Direct standardization method according to Robson classification for comparison of cesarean rates.

Background: Compare cesarean section rates between populations or within a population over time using the crude measure is biased mainly due to differences in the characteristics of the obstetric population. The Robson Ten Group Classification (RTGC) is being widely used all over the world based on a few basic obstetrics variables.

Objectives: Propose a method of direct standardization according to RTGC to make the overall rates of cesarean sections comparable between different populations or within the same population over time.

Longitudinal association of 25-hydroxyvitamin D with adipokines and markers of glucose metabolism among Brazilian pregnant women.

This study aimed to evaluate the longitudinal association of vitamin D status with glycaemia, insulin, homoeostatic model assessment of insulin resistance, adiponectin and leptin. A prospective cohort with 181 healthy, pregnant Brazilian women was followed at the 5th-13th, 20th-26th and 30th-36th gestational weeks. In this cohort, 25-hydroxyvitamin D (25(OH)D) plasma concentrations were analysed using liquid chromatography-tandem MS.

Sleep duration of 24 h is associated with birth weight in nulli- but not multiparous women.

Objectives: This study aimed to evaluate the association between nightly, napping, and 24-h sleep duration throughout pregnancy and birth weight z-score among nulli- and multiparous women.

Methods: Nightly,napping, and 24-h sleep duration and birth weight z-score (calculated on thebasis of the International Fetal and Newborn Growth Consortium for the 21st century standards) were studied in a cohort of 176 pregnant women from Brazil. Linear mixed-effect analyses were performed to assess the longitudinal evolution of sleep duration and the best unbiased linear predictors of the random coefficients were estimated.

Association between plasma concentrations of vitamin D metabolites and depressive symptoms throughout pregnancy in a prospective cohort of Brazilian women.

Plasma concentrations of vitamin D metabolites can be inversely associated with depressive symptoms. However, few longitudinal studies have investigated this association, especially during pregnancy. The aim of this study was to investigate the association between concentrations of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxivitamin D [1,25(OH)D] with the occurrence of depressive symptoms throughout pregnancy.

Maternal lipids and leptin concentrations are associated with large-for-gestational-age births: a prospective cohort study.

The change in maternal lipid, leptin and adiponectin concentrations during pregnancy and infant birth weight (BW) is still poorly characterized. Thus, the aim of the study was to evaluate the association of maternal lipids, leptin and adiponectin throughout pregnancy with large-for-gestational-age (LGA) births and BW z-score. A prospective cohort of 199 mothers was followed during pregnancy in Rio de Janeiro, Brazil.

Changes in plasma concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D during pregnancy: a Brazilian cohort.

Purpose: To characterize the physiological changes in 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)D] throughout pregnancy.

Methods: Prospective cohort of 229 apparently healthy pregnant women followed at 5th-13th, 20th-26th, and 30th-36th gestational weeks. 25(OH)D and 1,25(OH)D concentrations were measured by LC-MS/MS.

Prepregnancy Dietary Patterns Are Associated with Blood Lipid Level Changes During Pregnancy: A Prospective Cohort Study in Rio de Janeiro, Brazil.

Background: Physiologic adaptations lead to an increase in blood lipid levels during pregnancy, yet little is known about the influence of prepregnancy dietary patterns.

Aim: To identify whether prepregnancy dietary patterns that explain the consumption of fiber, energy, and saturated fat are associated with blood lipid levels throughout pregnancy.

Design: Prospective cohort study, with data collection at gestational weeks 5 to 13, 20 to 26, and 30 to 36.

Maternal C-reactive protein concentrations during pregnancy and birth weight in a prospective cohort in Rio de Janeiro, Brazil.

Objective: To evaluate the association between maternal C-reactive protein (CRP) concentrations during pregnancy and birth weight (BW) Z-score.

Methods: A prospective cohort of pregnant women were followed at 5-13 (n = 203), 20-26 (n = 181), and 30-36 (n = 181) gestational weeks and at 30-45 d postpartum. Maternal CRP concentrations were assessed three times during pregnancy using immunoturbidimetric methods (ultra-sensitive kits).

Changes in Maternal Plasma Adiponectin from Late Pregnancy to the Postpartum Period According to the Mode of Delivery: Results from a Prospective Cohort in Rio de Janeiro, Brazil.

Introduction: Maternal plasma adiponectin is inversely related to insulin resistance, atherosclerosis and child health. However, little is known about its concentrations in the perinatal period, especially according to mode of delivery. Our aim is to evaluate the association between mode of delivery and changes in maternal plasma adiponectin from 3rd trimester of pregnancy to 30-45 days postpartum.

