Impact of fetal growth restriction on body composition and hormonal status at birth in infants of small and appropriate weight for gestational age

Decreased placental expression of hPGH, IGF-I and IGFBP-1 in pregnancies complicated by fetal growth restriction

OBJECTIVE

The human Placental Growth Hormone (hPGH) and the Insulin-like Growth Factor (IGF) system are implicated in fetal development. This study aimed to evaluate the expression of hPGH, IGF-I, IGFBP-1 and IGFBP-3 genes in placentas from pregnancies complicated by fetal growth restriction (FGR).

DESIGN

The study group was comprised of term placentas from 47 FGR-complicated pregnancies of no recognizable cause. Thirty-seven placentas from normal pregnancies with appropriate for gestational age birth weight were used as controls. The expression status of the genes was evaluated by quantitative real-time PCR.

RESULTS

hPGH, IGF-I and IGFBP-1 exhibited significantly lower expression compared to the controls (p=0.003, p=0.049 and p=0.001, respectively). Numerically, lower IGFBP-3 expression was also demonstrated in the FGR-affected group, without however reaching statistical significance (p=0.129). Significant co-expression patterns were detected among the study genes in both the FGR and normal pregnancies.

CONCLUSION

Decreased placental expression levels of hPGH, IGF-I and IGFBP-1 were demonstrated in pregnancies with FGR. Whether these alterations are a causative factor of FGR or accompany other pathogenetic mechanisms requires further investigation.

Growth patterns of large, small, and appropriate for gestational age infants: impacts of long-term breastfeeding: a retrospective cohort study

BACKGROUND

In several studies, since high and low birth weights are demonstrated as associated with obesity in childhood, these values should be followed up and documented carefully.

OBJECTIVE

The aim of this retrospective cohort study is to demonstrate the variation on body mass index outcomes of large (LGA), small (SGA), appropriate (AGA) for gestational age infants from birth to the end of fourth year of age and the effects of breastfeeding duration on these outcomes.

METHODS AND RESULTS

Four hundred and seven infants were recruited in the study (304AGA, 85 LGA, 18 SGA infants). LGA was frequent in boys and SGA in girls (p = 0.001). The mothers with gestational diabetes mellitus did have LGA infants (10.0% vs. 3.3%) (p = 0.022). The SGA infants performed rapid catch-up growth in the second month while the LGA infants performed catch-down growth in the ninth month. After the first 4 months, there was no difference on the values of BMI depending on breastfeeding time, less or more than 4 months, on the basis of the AGA and LGA infants. However, the body mass index (BMI) of LGA infants breastfed more than 12 months were not different from the AGA; unless the breastfeeding ceased earlier, the means of BMI remained significantly higher until 3 years.

CONCLUSION

Consequently, long duration of breastfeeding might protect LGA infants from childhood obesity risk.

Consequences of intrauterine growth and early neonatal catch-up growth

The long-term consequences of small size at birth have been well described during the last 2 decades. It is important to assess the fetal growth velocity and to recognize that newborns may have growth restriction even with a normal birth weight. Intrauterine growth retardation suggests decreased growth velocity in the fetus as the result of a certain pathophysiologic process. An infant born after a short period of intrauterine growth retardation may not necessarily be small for gestation at birth. Several cohorts of adults born after a normal intrauterine growth have been followed for long term. Greater weight gain and fat mass early in life after thinness at birth are risk factors for overweight and cardiovascular diseases. Other risk factors include prematurity, bottle feeding, and tobacco exposure in utero. Early catch-up growth after fetal growth restriction replaces the organism on its growth trajectory with similar gain in weight and height.

Reduction of IGF-binding protein-3 as a potential marker of intra-uterine growth restriction

BACKGROUND

Growth factor-binding proteins influence the growth of infants starting in utero. Adaptation of the fetus to an adverse uterine environment is associated with changes in the growth hormone-growth factor-insulin axis.

AIMS

To evaluate serum levels of IGF-I and IGFBP-3 in small and appropriate for gestational age newborn infants.

METHODS

Fifty-four newborn infants, small (SGA, n=28) or appropriate (AGA, n=26) for gestational age were matched by gestational age and sex. Blood was collected on the first day of life, and anthropometric measurements were taken at birth. The serum levels of IGF-I and IGFBP-3 were compared, and correlated with the anthropometric measurements.

