Current concepts in intrauterine growth restriction

Stress, depression, social support, and eating habits reduce diet quality in the first trimester in low-income women: a pilot study

Maternal diet quality influences birth outcomes. Yet, little research exists that assesses women's diet quality during the first trimester of pregnancy, a crucial time of placental and fetal development. This cross-sectional study, describing diet quality and its relationship with stress, depression, social support, and eating habits in the first trimester, may identify low-income women needing intensive dietary intervention. Seventy-one low-income women completed validated instruments measuring stress, depression, social support, and eating habits; had their height and weight measured; received training on portion-size estimation; and completed three 24-hour dietary recalls (1 weekend day and 2 nonconsecutive weekdays) from July 2009 to February 2010. Comparative and correlational analyses were done. Women with diet quality scores below the median (n=35) had more depression (9.6±5.1 vs 6.7±5.1) and stress (22.1±5.4 vs 19.3±4.8) and less control over meal preparation (5.0±1.5 vs 4.2±1.5) and support from others (52.0±12.0 vs 57.4±7.2) than did women with high diet quality scores (n=36). Diet quality was negatively related to depression (r=-0.41), stress (r=-0.35), skipping meals (r=-0.41), and control over meal preparation (r=-0.33), and positively related to support from others (r=0.38). Low-income women experiencing life stressors represent an at-risk group for low diet quality and may need intensive dietary intervention before and during pregnancy. More research designed to improve diet quality in low-income pregnant women is needed.

Extrinsic factors influencing fetal deformations and intrauterine growth restriction

The causes of intrauterine growth restriction (IUGR) are multifactorial with both intrinsic and extrinsic influences. While many studies focus on the intrinsic pathological causes, the possible long-term consequences resulting from extrinsic intrauterine physiological constraints merit additional consideration and further investigation. Infants with IUGR can exhibit early symmetric or late asymmetric growth abnormality patterns depending on the fetal stage of development, of which the latter is most common occurring in 70-80% of growth-restricted infants. Deformation is the consequence of extrinsic biomechanical factors interfering with normal growth, functioning, or positioning of the fetus in utero, typically arising during late gestation. Biomechanical forces play a critical role in the normal morphogenesis of most tissues. The magnitude and direction of force impact the form of the developing fetus, with a specific tissue response depending on its pliability and stage of development. Major uterine constraining factors include primigravida, small maternal size, uterine malformation, uterine fibromata, early pelvic engagement of the fetal head, aberrant fetal position, oligohydramnios, and multifetal gestation. Corrective mechanical forces similar to those that gave rise to the deformation to reshape the deformed structures are often used and should take advantage of the rapid postnatal growth to correct form.

The role of imprinted genes in humans

Genomic imprinting, a process of epigenetic modification which allows the gene to be expressed in a parent-of-origin specific manner, has an essential role in normal growth and development. Imprinting is found predominantly in placental mammals, and has potentially evolved as a mechanism to balance parental resource allocation to the offspring. Therefore, genetic and epigenetic disruptions which alter the specific dosage of imprinted genes can lead to various developmental abnormalities often associated with fetal growth and neurological behaviour. Over the past 20 years since the first imprinted gene was discovered, many different mechanisms have been implicated in this special regulatory mode of gene expression. This review includes a brief summary of the current understanding of the key molecular events taking place during imprint establishment and maintenance in early embryos, and their relationship to epigenetic disruptions seen in imprinting disorders. Genetic and epigenetic causes of eight recognised imprinting disorders including Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS), and also their association with Assisted reproductive technology (ART) will be discussed. Finally, the role of imprinted genes in fetal growth will be explored by investigating their relationship to a common growth disorder, intrauterine growth restriction (IUGR) and also their potential role in regulating normal growth variation.

Caffeine reduces 11β-hydroxysteroid dehydrogenase type 2 expression in human trophoblast cells through the adenosine A(2B) receptor

Maternal caffeine consumption is associated with reduced fetal growth, but the underlying molecular mechanisms are unknown. Since there is evidence that decreased placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) is linked to fetal growth restriction, we hypothesized that caffeine may inhibit fetal growth partly through down regulating placental 11β-HSD2. As a first step in examining this hypothesis, we studied the effects of caffeine on placental 11β-HSD2 activity and expression using our established primary human trophoblast cells as an in vitro model system. Given that maternal serum concentrations of paraxanthine (the primary metabolite of caffeine) were greater in women who gave birth to small-for-gestational age infants than to appropriately grown infants, we also studied the effects of paraxanthine. Our main findings were: (1) both caffeine and paraxanthine decreased placental 11β-HSD2 activity, protein and mRNA in a concentration-dependent manner; (2) this inhibitory effect was mediated by the adenosine A(2B) receptor, since siRNA-mediated knockdown of this receptor prevented caffeine- and paraxanthine-induced inhibition of placental 11β-HSD2; and (3) forskolin (an activator of adenyl cyclase and a known stimulator of 11β-HSD2) abrogated the inhibitory effects of both caffeine and paraxanthine, which provides evidence for a functional link between exposure to caffeine and paraxanthine, decreased intracellular levels of cAMP and reduced placental 11β-HSD2. Taken together, these findings reveal that placental 11β-HSD2 is a novel molecular target through which caffeine may adversely affect fetal growth. They also uncover a previously unappreciated role for the adenosine A(2B) receptor signaling in regulating placental 11β-HSD2, and consequently fetal development.

The M2 haplotype in the ANXA5 gene is an independent risk factor for idiopathic small-for-gestational age newborns

Hereditary thrombophilias can impair vascular placental functions and predispose to the birth of small-for-gestational age (SGA) babies. The placental anticoagulant protein annexin A5 (ANXA5) may contribute to this process. A functional haplotype (M2) within the ANXA5 gene is associated with fetal loss and venous thrombosis. This study investigated the prevalence of the M2 haplotype in a group of women with idiopathic SGA newborn babies. Seventy-eight women with at least one previous unexplained SGA birth and 195 controls all from Southern Italy were investigated. Hereditary thrombophilia was found in 13 (16.5%) cases and 21 (11%) controls (P < 0.05.). The M2 haplotype was found in 29% of cases (n = 23) and 15% of controls [n = 30; P = 0.001; OR = 2.3, 95% CI (1.17-4.48)]. Within the case group, 82.5% of the M2 haplotype carriers gave birth to babies with a birthweight below the 3rd percentile [P = 0.01; OR = 2.4, 95% CI (1.26-4.73)]. A logistic regression, corrected for age, parity and gravity showed that the M2 haplotype was independently associated with the delivery of an SGA new born [P = 0.029; OR = 2.6, 95% CI (1.1-6.0)]. In conclusion, the M2 haplotype of the ANXA5 gene confers a risk of delivering SGA babies.

Plasma 25-hydroxyvitamin D during pregnancy and small-for-gestational age in black and white infants

PURPOSE

In a prospective prenatal cohort study, we examined associations of second trimester and cord plasma 25-hydroxyvitamin D (25[OH]D) with small-for-gestational age (SGA) and the extent to which vitamin D might explain black/white differences in SGA.

