Investigating the relationship between prenatal growth and postnatal outcomes: a systematic review of the literature

Bone trait ranking in the population is not established during antenatal growth but is robustly established in the first postnatal year

Efforts to understand the pathophysiology of bone fragility must focus on bone traits during growth. We hypothesized that variance in individual trait ranking in the population distribution is established by genetic factors and is reflected in foetal trait ranking in early pregnancy, but intrauterine factors modify trait ranking in late pregnancy, followed by the reinstating of this ranking during the first postnatal year. Thus, relations with paternal factors are present in early pregnancy but are then lost and subsequently reinstated postnatal. We recruited 399 healthy pregnant women aged 20–42 years from The Mercy Hospital for Woman in Melbourne, Australia. Foetal femur length (FL) and knee-heel length (KHL) were measured by ultrasound during gestation, and FL, KHL, body length and weight were measured in neonates, infants, and parents. The z-scores were calculated using Royston models. Pearson correlation was used to assess tracking and linear mixed models to test the associations. Correlations between FL and KHL z-scores of the same trait at 20 and 30 weeks gestation, at birth, and at 12 and 24 months of age (r = 0.1–0.3) and of body length and weight at birth, and 6, 12 and 24 months (r = 0.3–0.5) became more robust after 6–12 months (r = 0.4–0.8). FL and KHL z-scores at 20 weeks gestation accounted for 4–5% of total variance, while FL, KHL, body length and weight z-scores at birth accounted for 13–26% of total variance in the same traits at 24 months. Maternal FL and KHL were associated with foetal FL and KHL at 20 and 30 weeks, but there were no such associations for paternal FL and KHL with foetal traits during gestation. Both maternal and paternal traits were associated with infant traits. Tracking in traits is not established antenatal but is robustly established at 6–12 months of age.

Maternal and Fetal Determinants of Neonatal Body Composition

BACKGROUND

Body composition in early life influences the development of obesity during childhood and beyond. It is, therefore, important to adequately determine neonatal body composition. Fetal growth and maternal factors might influence neonatal fat mass percentage (FM%), independent of birth weight.

METHODS

In 194 healthy neonates, we investigated neonatal body composition, measured by air-displacement plethysmography (PEAPOD), and its associations with estimated fetal weight (EFW), neonatal anthropometric data, maternal preconceptional body mass index (BMI) and maternal weight gain during pregnancy.

RESULTS

There was a large variation in neonatal FM%, even in case of a similar birth weight, corrected for gender and gestational age. Neonatal FM% was associated with EFW at 30 and 36 weeks of gestation and with catch-up in weight between 30 and 36 weeks of gestation, but not with EFW at 20 weeks (p < 0.01, p < 0.01 and p = 0.64, respectively). Neonatal FM% was also associated with preconceptional BMI of the mother (p < 0.01). There was no correlation with maternal weight gain.

CONCLUSION

Our study shows that term neonates have a large variation in FM%. Neonatal FM% is associated with EFW at 30 and 36 weeks, catch-up in weight between 30 and 36 weeks of gestation and preconceptional BMI of the mother.

On the relationship between economic conditions around the time of birth and late life cognitive abilities: Evidence from Taiwan

This study investigates the casual linkage between economic conditions around the time of birth and late life cognitive abilities. The zero-inflated negative binomial and multivariate logistic regression models were used to evaluate the direct and indirect effect of economic conditions around the time of birth on late life cognitive abilities, respectively. Both direct and indirect effects of economic conditions around the time of birth on late life cognitive abilities were identified. The relative risk ratio in adjusted mean scores of the Short Portable Mental Status Questionnaire (a means to measure cognitive impairment) indicates that being born in an economic recession year (experiencing economic recession during the year prior to birth) increases the risk of difficulties with cognition by 17.40% (11.70%). Being born in an economic recession year decreases the likelihood of high educational attainment in later life by an odds ratio of 0.962.

Heterogeneity identified at birth and blood pressure in adulthood

OBJECTIVE

In the developmental programming literature, the association of birth weight and blood pressure later in life is modest at best. This article reexamines this issue using Covariate Density Defined mixture of regressions (CDDmr) to determine if a latent variable, based on birth weight, and known to influence infant mortality, provides a stronger indicator of developmental programming.

