Birth weight and cognitive function in the British 1946 birth cohort: longitudinal population based study

Association of cord plasma metabolites with birth weight: results from metabolomic and lipidomic studies of discovery and validation cohorts

OBJECTIVE

Birth weight is a good predictor of fetal intrauterine growth and long-term health, and several studies have evaluated the relationship between metabolites and birth weight. The aim of this study was to investigate the association of cord blood metabolomics and lipidomics with birth weight, using a two-stage discovery and validation approach.

METHODS

Firstly, a pseudotargeted metabolomics approach was applied to detect metabolites in 504 cord blood samples in the discovery set enrolled from the Wuhan Healthy Baby Cohort, China. Metabolome-wide association scan analysis and pathway enrichment were applied to identify metabolites and metabolic pathways that were significantly associated with birth weight adjusted for gestational age Z-score (BW Z-score). Logistic regression models were used to analyze the association of metabolites in the most significantly associated pathways with small-for-gestational age (SGA) at delivery and low birth weight (LBW). Subsequently, 350 cord blood samples in a validation cohort were subjected to targeted analysis to validate the metabolites identified by screening in the discovery cohort.

RESULTS

In the discovery set, of 2566 metabolites detected, 2418 metabolites were retained for subsequent analysis after data preprocessing. Of these, 513 metabolites were significantly associated with BW Z-score (P-value adjusted for false discovery rate (PFDR) < 0.05), of which 298 Kyoto Encyclopedia of Genes and Genomes (KEGG)-annotated metabolites were included in the pathway analysis. The primary bile acid biosynthesis pathway was the most relevant metabolic pathway associated with BW Z-score. Elevated cord plasma primary bile acids were associated with lower BW Z-score and higher risk of SGA or LBW in the discovery and validation cohorts. In the validation set, a 2-fold increase in taurochenodeoxycholic acid (TCDCA) and in taurocholic acid (TCA) was associated with a decrease in BW Z-score (estimated β coefficient, -0.10 (95% CI, -0.20 to 0.00) and -0.18 (95% CI, -0.31 to -0.04), respectively), after adjusting for covariates. In addition, a 2-fold increase in cord plasma TCDCA and of cord plasma TCA was associated with an increased risk of SGA (adjusted odds ratio (OR), 1.52 (95% CI, 1.00-2.30) and 1.77 (95% CI, 1.05-2.98), respectively). The adjusted OR for LBW, for a 2-fold increase in TCDCA and TCA concentration, were 2.39 (95% CI, 1.00-5.71) and 3.21 (95% CI, 0.96-10.74), respectively.

CONCLUSIONS

These results indicate a significant association of elevated primary bile acids, particularly TCDCA and TCA, in cord blood with lower BW Z-score, as well as increased risk of SGA and LBW. Abnormalities of primary bile acid metabolism may play an important role in restricted fetal development. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Reassuring pregnancy outcomes in women with mild COL4A3-5-related disease (Alport syndrome) and genetic type of disease can aid personalized counseling

Individualized pre-pregnancy counseling and antenatal care for women with chronic kidney disease (CKD) require disease-specific data. Here, we investigated pregnancy outcomes and long-term kidney function in women with COL4A3-5 related disease (Alport Syndrome, (AS)) in a large multicenter cohort. The ALPART-network (mAternaL and fetal PregnAncy outcomes of women with AlpoRT syndrome), an international collaboration of 17 centers, retrospectively investigated COL4A3-5 related disease pregnancies after the 20th week. Outcomes were stratified per inheritance pattern (X-Linked AS (XLAS)), Autosomal Dominant AS (ADAS), or Autosomal Recessive AS (ARAS)). The influence of pregnancy on estimated glomerular filtration rate (eGFR)-slope was assessed in 192 pregnancies encompassing 116 women (121 with XLAS, 47 with ADAS, and 12 with ARAS). Median eGFR pre-pregnancy was over 90ml/min/1.73m2. Neonatal outcomes were favorable: 100% live births, median gestational age 39.0 weeks and mean birth weight 3135 grams. Gestational hypertension occurred during 23% of pregnancies (reference: 'general' CKD G1-G2 pregnancies incidence is 4-20%) and preeclampsia in 20%. The mean eGFR declined after pregnancy but remained within normal range (over 90ml/min/1.73m2). Pregnancy did not significantly affect eGFR-slope (pre-pregnancy β=-1.030, post-pregnancy β=-1.349). ARAS-pregnancies demonstrated less favorable outcomes (early preterm birth incidence 3/11 (27%)). ARAS was a significant independent predictor for lower birth weight and shorter duration of pregnancy, next to the classic predictors (pre-pregnancy kidney function, proteinuria, and chronic hypertension) though missing proteinuria values and the small ARAS-sample hindered analysis. This is the largest study to date on AS and pregnancy with reassuring results for mild AS, though inheritance patterns could be considered in counseling next to classic risk factors. Thus, our findings support personalized reproductive care and highlight the importance of investigating kidney disease-specific pregnancy outcomes.

Assessing cognitive function in longitudinal studies of ageing worldwide: some practical considerations

Over 55 million people live with dementia worldwide. With 40% of modifiable risk factors estimated to contribute to dementia, the potential for prevention is high, and preventive measures, at an early stage of cognitive decline, are likely to positively influence future dementia trends. Countries need reliable health data and adequate measurement tools to quantify, monitor and track early changes in cognitive capacity in the general population. Many cognitive tests exist; however, there is no consensus to date about which instruments should be employed, and important variations in measurement have been observed. In this narrative review, we present a number of cognitive tests that have been used in nationally representative population-based longitudinal studies of ageing. Longitudinal panel studies of ageing represent critical platforms towards capturing the process of cognitive ageing and understanding associated risk and protective factors. We highlight optimal measures for use at a population level and for cross-country comparisons, taking into consideration instrument reliability, validity, duration, ease of administration, costs, literacy and numeracy requirements, adaptability to sensory and fine motor impairments and portability to different cultural and linguistic milieux. Drawing upon the strengths and limitations of each of these tests, and the experience gained and lessons learnt from conducting a nationally representative study of ageing, we indicate a comprehensive battery of tests for the assessment of cognitive capacity, designed to facilitate its standardised operationalisation worldwide.

Association between urinary iodine excretion, genetic disposition and fluid intelligence in children, adolescents and young adults: the DONALD study

PURPOSE

Iodine deficiency increases the risk of cognitive impairment and delayed physical development in children. It is also associated with cognitive impairment in adults. Cognitive abilities are among the most inheritable behavioural traits. However, little is known about the consequences of insufficient postnatal iodine intake and whether the individual genetic disposition modifies the association between iodine intake and fluid intelligence in children and young adults.

METHODS

The cultural fair intelligence test was used to assess fluid intelligence in the participants of the DONALD study (n = 238; mean age, 16.5 [SD = 7.7] years). Urinary iodine excretion, a surrogate iodine intake marker, was measured in 24-h urine. Individual genetic disposition (n = 162) was assessed using a polygenic score, associated with general cognitive function. Linear regression analyses were conducted to determine whether Urinary iodine excretion was associated with fluid intelligence and whether this association was modified by individual genetic disposition.

RESULTS

Urinary iodine excretion above the age-specific estimated average requirement was associated with a five-point higher fluid intelligence score than that below the estimated average requirement (P = 0.02). The polygenic score was positively associated with the fluid intelligence score (β = 2.3; P = 0.03). Participants with a higher polygenic score had a higher fluid intelligence score.

CONCLUSION

Urinary iodine excretion above the estimated average requirement in childhood and adolescence is beneficial for fluid intelligence. In adults, fluid intelligence was positively associated with a polygenic score for general cognitive function. No evidence showed that the individual genetic disposition modifies the association between Urinary iodine excretion and fluid intelligence.

Altitude Modifies the Effect of Parity on Birth Weight/Length Ratio: A Study Comprising 2,057,702 Newborns between 1984 and 2020 in Austria

(1) Background: Lower birth weight among newborns in higher altitudes has been well documented in previous literature. Several possible causes for this phenomenon have been investigated, including biophysiological adaptation, epigenetic or genetic mechanisms or lifestyle changes. This is the first study to show the effect modification of altitude and parity on the birth weight length ratio (BWLR) in women resident in moderate altitudes compared to a low sea level.; (2) Methods: This population-based study obtained data on altitude (0-300, 300-500, 500-700,700-900, >900 m), parity (1, 2, …, 7, 8/9), birth weight and length on all births in Austria between 1984 and 2020 from birth certificates provided by Statistics Austria. The BWLR was calculated, and the effect of moderate altitude and parity was estimated using multivariable linear mixed models adjusting for predefined variables. Sub-group regression analyses were conducted by altitude group. (3) Results: Data on 2,057,702 newborns from 1,280,272 mothers were analyzed. The effect of parity on BWLR, as indicated by the difference of BWLR between the first- and second-born infants, ranged between 1.87 to 2.09 g per centimeter across all altitude groups. Our analyses found that the effect of parity on BWLR diminished from parity three onwards at altitude 0-300, whilst the effect of parity on BWLR continued to increase at higher than 300 m and was most notable in the highest altitude group >900 m. (4) Conclusions: Findings from our study indicated that the negative effect of increasing altitude on BWLR was deprived for newborns of higher parity. It shows that the residential altitude can modify the effect of parity on BWLR.