METHODS

We studied 1067 white and 236 black mother-infant pairs recruited from eight obstetrical offices early in pregnancy in Massachusetts. We analyzed 25(OH)D levels using an immunoassay and performed multivariable logistic models to estimate the odds of SGA by category of 25(OH)D level.

RESULTS

Mean (SD) second trimester 25(OH)D level was 60 nmol/L (SD, 21) and was lower for black (46 nmol/L [SD, 22]) than white (62 nmol/L [SD, 20]) women. Fifty-nine infants were SGA (4.5%), and more black than white infants were SGA (8.5% vs. 3.7%). The odds of SGA were higher with maternal 25(OH)D levels less than 25 versus 25 nmol/L or greater (adjusted odds ratio, 3.17; 95% confidence interval, 1.16-8.63). The increased odds of SGA among black versus white participants decreased from an odds ratio of 2.04(1.04, 4.04) to 1.68(0.82, 3.46) after adjusting for 25(OH)D.

CONCLUSIONS

Second trimester 25(OH)D levels less than 25 nmol/L were associated with higher odds of SGA. Our data raise the possibility that vitamin D status may contribute to racial disparities in SGA.

Maternal exposure to drinking-water chlorination by-products and small-for-gestational-age neonates

BACKGROUND

There is concern about possible effects of disinfection by-products on reproductive outcomes. The purpose of this study was to evaluate the association between maternal exposure to chlorination by-products and the risk of delivering a small for-gestational-age (SGA) neonate.

METHODS

We conducted a population-based case-control study in the Québec City (Canada) area. Term newborn cases with birth weights <10th percentile (n = 571) were compared with 1925 term controls with birth weights ≥10th percentile. Concentrations of trihalomethanes and haloacetic acids in the water-distribution systems of participants were monitored during the study period, and a phone interview on maternal habits was completed within 3 months after childbirth. We estimated chlorination by-products ingestion during the last trimester of pregnancy and trihalomethanes doses resulting from inhalation and dermal exposure. We evaluated associations between chlorination by-products in utero exposure and SGA by means of unconditional logistic regression with control of potential confounders.

RESULTS

When total trihalomethanes and the 5 regulated haloacetic acids concentrations were divided into quartiles, no clear dose-response relationship was found with SGA. However, increased risk was observed when haloacetic concentrations were above the fourth quartile and when either trihalomethanes or haloacetic acids concentrations were above current water standards (adjusted OR= 1.5 [95% confidence interval = 1.1-1.9] and 1.4 [1.1-1.9], respectively). Inhalation and dermal absorption of trihalomethanes did not contribute to this risk, but a monotonic dose-response was found with haloacetic acids ingestion.

CONCLUSION

Oral exposure to high levels of chlorination by-products in drinking water could be a risk factor for term SGA.

Relationships among maternal nutrient intake and placental biomarkers during the 1st trimester in low-income women

PURPOSE

Pre-eclampsia is a multi-system disorder caused by inadequate placentation in early pregnancy; however, little is known about the influence of nutrient intake on placental development during the crucial 1st trimester. The objective of this study was to examine the relationships between nutrient intake and the raw values and ratios of angiogenic [placental growth factor (PlGF)] and antiangiogenic [soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng)] placental biomarkers in the 1st trimester.

METHODS

A cross-sectional study of low-income, pregnant women (n = 118). Average nutrient intake was calculated from three 24-h dietary recalls. Biomarker values were adjusted for gestational age and nutrients were adjusted for energy.

RESULTS

The angiogenic to antiangiogenic ratio [PlGF/(sFlt-1 × sEng)] was positively related to intake of vitamin D (r = 0.24), vitamin B(2) (r = 0.25), B(12) (r = 0.20), dietary folate equivalents (r = 0.19), iron (r = 0.19), and zinc (r = 0.19) and negatively related to transfats (r = -0.24). Principal component analysis revealed that a vitamin/mineral factor [t (112) = 2.58, p = 0.011] and transfats factor [t (112) = -2.03, p = 0.045] were significant predictors of the PlGF/(sFlt-1 × sEng) ratio. The vitamin and mineral factor was a significant predictor of sFlt-1 [t (122) = 2.29, p = 0.024].

CONCLUSIONS

Expression of placental biomarkers in the early weeks of pregnancy may be influenced by intake of nutrients. Understanding the influence of maternal nutrient intake and placental development in the 1st trimester may provide the opportunity to avert the development or blunt the severity of preeclampsia.

Intrauterine growth restriction may not suppress bone formation at term, as indicated by circulating concentrations of undercarboxylated osteocalcin and Dickkopf-1

The objective was to investigate circulating concentrations of bone formation markers (undercarboxylated osteocalcin [Glu-OC], an established marker of bone formation during fetal and early postnatal life], and Dickkopf-1 [DKK-1], a natural inhibitor of osteoblastogenesis during fetal development]) in intrauterine-growth-restricted (IUGR; associated with impaired fetal skeletal development) and appropriate-for-gestational-age (AGA) pregnancies. Circulating concentrations of Glu-OC and DKK-1 were determined by enzyme immunoassay in 40 mothers and their 20 asymmetric IUGR and 20 AGA singleton full-term fetuses and neonates on postnatal day 1 (N1) and 4 (N4). Parametric tests were applied in the statistical analysis. No significant differences in Glu-OC concentrations were observed between IUGR and AGA groups, whereas fetal DKK-1 concentrations were lower in the IUGR group (P = .028). In both groups, maternal Glu-OC and DKK-1 concentrations were lower than fetal, N1, and N4 concentrations (P ≤ .012 in all cases), whereas fetal Glu-OC concentrations were higher than N1 and N4 ones (P ≤ .037 in all cases). In addition, N1 Glu-OC concentrations were higher than N4 concentrations (P = .047). Finally, maternal Glu-OC and DKK-1 concentrations positively correlated with fetal, N1, and N4 ones (r ≥ 0.404, P ≤ .01 in all cases). Fetal/neonatal bone formation may not be impaired in full-term asymmetric IUGR infants, as indicated by the similar Glu-OC concentrations in both groups. Fetal DDK-1 concentrations are lower in the IUGR group, representing probably a compensatory mechanism, favoring the formation of mineralized bone. Fetal/neonatal bone turnover is markedly enhanced compared with maternal one and seems to be associated with the latter in both late pregnancy and early postpartum.

