Fetal position
Decelerated Early Growth in Infants of Overweight and Obese Mothers
Katie Larson Ode et al.
Journal of Pediatrics, forthcoming
Objective: To investigate the relationship between maternal prepregnancy body mass index and early infant growth and body composition.
Study design: Prospective cohort study performed at a university hospital/surrounding community. Ninety-seven nondiabetic mothers with singleton, term, healthy infants completed study visits at 2 weeks and 3 months of age. Before pregnancy, 59 mothers were normal weight, 18 were overweight, and 20 were obese. Infant anthropometrics and body composition via air-displacement plethysmography were measured. Infant feeding information and maternal prepregnancy weight were self-reported. Additional data were obtained via self-report and the medical record. Main outcome measures were change in weight, length, fat-free mass, and fat mass from 2 weeks to 3 months of age. Analysis was done via multivariate linear regression.
Results: At 2 weeks, anthropometrics and body composition did not differ across maternal body mass index groups. At 3 months, infants of overweight or obese mothers had gained less weight (P = .02), grew less in length (P = .01), and gained less fat mass (P = .01). Adjustment for breastfeeding status and regression to the mean via conditional change variables did not alter the results. The results were not altered after adjusting for maternal glucose values from a 50-g glucose challenge and for maternal smoking in a subset including 80% of the women.
Conclusions: Maternal overweight/obesity is associated with early deceleration in linear growth and adipose tissue accrual; replication of these findings is needed.
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Income, the Earned Income Tax Credit, and Infant Health
Hilary Hoynes, Douglas Miller & David Simon
NBER Working Paper, July 2012
Abstract:
This paper evaluates the health impact of a central piece in the U.S. safety net for families with children: the Earned Income Tax Credit. Using tax-reform induced variation in the federal EITC, we examine the impact of the credit on infant health outcomes. We find that increased EITC income reduces the incidence of low birth weight and increases mean birth weight. For single low education (<= 12 years) mothers, a policy-induced treatment on the treated increase of $1000 in EITC income is associated with 6.7 to 10.8% reduction in the low birth weight rate, with larger impacts for births to African American mothers. These impacts are evident with difference-in-difference models and event study analyses. Our results suggest that part of the mechanism for this improvement in birth outcomes is the result of more prenatal care and less negative health behaviors (smoking). We find little role for changes in health insurance. We contribute to the literature by establishing that an exogenous increase in income can improve health, and illustrating a health impact of a non-health program. More generally, we demonstrate the potential for positive external benefits of the social safety net.
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Eugenic Selection Benefits Embryos
Mark Walker
Bioethics, forthcoming
Abstract:
The primary question to be addressed here is whether pre-implantation genetic diagnosis (PGD), used for both negative and positive trait selection, benefits potential supernumerary embryos. The phrase ‘potential supernumerary embryos' is used to indicate that PGD is typically performed on a set of embryos, only some of which will be implanted. Prior to any testing, each embryo in the set is potentially supernumerary in the sense that it may not be selected for implantation. Those embryos that are not selected, and hence destroyed or frozen, are ‘actually supernumerary'. The argument to be advanced is hypothetical: If embryos may be said to benefit or be harmed by our actions, then PGD used to select for an embryo or embryos with the highest expected Wellbeing benefits potential supernumerary embryos. The argument shows that the ‘non-identity' problem is not sufficient to show that eugenic selection does not benefit supernumerary embryos.
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Temporal Changes in Socioeconomic Influences on Health: Maternal Education and Preterm Birth
Abdulrahman El-Sayed & Sandro Galea
American Journal of Public Health, September 2012, Pages 1715-1721
Objectives: To consider how the relationships between social determinants and health indicators change over time, we assessed the time-varying influence of maternal education on risk of preterm birth (PTB) between 1989 and 2006.
Methods: We used bivariate and multivariable Poisson regression models with robust variation estimates to examine (1) the association between maternal education and PTB risk by year; (2) the relationship between low maternal education and PTB, late PTB, and very PTB risk by year relative to 1989; and (3) the relationship between high maternal education and PTB, late PTB, and very PTB risk by year relative to 1989.
Results: After adjustment, PTB risk increased among the most educated and did not change among the least educated women over time. Risk of PTB among the least educated relative to the most educated women decreased with time. Late PTB risk increased among both the most and the least educated groups but more among the most educated.