Speech-Encoding Deficits in Neonates Born Large-for-Gestational Age as Revealed With the Envelope Frequency-Following Response

OBJECTIVES

The present envelope frequency-following response (FFRENV) study aimed at characterizing the neural encoding of the fundamental frequency of speech sounds in neonates born at the higher end of the birth weight continuum (>90th percentile), known as large-for-gestational age (LGA).

DESIGN

Twenty-five LGA newborns were recruited from the maternity unit of Sant Joan de Déu Barcelona Children's Hospital and paired by age and sex with 25 babies born adequate-for-gestational age (AGA), all from healthy mothers and normal pregnancies. FFRENVs were elicited to the/da/ syllable and recorded while the baby was sleeping in its cradle after a successful universal hearing screening. Neural encoding of the stimulus' envelope of the fundamental frequency (F0ENV) was characterized through the FFRENV spectral amplitude. Relationships between electrophysiological parameters and maternal/neonatal variables that may condition neonatal neurodevelopment were assessed, including pregestational body mass index (BMI), maternal gestational weight gain and neonatal BMI.

RESULTS

LGA newborns showed smaller spectral amplitudes at the F0ENV compared to the AGA group. Significant negative correlations were found between neonatal BMI and the spectral amplitude at the F0ENV.

CONCLUSIONS

Our results indicate that in spite of having a healthy pregnancy, LGA neonates' central auditory system is impaired in encoding a fundamental aspect of the speech sounds, namely their fundamental frequency. The negative correlation between the neonates' BMI and FFRENV indicates that this impaired encoding is independent of the pregnant woman BMI and weight gain during pregnancy, supporting the role of the neonatal BMI. We suggest that the higher adipose tissue observed in the LGA group may impair, via proinflammatory products, the fine-grained central auditory system microstructure required for the neural encoding of the fundamental frequency of speech sounds.

Adulthood cognitive trajectories over 26 years and brain health at 70 years of age: findings from the 1946 British Birth Cohort

Few studies can address how adulthood cognitive trajectories relate to brain health in 70-year-olds. Participants (n = 468, 49% female) from the 1946 British birth cohort underwent 18F-Florbetapir PET/MRI. Cognitive function was measured in childhood (age 8 years) and across adulthood (ages 43, 53, 60-64 and 69 years) and was examined in relation to brain health markers of β-amyloid (Aβ) status, whole brain and hippocampal volume, and white matter hyperintensity volume (WMHV). Taking into account key contributors of adult cognitive decline including childhood cognition, those with greater Aβ and WMHV at age 70 years had greater decline in word-list learning memory in the preceding 26 years, particularly after age 60. In contrast, those with smaller whole brain and hippocampal volume at age 70 years had greater decline in processing search speed, subtly manifest from age 50 years. Subtle changes in memory and processing speed spanning 26 years of adulthood were associated with markers of brain health at 70 years of age, consistent with detectable prodromal cognitive effects in early older age.

Birth anthropometry among three Asian racial groups in Singapore: proposed new growth charts

OBJECTIVE

We analysed birth anthropometry of babies of Chinese, Malay and Indian ancestry living in Singapore with an aim to develop gestational age (GA) and gender-specific birth anthropometry charts and compare these with the widely used Fenton charts.

DESIGN

Retrospective observational study.

SETTING

Department of Neonatology, National University Hospital, Singapore.

POPULATION

We report data from 52 220 infants, born between 1991-1997 and 2010-2017 in Singapore.

METHODS

Anthropometry charts were built using smoothened centile curves and compared with Fenton's using binomial test. Birth weight (BW), crown-heel length and head circumference (HC) were each modelled with maternal exposures using general additive model.

MAIN OUTCOME MEASURES

BW, crown-heel length and HC.

RESULTS

There were 22 248 Chinese (43%), 16 006 Malay (31%) and 8543 Indian (16%) babies. Mean BW was 3103 g (95% CI 3096 to 3109), 3075 g (95% CI 3067 to 3083) and 3052 g (95% CI 3041 to 3062) for Chinese, Malays and Indians, respectively. When exposed to a uniform socioeconomic environment, intrauterine growth and birth anthropometry of studied races were almost identical. From our GA-specific anthropometric charts until about late prematurity, Asian growth curves mirrored that of Fenton's; thereafter, Asian babies showed a reduction in growth velocity.

CONCLUSIONS

These findings suggest that Asian babies living in relatively uniform socioeconomic strata exhibit similar growth patterns. There is a slowing of growth among Asian babies towards term, prompting review of existing birth anthropometry charts. The proposed charts will increase accuracy of identification of true fetal growth restriction as well as true postnatal growth failure in preterm infants when applied to the appropriate population.

Partnership, living arrangements, and low birth weight: evidence from a population-based study on Spanish mothers

BACKGROUND

Birth weight is considered a crucial indicator of individual and population health, as it determines a newborn's growth and development. An extensive body of research has explored various determinants of perinatal health, including the impact of living arrangements. This population-based study analyzes the relationship between mothers' partnership status and household structure and children's low birth weights. It addresses two basic research objectives: on one hand, how living/not living in a couple affects birth weight; on the other, how partnership status impact on birthweight when mothers live in extended households with other non-nuclear members.

METHODS

A novel database provided by the Spanish Office for National Statistics (INE), which links the 2011 census with births registered from 2011 to 2015 (sample size 22,433) is used. Llogistic regression models are estimated tto obtain adjusted odds ratios (OR) for the relative effects of living arrangements and other covariates such as characteristics of births and mothers' socioeconomic profiles, on birth weight.

RESULTS

Differences in low-birth-weight rates may be attributed to the dissimilar socio-demographic characteristics of the groups of mothers in the different coresidential situations. Although our models revealed that the impact of the covariates on birth weight was similar to that shown by previous studies, this was not the case for the effect of the main explanatory variable. Contrary to expectations, the presence/absence of a male partner in nuclear or in extended households does not reveal significant protection against low birth weight. Children born in households in which the male partner was absent were not more likely to have a low birth weight. On the other hand, analyzing the possible protective effect of extended households, we did not detect significant differences in the likelihood of low birth weight between single mothers without and with non-nuclear coresidents in their households.

CONCLUSIONS

Our analysis provides novel evidence regarding the effect of partnership status and household type on perinatal health in Spain. First, contrary to what has been observed in previous studies in Spain and elsewhere, our study shows that living without a partner has no effect on low birth weight. Second, we reveal that households including non-nuclear coresidents are associated with low birth weight suggesting that even in a basically familist societal context such as the Spanish one, the extended family does not fully protect against poor perinatal outcomes.

Maternal exposure to black carbon and nitrogen dioxide during pregnancy and birth weight: Using machine-learning methods to achieve balance in inverse-probability weights

BACKGROUND

Low birth weight is associated with increased risks of health problems in infancy and later life. Among the epidemiological analyses suggesting an association between air pollution and birth weight, few have estimated the effects of black carbon (BC) or together with nitrogen dioxide (NO₂), and even fewer studies have used causal modelling.

METHODS

We examined 1,119,011 birth records between 2001/01/01 and 2015/12/31 from the Massachusetts Birth Registry to investigate causal associations between prenatal exposure to BC and NO₂ and birth weight. We calculated mean residential BC and NO₂ exposures 0-30, and 31-280 days prior to birth from validated spatial-temporal models. We fit generalized propensity score models with gradient boosting tuned by a new algorithm to achieve covariate balance, then fit marginal structural models with stabilized inverse-probability weights.

RESULTS

Throughout pregnancy, the average birth weight would drop by 17.0 g (95% CI: 15.4, 18.6) for an IQR increase of 0.14 μg/m³ in BC and would independently drop by 19.9 g (95% CI: 18.6, 21.3) for an IQR increase of 9.8 ppb in NO₂. Most of the negative effects of BC on birth weight are from 0 to 30 days before the delivery date. The estimated odds ratio of low birth weight for every IQR increase during the entire pregnancy was 1.131 (95% CI: 1.106, 1.156) for BC and 1.082 (95% CI: 1.062, 1.103) for NO₂.

CONCLUSIONS

We found that prenatal exposures to both BC and NO₂ were associated with lower birth weight.

Prevalence, predictors of low birth weight and its association with maternal iron status using serum ferritin concentration in rural Eastern Ethiopia: a prospective cohort study

Introduction

Low birth weight (LBW) is one of the major predictors of perinatal survival, infant morbidity, and mortality, as well as the risk of developmental disabilities and illnesses in future lives. The effect of the nutritional status of pregnant women on birth outcomes is becoming a common research agenda, but evidence on the level of low birth weight (LBW) and its association with prenatal iron status in Ethiopia, particularly among rural residents, is limited. Thus, this study aimed to assess the prevalence, predictors of LBW, and its association with maternal iron status using serum ferritin concentration in Haramaya district, eastern Ethiopia, 2021.