Moderate to severe, but not mild, maternal anemia is associated with increased risk of small-for-gestational-age outcomes

Anemia is highly prevalent globally, estimated at 40-50% in women of reproductive age. Prior studies have produced inconclusive evidence as to the association between maternal anemia and intrauterine growth restriction (IUGR). We conducted a systematic review of the literature containing associations between maternal anemia and small for gestational age (SGA) outcomes (as a proxy for IUGR). A meta-analysis was performed to pool associations, categorized by the hemoglobin cutoffs presented by the authors. We identified 12 studies reporting associations between maternal anemia and SGA. For the meta-analysis, there were 7 associations with a hemoglobin cutoff <110 g/L, 7 with a cutoff <100 g/L, and 5 with a cutoff <90 or <80 g/L. Although the <110- and <100-g/L categories showed no significant relationship with SGA, the <90- or <80-g/L category was associated with a 53% increase in risk of the newborn being SGA [pooled OR = 1.53 (95% CI: 1.24-1.87); P < 0.001]. Moderate to severe, but not mild, maternal anemia appears to have an association with SGA outcomes, but the findings must be viewed with caution due to the great heterogeneity of the studies. Further examination should be conducted using datasets with better standardized definitions and measurements of exposure and outcome.

DNA methylation in the human placenta and fetal growth (review)

Throughout in utero development, the placenta plays a key role in controlling growth and development. The placenta acts not only as a gatekeeper of nutrient and waste exchange between mother and developing fetus, but also as a regulator of the intrauterine environment. Its functions can be influenced by the environment encountered throughout pregnancy, thereby altering the appropriate genetic programming needed to allow for appropriate fetal growth. Epigenetic alterations related to environmental exposures have been linked to aberrant fetal growth. DNA methylation, which is the best known DNA epigenetic modification, may provide an attractive mechanism linking environmental cues to placental pathology, with consequences for fetal growth and adult life. Alteration of the methylation patterns of genes expressed in the placenta has recently been found to modify gene expression and subsequently impair function of the placenta. Although there is strong evidence to demonstrate that the environment can affect the pattern of DNA methylation of the placenta during fetal development, a direct association between environmental conditions, methylation alterations and gene expression is difficult to confirm. DNA methylation in the placenta has mainly been investigated in the context of imprinted and non-imprinted genes transcription. Several environmental factors have also been assessed in regard to their association with changes to the epigenetic motives of embryonic and extraembryonic tissues and their impact on pregnancy outcome. In this review, we briefly present the available evidence regarding the role of DNA methylation patterns of the placenta on aberrant fetal growth.

Relationship between placental expression of the imprinted PHLDA2 gene, intrauterine skeletal growth and childhood bone mass

Alterations in expression of the imprinted gene PHLDA2 are linked to low birth weight in both humans and the mouse. However birth weight is a summary measure of fetal growth and provides little information on the growth rate of the fetus in early and late pregnancy. To examine the relation of PHLDA2 expression with rates of fetal growth and explore associations with the infant's body composition in early childhood, we measured PHLDA2 mRNA levels in the term placenta of 102 infants whose mothers were participating in the Southampton Women's Survey (SWS). Higher PHLDA2 expression was associated with a lower fetal femur growth velocity between 19 and 34 weeks gestation. In addition, higher placental PHLDA2 gene expression was associated with a lower child's bone mineral content at four years of age, measured using dual-energy X-ray absorptiometry. The results suggest that placental PHLDA2 may provide a biomarker for suboptimal skeletal growth in pregnancies uncomplicated by overt fetal growth restriction.

Intrauterine growth restriction: cytokine profiles of trophoblast antigen-stimulated maternal lymphocytes

Intrauterine growth restriction (IUGR) is an important perinatal syndrome that poses several serious short- and long-term effects. We studied cytokine production by maternal peripheral blood lymphocytes stimulated by trophoblast antigens. 36 women with a diagnosis of IUGR and 22 healthy women with normal fetal growth were inducted. Peripheral blood mononuclear cells were stimulated with trophoblast antigens and levels of the proinflammatory cytokines IL-6, IL-8, IL-12, IL-23, IFNγ, and TNFα and the anti-inflammatory cytokines IL-4, IL-10, and IL-13 were measured in culture supernatants by ELISA. IL-8 was produced at higher levels by blood cells of the IUGR group than normal pregnant women, while IL-13 was produced at lower levels. IL-8, IFNγ, and TNFα were higher in IUGR with placental insufficiency than in normal pregnancy. IL-12 levels were higher and IL-10 levels were lower in IUGR with placental insufficiency than in IUGR without placental insufficiency. We suggest that a stronger pro-inflammatory bias exists in IUGR as compared to normal pregnancy and in IUGR with placental insufficiency when compared to IUGR without placental insufficiency. Several ratios of proinflammatory to anti-inflammatory cytokines also support the existence of an inflammatory bias in IUGR.

Exposure to anti-infective drugs during pregnancy and the risk of small-for-gestational-age newborns: a case-control study

OBJECTIVE

To determine the association between anti-infective exposure during the last two trimesters of pregnancy and the risk of small-for-gestational-age (SGA) newborns.

DESIGN

Case-control study within the Québec Pregnancy Registry.

SETTING

Province of Québec, Canada.

SAMPLE

Analyses were performed on prospectively collected data of 63,338 pregnant women that met eligibility criteria for the study (8192 cases and 55,146 controls).

METHODS

Unconditional logistic regression models were used to quantify the association between exposure to anti-infective drugs and the risk of SGA.

MAIN OUTCOME MEASURES

A case of SGA was defined as a pregnancy resulting in a baby that weighs below the tenth percentile, adjusted for gestational age and gender, according to the Canadian gender-specific reference curves. A control was defined as a pregnancy resulting in a baby that weighs greater or equal to the tenth percentile, adjusted for gestational age and gender.

RESULTS

Exposure to all combined anti-infective drugs was not associated with the risk of SGA (OR 0.97; 95% CI 0.91-1.04). The use of sulfamethoxazole/trimethoprim was associated with SGA (OR 1.61; 95% CI 1.16-2.23), whereas the use of urinary anti-infective drugs decreased the risk (OR 0.80; 95% CI 0.65-0.97).

CONCLUSIONS

Exposure to sulfamethoxazole/trimethoprim during the last two trimesters of pregnancy was associated with SGA. Further research is needed to address the use of other therapeutic alternatives in the management of infections that predispose infants being born SGA in pregnant women with other risk factors for this condition.

Safety of topical corticosteroids in pregnancy: a population-based cohort study

Topical corticosteroids may be indicated in pregnant women with skin conditions, but their safety in pregnancy is unclear. We used the UK General Practice Research Database to conduct a population-based cohort study to investigate whether maternal exposure to topical corticosteroids results in adverse pregnancy outcomes. We identified 35,503 pregnant women prescribed topical corticosteroids during the period from 85 days before last menstrual period (LMP) to delivery or fetal death and 48,630 unexposed women. We found no associations of maternal exposure to topical corticosteroids with orofacial cleft (and its two subtypes, i.e., cleft lip ± palate (CLP) and cleft palate alone (CP)), preterm delivery, and fetal death (including miscarriage and stillbirth). The findings were similar when excluding exposure before LMP. In contrast, maternal exposure to potent/very potent topical corticosteroids shortly before and during pregnancy was significantly associated with fetal growth restriction (adjusted relative risk 2.08; 95% confidence interval 1.40-3.10; number needed to harm, 168), which was confirmed by a significant dose-response relationship (P=0.025) and the sensitivity analysis excluding exposure before LMP. The increased risk for fetal growth restriction should be considered when prescribing potent/very potent topical corticosteroids to pregnant women, and appropriate obstetric care should be provided.

