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Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Introduction: childhood obesity is a public health problem whose prevalence has grown steadily in recent decades. Objective: to describe the weight status of schoolchildren aged 6 to 9 years in Spain in 2019, and their associated factors. Methods: ALADINO is a cross-sectional study in schoolchildren aged 6 to 9 years, representative of the Spanish population, and aligned with the Child Obesity Surveillance Initative of the WHO Regional Office for Europe. Participants' weight, height, and abdominal circumference were measured, defining weight status according to different standards (WHO, IOTF, and Orbegozo). A questionnaire on lifestyle and socio-demographic characteristics was administered to parents. Results: a total of 16,665 schoolchildren from 276 schools were measured. Excess weight was observed in 40.6 %: 23.3 % overweight and 17.3 % obesity, with obesity being more prevalent in boys and overweight in girls, both increasing with age. The prevalence of abdominal obesity was 22.6 %. Excess weight decreased by 3.9 percentage points since 2011, mainly due to overweight in boys. Obesity remained stable. Excess weight was more prevalent in schoolchildren with less healthy eating and physical activity habits, and in families with a lower socioeconomic status. Conclusions: the prevalence of excess weight is high, although it has declined since 2011 and remains stable since 2015 among schoolchildren aged 6-9 years in Spain, this reduction being mainly due to a decrease in overweight in children. It is necessary to continue promoting healthy habits from the earliest stages of life, thus reducing health inequalities. [ABSTRACT FROM AUTHOR]

Introduction: Introduction and objective: pregnancy is a stage of life with high nutritional vulnerability and increased levels of maternal oxidative stress. Total antioxidant capacity (CAT) identifies the protective effect of a balanced diet rich in foods of plant origin with antioxidant activity. The aim of this study was to relate CAT with dietary intake and body mass index (BMI) in pregnant women in the Community of Madrid. Methods: a cross-sectional, comparative study was conducted in 89 pregnant women and 61 healthy women of reproductive age. Age, place of origin, weight, height, BMI, macronutrient and micronutrient intake, and dietary CAT by food frequency were recorded; CAT was classified as desirable (≥ 19,301.0 µm/g) or undesirable (< 19,301.0 µm/g); the statistical analysis, including χ², Student's t-test or Mann Whitney U-test, was made using the SPSS program v.23. Results: differences were found in caloric profile, intake of antioxidant micronutrients, and dietary CAT (p < 0.05). Mean CAT in pregnant women was 23,163.0 ± 10,829.0 µm/g, whereas in non-pregnant women it was 25,916.0 ± 9,703.0 µm/g (p = 0.035). Pregnant women with a desirable CAT (56.2 %) preferred to consume fruits and vegetables, and 65.6 % of non-pregnant women preferred bread, pasta and cereals (p = 0.02). Hand fruit, citrus fruits, green leafy vegetables, and tomato were preferentially consumed by both groups. In pregnant women, poor nutritional status, overweight, and obesity rates of 36.0 % were found versus 28.0 % in non-pregnant women (p < 0.001). Conclusion: the BMI of pregnant women is not related to dietary CAT or the relatively low consumption of antioxidant components. [ABSTRACT FROM AUTHOR]

Introduction: Introduction: early detection of childhood obesity plays a crucial role in the prevention of diseases during adulthood. At present, the most commonly used screening tool for detecting overweight/obesity in children is the percentile for age of body mass index, although this rate is unable to provide information about fat distribution. An emerging marker of abdominal fat distribution is waist circumference (WC). Objective: the aim of this study was to evaluate the differences between the different diagnostic criteria available to define overweight and obesity in order to establish the optimal WC cut-off values for the Spanish children population. Methods: a cross-sectional study was carried out in 8,241 schoolchildren aged 3 to 12 years from Villanueva de la Cañada (Madrid, Spain). WC (cm), weight (kg) and height (cm) were measured according to the recommendations of the Society for the Advancement of Kineanthropometry (ISAK). The values obtained for the diagnostic criteria (Spanish Orbegozo Foundation (OF), the International Obesity Task Force (IOTF), and the World Health Organization (WHO) were compared using McNemar's test for paired proportions. The kappa coefficient (κ) was used to assess the degree of agreement of the three classifications. We analyzed the validity of body mass index (BMI) and WC using the receiver operating characteristic (ROC) curve analysis. The Youden index was used to determine cut-off values for WC that identify childhood obesity Results: overweight and obesity prevalences were calculated according to the OF, IOTF, and WHO criteria. There was a "substantial" agreement for the overweight and obesity categories between the Spanish criteria and IOTF (κ = 0.636), while agreement was "slight" between the Spanish criteria and those of WHO (κ = 0.198). The estimated cut-off WC criteria ranged from 54.5 to 88.0, varying according to sex and age. Conclusion: the proposed WC cut-off values, stated for the first time in a young Spanish population, are a simple and valid alternative as diagnostic criteria of abdominal obesity. [ABSTRACT FROM AUTHOR]