Methods

A community-based prospective cohort study design was conducted. Of a total of 427 eligible pregnant women followed until birth, 412 (96.48%) were included in the final analysis. Iron status was determined using serum ferritin (SF) concentration from venous blood collected aseptically from the ante-cubital veins analyzed on a fully automated Cobas e411 (German, Japan Cobas 4000 analyzer series) immunoassay analyzer. Iron deficiency(ID) and iron deficiency anemia (IDA) were classified as having SF less than 15 μg/L and SF less than 15 μg/L and Hb level of < 11.0 g/dl during the first or third trimester or < 10.5 g/dl during the second trimester as well, respectively. Birthweight was measured within 72 h of birth and < 2500 g was considered LBW. Birthweight was measured within 72 h of birth and < 2500 g was considered as LBW. A Poisson regression model with robust variance estimation was used to investigate the factors associated with LBW and the association between maternal iron status and LBW. An adjusted prevalence ratio with a 95% confidence interval was reported to show an association using a p-value < 0.05.

Results

About 20.2% (95% CI: 16%-24%) of neonates were born with LBW. The prevalence of LBW was 5.04 (95% CI = 2.78–9.14) times higher among women who were iron deficient during pregnancy compared to those who were normal. The neonates of women who were iron deficient during pregnancy had lower birth weight (aPR=5.04; 95% CI = 2.78–9.14) than the neonates of women who were normal. Prevalence of LBW was higher among mothers who were undernourished (MUAC < 23cm) (aPR = 1.92; 95% CI= 1.33–2.27), stunted (height <145cm) (aPR=1.54; 95% CI=1.04–2.27) and among female neonates (aPR=3.70; 95% CI= 2.28–6.00). However, women who were supplemented with iron and folic acid (IFAS) during pregnancy had a 45% decreased chance of delivering low birth weight (aPR= 0.55; 95% CI=0.36–0.84).

Conclusion

We found that LBW is of public health significance in this predominantly rural setting. ID during pregnancy is found to have a negative effect on birth weight. IFA supplementation, the maternal under-nutrition, height, and sex of neonates were identified as predictors of low weight at birth. To improve maternal nutritional status, health interventions must address targeted strategies promoting desirable food behavior and nutritional practices. These include; promoting the consumption of diversified and rich iron food to improve the maternal nutritional status. A continued effort is needed in enhancing universal access and compliance with IFA supplementation to improve maternal health. Intervention strategies that are complementary and comprehensive across the vulnerable periods for women during pregnancy and their neonates that are based on a life-cycle approach are suggested.

Associations between prenatal exposure to volatile organic compounds and neurodevelopment in 12-month-old children: The Japan Environment and Children's Study (JECS)

In recent years, there has been an increase in the number of problems associated with neurodevelopmental disorders in children, and there has been a growing interest in the relationship between environmental chemicals and children's health. The objective of this study was to examine whether an association exists between occupational or environmental prenatal maternal exposure to volatile organic compounds and the risk of neurodevelopmental disorders in children using Japanese translations of the Ages & Stages Questionnaires, Third Edition (J-ASQ-3). An increase in the risk of neurodevelopmental delay in 12-month-old children associated with maternal exposure to formalin or formaldehyde was identified in terms of problem-solving (odds ratio (OR): 1.76, 95% confidence interval (CI): 0.99-3.12) and personal-social skills (OR: 3.32, 95% CI: 1.46-7.55). It is not clear whether or not this tendency is reversible, and whether it is observed past 12 months of age. Further research and a preventive approach are needed.

The association between birth weight and proxy-reported health-related quality of life among children aged 5 - 10 years old: A linked data analysis

Background

Birth weight has a substantial effect on children’s cognitive development, physical capability, and emotional development, which in turn impact on Health-Related Quality of Life (HRQoL). Generally, evidence indicates that children born with low birth weight tend to have poorer proxy-reported HRQoL, particularly at school age. However, there is limited evidence on whether variation in HRQoL exists across the entire range of possible birth weights. This study aimed to examine the association between birth weight and proxy-reported HRQoL among children aged 5–10 years old.

Methods

Data from the 1973–78 cohort of the Australian Longitudinal Study on Women’s Health were linked with state-based Perinatal Data Collections and the Mothers and their Children’s Health study for 1,589 mothers and 2,092 children aged 5 − 10 years old. Generalized estimating equations were used to model the association between birth weight and proxy-reported HRQoL measured by the Pediatric Quality of Life Inventory 4.0. Results are presented as odds ratios with 95 % confidence intervals.

Results

In this study, 15.61 % of children were at risk of impaired proxy-reported HRQoL. Each 100-gram increase in birth weight was associated with a 3 % reduction in the odds of impaired HRQoL (AOR = 0.97; 95 % CI: 0.94, 0.99). However, there was only limited evidence of an effect within the normal birth weight range (AOR = 0.97; 95 % CI: 0.94, 1.01).

Conclusions

The findings indicate that increased birth weight was protective against impaired HRQoL, although there was limited evidence of variability within the normal birth weight range. This study contributes to the existing literature by not only emphasizing the impact of low birth weight on children’s health and health-related outcomes but also by focusing on the variability within the normal birth weight range, particularly in a setting where low birth weight is less prevalent.

Birth weight and adult earnings: a systematic review and meta-analysis

While substantial evidence has identified low birth weight (LBW; <2500 g) as a risk factor for early life morbidity, mortality and poor childhood development, relatively little is known on the links between birth weight and economic outcomes in adulthood. The objective of this study was to systematically review the economics (EconLit) and biomedical literature (Medline) and estimate the pooled association between birth weight and adult earnings. A total of 15 studies from mostly high-income countries were included. On average, each standard deviation increase in birth weight was associated with a 2.75% increase in annual earnings [(95% CI: 1.44 to 4.07); 9 estimates]. A negative, but not statistically significant, association was found between being born LBW and earnings, compared to individuals not born LBW [mean difference: -3.41% (95% CI: -7.55 to 0.73); 7 estimates]. No studies from low-income countries were identified and all studies were observational. Overall, birth weight was consistently associated with adult earnings, and therefore, interventions that improve birth weight may provide beneficial effects on adult economic outcomes.

Relationship between changing malaria burden and low birth weight in sub-Saharan Africa: A difference-in-differences study via a pair-of-pairs approach

Background

According to the World Health Organization (WHO), in 2018, an estimated 228 million malaria cases occurred worldwide with most cases occurring in sub-Saharan Africa. Scale-up of vector control tools coupled with increased access to diagnosis and effective treatment has resulted in a large decline in malaria prevalence in some areas, but other areas have seen little change. Although interventional studies demonstrate that preventing malaria during pregnancy can reduce the rate of low birth weight (i.e. child's birth weight <2500 g), it remains unknown whether natural changes in parasite transmission and malaria burden can improve birth outcomes.

Methods

We conducted an observational study of the effect of changing malaria burden on low birth weight using data from 18,112 births in 19 countries in sub-Saharan African countries during the years 2000-2015. Specifically, we conducted a difference-in-differences study via a pair-of-pairs matching approach using the fact that some sub-Saharan areas experienced sharp drops in malaria prevalence and some experienced little change.

Results

A malaria prevalence decline from a high rate (Plasmodium falciparum parasite rate in children aged 2-up-to-10 (i.e. PfPR2-10) > 0.4) to a low rate (PfPR2-10 < 0.2) is estimated to reduce the rate of low birth weight by 1.48 percentage points (95% confidence interval: 3.70 percentage points reduction, 0.74 percentage points increase), which is a 17% reduction in the low birth weight rate compared to the average (8.6%) in our study population with observed birth weight records (1.48/8.6 ≈ 17%). When focusing on first pregnancies, a decline in malaria prevalence from high to low is estimated to have a greater impact on the low birth weight rate than for all births: 3.73 percentage points (95% confidence interval: 9.11 percentage points reduction, 1.64 percentage points increase).

Conclusions

Although the confidence intervals cannot rule out the possibility of no effect at the 95% confidence level, the concurrence between our primary analysis, secondary analyses, and sensitivity analyses, and the magnitude of the effect size, contribute to the weight of the evidence suggesting that declining malaria burden can potentially substantially reduce the low birth weight rate at the community level in sub-Saharan Africa, particularly among firstborns. The novel statistical methodology developed in this article-a pair-of-pairs approach to a difference-in-differences study-could be useful for many settings in which different units are observed at different times.

Funding

Ryan A. Simmons is supported by National Center for Advancing Translational Sciences (UL1TR002553). The funder had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Bidirectional association of neurodevelopment with growth: a prospective cohort study

BACKGROUND

The study aims to use the cross-lagged model and utilize data from the Born in Shenyang Cohort Study to characterize the bidirectional associations of the term-born infants' neurodevelopment in five domains and physical growth in early life.

METHOD

This study consists of 688 mother-child dyads from the Born in Shenyang Cohort Study. Infants' anthropometric (weight and length) and development in neurological outcomes (Gesell Development Scale) were measured at the age of 6 and 12 months. Cross-lagged analyses and multiple linear regression analyses were used to explore the longitudinal relationships in both directions.