Circulating levels of inflammatory markers in intrauterine growth restriction

We aimed to investigate possible alterations in circulating levels of the perinatal stress markers high sensitivity (hs)-CRP, PAI-1, and S100B—probably reflecting brain and adipose tissue inflammation—in intrauterine growth-restricted-(IUGR) and appropriate-for-gestational-age-(AGA) pregnancies, given that these groups differ in fat mass and metabolic mechanisms involving aseptic inflammation. Serum hs-CRP, PAI-1, and S100B levels were measured in 40 mothers, and their 20 AGA and 20 IUGR full-term fetuses and neonates on postnatal days 1 and 4. hs-CRP, PAI-1, and S100B levels did not differ at all time points between AGA and IUGR groups. We conclude that the lack of difference in hs-CRP, PAI-1 and S100B levels, between IUGR and AGA fetuses/neonates—despite the lower birth weight, reflecting reduced fat mass in the former—might indicate more intense adipose tissue and nervous system inflammation in IUGRs. However, implication of other inflammation-related mechanisms, common in the IUGR state (e.g. preeclampsia), cannot be excluded.

The Mediator complex protein Med31 is required for embryonic growth and cell proliferation during mammalian development

During development, the mammalian embryo must integrate signals to control growth and proliferation. A failure in the ability to respond to mitogenic stimuli can cause embryonic growth restriction. We have identified a mouse mutant, l11Jus15, from a mutagenesis screen that exhibits growth defects and late-gestation lethality. Here we demonstrate that this phenotype results from a mutation in the Mediator complex gene Med31, which causes degradation of Med31 protein. The Med31 mutant phenotype is not similar to other Mediator complex mouse mutants, and target genes of other Mediator proteins are expressed normally in Med31 mutants, suggesting that Med31 has distinct target genes required for mammalian development. Med31 mutant embryos have fewer proliferating cells than controls, especially in regions that expand rapidly during development such as the forelimb buds. Likewise, embryonic fibroblast cells cultured from mutant embryos have a severe proliferation defect, as well as reduced levels of the cell cycle protein Cdc2. Med31 mutants have normal limb bud patterning but defective or delayed chondrogenesis due to a lack of Sox9 and Col2a1 expression. As the Mediator complex is a transcriptional co-activator, our results suggest that Med31 functions to promote the transcription of genes required for embryonic growth and cell proliferation.

Regulation of amino acid transporters by glucose and growth factors in cultured primary human trophoblast cells is mediated by mTOR signaling

Inhibition of mammalian target of rapamycin (mTOR) signaling in cultured human primary trophoblast cells reduces the activity of key placental amino acid transporters. However, the upstream regulators of placental mTOR are unknown. We hypothesized that glucose, insulin, and IGF-I regulate placental amino acid transporters by inducing changes in mTOR signaling. Primary human trophoblast cells were cultured for 24 h with media containing various glucose concentrations, insulin, or IGF-I, with or without the mTOR inhibitor rapamycin, and, subsequently, the activity of system A, system L, and taurine (TAUT) transporters was measured. Glucose deprivation (0.5 mM glucose) did not significantly affect Thr172-AMP-activated protein kinase phosphorylation or REDD1 expression but decreased S6 kinase 1 phosphorylation at Thr389. The activity of system L decreased in a dose-dependent manner in response to decreasing glucose concentrations. This effect was abolished in the presence of rapamycin. Glucose deprivation had two opposing effects on system A activity: 1) an "adaptive" upregulation mediated by an mTOR-independent mechanism and 2) downregulation by an mTOR-dependent mechanism. TAUT activity was increased after incubating cells with glucose-deprived media, and this effect was largely independent of mTOR signaling. Insulin and IGF-I increased system A activity and insulin stimulated system L activity, effects that were abolished by rapamycin. We conclude that the mTOR pathway represents an important intracellular regulatory link between nutrient and growth factor concentrations and amino acid transport in the human placenta.

Complexity analysis of the fetal heart rate variability: early identification of severe intrauterine growth-restricted fetuses

The main goal of this work is to suggest new indices for a correct identification of the intrauterine growth-restricted (IUGR) fetuses on the basis of fetal heart rate (FHR) variability analysis performed in the antepartum period. To this purpose, we analyzed 59 FHR time series recorded in early periods of gestation through a Hewlett Packard 1351A cardiotocograph. Advanced analysis techniques were adopted including the computation of the Lempel Ziv complexity (LZC) index and the multiscale entropy (MSE), that is, the entropy estimation with a multiscale approach. A multiparametric classifier based on k-mean cluster analysis was also performed to separate pathological and normal fetuses. The results show that the proposed LZC and the MSE could be useful to identify the actual IUGRs and to separate them from the physiological fetuses, providing good values of sensitivity and accuracy (Se = 77.8%, Ac = 82.4%).

Reviews: adipocytokines in normal and complicated pregnancies

Human pregnancy is characterized by insulin resistance, traditionally attributed to the effects of placental hormones. Normal pregnancy-induced insulin resistance is further enhanced in pregnancy complications, associated with disturbed placental function, such as gestational diabetes mellitus, preeclampsia, and intrauterine growth restriction. Compelling evidence suggests that these pregnancy disorders are associated with future development of maternal metabolic syndrome. However, the pathogenetic mechanisms underlying the association between abnormal placental development, insulin resistance, and maternal metabolic syndrome are not fully understood. A large body of evidence has recently supported the role of adipose tissue in the regulation of insulin resistance in both nonpregnant and pregnant participants. In this respect, adipocytokines, which are adipocyte-derived hormones, have been implicated in the regulation of maternal metabolism and gestational insulin resistance. Adipocytokines, including leptin, adiponectin, tumor necrosis factor alpha, interleukin 6, as well as the newly discovered resistin, visfatin, and apelin, are also known to be produced within the intrauterine environment. However, data concerning the pattern of adipocytokines secretion in normal and complicated pregnancies are still limited and partially contradictory. Given the importance of adipose tissue and its hormones in terms of adequate metabolic control and energy homeostasis, we present a review of published data related to the role of adipocytokines in pregnancy, especially in relation to pregnancy complications. Focus will be placed on the functions and other potential roles of the novel adipocytokines resistin, visfatin, and apelin.

[Influence of socioeconomic factors on weight, length and head circumference measurements in newborns from 35 to 42 weeks gestational age]

BACKGROUND AND OBJECTIVE

gestational age and anthropometric measurements, i.e. weight, length and head circumference at birth, have all been used as predictors of neonatal morbidity-mortality and adult morbidity. Differences in ethnic or socioeconomic background of newborn cohorts, as well as methodological differences between studies limit the validity and application of current anthropometric curves across different populations. Thus, we conducted a study to obtain local reference data in a Hospital that had a medium-high socio-economic class population, probably different to others recently published in our geographic area, and to compare them.