Dietary intake variations from pre-conception to gestational period according to the degree of industrial processing: A Brazilian cohort.

Objective: To estimate food intake changes from pre-conception to gestational period according to the degree of food processing.

Methods: Prospective cohort conducted in a public health care center in Rio de Janeiro with Brazilian pregnant women (n = 189). A food frequency questionnaire was applied at the first (5(th)-13(th)) and third (30(th)-36(th)) gestational trimesters.

Factors associated with maternal serum C-reactive protein throughout pregnancy: A longitudinal study in women of Rio de Janeiro, Brazil.

Objectives: The aim of this study was to evaluate the longitudinal changes of C-reactive protein (CRP) concentrations during pregnancy and to assess whether socioeconomic, anthropometric, dietary, behavioral, and biochemical factors are associated with these changes.

Methods: This was a prospective cohort study of 115 adult pregnant women, followed at gestational weeks 5 to 13, 20 to 26, and 30 to 36. Serum concentrations of CRP (mg/L) were measured by the immunoturbidimetric method with ultrasensitive kits (sensitivity 0.

Blood pressure in healthy pregnancy and factors associated with no mid-trimester blood pressure drop: a prospective cohort study.

Background: The well-known mid-trimester drop in blood pressure (BP) during normal pregnancy was recently questioned.

Objective: To describe longitudinal changes in BP during healthy pregnancies and to investigate factors associated with no mid-trimester drop in BP.

Methods: A prospective cohort with 158 healthy pregnant women was followed up in a public health care center in Rio de Janeiro, Brazil.

Plasma adiponectin is inversely associated with antenatal anxiety: Results from a Brazilian cohort.

Antenatal anxiety may increase the risk of undesirable birth outcomes. Studies have demonstrated an association between adiponectin and anxiety, but this issue has not been investigated during pregnancy. This study aimed to evaluate the association between plasma adiponectin, measured throughout gestation, and the occurrence of anxiety at late pregnancy (30-36th weeks).

Prepregnancy healthy dietary pattern is inversely associated with depressive symptoms among pregnant Brazilian women.

Dietary patterns before pregnancy may be associated with depressive symptomatology during pregnancy. The aim of this study was to identify dietary patterns before pregnancy and to examine the association between these dietary patterns and depressive symptoms during pregnancy. A prospective cohort of 248 healthy pregnant women were followed at 5-13, 20-26, and 30-36 gestational weeks.

Factors associated with prospective leptin concentrations throughout pregnancy in pregestational normal weight, overweight and obese women.

Background: Leptin concentrations increase throughout pregnancy but little is known about factors that influence this physiological change and whether they differ according to pregestational body mass index (BMI).

Objective: To assess whether longitudinal trends of leptin in pregnancy are influenced by biochemical, anthropometric and lifestyle factors in women with normal weight (NW), overweight (OW) or obese (OB) pregestational BMI.

Design And Methods: Prospective cohort of 232 pregnant women followed at 5-13th, 20-26th and 30-36th gestational weeks.

Television viewing and abdominal obesity in women according to smoking status: results from a large cross-sectional population-based study in Brazil.

Objective: To investigate the associations between television viewing and abdominal obesity (AO) in Brazilian women, according to smoking status.

Methods: Data of 13,262 adult women (18-49 years) from the 2006's Demographic Health Survey, a cross-sectional household study with complex probabilistic sample and national representativeness, were analyzed. AO, defined as waist circumference ≥ 80.

C-reactive protein and later preeclampsia: systematic review and meta-analysis taking into account the weight status.

Objectives: This study aims to determine whether high C-reactive protein (CRP) concentration during pregnancy is associated with later preeclampsia and whether weight status (BMI) is a potential modifier of the relation between CRP and preeclampsia.

Methods: Twenty-three studies were included in a systematic literature review and a subset of 18 in a meta-analysis. Weighted mean difference (WMD) [with their 95% confidence intervals (CI)] of CRP in preeclampsia and control groups was the estimator.

Low leptin concentration in the first gestational trimester is associated with being born small for gestational age: prospective study in Rio de Janeiro, Brazil.

Background: Being born small for gestational age (SGA) is a known risk factor for greater neonatal mortality and disease in later life. Some determinants of the incidence of SGA newborns have been studied but little is known about the role of leptin in the beginning of pregnancy.

Objectives: To investigate the effect of serum leptin concentration in the 1st gestational trimester on the incidence of SGA newborns and to identify other determining factors in the occurrence of SGA.