RESULTS

In terms of longitudinal studies, the inverse associations between infants' two skills (gross motor and social behavior) at the age of 6 months with BMI Z -scores at the age of 12 months (gross motor: aβ = - 0.20, 95% CI: - 0.31 to- 0.09; social behavior: aβ = - 0.23, 95% CI: - 0.33 to- 0.13) were found. Conversely, a higher infant Z -scored BMI at the age of 6 months predicted a lower gross motor at the age of 12 months (aβ = - 0.08, 95% CI: - 0.12 to- 0.04). In cross-lagged analyses, an adverse association in both directions between gross motor and Z -scored BMI was observed.

CONCLUSION

We found bidirectional relationships between infants' neurodevelopment of gross motor with physical growth and suggested the term-born infants, who are on the edge of the developmental danger, should not be overlooked.

Feasibility study of assessing the Preclinical Alzheimer Cognitive Composite (PACC) score via videoconferencing

Background

The Preclinical Alzheimer Cognitive Composite (PACC) is a composite score which can detect the first signs of cognitive impairment, which can be of importance for research and clinical practice. It is designed to be administered in person; however, in-person assessments are costly, and are difficult during the current COVID-19 pandemic.

Objective

To assess the feasibility of performing the PACC assessment with videoconferencing, and to compare the validity of this remote PACC with the in-person PACC obtained previously.

Methods

Participants from the HEalth and Ageing Data IN the Game of football (HEADING) Study who had already undergone an in-person assessment were re-contacted and re-assessed remotely. The correlation between the two PACC scores was estimated. The difference between the two PACC scores was calculated and used in multiple linear regression to assess which variables were associated with a difference in PACC scores.

Findings

Of the 43 participants who were invited to this external study, 28 were re-assessed. The median duration in days between the in-person and the remote assessments was 236.5 days (7.9 months) (IQR 62.5). There was a strong positive correlation between the two assessments for the PACC score, with a Pearson correlation coefficient of 0·82 (95% CI 0·66, 0·98). The multiple linear regression found that the only predictor of the PACC difference was the time between assessments.

Interpretation

This study provides evidence on the feasibility of performing cognitive tests online, with the PACC tests being successfully administered through videoconferencing. This is relevant, especially during times when face-to-face assessments cannot be performed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10403-1.

The Association Between High Birth Weight and Long-Term Outcomes-Implications for Assisted Reproductive Technologies: A Systematic Review and Meta-Analysis

Background: Studies have shown that the prevalence of children born with high birth weight or large for gestational age (LGA) is increasing. This is true for spontaneous pregnancies; however, children born after frozen embryo transfer (FET) as part of assisted reproductive technology (ART) also have an elevated risk. In recent years, the practice of FET has increased rapidly and while the perinatal and obstetric risks are well-studied, less is known about the long-term health consequences. Objective: The aim of this systematic review was to describe the association between high birth weight and LGA on long-term child outcomes. Data Sources: PubMed, Scopus, and Web of Science were searched up to January 2021. Exposure included high birth weight and LGA. Long-term outcome variables included malignancies, psychiatric disorders, cardiovascular disease, and diabetes. Study Selection: Original studies published in English or Scandinavian languages were included. Studies with a control group were included while studies published as abstracts and case reports were excluded. Data Extraction: The methodological quality, in terms of risk of bias, was assessed by pairs of reviewers. Robins-I (www.methods.cochrane.org) was used for risk of bias assessment in original articles. For systematic reviews, AMSTAR (www.amstar.ca) was used. For certainty of evidence, we used the GRADE system. The systematic review followed PRISMA guidelines. When possible, meta-analyses were performed. Results: The search included 11,767 articles out of which 173 met the inclusion criteria and were included in the qualitative analysis, while 63 were included in quantitative synthesis (meta-analyses). High birth weight and/or LGA was associated with low to moderately elevated risks for certain malignancies in childhood, breast cancer, several psychiatric disorders, hypertension in childhood, and type 1 and 2 diabetes. Conclusions: Although the increased risks for adverse outcome in offspring associated with high birth weight and LGA represent serious health effects in childhood and in adulthood, the size of these effects seems moderate. The identified risk association should, however, be taken into account in decisions concerning fresh and frozen ART cycles and is of general importance in view of the increasing prevalence in high birthweight babies.

Understanding the cumulative risk of maternal prenatal biopsychosocial factors on birth weight: a DynaHEALTH study on two birth cohorts

Background

There are various maternal prenatal biopsychosocial (BPS) predictors of birth weight, making it difficult to quantify their cumulative relationship.

Methods

We studied two birth cohorts: Northern Finland Birth Cohort 1986 (NFBC1986) born in 1985–1986 and the Generation R Study (from the Netherlands) born in 2002–2006. In NFBC1986, we selected variables depicting BPS exposure in association with birth weight and performed factor analysis to derive latent constructs representing the relationship between these variables. In Generation R, the same factors were generated weighted by loadings of NFBC1986. Factor scores from each factor were then allocated into tertiles and added together to calculate a cumulative BPS score. In all cases, we used regression analyses to explore the relationship with birth weight corrected for sex and gestational age and additionally adjusted for other factors.

Results

Factor analysis supported a four-factor structure, labelled closely to represent their characteristics as ‘Factor1-BMI’ (body mass index), ‘Factor2-DBP’ (diastolic blood pressure), ‘Factor3-Socioeconomic-Obstetric-Profile’ and ‘Factor4-Parental-Lifestyle’. In both cohorts, ‘Factor1-BMI’ was positively associated with birth weight, whereas other factors showed negative association. ‘Factor3-Socioeconomic-Obstetric-Profile’ and ‘Factor4-Parental-Lifestyle’ had the greatest effect size, explaining 30% of the variation in birth weight. Associations of the factors with birth weight were largely driven by ‘Factor1-BMI’. Graded decrease in birth weight was observed with increasing cumulative BPS score, jointly evaluating four factors in both cohorts.

Conclusion

Our study is a proof of concept for maternal prenatal BPS hypothesis, highlighting the components snowball effect on birth weight in two different European birth cohorts.

Facts and hypotheses about the programming of neuroplastic deficits by prenatal malnutrition

Studies in rats have shown that a decrease in either protein content or total dietary calories results in molecular, structural, and functional changes in the cerebral cortex and hippocampus, among other brain regions, which lead to behavioral disturbances, including learning and memory deficits. The neurobiological bases underlying those effects depend at least in part on fetal programming of the developing brain, which in turn relies on epigenetic regulation of specific genes via stable and heritable modifications of chromatin. Prenatal malnutrition also leads to epigenetic programming of obesity, and obesity on its own can lead to poor cognitive performance in humans and experimental animals, complicating understanding of the factors involved in the fetal programming of neuroplasticity deficits. This review focuses on the role of epigenetic mechanisms involved in prenatal malnutrition-induced brain disturbances, which are apparent at a later postnatal age, through either a direct effect of fetal programming on brain plasticity or an indirect effect on the brain mediated by the postnatal development of obesity.

Maternal depressive symptoms and children's cognitive development: Does early childcare and child's sex matter?

BACKGROUND

Maternal depressive symptoms (MDS) have been associated with poorer child cognitive development. Some studies have shown that childcare attendance moderates associations between MDS and child behavior problems, but we do not know if this is the case for children's cognitive development. Furthermore, few studies have evaluated whether associations between MDS and child cognitive development differ for boys and girls at school entry.

METHODS

This study used data from a population-based cohort study (n = 1364) comprising well-validated measures of children's cognitive development including academic readiness and language development in kindergarten and reading and mathematics achievement in first grade. Information on MDS was collected repeatedly from the child's age of 5 months to 5 years and on childcare from 5 months to 4.5 years. Moderation analyses were conducted to evaluate the differential associations of MDS with children's outcomes depending on the type of childcare attended and the child's sex.

RESULTS

Childcare type or child's sex did not moderate associations between MDS and children's cognitive outcomes except for MDS being associated with lower scores on reading achievement in first grade for girls with a very small effect size (sr2 = .003). Childcare attendance was associated with higher scores for children's cognitive development, however these associations disappeared after adjusting for covariates including child, mother and family characteristics. Regardless of MDS and childcare type, boys had, even after adjusting for covariates, lower scores on academic readiness (sr2 = .029) and higher scores on mathematics achievement (sr2 = .004).

CONCLUSIONS

Children's cognitive development at school entry was more strongly associated with maternal education, children's age in kindergarten and number of months of schooling in first grade than MDS. Contrary to associations between MDS and child behavior problems, childcare attendance did not moderate associations between MDS and children's cognitive development at school entry.

Moderate altitude impacts birth weight: 30 years retrospective sibling analyses using record linkage data

OBJECTIVE

We investigated the effect of a change of altitude of maternal living address on infant birth weight.

METHOD

Data on infant birth weights of the first and second pregnancies from same women were extracted from all Austrian birth certificates between 1984 and 2016.