PATIENTS AND METHOD

Weight, length and head circumference at birth were retrospectively analysed in 31,397 live Caucasian neonates born at 23-42 weeks in SCIAS-Hospital de Barcelona between 1992 and 2006. Only single gestations were selected and no other exclusion by materno-fetal or neonatal pathology criteria were applied. Percentile values, mean and standard deviation for each anthropometric measurement were calculated according to gestational age and gender. They were compared with the results from recent publications of our geographic area.

RESULTS

Males were found to have significantly higher weight, length and head circumference values than females from 36 weeks. There was a trend towards higher values in our population when compared with others in our geographic area.

CONCLUSIONS

The influence of socioeconomic factors on fetal growth seems evident. Nevertheless, it is difficult to assume that the observed differences must be exclusively due to the population characteristics or the different methodologies in the selection of the sample. Thus, it is desirable to have anthropometric reference curves obtained from populations of surrounding areas, with epidemiological methodologies that might be more appropriate in identifying valid outcome predictors, and enable us to compare with others groups according to racial, socioeconomic and disease factors.

Regulation of placental amino acid transporter activity by mammalian target of rapamycin

The activity of placental amino acid transporters is decreased in intrauterine growth restriction (IUGR), but the underlying regulatory mechanisms have not been established. Inhibition of the mammalian target of rapamycin (mTOR) signaling pathway has been shown to decrease the activity of the system L amino acid transporter in human placental villous fragments, and placental mTOR activity is decreased in IUGR. In the present study, we used cultured primary trophoblast cells to study mTOR regulation of placental amino acid transporters in more detail and to test the hypothesis that mTOR alters amino acid transport activity by changes in transporter expression. Inhibition of mTOR by rapamycin significantly reduced the activity of system A (−17%), system L (−28%), and taurine (−40%) amino acid transporters. mRNA expression of isoforms of the three amino acid transporter systems in response to mTOR inhibition was measured using quantitative real-time PCR. mRNA expression of l-type amino acid transporter 1 (LAT1; a system L isoform) and taurine transporter was reduced by 13% and 50%, respectively; however, mTOR inhibition did not alter the mRNA expression of system A isoforms (sodium-coupled neutral amino acid transporter-1, -2, and -4), LAT2, or 4F2hc. Rapamycin treatment did not significantly affect the protein expression of any of the transporter isoforms. We conclude that mTOR signaling regulates the activity of key placental amino acid transporters and that this effect is not due to a decrease in total protein expression. These data suggest that mTOR regulates placental amino acid transporters by posttranslational modifications or by affecting transporter translocation to the plasma membrane.

Differences in short-term neonatal outcomes between discordant twins

PURPOSE

To evaluate short-term outcomes associated with discordant twin pairs admitted to the NICU.

DESIGN

A retrospective descriptive study comparing discordant twin pairs.

SUBJECTS

Three hundred eighty-four discordant twin pairs were included. Mean gestational age of the twin pairs was 32.6 weeks (range, 24-39).

METHODS

The ParadigmHealth database was queried for all twin admissions from January 2001 to June 2004 admitted to 453 NICUs across the United States. Discordance was calculated for each twin set as defined as greater than 20% difference in birth weight. Exclusion criteria were death of a twin, congenital anomalies, or extracorporeal life support.

MAIN OUTCOME MEASURES

Demographics, respiratory needs, feeding characteristics, complications, and discharge needs.

RESULTS

A total of 384 discordant twin pairs met inclusion criteria. The larger twins required more ventilation/continuous positive airway pressure (55% vs 44%, P < .01) and/or oxygen therapy (50% vs 41%, P = .02) compared with smaller twins. Smaller twins reached full oral (PO) feeds an average of 0.6 weeks later than larger twins (P < .0001) but had more weight gain per day. Smaller twins transitioned to an open crib at lower weights but at slightly greater age. No differences were noted with necrotizing enterocolitis or apnea. Smaller twins had increased nosocomial infections. Mean length of stay was shorter (P = .0036) in the larger twin group. Only 33% of the twin pairs were discharged on the same day.

CONCLUSIONS

Larger twins had more acute respiratory issues but achieved certain milestones more rapidly with fewer complications, thus leading to earlier discharge compared with their smaller twin counterparts.

Non-placental causes of intrauterine growth restriction

Placental insufficiency, in some form or fashion, is associated with the majority of cases of intrauterine growth restriction (IUGR). There are numerous causes of IUGR which are not caused primarily by placental insufficiency, but indirectly lead to it. The causes of IUGR can be subdivided into fetal and maternal etiologies. The fetal etiologies consist of genetic diseases, congenital malformations, infections, multiple gestations, and placental/cord abnormalities. The maternal etiologies are categorized as follows: (1) decreased uteroplacental blood flow, (2) reduced blood volume, (3) decreased oxygen carrying capacity, (4) nutrition status, (5) teratogens, and (6) miscellaneous causes such as short interpregnancy intervals, race, maternal age, and low socioeconomic status. Knowledge of the etiologies of fetal growth restriction is essential, so that future care can be targeted at prevention. There are several primary and secondary prevention strategies that can be adopted.

Altered gene expression and methylation of the human chromosome 11 imprinted region in small for gestational age (SGA) placentae

Imprinted genes are known to be crucial for placental development and fetal growth in mammals, but no primary epigenetic abnormality in placenta has been documented to compromise human fetal growth. Imprinted genes demonstrate parent-of-origin-specific allelic expression that is epigenetically regulated i.e. extrinsic to the primary DNA sequence. To undertake an epigenetic analysis of poor fetal growth in placentae and cord blood tissues, we first established the tissue-specific patterns of methylation and imprinted gene expression for two imprinting clusters (KvDMR and H19 DMR) on chromosome 11p15 in placentae and neonatal blood for 20 control cases and 24 Small for Gestational Age (SGA) cases. We confirmed that, in normal human placenta, the H19 promoter is unmethylated. In contrast, most other human tissues show paternal methylation. In addition, we showed that the IGF2 DMR2, also paternally methylated in most human tissues, exhibits hypomethylation in placentae. However, in neonatal blood DNA, these two regions maintain the differential methylation status seen in most other tissues. Significantly, we have been able to demonstrate that placenta does maintain differential methylation at the imprinting control regions H19 DMR and KvDMR. Of note, in one SGA placenta, we found a methylation alteration at the H19 DMR and concomitant biallelic expression of the H19 gene, suggesting that loss of imprinting at H19 is one cause of poor fetal growth in humans. Of particular interest, we demonstrated also a decrease in IGF2 mRNA levels in all SGA placentae and showed that the decrease is, in most cases, independent of H19 regulation.

