Maternal body composition, HIV infection and other predictors of gestation length and birth size in Zimbabwe

The role of maternal infections, nutritional status and obstetric history in low birth weight is not clear. Thus, the objective of the present study was to assess the effects of maternal HIV infection, nutritional status and obstetric history, and season of birth on gestation length and birth size. The study population was 1669 antenatal care attendees in Harare, Zimbabwe. A prospective cohort study was conducted as part of a randomised, controlled trial. Maternal anthropometry, age, gravidity, and HIV status and load were assessed in 22nd-35th weeks gestation. Outcomes were gestation length and birth size. Birth data were available from 1106 (66.3%) women, of which 360 (32.5%) had HIV infection. Mean gestation length was 39.1 weeks with 16.6% <37 weeks, mean birth weight was 3030 g with 10.5% <2500 g. Gestation length increased with age in primigravidae, but not multigravidae (interaction, P=0.005), and birth in the early dry season, low arm fat area, multiple pregnancies and maternal HIV load were negative predictors. Birth weight increased with maternal height, and birth in the late rainy and early dry season; primi-secundigravidity, low arm fat area, HIV load, multiple pregnancies and female sex were negative predictors. In conclusion, gestation length and birth weight decline with increasing maternal HIV load. In addition, season of birth, gravidity, maternal height and body fat mass, and infant sex are predictors of birth weight.     

Genetic and environmental influences on the tracking of body size from birth to early adulthood

OBJECTIVE: This study identified genetic and environmental influences on the tracking of body size from birth to 16 to 18.5 years of age. RESEARCH METHODS AND PROCEDURES: Longitudinal information was collected from a nationally representative sample of Finnish twin adolescents (birth cohorts 1975 to 1979) and their parents through questionnaires mailed when the twins were ages 16 and 18.5 years old. The sample included 702 monozygotic, 724 same-sex dizygotic, and 762 opposite-sex dizygotic sets of twins. The measures used were length, weight, ponderal index (kilograms per cubic meters), and gestational age at birth, and height, weight, and body mass index (kilograms per square meters) at 16 to 18.5 years of age. The changes in genetic and environmental influences on body size from birth to early adulthood were analyzed by quantitative genetic modeling. RESULTS: The twins who had a higher weight or ponderal index at birth were taller and heavier in early adulthood, whereas those who were longer at birth were taller, but not heavier, later in life. Adult height was affected more by the birth size than body mass index. In the genetic modeling analyses, the genetic factors accounting for the variation of body size became more apparent with age, and both genetic and environmental influences on stature had a sizable carry-over effect from birth to late adolescence, whereas for relative weight, the influences were more age-specific. DISCUSSION: The genetic and environmental architecture of body size changes from birth to adulthood. Even in monozygotic twins who share their genetic background, the initially larger twin tended to remain larger, demonstrating the long-lasting effects of fetal environment on final body size.     

Tracking of body size from birth to late adolescence: contributions of birth length, birth weight, duration of gestation, parents' body size, and twinship.

Birth weight has correlated positively with adult body mass index (BMI), but rarely have birth length, duration of gestation, or parents' body size been taken into account. The authors examined tracking of birth length and weight, adjusted for gestational age, to late adolescence, with special reference to parents' height and BMI. Longitudinal information from a nationally representative sample of Finnish twin adolescents (birth cohorts 1975-1979) and their parents was collected via questionnaires mailed when the twins were aged 16 years (n = 4,376; 2,062 males, 2,314 females) and 18 years (n = 3,917; 1,742 males, 2,175 females). The twins showed significant tracking of body size from birth to late adolescence, which was greatly influenced by their parents' body size. Height in adolescence was predicted by length and weight at birth and by parents' height, whereas BMI was predicted by birth weight and parents' BMI. An especially high risk for overweight was found for subjects of average length but a high weight at birth. These findings suggest that the intrauterine period has enduring effects on later body size but leave unresolved whether these effects are genetic or environmental.     