RESULTS

A total of 544,624 pair pregnancies were identified and analyzed. We observed a statistically significant interaction (p < .0001) between altitudes of two births and birth weight. Among women having first birth at low altitude (200 m), the estimated second mean birth weight was 3567 g for those remained at low altitudes, and reduced to 3536 g for those ascended (1200 m). In contrast, among women having first births at high altitudes, the estimated birth weight of second birth at high altitude was 3414 g, yet increased to 3499 g compared to those descended to lower altitudes.

CONCLUSION

We demonstrated a longitudinal negative effect of altitude on birth weight within the same mother from first and second birth. This association is likely to be casual. Relocation of mothers within low-to-medium altitude level may have profound effects on infants' birth weight.

Polygenic risk score for Alzheimer's disease and trajectories of cardiometabolic risk factors in children

Introduction: Cardiometabolic factors are implicated in the aetiology of Alzheimer's disease and may lie on the pathways linking genetic variants to Alzheimer's disease across the life course. We examined whether polygenic risk scores (PRS) were associated with cardiometabolic health indicators through childhood and adolescence. Methods: In 7,977 participants from the Avon Longitudinal Study of Parents and Children, we tested whether a PRS for Alzheimer's disease was associated with trajectories of cardiometabolic risk factors. We examined trajectories for height at 1-18 years; lean and fat mass at 9-18 years; systolic and diastolic blood pressure at 7-18 years; glucose and C-reactive protein at 9-18 years; insulin at 10-18 years; and high and low-density lipoproteins and triglycerides birth at 18 years. We also examined birthweight and interleukin-6 (IL-6) at age 9 years and physical activity at ages 11, 12, and 15 years. Results: No consistent associations were observed between the PRS excluding genetic variants in the apolipoprotein E gene region and cardiometabolic factors trajectories across childhood and adolescence. Conclusions: We did not detect evidence to suggest that the PRS for Alzheimer's disease acts through childhood and adolescent cardiometabolic risk factors. Further studies should examine whether these associations emerge later in adulthood when variation in cardiometabolic risk factors is likely to be greater.

Size at birth and cognitive ability in late life: A systematic review

INTRODUCTION

Recent evidence suggests that growth restriction in utero may lead to neurocognitive disorders in late life, either through impaired brain development or adverse metabolic programming.

METHODS

Systematic review of literature investigating the relationship between size at birth and cognitive abilities in late life. The search, data extraction, and rating for the quality of reporting were conducted independently by two researchers.

RESULTS

Of 533 selected studies, 11 were included in this systematic review and 10 of these were from high-income setting. Of these 11 studies, eight indicated that lower birth weight is a risk factor for lower cognitive function in late life, at least in high-income countries. The reported effect sizes were small and it was not possible to conduct meta-analyses because of clinical heterogeneity DISCUSSION: A modest association of lower birth weight with lower cognitive abilities in late life is consistent with persisting effects of the prenatal environment on brain function. As with all observational studies, confounding is an alternative explanation. Further studies are required to elucidate the mechanisms.

Risk factors for recurrent macrosomia and child outcomes

BACKGROUND

Women who had delivered a macrosomic newborn will have a higher risk to deliver another macrosomia. We aimed to examine the recurrence risk of macrosomia in the subsequent pregnancy and the implications in long-term child health.

METHODS

Data from the Collaborative Perinatal Project, a longitudinal birth cohort with 54,371 singleton births, were used. 401 recurrent macrosomic infants (macro-macro) and 1327 normal weight babies with a macrosomia in the last pregnancy (macro-normal) were selected to explore risk factors for recurrent macrosomia. Furthermore, 768 newly onset macrosomia with normal birthweight infant in previous pregnancies (normal-macro) were identified to examine long-term health effects of recurrent macrosomia.

RESULTS

The recurrent rate of macrosomia was 23.2% [95% confidence interval (CI) 21.2%, 25.2%]. White race, higher pre-pregnant body mass index (BMI), more gestational weight gain, male infant and more prior macrosomic infants were significant risk factors for recurrent macrosomia. At 4 years of age, recurrent macrosomic infants had a higher BMI (16.7 vs. 16.1 kg/m², adjusted β: 0.36, 95% CI: 0.12, 0.60) and a higher risk of overweight and obesity (adjusted OR: 1.56, 95% CI: 1.10, 2.23) than infants with normal birthweight after a previous macrosomic sibling. There was no significant difference between recurrent macrosomia and newly onset macrosomia in child outcomes after adjustment for covariates.

CONCLUSIONS

Fetal macrosomia has a high recurrence rate in the following pregnancy. Higher maternal pre-pregnant BMI and gestational weight gain are still important risk factors for recurrence of macrosomia, which in turn increases the risk for childhood obesity.

Growth parameters at birth mediate the relationship between prenatal manganese exposure and cognitive test scores among a cohort of 2- to 3-year-old Bangladeshi children

Background

Our previous study demonstrated that prenatal manganese exposure is associated with cognitive test scores among a cohort of 2- to 3-year-old Bangladeshi children. This study tested the hypothesis that the adverse effects of manganese are mediated through poor prenatal growth.

Methods

Pregnant mothers were enrolled in a birth cohort in Bangladesh between 2008 and 2011, and children were followed at birth and age 20-40 months. Manganese concentration was measured in umbilical cord blood. Anthropometric measurements (weight, length, head circumference) were assessed at delivery. Children's cognitive development was assessed at age 20-40 months using the Bayley Scales of Infant and Toddler Development-Third Edition. Using recently developed statistical approaches that estimate mediation and interaction effects simultaneously, we evaluated whether the association between cord blood manganese and cognitive score was mediated through anthropometric measures at birth.

Results

This analysis included 764 mother-child pairs. Higher manganese concentration was associated with lower cognitive score [β=-0.61, standard error (SE)=0.23, p = 0.009]. Among the birth measures, we found a significant indirect effect only through birth length (β =-0.10, SE = 0.03, p = 0.001). We also found evidence of mediated interaction (both mediation and interaction, β =-0.03, SE = 0.01, p = 0.01) with birth length in the association between cord blood manganese and cognitive score. The overall proportion mediated by birth length was 33% (p = 0.02) and the proportion attributed to interaction was 11% (p = 0.04). We did not find evidence of a mediating effect through birth weight or head circumference.

Conclusions

Our findings confirm that prenatal growth, particularly birth length, contributes to the overall effect of environmental manganese exposure on a child's cognitive development.

Effects of oral zinc supplementation on zinc status and catch-up growth during the first 2 years of life in children with non-organic failure to thrive born preterm and at term

BACKGROUND

We aimed to analyze the effect of oral zinc supplementation on serum insulin-like growth factor-1 (IGF-1) levels and catch-up growth in infants with non-organic failure to thrive (NOFTT) who were born preterm as compared to those born at term.

METHODS

Totally, 105 NOFTT infants aged 2 years or less were enrolled and divided into two groups according to gestational age at birth. Oral zinc sulfate was administered for 6 months to 49/66 children born at term, and 21/39 children born preterm. Serum zinc, IGF-1, weight, and height were measured at baseline and at 6 months.

RESULTS

There were no differences in baseline serum zinc levels between the two groups. In preterm NOFTT infants, zinc supplementation significantly increased serum zinc levels compared to those in the non-supplementation group (Δ zinc _{0-6 month} 10.3 ± 26.4 μg/dL vs. -8.8 ± 23.7 μg/dL, p = 0.018), but it did not significantly change serum IGF-1 levels or weight- and height for age Z-scores. In NOFTT infants born at term who received zinc supplementation, serum zinc levels, IGF-1, weight for age Z-score, and height for age Z-score increased at 6 months (p = 0.001, p = 0.014, p = 0.049, and p = 0.029, respectively), but this increase was not significantly greater than in the non-supplementation group. Only the increase in serum zinc levels was significant after 6 months (Δ zinc _{0-6 month} 16.8 ± 32.0 μg/dL vs. -10.0 ± 22.6 μg/dL, p = 0.002).

CONCLUSION

Zinc supplementation in NOFTT infants improves serum zinc status, regardless of gestational age at birth. Zinc supplementation in NOFTT infants born at term may improve serum IGF-1 levels and growth, but it does not in NOFTT infants born preterm. Overall nutritional support rather than supplementation of a single nutrient may be more effective for catch-up growth in NOFTT infants born preterm.

Secular changes in the association between advanced maternal age and the risk of low birth weight: A cross-cohort comparison in the UK

Existing studies provide contradictory evidence concerning the association between child health and advanced maternal age. A potential explanation for the lack of consensus on this issue is changes over time in the costs and benefits of giving birth at an advanced age. This is the first study to investigate secular changes in the characteristics of older mothers and in the association between advanced maternal age and child health. We use data from four UK cohort studies, covering births from 1958 to 2001, and use low birth weight (LBW) as a marker for child health. We find that across successive birth cohorts, the negative association between advanced maternal age and LBW becomes progressively weaker; and that this pattern is partially explained by secular changes in the characteristics of older mothers. Our results suggest that associations between maternal age and child outcomes are tied to a specific population and point in time.