Background: to examine relations between functional movement patterns and weight status in Spanish primary school children and to determine the differences between sexes.Methods: three hundred and thirty-three, 6-13 years old children (164 boys and 169 girls), participated in this study. The main outcome measures were the body mass index (BMI) and the Functional Movement Screen™ (FMS). Children were classified as normal weight (NW), overweight (OV) or obese (OB) according to international cut-offs.Results: total FMS score was negatively correlated with BMI (p < 0.001). FMS score was different between children from NW, OV and OB groups (p = 0.001), lower with the increased BMI (p < 0.001 between all groups). Significant differences (p < 0.05) between NW, OV and OB were found in deep squat, hurdle step, in-line lunge, shoulder mobility, straight leg-raise and push-up tests. As for the sex differences, girls obtained higher scores (p < 0.05) in in-line lunge, shoulder mobility and straight leg-raise, whereas boys did it in push-up (p = 0.044) test.Conclusions: these results confirm that total FMS score significantly and inversely correlates with BMI in a group of 333 school-age children. As for the sex differences, girls outperform boys in movements requiring flexibility and balance, whilst boys outperform girls in tests where muscular strength is required. [ABSTRACT FROM AUTHOR]

Introduction: obesity has been associated with an increased risk of preeclampsia and gestational hypertension.Objective: to determine if overweight and/or maternal obesity at the beginning of the pregnancy are associated with an increased risk of suffering from some hypertensive state of pregnancy in a population of southern Spain.Methods: retrospective cohort study. We studied 4,711 cases where the IMC had been registered at the beginning of pregnancy. Two study groups were included: overweight/obesity at the beginning of the gestation.Control Group: pregnant women with normal BMI at the beginning of gestation. Global risk of hypertensive disorders of pregnancy (HDP) and the risk of gestational hypertension, preeclampsia, chronic hypertension and preeclampsia superimposed on chronic hypertension were evaluated.Results: maternal overweight was associated with an increased risk of HDP (OR 2.04, 95% CI: 1.43-2.91) and an increased risk of gestational hypertension (OR 1.68, 95% CI: 1.03-2.72) and chronic HT (OR: 3.70, 95% CI: 1.67-8.18). Maternal obesity was associated with an increase in some HDP (OR 3.54, 95% CI: 2.65-4.73), gestational hypertension (OR 2.94, 95% CI: 2-4.33), chronic HT (OR 8.31, 95% CI: 4.23-16.42) and preeclampsia (OR 2.08, 95% CI: 1.12-3.87) In the multivariate analysis (adjusted for parity and maternal age), overweight was associated with an increased risk of gestational hypertension (OR: 1.74, 95% CI: 1.06-2.85), chronic HT (OR 3.76, 95% CI: 1.69-8.35) and preeclampsia (OR 2.12, 95% CI: 1.005-4.48); obesity also increased the risk of gestational hypertension (OR 2.40, 95% CI: 1.39-4.13), chronic hypertension (OR 17.96, 95% CI: 8.78-36.76) and preeclampsia (OR 3, 69; 95% CI: 1.64-8.27).Conclusions: in conclusion, a significant and independent association was found between maternal overweight/obesity and HDP. The risk is significantly higher as the BMI increases (from overweight to obesity grade 3). [ABSTRACT FROM AUTHOR]