METHODS

CDDmr identifies two latent components in the birth weight distribution, generally interpreted in the infant mortality literature as "compromised" and "normal" fetal development. The data are taken from the 1958 British National Child Development Study.

RESULTS

In the 1958 cohort, the "compromised" component consists of about 10% of the birth weight distribution. Compared to "normal" births, the mean systolic blood pressure at age 45 of "compromised" births is 20.3 (females) and 26.4 (males) mm Hg higher than "normal" births. The relative risks of stage-I-II systolic hypertension (>140 mm Hg) of "compromised" births compared to "normal" births are 10.7 (females) and 4.2 (males). The relative risks of stage-II systolic hypertension (>160 mm Hg) are considerably higher, 241.6 (females) and 74.3 (males). In general, the highest blood pressures are observed in "compromised" births with birth weights within the normal (about 3.0-3.5 kg) birth weight range. Results for diastolic blood pressure are similar.

CONCLUSIONS

These associations are much stronger than those identified using conventional methods. CDDmr is likely to be useful for studying the dynamics of developmental programming particularly in large cohort studies where birth weight is often the only indicator of programming available. Am. J. Hum. Biol. 28:545-554, 2016. © 2016 Wiley Periodicals, Inc.

Metals exposure and risk of small-for-gestational age birth in a Canadian birth cohort: The MIREC study

BACKGROUND

Lead, mercury, cadmium and arsenic are some of the most common toxic metals to which Canadians are exposed. The effect of exposure to current low levels of toxic metals on fetal growth restriction is unknown.

OBJECTIVE

The aim of this study was to examine relationships between exposure to lead, mercury, cadmium and arsenic during pregnancy, and risk of small for gestational age (SGA) birth.

METHODS

Lead, mercury, cadmium and arsenic levels were measured in blood samples from the first and third trimesters in 1835 pregnant women from across Canada. Arsenic species in first trimester urine were also assessed. Relative risks and 95% confidence intervals were estimated using log binomial multivariate regression. Important covariates including maternal age, parity, pre-pregnancy BMI, and smoking, were considered in the analysis. An exploratory analysis was performed to examine potential effect modification of these relationships by single nucleotide polymorphisms (SNPs) in GSTP1 and GSTO1 genes.

RESULTS

No association was found between blood lead, cadmium or arsenic and risk for SGA. We observed an increased risk for SGA for the highest compared to the lowest tertile of exposure for mercury (>1.6 µg/L, RR=1.56.; 95% CI=1.04-2.58) and arsenobetaine (>2.25 µg/L, RR=1.65; 95% CI=1.10-2.47) after adjustment for the effects of parity and smoking. A statistically significant interaction was observed in the relationship between dimethylarsinic acid (DMA) levels in urinary arsenic and SGA between strata of GSTO1 A104A (p for interaction=0.02). A marginally significant interaction was observed in the relationship between blood lead and SGA between strata of GSTP1 A114V (p for interaction=0.06).

CONCLUSIONS

These results suggest a small increase in risk for SGA in infants born to women exposed to mercury and arsenic. Given the conflicting evidence in the literature this warrants further investigation in other pregnant populations.

Developmental Origins of Cardiovascular Disease

Although cardiovascular disease has traditionally been viewed as a condition of aging individuals, increasing focus has turned to its developmental origins. Since birthweight has been related to cardiovascular disease risk, research into factors such as gravid conditions that affect fetal growth have grown. Associations between maternal diabetes and childhood obesity from sibling studies suggest a causal role but prospective studies of gestational diabetes remain mixed. Preeclampsia and increased offspring blood pressure has been consistently observed but evidence for other cardiovascular outcomes is lacking. While maternal obesity is associated with childhood obesity, causality remains unclear and paternal obesity should be investigated as an independent risk factor. Environmental chemical exposures in utero, particularly obesogens, are now emerging as another concern, as is conception by infertility treatment. Few studies have investigated subclinical measures of endothelial function or atherosclerosis and more research in these areas may help reveal the underlying pathogenesis.