Methylmercury Exposure and Developmental Outcomes in Tohoku Study of Child Development at 18 Months of Age

Seafood is an important component in a healthy diet and may contain methylmercury or other contaminants. It is important to recognize the risks and benefits of consuming seafood. A longitudinal prospective birth cohort study has been conducted to clarify the effects of neurotoxicants on child development—the Tohoku Study of Child Development (TSCD) in Japan. TSCD comprises two cohorts; a polychlorinated biphenyls (PCB) cohort (urban area) and a methylmercury cohort (coastal area). Our previous results from the coastal area showed prenatal methylmercury exposure affected psychomotor development in 18-month-olds, and boys appear to be more vulnerable to the exposure than girls. In this report, we have added the urban area cohort and we reanalyzed the impact of prenatal exposure to methylmercury, which gave the same results as before. These findings suggest prenatal exposure to low levels methylmercury may have adverse effects on child development, especially in boys.

Association between birth weight and educational attainment: an individual-based pooled analysis of nine twin cohorts

BACKGROUND

There is evidence that birth weight is positively associated with education, but it remains unclear whether this association is explained by familial environmental factors, genetic factors or the intrauterine environment. We analysed the association between birth weight and educational years within twin pairs, which controls for genetic factors and the environment shared between co-twins.

METHODS

The data were derived from nine twin cohorts in eight countries including 6116 complete twin pairs. The association between birth weight and educational attainment was analysed both between individuals and within pairs using linear regression analyses.

RESULTS

In between-individual analyses, birth weight was not associated with educational years. Within-pairs analyses revealed positive but modest associations for some sex, zygosity and birth year groups. The greatest association was found in dizygotic (DZ) men (0.65 educational years/kg birth weight, p=0.006); smaller effects of 0.3 educational years/kg birth weight were found within monozygotic (MZ) twins of both sexes and opposite-sex DZ twins. The magnitude of the associations differed by birth year in MZ women and opposite-sex DZ twins, showing a positive association in the 1915-1959 birth cohort but no association in the 1960-1984 birth cohort.

CONCLUSION

Although associations are weak and somewhat inconsistent, our results suggest that intrauterine environment may play a role when explaining the association between birth weight and educational attainment.

Gestational age at birth and academic performance: population-based cohort study

Background

Numerous studies suggest pre-term birth is associated with cognitive deficit. However, less is known about cognitive outcomes following post-term birth, or the influence of weight variations within term or post-term populations. We examined associations between gestational age (GA) and school performance, by weight-for-GA, focusing on extremely pre- and post-term births.

Method

Record linkage study of Swedish children born 1973-94 ( n =  2 008 102) with a nested sibling comparison ( n =  439 629). We used restricted cubic regression splines to examine associations between GA and the grade achieved on leaving secondary education, comparing siblings to allow stronger causal inference with regard to associations between GA and school performance.

Results

Grade averages of both pre- and post-term children were below those of full-term counterparts and lower for those born small-for-GA. The adjusted grades of extremely pre-term children (at 24 completed weeks), while improving in later study periods, were lower by 0.43 standard deviations (95% confidence interval 0.38-0.49), corresponding with a 21-point reduction (19 to 24) on a 240-point scale. Reductions for extremely post-term children (at 45 completed weeks) were lesser [-0.15 standard deviation (-0.17 to -0.13) or -8 points (-9 to -7)]. Among matched siblings, we observed weaker residual effects of pre-term and post-term GA on school performance.

Conclusions

There may be independent effects of fetal maturation and fetal growth on school performance. Associations among matched siblings, although attenuated, remained consistent with causal effects of pre- and post-term birth on school performance.

Anthropometric measures at birth and early childhood are associated with neurodevelopmental outcomes among Bangladeshi children aged 2-3years

Among a cohort of children located in rural areas of Bangladesh affected by high levels of exposure to environmental metals, we investigated the associations between anthropometric measures, growth trajectory, and neurodevelopment at age 20-40months. Our study population included mothers and their children who participated in a longitudinal birth cohort study that took in place in the Pabna and Sirajdikhan areas of Bangladesh. Anthropometric measures including weight, length, and head circumference were measured at birth, age 12months, and age 20-40months. Neurodevelopment was assessed using Bayley Scales of Infant and Toddler Development Third Edition (BSID-III) multi-scale at age 20-40months. A total of 777 mother-child pairs were included. Higher anthropometric measures at 20-40months were associated with higher cognitive, language, and motor scores on BSID-III. For example, a 1-kg increment in birthweight was associated with an increase of 2.11 for cognitive score (p<0.0001), 1.63 for language score (p=0.006), and 0.89 for motor scores (p=0.03). Greater positive changes in growth parameters, or growth trajectory, between birth and 20-40months were also associated with higher BSID-III scores. These associations remained significant after adjusting for potential confounders and prenatal exposure to environmental metals. These findings suggest that even when taking into account high environmental metal exposures, prenatal and early childhood growth have strong associations with neurodevelopmental test scores in early childhood.

The relation between cesarean birth and child cognitive development

This is the first detailed study of the relation between cesarean birth and child cognitive development. We measure differences in child cognitive performance at 4 to 9 years of age between cesarean-born and vaginally-born children (n = 3,666) participating in the Longitudinal Study of Australian Children (LSAC). LSAC is a nationally representative birth cohort surveyed biennially. Using multivariate regression, we control for a large range of confounders related to perinatal risk factors and the socio-economic advantage associated with cesarean-born children. Across several measures, we find that cesarean-born children perform significantly below vaginally-born children, by up to a tenth of a standard deviation in national numeracy test scores at age 8–9. Estimates from a low-risk sub-sample and lower-bound analysis suggest that the relation is not spuriously related to unobserved confounding. Lower rates of breastfeeding and adverse child and maternal health outcomes that are associated with cesarean birth are found to explain less than a third of the cognitive gap, which points to the importance of other mechanisms such as disturbed gut microbiota. The findings underline the need for a precautionary approach in responding to requests for a planned cesarean when there are no apparent elevated risks from vaginal birth.

The transformative potential of an integrative approach to pregnancy

BACKGROUND

Complex traits typically involve diverse biological pathways and are shaped by numerous genetic and environmental factors. Pregnancy-associated traits and pathologies are further complicated by extensive communication across multiple tissues in two individuals, interactions between two genomes-maternal and fetal-that obscure causal variants and lead to genetic conflict, and rapid evolution of pregnancy-associated traits across mammals and in the human lineage. Given the multi-faceted complexity of human pregnancy, integrative approaches that synthesize diverse data types and analyses harbor tremendous promise to identify the genetic architecture and environmental influences underlying pregnancy-associated traits and pathologies.

METHODS

We review current research that addresses the extreme complexities of traits and pathologies associated with human pregnancy.

RESULTS

We find that successful efforts to address the many complexities of pregnancy-associated traits and pathologies often harness the power of many and diverse types of data, including genome-wide association studies, evolutionary analyses, multi-tissue transcriptomic profiles, and environmental conditions.

CONCLUSION

We propose that understanding of pregnancy and its pathologies will be accelerated by computational platforms that provide easy access to integrated data and analyses. By simplifying the integration of diverse data, such platforms will provide a comprehensive synthesis that transcends many of the inherent challenges present in studies of pregnancy.

Birth Weight and Intelligence in Young Adulthood and Midlife

OBJECTIVES

We examined the associations between birth weight and intelligence at 3 different adult ages.

METHODS

The Copenhagen Perinatal Cohort is comprised of children born in Copenhagen from 1959 to 1961. Information on birth weight and ≥1 tests of intelligence was available for 4696 members of the cohort. Intelligence was assessed at a mean age of 19 years with the Børge Priens Prøve test, at age 28 years with the Wechsler Adult Intelligence Scale, and at age 50 years with the Intelligenz-Struktur-Test 2000 R.

RESULTS

Birth weight was significantly associated with intelligence at all 3 follow-up assessments, with intelligence scores increasing across 4 birth weight categories and declining for the highest birth weight category. The adjusted differences between those in the <2.5kg birth weight group and those in the 3.5 to 4.00kg group were >5 IQ points at all 3 follow-up assessments, corresponding to one-third of a SD. The association was stable from young adulthood into midlife,and not weaker at age 50 years. Adjustment for potential confounding factors, including infant socioeconomic status and gestational age, did not dilute the associations, and associations with intelligence were evident across the normal birth weight range and so were not accounted for by low birth weight only.

CONCLUSIONS

The association between birth weight and intelligence is stable from young adulthood into midlife. These long-term cognitive consequences may imply that even small shifts in the distribution of birth size, in normal-sized infants as well, may have a large impact at the population level.

Influence of catch up growth on spatial learning and memory in a mouse model of intrauterine growth restriction

Background

Intrauterine growth restriction (IUGR) and rapid postnatal weight gain or catch up growth (CUG) increase the susceptibility to metabolic syndrome during adult life. Longitudinal studies have also revealed a high incidence of learning difficulties in children with IUGR. The aim of the present study was to investigate the effect of nutrition and CUG on learning memory in an IUGR animal model. We hypothesized that synaptic protein expression and transcription, an essential mechanism for memory consolidation, might be affected by intrauterine undernutrition.