Chronic hypoxia increases fetoplacental vascular resistance and vasoconstrictor reactivity in the rat

An increase in fetoplacental vascular resistance caused by hypoxia is considered one of the key factors of placental hypoperfusion and fetal undernutrition leading to intrauterine growth restriction (IUGR), one of the serious problems in current neonatology. However, although acute hypoxia has been shown to cause fetoplacental vasoconstriction, the effects of more sustained hypoxic exposure are unknown. This study was designed to test the hypothesis that chronic hypoxia elicits elevations in fetoplacental resistance, that this effect is not completely reversible by acute reoxygenation, and that it is accompanied by increased acute vasoconstrictor reactivity of the fetoplacental vasculature. We measured fetoplacental vascular resistance as well as acute vasoconstrictor reactivity in isolated perfused placentae from rats exposed to hypoxia (10% O2) during the last week of a 3-wk pregnancy. We found that chronic hypoxia shifted the relationship between perfusion pressure and flow rate toward higher pressure values (by ∼20%). This increased vascular resistance was refractory to a high dose of sodium nitroprusside, implying the involvement of other factors than increased vascular tone. Chronic hypoxia also increased vasoconstrictor responses to angiotensin II (by ∼75%) and to acute hypoxic challenges (by >150%). We conclude that chronic prenatal hypoxia causes a sustained elevation of fetoplacental vascular resistance and vasoconstrictor reactivity that are likely to produce placental hypoperfusion and fetal undernutrition in vivo.

Perinatal bone turnover in term pregnancies: the influence of intrauterine growth restriction

Intrauterine growth restriction (IUGR) has been associated with low bone mass in infancy and increased risk for osteoporosis development in adult life. We aimed to investigate the effect of IUGR on bone metabolism in mother/infant pairs, by determining circulating biochemical markers of bone turnover in IUGR and appropriate for gestational age (AGA) pregnancies. Circulating markers of bone formation [bone specific alkaline phosphatase (BALP), total alkaline phosphatase (ALP), osteocalcin (OC)] and bone resorption [cross-linked N-telopeptide of type I collagen (NTx)], as well as intact parathormone (PTH), calcium and phosphorus levels were measured in 40 mothers and their 20 IUGR and 20 AGA singleton full-term fetuses and neonates on postnatal days 1 (N1) and 4 (N4). No significant differences in BALP, ALP, OC, NTx, PTH, calcium or phosphorus levels were observed between the AGA and the IUGR groups. In both groups, maternal BALP levels were lower compared to fetal, N1 and N4 levels (p< or =0.005 in all cases). In the AGA group, maternal NTx and OC levels were lower compared to fetal, N1 and N4 levels (p<0.001 in all cases), and fetal NTx levels were lower compared to N1 and N4 ones (p<0.001 and p=0.002, respectively). In the IUGR group, maternal OC levels were lower compared to fetal, N1 and N4 ones (p<0.001 in each case) and fetal OC levels were elevated compared to N1 and N4 ones (p<0.001 and p=0.003, respectively). N4 NTx levels were elevated compared to maternal, fetal and N1 levels (p=0.009, p<0.001 and p=0.002, respectively) and fetal NTx levels were lower compared to N1 and N4 ones (p=0.001 and p<0.001, respectively). Finally, positive correlations were found between maternal NTx and BALP (r=0.332, p=0.037), as well as ALP (r=0.329, p=0.038) levels, and between maternal, fetal, N1, N4 BALP and respective ALP levels (r=0.432, p=0.005, r=0.534, p=0.001, r=0.778, p<0.001, r=0.694, p<0.001, respectively). In conclusion, maternal, fetal and neonatal bone turnover in IUGR cases may not differ from respective bone metabolism in AGA controls. In addition, fetal and neonatal bone remodeling is markedly enhanced and independent of maternal bone turnover in late pregnancy.

Adverse birth outcome among mothers with low serum cholesterol

OBJECTIVE

The objective of this study was to assess whether low maternal serum cholesterol during pregnancy is associated with preterm delivery, impaired fetal growth, or congenital anomalies in women without identified major risk factors for adverse pregnancy outcome.

METHODS

Mother-infant pairs were retrospectively ascertained from among a cohort of 9938 women who were referred to South Carolina prenatal clinics for routine second-trimester serum screening. Banked sera were assayed for total cholesterol; <10th percentile of assayed values (159 mg/dL at mean gestational age of 17.6 weeks) defined a "low total cholesterol" prenatal risk category. Eligible women were aged 21 to 34 years and nonsmoking and did not have diabetes; neonates were liveborn after singleton gestations. Total cholesterol values of eligible mothers were adjusted for gestational age at screening before risk group assignment. The study population included 118 women with low total cholesterol and 940 women with higher total cholesterol. Primary analyses used multivariate regression models to compare rates of preterm delivery, fetal growth parameters, and congenital anomalies between women with low total cholesterol and control subjects with mid-total cholesterol values >10th percentile but <90th percentile.

RESULTS

Prevalence of preterm delivery among mothers with low total cholesterol was 12.7%, compared with 5.0% among control subjects with mid-total cholesterol. The association of low maternal serum cholesterol with preterm birth was observed only among white mothers. Term infants of mothers with low total cholesterol weighed on average 150 g less than those who were born to control mothers. A trend of increased microcephaly risk among neonates of mothers with low total cholesterol was found. Low maternal serum cholesterol was unassociated with risk for congenital anomalies.

CONCLUSIONS

Total serum cholesterol <10th population percentile was strongly associated with preterm delivery among otherwise low-risk white mothers in this pilot study population. Term infants of mothers with low total cholesterol weighed less than control infants among both racial groups.

Fetal kidney volume and its association with growth and blood flow in fetal life: The Generation R Study

An adverse fetal environment may lead to smaller kidneys and subsequent hypertension with renal disease in adult life. The aim of our study was to examine whether maternal characteristics, fetal growth, fetal blood flow redistribution, or inadequate placental perfusion in different periods of fetal life affect kidney volume in late fetal life. We also determined if fetal kidney volume was linked to the amount of amniotic fluid. In a population-based prospective study from early fetal life, fetal growth characteristics and fetal blood flow parameters were assessed by ultrasound and Doppler examinations in 1215 women in mid- and late-pregnancy. Kidney volume was measured in late pregnancy. Maternal height and pre-pregnancy weight were associated with kidney volume. After adjustment for the same characteristics in late pregnancy, fetal growth and blood flow in mid-pregnancy were not associated with kidney volume in late pregnancy. In late pregnancy, however, all fetal growth parameters were positively linked with kidney volume. The largest effect on kidney volume was found for abdominal circumference. Signs of fetal blood flow redistribution and increased placental resistance were associated with decreased kidney volume in late pregnancy. Amniotic fluid volume was positively associated with kidney volume. Our study shows that maternal anthropometrics, fetal growth, fetal blood flow redistribution, and raised placental resistance all correlate with kidney volume.

Regulation of Placental Nutrient Transport – A Review

Fetal growth is primarily determined by nutrient availability, which is intimately related to placental nutrient transport. Detailed information on the regulation of placental nutrient transporters is therefore critical in order to understand the mechanisms underlying altered fetal growth and fetal programming. After briefly summarizing the cellular mechanisms for placental transport of glucose, amino acids and free fatty acids, we will discuss factors shown to regulate placental nutrient transporters and review the data describing how these factors are altered in pregnancy complications associated with abnormal fetal growth. We propose an integrated model of regulation of placental nutrient transport by maternal and placental factors in IUGR.