Conclusions: Maternal education may be becoming less protective against PTB. The influence of the social determinants of health is dynamic, warranting revisions of our understanding of their roles over time.
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Acculturation, Maternal Cortisol, and Birth Outcomes in Women of Mexican Descent
Kimberly D'Anna-Hernandez et al.
Psychosomatic Medicine, April 2012, Pages 296-304
Objective: This study investigated the effects of acculturation on cortisol, a biological correlate of maternal psychological distress, and perinatal infant outcomes, specifically gestational age at birth and birth weight.
Methods: Fifty-five pregnant women of Mexican descent were recruited from a community hospital, and their saliva samples were collected at home for 3 days during pregnancy at 15 to 18 weeks (early), 26 to 32 weeks (mid), and more than 32 weeks (late) of gestation and once in the postpartum period (4-12 weeks). These values were used to determine the diurnal cortisol slope at each phase of pregnancy. Mothers also completed an acculturation survey and gave permission for a medical chart review to obtain neonate information.
Results: Multiple regression analyses determined that greater acculturation levels significantly predicted earlier infant gestational age at birth (R2 = 0.09, p = .03). Results from t tests revealed that mothers of low-birth-weight infants (<2500 g) had significantly higher acculturation scores than mothers of infants with birth weight greater than 2500 g (t = -2.95, p = .005). A blunted maternal cortisol slope during pregnancy was also correlated with low birth weight (r = -0.29, p = .05) but not gestational age (r = -0.08, p = .59). In addition, more acculturated women had a flatter diurnal cortisol slope late in pregnancy (R2 = 0.21, p = .01). Finally, diurnal maternal cortisol rhythms were identified as a potential mediator between increased acculturation and birth weight.
Conclusions: This study associated increased acculturation with perinatal outcomes in the US Mexican population. This relationship may be mediated by prenatal maternal diurnal cortisol, which can program the health of the fetus leading to several adverse perinatal outcomes.
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Claudia Snijder et al.
Occupational & Environmental Medicine, forthcoming
Objectives: Work-related risk factors, such as long work hours, and physically demanding work have been suggested to adversely influence pregnancy outcome. The authors aimed to examine associations between various aspects of physically demanding work with fetal growth in different trimesters during pregnancy and the risks of adverse birth outcomes.
Methods: Associations between physically demanding work and fetal growth were studied in 4680 pregnant women participating in a population-based prospective cohort study from early pregnancy onwards in the Netherlands (2002-2006). Mothers who filled out a questionnaire during mid-pregnancy (response 77% of enrolment) were included if they conducted paid employment and had a spontaneously conceived singleton live born pregnancy. Questions on physical workload were obtained from the Dutch Musculoskeletal Questionnaire and concerned questions on lifting, long periods of standing or walking, night shifts and working hours. Fetal growth characteristics were repeatedly measured by ultrasound and were used in combination with measurements at birth.
Results: There were no consistent significant associations between physically demanding work nor working hours in relation to small for gestational age, low birth weight or preterm delivery. Women exposed to long periods of standing had lower growth rates for fetal head circumference (HC), resulting in a reduction of approximately 1 cm (3%) of the average HC at birth. Compared with women working <25 h/week, women working 25-39 h/week and >40 h/week had lower growth rates for both fetal weight and HC, resulting in a difference of approximately 1 cm in HC at birth and a difference of 148-198 g in birth weight.
Conclusion: Long periods of standing and long working hours per week during pregnancy seem to negatively influence intrauterine growth.
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Selma Bouthoorn et al.
PLoS ONE, June 2012
Objective: Head circumference (HC) reflect growth and development of the brain in early childhood. It is unknown whether socioeconomic differences in HC are present in early childhood. Therefore, we investigated the association between socioeconomic position (SEP) and HC in early childhood, and potential underlying factors.
Methods: The study focused on Dutch children born between April 2002 and January 2006 who participated in The Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. Maternal educational level was used as indicator of SEP. HC measures were concentrated around 1, 3, 6 and 11 months. Associations and explanatory factors were investigated using linear regression analysis, adjusted for potential mediators.