Methods

IUGR was induced by 50% maternal caloric undernutrition throughout late gestation. During the suckling period, dams were either fed ad libitum or food restricted. The pups were divided into: Normal prenatal diet-Normal postnatal diet (NN), Restricted prenatal diet- Normal postnatal diet + catch up growth (RN+), Normal prenatal diet-Restricted postnatal diet (NR) and Restricted prenatal diet-Restricted postnatal diet (RR). At 4 weeks of age, memory was assessed via a water maze test. To evaluate synaptic function, 2 specific synaptic proteins (postsynaptic density-95 [PSD95], synaptophysin) as well as insulin receptors (IR) were tested by Western Blot and quantitative polymerase chain reaction (qPCR). Brain-derived neurotrophic factor and serum insulin levels were also studied.

Results and conclusions

The RN+ group presented a learning curve similar to the NN animals. The RR animals without CUG showed learning disabilities. PSD95 was lower in the RR group than in the NN and RN+ mice. In contrast, synaptophysin was similar in all groups. IR showed an inverse expression pattern to that of the PSD95. In conclusion, perinatal nutrition plays an important role in learning. CUG after a period of prenatal malnutrition seems to improve learning skills. The functional alterations observed might be related to lower PSD95 activity and a possible dysfunction in the hormone regulation of synaptic plasticity.

Inadequate Utilization of Prenatal Care Services, Socioeconomic Status, and Educational Attainment Are Associated with Low Birth Weight in Zimbabwe

Background

Globally, low birth weight (LBW) remains a leading cause of neonatal and infant mortality and poses significant challenges toward the progress of achieving infant mortality-related goals. Experience from developed countries shows that two major causes of LBW (premature delivery and intrauterine growth restriction) can be averted to a great extent by adequate utilization of maternal health-care services, during pregnancy. In this study, we attempt to measure the prevalence of LBW in Zimbabwe and explore the association between adequate utilization of prenatal care (PNC) services and LBW in Zimbabwe. We also explore other possible associations with LBW.

Methodology

This study was based on nationally representative, cross-sectional data from Multiple Indicator Cluster Survey round 5, conducted in 2014. Participants included 3,221 mothers from both rural and urban areas. The participants were selected regardless of their current pregnancy status. Sample characteristics were presented using descriptive statistics. Association between utilization status of ANC and LBW was measured by chi-square (bivariate) test and logistic regression methods.

Results

Prevalence of LBW was 12.8%. There was 11% reduction in the odds of having LBW babies for participants from urban area when compared with rural area (AOR = 0.897; 95% CI = 0.707–1.138). When compared to women with higher education, those having primary/below primary and secondary level qualification had higher odds of experiencing LBW babies by 73 and 56%, respectively. Participants who had less than four PNC/ANC visits had 34% higher odds (AOR = 1.340; 95% CI = 1.065–1.685) than those with at least four visits, and those who had given birth more than once, had 38% lower odds (AOR = 0.620; 95% CI = 0.493–0.780) of giving birth to LBW babies when compared to those who had given birth only once.

Conclusion

The findings of this study have programmatic and policy implications for low-resource nations and suggest that promoting access to ANC services especially in the rural areas is likely to reduce prevalence of LBW in Zimbabwe. This is important as LBW babies consume lot of health resources per se and not only in terms of hospitalization but also in terms of outpatient and physician visits during the first year of their life.

Financial strain and birth weight: the mediating role of psychological distress

The effects of financial strain during pregnancy have received limited attention. In addition, data examining the pathways by which SES indicators contribute to birth weight are lacking. The objective of the current study was to examine the potential pathway of psychological distress in the relationship between financial strain and birth weight. Participants consisted of 138 pregnant women who completed measures assessing financial strain, depressive symptoms, pregnancy-specific distress, perceived stress, and general anxiety during pregnancy (mean gestational age = 18.5, SD = 7.2). Birth outcome data were obtained via medical record review. Simple and parallel mediation models were conducted using PROCESS. Simple mediation models showed that depressive symptoms (95% CI -24.65, -0.90) and pregnancy-specific distress (95% CI -37.31, -5.91), but not perceived stress (95% CI -31.17, 4.69) or anxiety (95% CI -25.84, 5.57), served as mediators in the relationship between financial strain and birth weight. When depressive symptoms and pregnancy-specific distress were included in the same mediation model, only pregnancy-specific distress remained significant. Financial strain was positively associated with all facets of psychological distress and negatively associated with birth weight during pregnancy. The current study demonstrated the mechanistic role of pregnancy-specific distress in the link between financial strain and birth weight in a racially diverse sample. Interventions targeting pregnancy-specific distress may mitigate the effects of financial strain on birth weight. Studies examining whether pregnancy-specific distress accounts for the relationship between other types of stressor exposures and birth weight would be informative.

Predictors of motor developmental milestones during the first year of life

Studies suggest that both pre- and postnatal factors are predictors of age of attaining milestones in infancy. However, no studies evaluate the comparative strength of these predictors and the amount of the variance in development they explain. This study aimed to conduct a systematic evaluation of a broad selection of possible predictors of age at milestone attainment and to identify factors that explain significant inter-individual variance. Mothers of 5765 children of the Copenhagen Perinatal Cohort (1959-61) recorded 12 developmental milestones prospectively during the child's first year of life. Information on possible predictors was collected during pregnancy and at follow-up and was categorized into the domains: Family background, Pregnancy and delivery, Postnatal influences, and Postnatal growth. The domain Pregnancy and delivery contributed most of the explained variance in Overall mean of milestones (14.4%), with especially gestational age (β = -0.15; p ≤ 0.001) and birth weight (β = -0.16; p ≤ 0.001) being important predictors.

CONCLUSION

Several individual factors, especially gestational age, birth weight, breastfeeding, having lived in a full-time institution, and weight and head increase in the first year, were significantly associated with milestone attainment in the first year of life. Variables within the domain of Pregnancy and delivery explained the largest proportion of variance in milestone attainment compared to the other domains. What is known: • Younger age at attainment of motor developmental milestones positively predicts cognitive outcomes in adulthood. • Both pre- and postnatal factors have been associated with age of attaining milestones in infancy. What is new: • First study to provide a systematic evaluation of a broad selection of predictors of infant milestone attainment. • Variables within the domain of Pregnancy and delivery, especially gestational age and birth weight, explained the largest proportion of variance in milestone attainment. • The variance explained by the predictors decreased time-dependently with later milestones.

Multivariate Analysis of Thyrotropin in Preterm Newborns Based on Adequacy of Weight for Gestational Age

BACKGROUND

Different and conflicting data have been published concerning thyrotropin (TSH) levels among small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) newborns. The hypothesis of this study was that SGA preterm infants have higher TSH levels than those who are not underweight do.

METHODS

This cross-sectional study analyzed the TSH levels of all preterm newborns with a negative congenital hypothyroidism screening result (TSH <7.5 μIU/mL). Secondary variables were sex, birth weight (SGA, AGA), days of life at blood extraction, maternal origin, gestational age, and being a twin or not. Two multiple linear regression models were constructed comparing TSH levels in SGA and AGA or the z-score for birth weight and the remaining variables.

RESULTS

A sample including 5819 preterm infants was obtained: 53.8% male, 23.3% twins, and 3.3% SGA. TSH concentrations were 2.16 ± 2.0 μIU/mL for the SGA infants and 1.80 ± 1.5 μIU/mL for the AGA infants (p = 0.012), with a negative correlation (p < 0.001) between TSH levels and the z-score for the weight of the newborn. The multivariate analysis comparing TSH levels between SGA and AGA gave the following: SGA (B = 0.46, p < 0.001), Latin American mother (B = -0.16, p = 0.029), days of life at blood extraction (B = -0.26, p < 0.001), and gestational age ≤28 weeks (B = -0.56, p < 0.001). Using the z-score for the weight, the associations were: maternal origin North Africa (B = 0.19, p = 0.042), days of life at blood extraction (B = -0.27, p < 0.001), gestational age ≤28 weeks (B = -0.55, p < 0.001), and z-score for weight (B = -0.12, p < 0.001).

CONCLUSIONS

Our multivariate analysis suggests that TSH concentrations are higher in SGA infants than they are in AGA infants, and this should be taken into account when establishing a reference interval appropriate for this population. The clinical relevance remains unknown, but lines of research are opened that may allow a better understanding of the long-term morbidities in these newborns.