Copyright of Enfermería Nefrológica is the property of Sociedad Espanola de Enfermeria Nefrologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: the high prevalence of body dissatisfaction among young women from developed countries is studied as a predictive factor, among others, of restrictive nutritional and feeding attitudes. Cultural and biological factors, such as body mass index and puberty, stand out as the most commonly studied variables in relation to body dissatisfaction. Objectives: To analyze the differential effect of body mass index on body dissatisfaction (BD) and its modulating effect in two different cultures, the Spanish and Mexican cultures. To look deeper into the evolution of body dissatisfaction according to age. Methodology: BMI and body dissatisfaction, measured with a 10-item scale, were studied in a big sample of young Spanish (N = 950) and Mexicans (N = 531) women, aged 15-21 years. The analyses were carried out according to the general linear model. Results and discussion: A differential effect of BMI on BD was observed for the Mexican and the Spanish populations. The estimated regression line for the Spanish population is steeper, which reflects a greater effect of the BMI indexes on BD in this population. In both samples a decreasing pattern of BD levels was observed according to age and a modulating effect of BMI. Conclusion: To properly study the effect of several factors on BD it is important to include the BMI as a modulating variable. Its effect is significant and differential depending on the culture. Its inclusion or exclusion in studies concerning BD may significantly impair the results of any investigation. [ABSTRACT FROM AUTHOR]

Objective: To modify the results of the longitudinal study on growth in Navarra (NA 09) by censoring the obesity cases from the population sample as well as to perform a comparative analysis with the most qualified Spanish and international growth curves. Materials and methods: all the cases with obesity according to Cole et al. standards have been censored out of the 930 participants in NA-09, the final sample being 782 participants (371 males and 411 females). The results obtained were compared with the Spanish studies by Serra-Majem et al. (enKid study), Carrascosa et al. (ESP 08), and NA 09, which do not censor the obesity cases, and with the Centers for Disease Control and Prevention (CDC, 2000) table, and the WHO tables (WHO, 2007) that apply depuration criteria of the poorly healthy anthropometric data (obesity and malnutrition). Results: We present the mean values adjusted by height, weight, and BMI with their percentile distribution for both genders. When comparing with the Spanish studies, we observe that the evolutionary values of the 3d and 50th percentiles for height, weight, and BMI are virtually the same; however, the evolutionary values for the 97th percentile for weight and BMI tend to differ more and more. When comparing them to the international standards, the evolutionary values for the 3d, 50th, and 97th percentiles for BMI lay between both references. Conclusions: for the growth curves and tables to be useful as reference patterns, all obese people should be excluded from their elaboration; otherwise, they should be considered as only descriptive studies of a population with a recognized tendency to excessive body weight and thus their clinical applicability would be put in question. [ABSTRACT FROM AUTHOR]

Copyright of Archivos de Bronconeumología (English Edition) is the property of Sociedad Espanola de Neumologia y Cirugia Toracica (SEPAR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nutritional aspects of breakfast, plasma levels of glucose and β-hydroxybutyrate, body mass index and academic performance have been studied in urban and rural children (Extremadura, Spain). Methods: Representative samples of schoolchildren (3 to 12 years old, random cluster-sampling in schools). Results: Children's mean caloric intake with breakfast was 331 kcal. Rural population ingested more carbohydrates (46,9 ± 12,3% versus 43,3 ± 13,2% of the total caloric intake) and fewer lipids (40,5 ± 11,8% versus 43,9 ± 12,8% of the total caloric intake) than the urban population. Academic performance was significantly better in the children inhabiting the rural zone than in those of the urban zone. The glycaemia was higher in the urban than in the rural children, and that the contrary was the case for the β-hydroxybutyrate values. Neither glucose nor β-hydroxybutyrate levels were correlated with academic performance values. BMI was significantly increased in the urban versus rural children. Conclusion: The present results emphasize the importance of breakfast and life style in the weight and the academic performance of children. [ABSTRACT FROM AUTHOR]