Results: The study included 3383 children. At 1, 3 and 6 months of age, children of mothers with a low education had a smaller HC than those with a high education (difference at 1 month: -0.42 SD; 95% CI: -0.54,-0.30; at 3 months: -0.27 SD; 95% CI -0.40,-0.15; and at 6 months: -0.13 SD; 95% CI -0.24,-0.02). Child's length and weight could only partially explain the smaller HC at 1 and 3 months of age. At 6 months, birth weight, gestational age and parental height explained the HC differences. At 11 months, no HC differences were found.
Conclusion: Educational inequalities in HC in the first 6 months of life can be mainly explained by pregnancy-related factors, such as birth weight and gestational age. These findings further support public health policies to prevent negative birth outcomes in lower socioeconomic groups.
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Most French Teenagers Who Obtain Abortions Had Been Using Contraceptives Before Conceiving
D. Hollander
Perspectives on Sexual and Reproductive Health, forthcoming
"Data from the first nationally representative survey of abortion patients in France, conducted in 2007, reveal that nine in 10 teenagers who had an abortion that year were terminating an unplanned pregnancy; two-thirds had been using a contraceptive method during the month in which they conceived."
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Ethnic differences in the accumulation of fat and lean mass in late gestation
Michelle Lampl et al.
American Journal of Human Biology, September/October 2012, Pages 640-647
Objectives: Lower birth weight within the normal range predicts adult chronic diseases, but the same birth weight in different ethnic groups may reflect different patterns of tissue development. Neonatal body composition was investigated among non-Hispanic Caucasians and African Americans, taking advantage of variability in gestational duration to understand growth during late gestation.
Methods: Air displacement plethysmography assessed fat and lean body mass among 220 non-Hispanic Caucasian and 93 non-Hispanic African American neonates. The two ethnic groups were compared using linear regression.
Results: At 36 weeks of gestation, the average lean mass of Caucasian neonates was 2,515 g vs. that of 2,319 g of African American neonates (difference, P = 0.02). The corresponding figures for fat mass were 231 and 278 g, respectively (difference, P = 0.24). At 41 weeks, the Caucasians were 319 g heavier in lean body mass (P < 0.001) but were also 123 g heavier in fat mass (P = 0.001). The slopes for lean mass vs. gestational week were similar, but the slope of fat mass was 5.8 times greater (P = 0.009) for Caucasian (41.0 g/week) than for African American neonates (7.0 g/week).
Conclusions: By 36 weeks of gestation, the African American fetus developed similar fat mass and less lean mass compared with the Caucasian fetus. Thereafter, changes in lean mass among the African American fetus with increasing gestational age at birth were similar to the Caucasian fetus, but fat accumulated more slowly. We hypothesize that different ethnic fetal growth strategies involving body composition may contribute to ethnic health disparities in later life.
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Abdullah Mamun et al.
PLoS ONE, July 2012
Background: Maternal smoking during pregnancy is associated with offspring obesity. However, little is known about whether maternal smoking in pregnancy predicts other offspring cardiovascular risk factors including waist circumference (WC), waist-hip-ratio (WHR), pulse rate (PR), systolic (SBP), and diastolic blood pressure (DBP).
Methods: We studied a sub-sample of 2038 (50% males) young adults who were born in Brisbane, Australia to investigate the prospective association of maternal smoking during pregnancy with young adult cardiovascular risk factors. We compared offspring mean BMI, WC, WHR, SBP, DBP and PR and the risk of being overweight and obese at 21 years by three mutually exclusive categories of maternal smoking status defined as never smoked, smoked before and/or after pregnancy but not in pregnancy or smoked during pregnancy and other times.
Results: Offspring of mothers who smoked during pregnancy had greater mean BMI, WC, WHR and PR and they were at greater risk of being obese at 21 years compared to offspring of those mothers who never smoked. The mean of these risk factors among those adult offspring whose mothers stopped smoking during pregnancy, but who then smoked at other times in the child's life, were similar to those mothers who never smoked. These results were independent of a range of potential confounding factors.
Conclusion: The findings of this study suggest a prospective association of maternal smoking during pregnancy and offspring obesity as well as PR in adulthood, and reinforce the need to persuade pregnant women not to smoke.