Decline in the negative association between low birth weight and cognitive ability

Low birth weight predicts compromised cognitive ability. We used data from the 1958 National Child Development Study (NCDS), the 1970 British Cohort Study (BCS), and the 2000-2002 Millennium Cohort Study (MCS) to analyze how this association has changed over time. Birth weight was divided into two categories, <2,500 g (low) and 2,500-4,500 g (normal) and verbal cognitive ability was measured at the age of 10 or 11 y. A range of maternal and family characteristics collected at or soon after the time of birth were considered. Linear regression was used to analyze the association between birth weight and cognitive ability in a baseline model and in a model that adjusted for family characteristics. The standardized difference (SD) in cognitive scores between low-birth-weight and normal-birth-weight children was large in the NCDS [-0.37 SD, 95% confidence interval (CI): -0.46, -0.27] and in the BCS (-0.34, 95% CI: -0.43, -0.25) cohorts, and it was more than halved for children born in the MCS cohort (-0.14, 95% CI: -0.22, -0.06). The adjustment for family characteristics did not explain the cross-cohort differences. The results show that the association between low birth weight and decreased cognitive ability has declined between the 1950s and 1970s birth cohorts and the 2000--2002 birth cohort, despite a higher proportion of the low-birth-weight babies having a very low birth weight (<1,500 g) in the more recent birth cohort. Advancements in obstetric and neonatal care may have attenuated the negative consequences associated with being born small.

Behavioral and intelligence outcome in 8- to 16-year-old born small for gestational age

Purpose

We investigated behavioral problems, attention problems, and cognitive function in children and adolescents born small for gestational age (SGA).

Methods

Forty-six SGA children born at term and 46 appropriate for gestational age (AGA) children born at term were compared. Psychiatric symptoms were examined with reference to the Korean-Child Behavior Checklist, Korean-Youth Self Report, and Attention Deficit Hyperactivity Disorder Rating Scale (ADHD-RS). Cognitive function was estimated using the Wechsler Intelligence Scale. Sociodemographic data were recorded from interviews.

Results

SGA children had high scores on delinquent behavior, aggressive behavior, and the externalizing scale, and they also showed a propensity for anxiety and depression. The SGA group had a higher mean ADHD-RS score than the AGA group (10.52±8.10 vs.9.93±7.23), but the difference was not significant. The SGA group had a significantly lower verbal intelligence quotient (IQ) than the AGA group, but the mean scores of both groups were within normal limits.

Conclusion

This study indicates marked behavioral problems, such as delinquency, aggressiveness, and anxiety and depression, as well as low verbal IQ in the SGA group than in the AGA group. Even in cases in which these symptoms are not severe, early detection and proper treatment can help these children adapt to society.

Progesterone supplementation for HIV-positive pregnant women on protease inhibitor-based antiretroviral regimens (the ProSPAR study): a study protocol for a pilot randomized controlled trial

Background

In Canada, the majority of HIV-positive pregnant women receive combination antiretroviral therapy that includes a ritonavir-boosted protease inhibitor to prevent mother-to-child HIV transmission. However, protease inhibitor-based combination antiretroviral therapy has been associated with increased rates of preterm, low birth weight, and small for gestational age births. Our previous experimental findings demonstrate that protease inhibitor use during pregnancy is associated with decreased progesterone levels that correlate with fetal growth, and that progesterone supplementation can improve protease inhibitor-induced fetal growth restriction. We hypothesize that HIV-positive pregnant women who receive protease inhibitor-based combination therapy may also benefit from progesterone supplementation during pregnancy.

Methods/design

In order to test this hypothesis, we have designed an open-label, multi-centre, randomized controlled (parallel group) pilot trial. The initial goal of this trial is to test feasibility and acceptability of our intervention. Forty HIV-positive pregnant women who are either on, or intending to start or switch to a boosted protease inhibitor-based combination antiretroviral regimen will be enrolled from six sites across Ontario, Canada. Twenty-five women will be randomized to self-administer natural progesterone (Prometrium, 200 mg) vaginally every night starting between gestational week 16 and 24 until week 36, and 15 women will be randomized to no intervention. While the participants and treating physicians will not be blinded, the laboratory personnel performing the biochemical and morphological evaluations will be blinded to ensure unbiased evaluation. The primary outcome of the pilot study is the feasibility of enrolment as measured by the recruitment rate and patient-reported reasons to decline participation. Secondary outcomes in participants include safety, acceptability, and adherence to progesterone supplementation.

Discussion

Given the safety of intravaginal progesterone and its current use in the general obstetrical population to prevent recurrent preterm delivery, this pilot study will provide data to determine the feasibility of a larger randomized controlled trial to assess the impact of this intervention on improving neonatal health in the context of HIV-positive pregnancies.

Trial registration

ClinicalTrials.gov, NCT02400021

Designing Multidisciplinary Longitudinal Studies of Human Development

This review identifies key issues associated with the design of future longitudinal studies of human development. Sixteen international studies were compared for initial response and retention rate, sample size, type of data collected, and sampling frames. The studies had little information about the influences of fathers, extended family members, childcare, and educational institutions; the effects of peers; children's use of time; the needs of disabled children; urban versus rural environments; or the influence of genetic factors. A contemporary longitudinal study should include measures of physical and mental health, cognitive capacity, educational attainment, social adjustment, conduct and behavior, resiliency, and risk-taking behaviors. It needs to address genetic and intergenerational factors, cultural identity, and the influences of neighborhood, community, and wider social and political environments and to encompass outcomes at all life stages to systematically determine the role each factor plays in individuals' lives, including interactions within and across variables.

Home-Based Early Intervention and the Influence of Family Resources on Cognitive Development

OBJECTIVE

To investigate whether early developmental intervention (EDI) can positively affect the trajectories of cognitive development among children from low-resource families.

METHODS

Longitudinal analyses were conducted of data from 293 children in the Brain Research to Ameliorate Impaired Neurodevelopment Home-based Intervention Trial, a randomized controlled trial of a home-based EDI program, to examine trajectories of Bayley Scales of Infant Development-Second Edition Mental Development Index (MDI) scores from 12 to 36 months of age among young children from high- and low-resource families in 3 low- to middle-resource countries.

RESULTS

A 3-way interaction among family resources, intervention group, and age was statistically significant after controlling for maternal, child, and birth characteristics (Wald χ(2)(1) = 9.41, P = .002). Among children of families with high resources, both the intervention and control groups had significant increases in MDI scores over time (P < .001 and P = .002, respectively), and 36-month MDI scores for these 2 groups did not differ significantly (P = .602). However, in families with low resources, the EDI group displayed greater improvement, resulting in significantly higher 36-month MDI scores than the control group (P < .001). In addition, the 36-month MDI scores for children in families with low resources receiving EDI did not differ significantly from children from high-resource families in either the EDI (P = .509) or control (P = .882) groups.

CONCLUSIONS

A home-based EDI during the first 3 years of life can substantially decrease the developmental gap between children from families with lower versus higher resources, even among children in low- to middle-resource countries.

Aerobic capacity as a mediator of the influence of birth weight and school performance

Low birth weight is associated with cognitive impairments persisting into adolescence and early adulthood. The purposes of this study was two-fold: to analyse the association between birth weight (BW) and school performance, and to determine the influence of adolescent aerobic capacity and muscular strength on the association between BW and school performance in children at 12-13 years. The study included 395 children (50.4% boys, aged 12-13 years). Self-reported BW was evaluated. We measured school performance (mean of the grades obtained in language and mathematics) and two physical fitness tests (aerobic capacity and muscular strength). Analysis of variance was used to analyse the differences in school performance according to BW categories (⩽2500, 2500-3500 and ⩾3500 g). Linear regression models fitted for mediation analyses examined whether the association between BW and school performance was mediated by aerobic capacity and/or muscular strength. Higher BW was associated with better school performance independent of current body mass index. These differences disappeared after controlling for aerobic capacity, which also mediated the association between BW and school performance (13.4%). The relationship between BW and school performance seems to be dependent on aerobic capacity fitness. Our results are of importance because the consequences of BW tend to continue into childhood, and current physical fitness of the children may potentially be modified to improve school performance.

Risk factors for low birth weight in Nigeria: evidence from the 2013 Nigeria Demographic and Health Survey

BACKGROUND

Low birth weight (LBW) continues to be the primary cause of infant morbidity and mortality.

OBJECTIVE

This study was undertaken to identify the predictors of LBW in Nigeria.

DESIGN

The data for this study was extracted from the 2013 Nigeria Demographic and Health Survey conducted by the National Population Commission. Several questionnaires were used in the survey, some covering questions on pregnancy characteristics. The inclusion criteria include mothers who gave birth to a child 5 years before the interview and aged 15-49 years who were either permanent residents or visitors present in the household on the night before the survey conducted. The birth weight of the infants was recorded from written records from the hospital cards or the mothers' recall.

RESULTS

The prevalence of LBW in this study was 7.3%. Multiple logistic regression analysis showed an adjusted significant odds ratio for mothers from North West region (aOR 10.67; 95% CI [5.83-19.5]), twin pregnancy (aOR 5.11; 95% CI [3.11-8.39]), primiparous mother (aOR 2.08; 95% CI [1.15-3.77]), maternal weight of less than 70 kg (aOR 1.92; 95% CI [1.32-2.78]), and manual paternal employment (aOR 1.91; 95% CI [1.08-3.37]).

CONCLUSIONS

The risk factors for LBW identified in this study are modifiable. In order to reduce this menace in Nigeria, holistic approaches such as health education, maternal nutrition, improvement in socio-economic indices, and increasing the quality and quantity of the antenatal care services are of paramount importance.