Maternal and cord blood hormones in relation to birth size

Birth size has been associated with adult life diseases, but the endocrine factors that are likely involved are not established. We evaluated the associations of maternal and cord blood hormones with birth size in normal pregnancies, and examined possible effect modification by maternal height, on the basis of prior suggestive evidence. In a prospective study of normal singleton pregnancies in Boston, USA and Shanghai, China, maternal hormone levels at the 27th gestational week were available for 225 pregnancies in Boston and 281 in Shanghai and cord blood measurements for 92 pregnancies in Boston and 110 in Shanghai. Pearson partial correlation coefficients of log-transformed hormone levels with birth weight and length were calculated. Overall, positive correlations with birth weight were found for maternal estriol (r = 0.19; p < 0.001) and progesterone (r = 0.15; p < 0.001) and these associations were more evident among taller mothers. There was an inverse association of cord blood progesterone (r = ?0.16; p < 0.03) with birth weight. In Boston, cord blood IGF-1 was positively associated with birth weight (r = 0.22; p < 0.04) and length (r = 0.25; p < 0.02), particularly among taller mothers (r = 0.43 and 0.38, respectively; p < 0.02), whereas among taller mothers in Shanghai the associations of IGF-2 with birth size appeared to be at least as strong as those of IGF-1. In conclusion, maternal estriol and progesterone, and cord blood IGF-1 were positively correlated with birth size. All correlations tended to be more pronounced among offspring of taller mothers. Among taller mothers in Shanghai, IGF-2 appeared to be at least as strongly associated with birth size as IGF-1.     

Giving birth, going home: influences on when low-income women leave hospital

The US Newborns' and Mothers' Health Protection Act of 1996 ('The Two-Day Law') mandates insurance coverage for women who have just given birth to remain in hospital for two days post-partum. However, many women are being discharged from hospital after 24 hours. To assess why early discharge is still occurring, a study of 406 new mothers was conducted at an urban metropolitan hospital in the USA. The women were aware of the new law (95%) but decision making was often relinquished to hospital authorities. Patients who stayed longer tended to be more assertive in decision making, and used the Two-Day Law as leverage in discussions about going home. The study concluded that the nurses were authoritative and often influential agents in the decision-making process, and that patients were likely to interpret specific interactions with hospital staff as a signal to leave.     

Revisiting the interaction between birth weight and current body size in the foetal origins of adult disease

The four models proposed for exploring the foetal origins of adult disease (FOAD) hypothesis use the product term between size at birth and current size to determine the relative importance of pre- and post-natal growth on disease in later life. This is a common approach for testing the interaction between an exposure (in this instance size at birth) and an effect modifier (in this instance current size)—incorporating the product term obtained by multiplying the exposure and effect modifier variables within a statistical regression model. This study examines the mathematical basis for this approach and uses computer simulations to demonstrate two potential statistical flaws that might generate misleading findings. The first of these is that the expected value of the partial regression coefficient for the product term (between exposure and effect modifier) will be zero when the outcome, exposure and effect modifier are all continuously distributed and follow a multivariate normal distribution. This is because testing the product interaction term amounts to testing for multivariate normality among the three variables, irrespective of the pair-wise correlations amongst them. The second flaw is that it is possible to generate a statistically significant interaction between exposure and effect modifier, even when none exists, simply by categorising either or both of these variables. These flaws pose a serious challenge to the four models approach proposed for exploring the FOAD hypothesis. The interaction between exposure and effect modifier variables should be interpreted with caution both here and elsewhere in epidemiological analyses.     

Maternal care and birth outcomes among ethnic minority women in Finland

Background

Chronic obstructive pulmonary disease (COPD) is a health problem that is becoming increasingly attended-to in Primary Care (PC). However, there is a scarcity of health-care programs and studies exploring the implementation of Clinical Practice Guidelines (CPG). The principal objective of the present study is to evaluate the effectiveness of a combined strategy directed towards health-care professionals and patients to improve the grade of clinical control and the quality-of-life (QoL) of the patients via a feedback on their state-of-health. A training plan for the health-care professionals is based on CPG and health education.