Standards for the measurement of birth weight, length and head circumference at term in neonates of European, Chinese and South Asian ancestry

BACKGROUND

Fetal growth restriction is associated with metabolic derangements in the newborn, impaired functioning in childhood and chronic diseases in adulthood. Differences between ethnic groups with respect to fetal growth may result in the misclassification of constitutionally small or large babies as having abnormal growth for their gestational age. We have developed intrauterine growth charts based on precise measurements of newborns whose parents were both of European, Chinese or South Asian ethnicity.

METHODS

Weight, length and head circumference were measured in 2695 infants born to healthy non-smoking mothers in British Columbia at 37-41 completed weeks of gestation. Gestational age was confirmed by ultrasound before 20 weeks of gestation. Weight was measured by digital scale, length by stadiometer and head circumference by firm plastic tape measures. Means and 95% confidence intervals were compared among newborns grouped by ethnicity and sex. Smoothed graphs were constructed for visual interpretation.

RESULTS

At 40 weeks, infants of European descent ("European" infants) weighed 225.5 g more on average than infants of Chinese descent ("Chinese" infants) (p < 0.001) and 254.6 g more than infants of South Asian descent ("South Asian" infants) (p < 0.001). The mean difference in birth weight between Chinese and South Asian infants (19.1 g) was not statistically significant. The mean length of European infants at 40 weeks of gestation was 0.89 cm greater than that of Chinese infants (p < 0.001). Differences in mean length between European and South Asian babies or between Chinese and South Asian babies was not statistically significant. The mean head circumferance of European babies was 0.50 cm larger than that of Chinese babies at 40 weeks (p < 0.001) but did not differ significantly from that of South Asian babies. South Asian and Chinese babies had similar mean head circumferences at 40 weeks. When differences in mean birth weight, length and head circumference were examined within boys and girls, the observed differences according to ethnicity remained statistically significant.

CONCLUSION

Important differences in weight, length and head circumferences are reported among babies according to ethnicity. The use of sex- and ethnicity-specific growth charts may prevent the misclassification of newborns as small or large for gestational age.

The ABC transporter BCRP/ABCG2 is a placental survival factor, and its expression is reduced in idiopathic human fetal growth restriction

The efflux pump ATP binding cassette superfamily member G2 (ABCG2)/breast cancer resistance protein (BCRP) is highly expressed in human placenta. We have investigated the role of BCRP in the protection of the human placental trophoblasts from apoptosis and its expression in idiopathic fetal growth restriction, a condition associated with abnormal placental apoptosis. Inhibition of BCRP activity with the selective inhibitor Ko143 augmented cytokine (tumor necrosis factor-alpha/interferon-gamma)-induced apoptosis and phosphatidylserine externalization in primary trophoblast and trophoblast-like BeWo cells. Silencing of BCRP expression in BeWo cells significantly increased their sensitivity to apoptotic injury in response to cytokines and exogenous C6 and C8 ceramides. BCRP silencing also increased intracellular ceramide levels after cytokine exposure but did not affect cellular protoporphyrin IX concentrations or sensitivity to activators of the intrinsic apoptotic pathway. BCRP expression in placentas from pregnancies complicated by idiopathic fetal growth restriction was decreased compared with controls, suggesting reduced transport of its substrates from the placenta. We conclude that BCRP may play a hitherto unrecognized survival role in the placenta, protecting the trophoblast against cytokine-induced apoptosis and possibly other extrinsic activators via modulation of ceramide signaling. Decreased placental BCRP expression may result in reduced viability and hence functional deficit, contributing to the fetal growth restriction phenotype.

Mammalian target of rapamycin in the human placenta regulates leucine transport and is down-regulated in restricted fetal growth

Pathological fetal growth is associated with perinatal morbidity and the development of diabetes and cardiovascular disease later in life. Placental nutrient transport is a primary determinant of fetal growth. In human intrauterine growth restriction (IUGR) the activity of key placental amino acid transporters, such as systems A and L, is decreased. However the mechanisms regulating placental nutrient transporters are poorly understood. We tested the hypothesis that the mammalian target of rapamycin (mTOR) signalling pathway regulates amino acid transport in the human placenta and that the activity of the placental mTOR pathway is reduced in IUGR. Using immunohistochemistry and culture of trophoblast cells, we show for the first time that the mTOR protein is expressed in the transporting epithelium of the human placenta. We further demonstrate that placental mTOR regulates activity of the l-amino acid transporter, but not system A or taurine transporters, by determining the mediated uptake of isotope-labelled leucine, methylaminoisobutyric acid and taurine in primary villous fragments after inhibition of mTOR using rapamycin. The protein expression of placental phospho-S6K1 (Thr-389), a measure of the activity of the mTOR signalling pathway, was markedly reduced in placentas obtained from pregnancies complicated by IUGR. These data identify mTOR as an important regulator of placental amino acid transport, and provide a mechanism for the changes in placental leucine transport in IUGR previously demonstrated in humans. We propose that mTOR functions as a placental nutrient sensor, matching fetal growth with maternal nutrient availability by regulating placental nutrient transport.

Doppler and birth weight Z score: predictors for adverse neonatal outcome in severe fetal compromise

Background

An adequate placental perfusion is crucial for the normal growth and well being of the fetus and newborn. The blood flow through the placenta can be compromised in a variety of clinical situations, always causing important damage to the gestation. Our objective is to identify significant predictors for adverse neonatal outcome in severe fetal compromise.

Methods

Consecutive premature fetuses at between 25 and 32 weeks with severe placental insufficiency were examined prospectively. Inclusion criteria were: (i) singletons (ii) normal anatomy; (iii) abnormal umbilical artery Doppler pulsatility index (PI); (iv) abnormal cerebroplacental ratio; (v) middle cerebral artery (MCA) PI < - 2SD ("brain sparing"); (vi) last Doppler examination performed within 24 hours prior to delivery. All 46 patients that met criteria and started the study were followed to the end. We considered as independent potential predicting variables: absent or reversed end diastolic flow in umbilical artery, abnormal ductus venosus S/A ratio, absent or reversed flow during atrial contraction in the ductus venosus and birth weight Z score. Outcome parameters were: neonatal mortality and severe neonatal morbidity.

Results

Backward stepwise logistic regression analysis was used to determine the optimal model for the prediction of neonatal mortality and severe neonatal morbidity. In this analysis birth weight Z score index showed the strongest association OR = 1,87 [1,17-2,99] with all neonatal outcome, all other independent variables were excluded for the optimal model. There was no mortality for the group with normal birth weight Z score.

Conclusion

Our study suggests that birth weight Z score is the strongest predictor of adverse neonatal outcome in severe placental insufficiencies. Such use of Z scores, allowing to get rid of gestational age or sex covariates could be extended to estimated fetal weight and might help in making important decisions in the management of compromised pregnancies.