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Birth timing and the mother-infant relationship predict variation in infant behavior and physiology
Jessica Vandeleest, Sally Mendoza & John Capitanio
Developmental Psychobiology, forthcoming
Abstract:
The current study explored whether birth timing, known to influence the mother-infant relationship, also affected infant physiology up to 9 months later and infant behavior at weaning. Infant blood samples were collected at 5.75 and 8.75 months of age to assess functioning of the hypothalamic-pituitary-adrenal axis as well as the antibody response to a Cholera vaccination. Path analysis indicated infants born late in the birth season had less Relaxed relationships with their mothers. A less-Relaxed relationship was associated with greater infant Positive Engagement and Distress, which were negatively correlated, suggesting infants may have different strategies of coping with this type of relationship. Low Relaxed scores were also associated with higher infant cortisol concentrations at 5.75 months, which was associated with a reduced immune response to a vaccination 3 months later. Together these results indicate that the influence of birth timing on the mother-infant relationship may have consequences for infant development.
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S. Leppälahti et al.
Human Reproduction, September 2012, Pages 2829-2836
Study question: What are the current trends in teenage termination of pregnancy (TOP) and its risk factors?
Summary answer: The incidence of teenage TOP fluctuated substantially during the study period and the incidence of repeat TOP among adolescents increased markedly in the 2000s.
What is known already: Teenage pregnancy is associated with difficulties in psychological, sexual and overall health. The proportion of teenage pregnancies resulting in termination varies by country and time, but only few countries have reliable statistics on TOPs.
Study design, size, duration: This nationwide retrospective register study included all the TOPs (n= 52 968) and deliveries (n= 58 882) in Finland between 1987 and 2009 among girls <20 years of age at the beginning of pregnancy.
Participants/materials, setting, methods: The cohorts were divided into three subgroups; 13-15- (n= 6087), 16-17- (n= 18 826) and 18-19- (n= 28 055) year-olds.
Main results and the role of chance: After an initial steady decline, the incidence of teenage TOP increased by 44% between 1993 (8.0/1000) and 2003 (11.5/1000), and thereafter declined by 16% until 2009 (9.7/1000). The incidence was higher in older adolescents, but the trends were alike in all age groups. Early TOPs (performed at <56 days of gestation) more than tripled from 11 to 36% during the study period. However, the proportion of second-trimester TOPs remained steady at ∼7%. Young age [13-15 years: odds ratio (OR) 1.75 (95% confidence interval (CI) 1.57-1.94), 16-17 years: OR 1.13 (1.05-1.23), 18-19 years: OR 1 (reference category)] and non-use of contraception [(OR 11.16 (10.15-12.27)] were related to a higher risk of second-trimester TOP. The incidence of repeat TOP increased by 95% from 1.9/1000 to 3.7/1000 in 18-19-year-olds and by 120% from 0.5/1000 to 1.1/1000 in 16-17-year-olds between 1993 and 2009. Increasing age [13-15 years: OR 0.16 (95% CI 0.14-0.19), 16-17 years: OR 0.49 (0.45-0.52), 18-19 years 1 (Ref)], living in an urban area [rural: OR 0.62 (0.56-0.67), urban: OR 1 (Ref)] and having undergone a second-trimester TOP [OR 1.46 (1.31-1.63)] were risk factors for repeat TOP. The planned use of intrauterine contraception for post-abortal contraception increased from 2.6 to 6.2% and among girls with repeat TOP from 10 to 19%.
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Abortion, Time-Relative Interests, and Futures Like Ours
Peter Nichols
Ethical Theory and Moral Practice, August 2012, Pages 493-506
Abstract:
Don Marquis (1989) has argued most abortions are immoral, for the same reason that killing you or me is immoral: abortion deprives the fetus of a valuable future (FLO). Call this account the FLOA. A rival account is Jeff McMahan's (2002), time-relative interest account (TRIA) of the wrongness of killing. According to this account, an act of killing is wrong to the extent that it deprives the victim of future value and the relation of psychological unity would have held between the victim at the time of death and herself at a later time if she had lived. The TRIA supposedly has two chief advantages over Marquis's FLOA. First, unlike the FLOA, the TRIA does not rely on the controversial thesis that identity is what matters in survival. Second, the TRIA yields more plausible verdicts about cases. Proponents of the TRIA use the account to argue that abortion is generally permissible, because there would be little to no psychological unity between the fetus and later selves if it lived. I argue that advocates of the TRIA have failed to establish its superiority to the FLOA, for two reasons. First, the two views are on a par with respect to the thesis that identity is what matters in survival. Second, Marquis's FLOA does not yield the counterintuitive implications about cases that advocates of the TRIA have attributed to it, and the TRIA yields its own share of implausible judgments about cases.