Method/Design

Multi-centred, before-after, quasi experimental, prospective study involving an intervention group and a control group of individuals followed-up for 12 months. The patients receive attention from urban and semi-urban Primary Care Centres (PCC) within the administrative area of the Costa de Ponent (near Barcelona). All the pacients corresponding to the PCC of one sub-area were assigned to the intervention group and patients from the rest of sub-areas to the group control. The intervention includes providing data to the health-care professionals (clinician/nurse) derived from a clinical history and an interview. A course of training focused on aspects of CPG, motivational interview and health education (tobacco, inhalers, diet, physical exercise, physiotherapy). The sample random includes a total of 801 patients (≥ 40 years of age), recorded as having COPD, receiving attention in the PCC or at home, who have had at least one clinical visit, and who provided written informed consent to participation in the study. Data collected include socio-demographic characteristics, drug treatment, exacerbations and hospital admissions, evaluation of inhaler use, tobacco consumption and life-style and health-care resources consumed. The main endpoints are dyspnoea, according to the modified scale of the Medical Research Council (MRC) and the QoL, evaluated with the St George's Respiratory Questionnaire (SGRQ). The variables are obtained at the start and the end of the intervention. Information from follow-up visits focuses on the changes in life-style activities of the patient.

Discussion

This study is conducted with the objective of generating evidence that shows that implementation of awareness programs directed towards health-care professionals as well as patients in the context of PC can produce an increase in the QoL and a decrease in the disease exacerbation, compared to standard clinical practice.

Trial Registration

Clinical Trials.gov Identifier: NCT00922545;     

Maternal care and birth outcomes among ethnic minority women in Finland

Background  

Care during pregnancy and labour is of great importance in every culture. Studies show that people of migrant origin have barriers to obtaining accessible and good quality care compared to people in the host society. The aim of this study is to compare the access to and use of maternity services, and their outcomes among ethnic minority women having a singleton birth in Finland.     

Maternal body mass, proportional weight gain, and fetal growth in parous women

Summary. This study is designed to examine the impact of maternal body mass index (BMI), proportional weight gain, and other variables on fetal growth. From a 10% random sample of 5722 Norwegian and Swedish para one and two women (n = 561), three hundred and sixty-nine women for whom prepregnant weight and height were recorded and for whom four fetal ultrasound measurements were taken at 17,25,33, and 37 weeks of gestation, were divided into low, average, and high body mass index groups (weight/height²). Fetal growth rate (mm/day) was determined by taking the mean of three measurements of the sagital and transverse diameters of the fetal abdomen (MAD) in each of three study time periods: weeks 17 to 25, first period; weeks 25 to 33, second period; weeks 33 to 37, third period. Proportional weight gain (kilograms gained within a specific time period/prepregnant weight) was measured in those same intervals. Fetal growth rate was significantly slower in the first and second periods, and significantly faster in the third time period for women with a low BMI, compared with those of average BMI. Fetal growth also significantly increased with increases in proportional weight gain in the second and third periods, but not in the first. Fetal growth appears to be independently associated with maternal BMI and proportional maternal weight gain.     

Maternal serum concentrations of perfluoroalkyl substances and birth size in British boys

Per- and polyfluoroalkyl substances (PFAS) have been widely used in commercial and industrial manufacturing processes since the 1950s. Inverse associations between prenatal exposure to PFAS and birth size have been found in populations around the globe. This study examined the association of prenatal maternal serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) and birth size in British boys. The study included 457 mother-son dyads participating in the Avon Longitudinal Study of Parents and Children (ALSPAC). Birth weight (g), crown to heel length (cm), and head circumference (cm) were collected at delivery. PFAS were detected in all maternal serum samples during pregnancy (median: 30 weeks gestation (interquartile range: 12–33)). Median concentrations (interquartile range) were 13.8 ng/mL (11.0, 17.7), 3.0 ng/mL (2.3, 3.8), 1.9 ng/mL (1.4, 2.5), and 0.4 ng/mL (0.3, 0.5) for PFOS, PFOA, PFHxS, and PFNA, respectively. In multivariable linear regression models, inverse associations were detected between PFOS (continuous) and birth weight (β = ?8.50 g, 95% CI = ?15.93, ?1.07 g), crown to heel length (β = ?0.04 cm, 95% CI = ?0.08, ?0.01 cm), and head circumference (β = ?0.02 cm, 95% CI = ?0.04, ?0.002 cm). In conclusion, prenatal exposure to high levels of PFOS may be associated with reduced birth size in male infants.     