Predicting adverse neonatal outcome in severe fetal compromise: A pivotal role for estimated fetal weight Z scores

OBJECTIVE

To identify significant predictors for adverse neonatal outcome in severe by compromised fetuses.

METHODS

Consecutive premature fetuses at between 25 and 32 weeks' with severe placental insufficiency were examined prospectively. Inclusion criteria were: singletons; normal anatomy; abnormal umbilical artery Doppler pulsatility index; abnormal cerebroplacental ratio; middle cerebral artery pulsatility index (PI) <or=2 standard deviations. We considered as independent potential predicting variables: absent or reversed end diastolic flow in umbilical artery, abnormal ductus venosus S/A ratio, absent or reversed flow during atrial contraction in the ductus venosus, and estimated fetal weight (EFW) Z score. Outcome parameters were: neonatal mortality and severe neonatal morbidity (Periventricular-Intraventricular Hemorrhage grade 03 or 04, Retinopathy of Prematurity stage 3 or 4, Periventricular Leukomalacia or Broncopulmonary Dysplasia).

RESULTS

Univariate analysis for all potential predicting variables was performed. EFW Z score index showed the strongest association with mortality and there was no fetal death or Retinopathy of Prematurity in the group with EFW Z-score index below lower limit. There was no case of Cystic Periventricular Leukomalatia in these analyses. The area under receiver-operator characteristic curve was significant for EFW Z-score index.

CONCLUSION

Our study suggests that EFW Z score is the strongest predictor of adverse neonatal outcome in severely compromised fetuses.

No effect of nutrient restriction from gestational days 28 to 78 on immunocytochemically detectable growth hormone-releasing hormone (GHRH) neurons and GHRH receptor colocalization in somatotropes of the ovine female fetus

The maternal environment affects fetal development and may permanently affect the physiology of the adult. Fetal growth hormone (GH) secretion is increased by maternal undernutrition but the physiological mechanisms responsible for this increase are unknown. We have recently found evidence suggesting that the GHRH component of the fetal neuroendocrine GH axis may be perturbed by undernutrition. This study sought to determine the effect of maternal undernutrition on immunocytochemically detectable GHRH neurons and the expression of GHRH receptors by somatotropes in the pituitary gland. Ewes were grouped (n=12 per group) randomly into control (fed 100% of requirements) or nutrient restricted (fed 50% of requirements) from days 28 to 78 of gestation, corresponding to the period from implantation to the end of placentation. At day 78, half the ewes were killed and the fetal brains were perfused. The remaining ewes were re-alimented to 100% of nutritional requirements and killed at day 135. There was no effect of nutrition restriction or age on the number of GHRH neurons. Similarly, the mean density and percentage of somatotropes expressing GHRH receptors was not significantly different between treatment groups at either age. This study found no effect, as determined by immunocytochemistry, of nutrient restriction on the GHRH component of the fetal neuroendocrine GH axis. It remains to be established if the release of GHRH and responsiveness of somatotropes to GHRH in the fetus are affected by undernutrition.

Twin birth weight standards

OBJECTIVE

The aim of this study was to present customized twin-specific birth weight standards. The relative contribution of gestational age, maternal factors, twin factors and placental factors to the birth weight was evaluated in a multivariate approach.

SUBJECTS AND METHODS

Perinatal data were obtained from 10,177 live-born twins from the East Flanders Prospective Twin Survey. Of 8,454 twins (4,227 pairs), of whom all data were available, the birth weights at different gestational ages were analyzed using a non-linear multivariate gaussian regression.

RESULTS

All considered covariates influenced birth weight of twins significantly, with the exception of sex of the co-twin and mode of conception and delivery. At 37 weeks of gestation, a difference of >1 kg existed between favourable and adverse prenatal environment. Up to 40 weeks, sex, site of the umbilical cord, parity, and birth order had a greater influence on birth weight than zygosity, chorionicity and fusion of the placentas. From 34 weeks on, the birth weight of the second-born twin deviated and after 40 weeks, birth weight of monozygotic monochorionic twins dropped, while the other twins continued to grow.

CONCLUSION

Customized twin-specific birth weight standards, which take these covariates into account, offer the opportunity for a better assessment of the influence of birth weight of the twin on neonatal health in future research. Already the Developmental Origins of Health and Disease hypothesis showed that these prenatal conditions might also be important for the follow-up of the twin.

Part 1: a matter of size: evaluating the growth-restricted neonate

The relative size of a neonate impacts many aspects of prenatal and postnatal surveillance and care. The designations of appropriate for gestational age, small-for-gestational age, intrauterine growth restriction, and large-for-gestational age are systematic categorizations used to assess and monitor growth throughout pregnancy and delivery. Each abnormal growth descriptor aids in anticipating neonatal needs after birth because each has the potential for complications related to feeding, glucose utilization, short- and long-term growth, and development. Maternal risk factors that impact the neonate's size-related can have immediate implications in the delivery room as well as significant effects postnatally. Caring for neonates at risk for size complications requires knowledge based on prenatal and postnatal complications. Neonates must be carefully measured and plotted on growth charts to confirm a visual assessment of size. Each growth complication requires individual attention to detail and careful planning to maximize adequate postnatal growth and nutrition. Size matters when it comes to the health and welfare of neonates. Anticipatory guidance can improve outcomes in the neonate at risk for failure to thrive from size complications at birth. Part 1 of this article provides an overview of the size classifications and a discussion of clinical factors that are associated with or contribute to small-for-gestational age births. Once the neonate's size for gestational age is calculated, a focused physical assessment is described along with nursing care and prognostic implications. Part 2 will focus on the physical assessment, nursing care, prognosis, and complications associated with large-for-gestational-age neonates.

Neuropsychological outcome of children with intrauterine growth restriction: a 9-year prospective study

OBJECTIVE

The aim was to evaluate the effect of late-onset intrauterine growth restriction on the neuropsychological profile and on academic achievements at 9 years of age using a large-scale prospective paradigm.

STUDY DESIGN

We followed up 123 infants diagnosed with late-onset intrauterine growth restriction yearly for 9 years. They were matched with 63 children for gestation age and multiple socioeconomic factors and evaluated by an extensive neuropsychological battery to assess intelligence quotient, academic achievements, learning and memory, visuomotor skills, visuospatial integration, attention, language, executive functions, and creativity.

RESULTS

Children with intrauterine growth restriction had lower intelligence quotient and more frequent neuropsychological difficulties. Difficulties in executive functioning, inflexibility-creativity, and language, indicative of frontal lobe dysfunction, were typically affected by intrauterine growth restriction and were rarely identified in the control group. Learning difficulties accompanied by lower academic achievements were more prevalent in the intrauterine growth restriction group, particularly when anthropometric catch-up was incomplete.

CONCLUSIONS

The longitudinal findings reaffirm that functional coherence depends on preestablished structural growth and reorganization of the central nervous system. The neuropsychological profile at 9 years of age indicates that late-onset intrauterine growth restriction compromises frontal network functioning.