Introduction: Overweight and obesity in childhood and adolescence has grown alarmingly in the last twenty years or so in many countries of Europe, including Spain. This study presents the prevalences of overweight and obesity in 6-9 year-old schoolchildren in 2015, and their associated characteristics., Methodology: ALADINO (Its initials in Spanish for Diet, physical activity, child development and obesity) is a cross-sectional study of a representative sample of 6-9 year-old schoolchildren in Spain, in line with the Childhood Obesity Surveillance Initiative (COSI) of the World Health Organisation (WHO). The height and weight of the participants, defining the weight status according to WHO standards, and a questionnaire was given to the parents on lifestyle and sociodemographic characteristics., Results: Anthropometric measurements were taken on 10,899 schoolchildren for 168 primary education centres. Excess weight was observed in 41.3% (95% CI: 40.0-42.6), overweight in 23.2% (95% CI: 22.1-24.3) and obesity in 18.1% (95% CI: 17.2-19.1), with obesity being more prevalent in boys, overweight in girls. The prevalence of abdominal obesity was 23.2% (95% CI: 21.8-24.6). The prevalence of overweight and obesity increased with age. Excess weight decreased by 3.2% compared to 2011, mainly due to the decrease in overweight in boys, while that of obesity remained stable. Excess weight was more prevalent in schoolchildren from families with a lower socioeconomic level., Conclusions: The prevalence of excess weight in 6-9 year-old schoolchildren in Spain has decreased by 3.2% since 2011, due to the decrease in overweight, whilst obesity remained stable. Action must be taken in the obesogenic environment, by promoting healthy eating habits and physical activity, bearing in mind the inequalities in health., (Copyright © 2021 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.)

Introduction and Objectives: Overweight and obese patients have an increased risk of cardiovascular disease and general mortality. It is not clear which obesity index should be used in the clinic. The objective is to compare the relationship between body mass index (BMI), waist circumference (WC), waist-height ratio (WHR), and conicity index (Conicity-I) with 10-year Framingham cardiovascular risk (CVR)., Material and Methods: Population cross-sectional study in subjects ≥18years, residents in the Toledo (Spain) Health Area. Selection by random sampling. Measurements were made of the BMI, WC, and weight to height ratio with standardised methods. Framingham CVR. Calculation of AUC, and optimal cut-off points., Results: The study included 1,309 subjects, with mean age of 48.9±15.8years, and 55% women. The response rate was 36.6%. In women, the index that was best associated with CVR in women was the WC with an AUC=0.85 (95%CI: 0.81-0.88). In men it was the I-Conicity, with an AUC=0.81 (95%CI: 0.77-0.84). Cut points for BMI were similar in women (27.08kg/m 2 ) and men (26.99kg/m 2 ). The WC was lower in women (87.75cm) than in men (94.5cm). The WHR was higher in women (0.59) than in men (0.56). The I-Conicity was slightly lower in women (1.25) than in men (1.28). In women, all the ROC curves were closest to each other., Conclusions: The central obesity indexes (WC and WHR) discriminated better than the BMI the CVR. In women, all the indices had greater AUCs than in men, except for the I-Conicity., (Copyright © 2019. Publicado por Elsevier España, S.L.U.)

Introduction: Several studies warn that overweight and obesity have become an epidemic with severe consequences in the population's health. The objetive of the present study is to estimate the prevalence of overweight and obesity in Castile and Leon in a sample of children at 6, 11 and 14 years of age, to describe its evolution and its association with life habits and antecedents., Material and Methods: Observational study, retrospective cohort, performed by the pediatricians of the Health Sentinel Network. The study is part of a joint Project with the National Research Center on Human Evolution (CENIEH) in Burgos to know the pattern of growth and development of the child population of Castile and Leon. In 2012, a health examination and a retrospective collection were carried out based on the clinical history of a simple of 326 children, from the cohort was born in 1998., Results: Following the WHO references, at age 14 there was 25.3% of boys and 18.5% of girls with overweight. Obesity was estimated to affect the 8.2% and 4.8% of them respectively. At 11 years of age there was the maximum of overweight in girls and of obesity in boys. At the urban-non urban environment, quantity and quality of sleep and the parents' BMI have been some of the associated factors to weight level of the children., Discussion: In Castile and Leon, as in other populations of our environment, there is a severe problema of overweight and obesity. For their control it is necesary to deepen understanding of lifestyles and antecedents related to the birth as well as to calculate the growth rate in the pediatric age., (Copyright © 2018 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.)