RESULTS

On the first day of life, mean serum IGFBP-3 levels were significantly lower in SGA babies and correlated with weight, length, head circumference, and ponderal index (weight/length 3) (P<0.0001). In contrast, no associations were found between IGF-I serum levels and these anthropometric measurements.

CONCLUSION

Our data show that SGA babies have significantly reduced IGFBP-3 concentrations at birth.

The role of IGF-1 and ghrelin in the compensation of intrauterine growth restriction

The role of insulin-like growth factor 1 (IGF-1) and ghrelin in intrauterine growth restricted (IUGR) neonates in comparison to appropriate for gestational age (AGA) ones was investigated. Levels of IGF-1/insulin-like growth factor binding protein 3 (IGFBP3), ghrelin, insulin, and cortisol were determined in 20 singleton, full-term IUGR and 20 respective AGA neonates at birth (umbilical cord-UC), on days 1 (d1) and 4 (d4) postnatally. The ratio of IGF-1 to birth weight was higher in IUGR than in AGA in both UC (18.2 +/- 1.2 vs14.4 +/- 0.9, P = .05) and d1 (9.6 +/- 0.5 vs 6.8 +/- 0.3, P = .05). A significant positive correlation was found between IGF-1 and ghrelin levels and a negative one between IGFBP3 and ghrelin only in IUGR. In both groups, fetal IGF-1 levels negatively correlated with fetal cortisol levels. Intrauterine growth restricted neonates demonstrate a relative IGF-1 resistance in an attempt to drive energy toward survival on the expense of growth. The observed correlations between ghrelin and IGF-1/IGFBP3 postnatally indicate that ghrelin might play a role in the compensation of intrauterine undernutrition, promoting postnatal growth.

Newborn adiposity measured by plethysmography is not predicted by late gestation two-dimensional ultrasound measures of fetal growth

Noninvasive measures of fetal and neonatal body composition may provide early identification of children at risk for obesity. Air displacement plethysmography provides a safe, precise measure of adiposity and has recently been validated in infants. Therefore, we explored relationships between term newborn percent body fat (%BF) measured by air displacement plethysmography to 2-dimensional ultrasound (2-D US) biometric measures of fetal growth and maternal and umbilical cord endocrine activity. A total of 47 mother/infant pairs were studied. Fetal biometrics by 2-D US and maternal blood samples were collected during late gestation (35 wk postmenstrual age); infants were measured within 72 h of birth. Fetal biometrics included biparietal diameter, femur length, head circumference, abdominal circumference (AC), and estimated fetal weight (EFW). Serum insulin, insulin-like growth factor (IGF) 1, IGF binding protein-3, and leptin concentrations were measured in umbilical cord and maternal serum. The mean %BF determined by plethysmography was 10.9 +/- 4.8%. EFW and fetal AC had the largest correlations with newborn %BF (R(2) = 0.14 and 0.10, respectively; P < 0.05); however, stepwise linear regression modeling did not identify any fetal biometric parameters as a significant predictor of newborn %BF. Newborn mid-thigh circumference (MTC; cm) and ponderal index (PI; weight, kg/length, cm(3)) explained 21.8 and 14.4% of the variability in %BF, respectively, and gave the best stepwise linear regression model (%BF = 0.446 MTC + 0.347 PI -29.692; P < 0.001). We conclude that fetal growth biometrics determined by 2-D US do not provide a reliable assessment of %BF in term infants.

Downward percentile crossing as an indicator of an adverse prenatal environment

BACKGROUND

Postnatal health sequelae of low birth weight have been attributed to 'poor fetal growth' from inferred adverse prenatal environments; risks augmented by infant growth rates. Identifying prenatal growth-restricting events is essential to clarify pathways and mechanisms of fetal growth.

AIM

The specific aim of this investigation was to examine whether an episode of preterm labor may compromise fetal growth.

SUBJECTS AND METHODS

Fetal size at the end of the second trimester and birth were compared among women with uncomplicated pregnancies (n = 3167) and those who experienced an episode of preterm labor (<37 weeks) and subsequently delivered at term (> or =37 weeks, n = 147). Fetal weight estimated from ultrasound measures, and changes in weight standard scores across the third trimester investigated significant centile crossing (>0.67 standard deviation score change).

RESULTS

Fetuses delivered at term after an episode of preterm labor were smaller at birth relative to their peers than at the end of the second trimester, and were 47% more likely to experience clinically significant downward centile crossing (p < 0.05) than their peers (OR 1.47, 95% CI 1.04-2.07).

