of infant death. Information supplied by the mother, prenatal care providers, and hospitals of delivery was linked with the vital records to expand knowledge of maternal and infant health in the United States. RESULTS: The response rates in all three components of the NMIHS differed according to the mothers' characteristics. Mothers were more likely to respond if they were 20-39 years of age, were white, were married, had fewer than four children, entered prenatal care early, had more prenatal visits, had more years of education, or resided in the Midwest Region. The percent of respondents was lower for teenage mothers, mothers of races other than white, and mothers with four or more children, little prenatal care, or fewer years of education. Mothers whose infants weighed less than 2,500 grams were less likely to respond in the live-birth and infant-death components than mothers whose infants weighed 2,500 grams or more. CONCLUSIONS: The NMIHS will provide an invaluable tool for researchers and practitioners seeking solutions to perinatal and obstetric problems.     

Risk factors for low birth weight and intrauterine growth retardation in Santiago, Chile

An epidemiologic case-control study to ascertain the determinants of low birthweight was carried out in Santiago, Chile, from January to December 1989. The cases were defined as livebirths < 2500 g. The controls were livebirths > or = 2500 g of birthweight. All cases and a random sample (1:1) of controls were selected among 8,254 singleton births occurring at the El Salvador Hospital in the Eastern area of Santiago. These deliveries represented 50% of institutional deliveries in the area. Home deliveries (2%) and private hospital deliveries were not included in the study. Information was obtained from hospital medical records by six trained medical students. Some information could not be obtained from the hospital medical records. Thus the second step in data collection was the tracking of all the selected subjects to their referring neighborhood health centers. For the analysis, the data were divided into 3 case (outcome) categories: 453 subjects were the total case group. From these, 153 were the IUGR case group and 300 were the LBW preterm case group. The general control group consisted of 605 normal birthweight infants. 565 were the IUGR control group and 40 were the preterm control group. A total of 25 risk factors showed a significant crude odds ratio for at least one of the groups. In the multivariate logistic regression analysis eight variables: No. of pregnancies, previous adverse outcomes, previous LBW, pregnancy maternal weight, No. of visits, month of first prenatal care visit, maternal smoking and intrahepatic cholestasis of pregnancy, were significantly associated with LBW after adjustment by confounding. Eight risk factors: IUGR in previous pregnancies, Previous adverse outcome, Maternal smoking, intrahepatic cholestasis, maternal pregnancy weight, maternal height, month first prenatal visit, No. of visit, were significant to IUGR. Only two variables: pregnancy weight, divorced mother, were significantly associated with low birth weight in the preterm group. The most relevant risk factors were included in stepwise logistic regression models carried out for the outcome LBW for the general group, term group and preterm group, in order to adjust by confounding. Adjusted odds ratios were then obtained. Prenatal care related factors and maternal adverse obstetric factors were at higher significance for LBW in the general and IUGR groups. Only nutritional factors were related to LBW in preterm group. Women who delivered a LBW or IUGR infant were more likely to have fewer pregnancies, a history of previous LBW, lower prepregnancy weight and lower gestational weight gain. ICP was associated with an elevated risk of LBW that was independent of gestational age.     

Local low-dose interleukin-2 induces systemic immunity when combined with radiotherapy of cancer. A pre-clinical study

OBJECTIVES: This study examined whether the decline in birth-weight with increasing altitude is due to an independent effect of altitude or an exacerbation of other risk factors. METHODS: Maternal, paternal, and infant characteristics were obtained from 3836 Colorado birth certificates from 1989 through 1991. Average altitude of residence for each county was determined. RESULTS: None of the characteristics related to birthweight (gestational age, maternal weight gain, parity, smoking, prenatal care visits, hypertension, previous small-for-gestational-age infant, female newborn) interacted with the effect of altitude. Birthweight declined an average of 102 g per 3300 ft (1000 m) elevation when the other characteristics were taken into account, increasing the percentage of low birthweight by 54% from the lowest to the highest elevations in Colorado. CONCLUSIONS: High altitude acts independently from other factors to reduce birthweight and accounts for Colorado's high rate of low birthweight.