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Lavinia Gordon et al.
Genome Research, August 2012, Pages 1395-1406
Abstract:
Comparison between groups of monozygotic (MZ) and dizygotic (DZ) twins enables an estimation of the relative contribution of genetic and shared and nonshared environmental factors to phenotypic variability. Using DNA methylation profiling of ∼20,000 CpG sites as a phenotype, we have examined discordance levels in three neonatal tissues from 22 MZ and 12 DZ twin pairs. MZ twins exhibit a wide range of within-pair differences at birth, but show discordance levels generally lower than DZ pairs. Within-pair methylation discordance was lowest in CpG islands in all twins and increased as a function of distance from islands. Variance component decomposition analysis of DNA methylation in MZ and DZ pairs revealed a low mean heritability across all tissues, although a wide range of heritabilities was detected for specific genomic CpG sites. The largest component of variation was attributed to the combined effects of nonshared intrauterine environment and stochastic factors. Regression analysis of methylation on birth weight revealed a general association between methylation of genes involved in metabolism and biosynthesis, providing further support for epigenetic change in the previously described link between low birth weight and increasing risk for cardiovascular, metabolic, and other complex diseases. Finally, comparison of our data with that of several older twins revealed little evidence for genome-wide epigenetic drift with increasing age. This is the first study to analyze DNA methylation on a genome scale in twins at birth, further highlighting the importance of the intrauterine environment on shaping the neonatal epigenome.
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Maternal choline intake alters the epigenetic state of fetal cortisol-regulating genes in humans
Xinyin Jiang et al.
Journal of the Federation of American Societies for Experimental Biology, August 2012, Pages 3563-3574
Abstract:
The in utero availability of methyl donors, such as choline, may modify fetal epigenetic marks and lead to sustainable functional alterations throughout the life course. The hypothalamic-pituitary-adrenal (HPA) axis regulates cortisol production and is sensitive to perinatal epigenetic programming. As an extension of a 12-wk dose-response choline feeding study conducted in third-trimester pregnant women, we investigated the effect of maternal choline intake (930 vs. 480 mg/d) on the epigenetic state of cortisol-regulating genes, and their expression, in placenta and cord venous blood. The higher maternal choline intake yielded higher placental promoter methylation of the cortisol-regulating genes, corticotropin releasing hormone (CRH; P=0.05) and glucocorticoid receptor (NR3C1; P=0.002); lower placental CRH transcript abundance (P=0.04); lower cord blood leukocyte promoter methylation of CRH (P=0.05) and NR3C1 (P=0.04); and 33% lower (P=0.07) cord plasma cortisol. In addition, placental global DNA methylation and dimethylated histone H3 at lysine 9 (H3K9me2) were higher (P=0.02) in the 930 mg choline/d group, as was the expression of select placental methyltransferases. These data collectively suggest that maternal choline intake in humans modulates the epigenetic state of genes that regulate fetal HPA axis reactivity as well as the epigenomic status of fetal derived tissues.
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Qian Long et al.
Social Science & Medicine, August 2012, Pages 733-737
Abstract:
The epidemic of Caesarean section (CS) is worldwide, and it has been argued that it is mainly due to non-medical factors, including healthcare financing patterns. We investigated the use of CS in rural China and the related factors, particularly health insurance in the form of the New Co-operative Medical Scheme introduced in 2003. A cross-sectional survey of women who gave birth in 2008-2009 was conducted in five rural counties in central and western China. Of the 5049 new mothers, 73% were interviewed. The association between health insurance coverage and self-reported CS (divided into emergency and non-emergency CS) were examined by cross-tabulation and logistic regression, adjusting for maternal age, education, occupation, household income, previous abortions, parity and type of birth health facility. We found that 46% of all births (3550) were CSs, with 13% having an emergency and 33% a non-emergency CS. Women reported that half of the non-emergency CSs were recommended by a doctor and half were requested by themselves. In those counties with mid-range CS rates (28%-63%), health insurance coverage was associated with having CS, and particularly with having non-emergency CS. In those counties with the highest (82%) and lowest (13%) rate, there was no statistically significant association. The findings suggest that health insurance coverage may have facilitated the overuse of CS. Further studies are needed to develop appropriate interventions to reduce non-medically indicated CS, focusing on payment mechanisms, healthcare provider practice patterns, and maternal requests.