Maternal activity in relation to birth size in rural India. The Pune Maternal Nutrition Study

OBJECTIVE: To describe the relationship of the mother's physical activity to the birth size of her baby in a rural Indian population. DESIGN:: Prospective observational study. SETTING: Six villages near Pune, Maharashtra, India. SUBJECTS:: A total of 797 women were studied after excluding abortions and termination of pregnancies (112), foetal anomalies (8), multiple pregnancies (3), incomplete pre-pregnancy anthropometry (14) and pregnancies detected later than 21 weeks of gestation (168). METHOD: An activity questionnaire was developed after focus group discussions and incorporated community-specific activities. It was validated against an observer-maintained diary. Activity scores were derived using published data on energy costs to weight the contributions of various activities. It was then administered to assess physical activity at 18 (+/-2) and 28 (+/-2) weeks of gestation. OUTCOME MEASURES: Birth outcome, maternal weight gain and neonatal anthropometry. RESULTS: The activity questionnaire was used to classify women into light, moderate and heavy activity categories. Maternal activity did not influence the incidence of prematurity or stillbirth, or the duration of gestation. It was inversely related to maternal weight gain up to 28 weeks of gestation (P=0.002). Higher maternal activity in early, as well as mid gestation, was associated with lower mean birth weight (P=0.05 and 0.02, respectively ), and smaller neonatal head circumference (P=0.005 and 0.009) and mid-arm circumference (P=0.03 and 0.01) after adjusting for the effect of major confounding factors. CONCLUSIONS: The Findings suggest that excessive maternal activity during pregnancy is associated with smaller foetal size in rural India, The approach described for developing an activity questionnaire has potential for adoption in other settings.     

Maternal body composition in relation to infant birth weight and subcutaneous adipose tissue

Infant birth weight has increased recently, representing an obstetric and potentially a public health problem since high birth weight involves a risk of obesity later in life. Maternal nutritional status is important for fetal growth and therefore relationships between maternal body weight and composition v. birth weight and infant subcutaneous adipose tissue were investigated in twenty-three healthy women and their newborn infants using multiple and simple linear regression analysis. Furthermore, using previously published data for nineteen infants, it was demonstrated that an anthropometric method could provide useful estimates of the amount of subcutaneous adipose tissue. Birth weight was correlated with the maternal content of total body fat (TBF) both before pregnancy and in gestational week 32 and, together with gestational age at birth, TBF (%) before pregnancy explained 45% of the variation in birth weight. This figure was not increased when gestational gains in weight or TBF were added to the model. Furthermore, in infants, birth weight correlated with the amount of their subcutaneous adipose tissue. Together maternal TBF (%) and amount of subcutaneous adipose tissue in infants explained 61-63% of the variation in birth weight while the amount of infant subcutaneous adipose tissue alone explained only 55%. The maternal TBF content is likely to be important for the recent increase in birth weight. This factor probably causes a general augmentation in fetal growth rather than a specific stimulation of adipose tissue growth.     

Poor agreement between self-reported birth weight and birth weight from original records in adult women

Data from an ongoing prospective population study of women in G?teborg, Sweden, were used to assess agreement between self-reported birth weight and birth weight obtained from original delivery records of women aged 44-60 years. Of the eligible population with traced delivery records (n = 693), only 28% (n = 192) could report their own birth weight. Spearman correlation between self-reported birth weight and birth weight from original records was r = 0.76. However, a difference plot, with limits of agreement at -1,028 to 1,038 g (95% confidence limits: lower limit, -1,157 to -901 g, upper limit, 910 to 1,166 g) revealed poor agreement between methods. Of the self-reported birth weights, 53% were in error by 250 g or more, and 31% were positively or negatively discordant by 500 g or more. Application in an analysis of cardiovascular risk factors in adulthood found conflicting results between self-reported and recorded birth weights. Low reporting rate, poor reporting accuracy, and misleading findings in application led to the conclusion that self-reported birth weights from middle-aged women would not be a satisfactory replacement for birth weights from original records.     

青岛市成人双生子体型指征的遗传度研究

目的探讨遗传因素对体质指数(BMI)和腰臀围比值(WHR)等体型指征的影响程度。方法青岛地区自愿参加本研究的496对24周岁及以上的双生子。在卵型鉴定的基础上。应用Mx软件构建结构方程模型分析遗传度。结果估计体质指数的遗传度为76％，男、女性分别为33％，74％；腰臀围比值的遗传度为62％，男、女性分别为0．12％，74％。结论在体型指征的相关指标中，BMI和WHR均受遗传因素影响较大。其中，女性的BMI和WHR受遗传因素的影响可能大于环境因素；男性体质指数受环境因素影响大于遗传因素，腰臀围比值则可能不受遗传因素影响。