CONCLUSION

An episode of preterm labor may signal an adverse prenatal environment for term-delivered neonates. Epidemiologically silent events in the natural history of pregnancy are an understudied source of fetal growth compromise as inferred by small birth size among peers.

In vivo quantification of embryonic and placental growth during gestation in mice using micro-ultrasound

BACKGROUND

Non-invasive micro-ultrasound was evaluated as a method to quantify intrauterine growth phenotypes in mice. Improved methods are required to accelerate research using genetically-altered mice to investigate the interactive roles of genes and environments on embryonic and placental growth. We determined (1) feasible age ranges for measuring specific variables, (2) normative growth curves, (3) accuracy of ultrasound measurements in comparison with light microscopy, and (4) weight prediction equations using regression analysis for CD-1 mice and evaluated their accuracy when applied to other mouse strains.

METHODS

We used 30-40 MHz ultrasound to quantify embryonic and placental morphometry in isoflurane-anesthetized pregnant CD-1 mice from embryonic day 7.5 (E7.5) to E18.5 (full-term), and for C57Bl/6J, B6CBAF1, and hIGFBP1 pregnant transgenic mice at E17.5.

RESULTS

Gestational sac dimension provided the earliest measure of conceptus size. Sac dimension derived using regression analysis increased from 0.84 mm at E7.5 to 6.44 mm at E11.5 when it was discontinued. The earliest measurement of embryo size was crown-rump length (CRL) which increased from 1.88 mm at E8.5 to 16.22 mm at E16.5 after which it exceeded the field of view. From E10.5 to E18.5 (full term), progressive increases were observed in embryonic biparietal diameter (BPD) (0.79 mm to 7.55 mm at E18.5), abdominal circumference (AC) (4.91 mm to 26.56 mm), and eye lens diameter (0.20 mm to 0.93 mm). Ossified femur length was measureable from E15.5 (1.06 mm) and increased linearly to 2.23 mm at E18.5. In contrast, placental diameter (PD) and placental thickness (PT) increased from E10.5 to E14.5 then remained constant to term in accord with placental weight. Ultrasound and light microscopy measurements agreed with no significant bias and a discrepancy of less than 25%. Regression equations predicting gestational age from individual variables, and embryonic weight (BW) from CRL, BPD, and AC were obtained. The prediction equation BW = -0.757 + 0.0453 (CRL) + 0.0334 (AC) derived from CD-1 data predicted embryonic weights at E17.5 in three other strains of mice with a mean discrepancy of less than 16%.

CONCLUSION

Micro-ultrasound provides a feasible tool for in vivo morphometric quantification of embryonic and placental growth parameters in mice and for estimation of embryonic gestational age and/or body weight in utero.

Gender specificity of body adiposity and circulating adiponectin, visfatin, insulin, and insulin growth factor-I at term birth: relation to prenatal growth

CONTEXT

Fetal development is thought to be gender specific for adiposity and circulating insulin and IGF-I but not adipokinemia, as judged by serum visfatin and adiponectin at term birth. We studied the potential relationship between these gender specificities and fetal growth.

SETTING

The study was conducted at a university hospital.

STUDY POPULATION

Subjects included 96 strictly matched neonates born appropriate for gestational age (AGA; 24 girls, 24 boys) or small for gestational age (SGA; 24 girls, 24 boys).

MAIN OUTCOMES

Outcomes included serum insulin, IGF-I, visfatin, total and high-molecular-weight (HMW) adiponectin, osteocalcin at term birth, and neonatal body composition by absorptiometry.

RESULTS

Cord insulin and IGF-I levels were higher in girls than boys (P < or = 0.01), in both the AGA and SGA subpopulation. In AGA newborns, fat and lean mass were each gender specific (P < 0.0001), whereas visfatin and total and HMW adiponectin were not. Conversely, in SGA newborns, visfatin and HMW adiponectin were gender specific (higher levels in girls), whereas body adiposity was not. In SGA fetuses, the distribution of adiponectin isoforms was in both genders shifted toward HMW (P < 0.005 vs. AGA). Cord osteocalcin did not differ by either gender or birth weight.

CONCLUSION

At term birth, the gender specificity of adiposity and circulating visfatin and HMW adiponectin appeared to depend on prenatal growth, whereas the gender specificity of insulin and IGF-I levels did not. The fetal shift in adiponectin isoforms may contribute to explain why SGA newborns tend to be hypersensitive to insulin.