Objectives: The Autonomous Community of Madrid procures the largest number of organs from uncontrolled non-heart-beating donors (NHBD) after circulatory death in Spain. The aim of this study was to analyze the yield of these donations in terms of viable organs procured (category IIa) according to information extracted from the CORE registry of the Spanish National Transplant Organization (ONT) for the Madrid area., Methods: Retrospective observational study of NHBD data registered between 2007 and 2017, including age, height, weight, body mass index (BMI), emergency care times, method of chest compressions applied (mechanical cardiopump vs manual compressions), and viable organs extracted., Results: A total of 679 circulatory death donors were registered; 458 (67.6%) of them were utilized donors. The median BMI correlated negatively (-0.161) with the number of viable organs extracted (P<.001). The method of applying chest compressions significantly influenced liver viability: only those extracted after mechanical cardiopump compressions were viable for transplantation. Type of compressions did not effect kidney or lung viability., Conclusion: Variables to bear in mind as predictors of success in NHBD donation are BMI and type of chest compressions applied.

Introduction: Body mass index-for age (BMI) and tri-ponderal mass index-for-age (TMI) values of healthy non-underweight, non-obese millennial children have not been reported until now. We aimed to obtain these values., Subjects and Methods: Longitudinal growth study (1995-2017) of 1,453 healthy non-underweight, non-obese millennial children, from birth (n = 477) or from 4 years of age (n = 976) to 18 years in girls and 19 years in boys (25,851 anthropometric measurements)., Results: In each sex, mean BMI-for-age values increased from birth to one year, declined until 5and increased from then onwards. Mean TMI-for-age values decreased abruptly during the first 6years of age and slowly thereafter, in both sexes. Although, at some ages, mean BMI-for age values differed statistically between sexes, differences were scant and of poor clinical significance. The same occurred for TMI-for-age values. BMI-for-age cut-off values to define underweight status (-2 SD) were similar to those proposed by Cole and the WHO for both sexes. However, BMI-for-age cut-off values to define obesity (+2 SD) were lower in both sexes (1.0-5.3) than those proposed by Cole and similar to those proposed by the WHO until 12 in girls and 14 in boys and lower (1.0-4.8) from these ages onwards., Conclusions: BMI-for-age and TMI-for-age values of healthy non-underweight, non-obese millennial children are provided. No clinically relevant differences were observed between sexes. These values may be used to measure underweight status and obesity in present pediatric populations and to evaluate the relationship between BMI-for-age and TMI-for-age in a clinical setting., (Copyright © 2017 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.)

Objectives: To determine the prevalence of urinary incontinence in the elderly Spanish population of both sexes and identify a possible relationship between physical activity habits and the presence of urinary incontinence in the elderly., Material and Methods: We used data from 8146 individuals older than 60 years (age range, 60-94 years), from which data from a 15-year cohort were obtained. Of these, 4745 (58.2%) were women and 3401 (41.8%) were men. We analysed the presence of urinary incontinence, physical activity habits and the influence of other variables such as sex, age, weight and body mass index., Results: We detected a prevalence of urinary incontinence of 15% for the women and 11.6% for the men. Those with urinary incontinence had a greater average age, weight and body mass index than the healthy participants. At the same time, the patient group with incontinence showed more sedentary habits compared with the healthy participants., Conclusions: A strong relationship was observed between the body mass index and prevalence of urinary incontinence. Urinary incontinence was also related to attitudinal aspects such as physical inactivity, a behaviour that predisposes the elderly to developing incontinence. For the first time, we observed a reduction in the prevalence of incontinence compared with previous studies., (Copyright © 2017 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background and Objective: Twin and family studies support large genetic influences on variability in body mass index (BMI), with heritability estimates ranging from 47% to over 90%. Our objective was to study the relative contributions of genetics and environment to BMI, evaluating sex differences, in an adolescent twin sample from Valencia, Spain., Material and Methods: Five hundred eighty-four pairs of adolescent twins between 13 and 18 years of age completed the study (82 monozygotic [MZ] and 87 dizygotic [DZ] pairs of male twins, 118 MZ and 102 DZ pairs of female twins, and 195 opposite-sex pairs of DZ twins). To determine zygosity, teachers responded a questionnaire on physical similarity. They also measured the participant's height and weight. BMI was calculated and weight status was determined according to age. We used twin models to assess genetic and environmental (common and unique) factors affecting BMI., Results: There was a 7.1% frequency of overweight and 2.8% of obesity. The estimated heritability of BMI was 88.0% in boys and 72.1% in girls, with the remaining variance attributable to non-shared environment in boys (12.0%) and 8.8% in girls. It was only in girls that common environment had an effect on BMI., Conclusions: Genetics appears to play an important role in explaining the variability in BMI in the adolescence, with slight variations between boys and girls. Common environmental factors exert their influence on BMI only in girls., (Copyright © 2014 Elsevier España, S.L.U. All rights reserved.)

Background and Objective: Little information exists about the prognostic impact of body mass index (BMI) in the elderly with acute coronary syndromes (ACS). We aimed to prospectively assess the association between BMI and midterm mortality in consecutive elderly patients with ACS., Patients and Method: We included consecutive ACS patients aged 75 years or older admitted to the Coronary Care Unit. Patients were stratified into 5 BMI subgroups (<20, 20-24.9, 25-29.9, 30-35, > 35 kg/m(2)). Primary endpoint was overall midterm mortality. Analyses were performed by Cox regression method., Results: During the study period 600 patients were admitted, of whom 579 had known BMI values. Low weight patients (BMI<20 kg/m(2)) were older, with higher prevalence of vasculopathy and lower creatinine clearance. Median follow up was 315 days. Patients with BMI< 20 kg/m(2) had higher mortality as compared to the rest of groups. Adjusted analysis showed an attenuation of these differences, while maintaining significance for the groups of BMI 20-24.9 and 30-35 kg/m(2)., Conclusions: The association between BMI and mortality was mainly due to worse prognosis in low weight patients. Prospective assessment of comorbidities and other variables linked to ageing should contribute to better understand the association between BMI and mortality., (Copyright © 2014 Elsevier España, S.L.U. All rights reserved.)

Introduction and Objectives: To analyze the association between higher body mass index and waist circumference, and the prognostic values of both indicators in total and cardiac mortality in patients with chronic heart failure., Methods: The study included 2254 patients who were followed up for 4 years. Obesity was classified as a body mass index ≥30 and overweight as a body mass index of 25.0-29.9. Central obesity was defined as waist circumference ≥88 cm for women and ≥102cm for men. Independent predictors of total and cardiac mortality were assessed in a multivariate Cox model adjusted for confounding variables., Results: Obesity was present in 35% of patients, overweight in 43%, and central obesity in 60%. Body mass index and waist circumference were independent predictors of lower total mortality: hazard ratio=0.84 (P<.001) and hazard ratio=0.97 (P=.01), respectively, and lower cardiac death (body mass index, hazard ratio=0.84, P<.001; waist circumference, hazard ratio=0.97, P=.01). The interaction between body mass index and waist circumference (hazard ratio=1.001, P<.01) showed that the protective effect of body mass index was lost in patients with a waist circumference >120cm., Conclusions: Mortality was significantly lower in patients with a high body mass index and waist circumference. The results also showed that this protection was lost when these indicators over a certain limit., (Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.)

Background and Objectives: El Bierzo area is characterized by low urinary iodine levels in the pregnant population. Guidelines recommend that local reference values are established for the diagnosis of thyroid dysfunction in pregnancy. Our objectives were to establish reference values for thyroid-stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) in women in the first trimester of pregnancy and to explore the factors influencing variability in these hormones., Patients and Methods: A retrospective study of 412 women in the first trimester of pregnancy who were measured serum levels of TSH, FT4, and FT3; 163 women with conditions with a potential influence on thyroid function were excluded. Thirty smoking pregnant women were also excluded from the study of reference values. Factors examined in the variability study included age, body mass index (BMI), and smoking. A multifactorial analysis of covariance was performed., Results: Reference values in first-trimester pregnant women were: TSH: 0.497-3.595 mIU/L; FT4: 0.90-1.42 ng/dL; FT3: 2.49-3.56 pg/mL. TSH levels depended on mother age and on interaction between age and smoking. FT3 levels depended on the mother's BMI and smoking, and there was also an interaction between both factors., Conclusion: The reference values found may be used to assess thyroid dysfunction in pregnant women from El Bierzo. TSH and FT3 levels are influenced by age and BMI of the mother and by smoking, in addition to the interaction of these factors., (Copyright © 2013 SEEN. Published by Elsevier Espana. All rights reserved.)