Clinical strategies for improving the detection of fetal growth restriction

Identifying the High-Risk Fetus in the Low-Risk Mother Using Fetal Doppler Screening

Continuous-wave Doppler ultrasound of the umbilical artery offers an inexpensive and scalable method of detecting undiagnosed fetal growth restriction. Using Doppler to screen low-risk pregnancies in low- and middle-income countries identifies fetuses at risk of stillbirth and, when managed appropriately, results in a step change reduction in the stillbirth rate.

Identifying the high-risk fetus in the low-risk pregnant mother (LRM) is a neglected area of research. Fetal growth restriction (FGR) is a major cause of stillbirths, especially in low- and middle-income countries (LMICs). FGR is very poorly detected particularly in healthy pregnant women classified as low risk. Umbiflow is an inexpensive continuous-wave Doppler ultrasound (CWDU) apparatus that is suitable for use by low-level health care providers for screening low-risk pregnant populations. It can easily detect umbilical artery blood flow in the cord, which correlates well with placental function, and poor placental function correlates well with FGR.

Use of CWDU to screen an LMIC population of more than 7,000 LRMs has demonstrated a high prevalence of abnormal umbilical artery flow of 13%, and absent end-diastolic flow, which is associated with end-stage placental disease, was found in 1.2%. This is 10 times higher than previously reported in high-income countries. Screening with CWDU together with a standard protocol managing those pregnancies with abnormal placental blood flow resulted in a 43% reduction in stillbirths (risk ratio: 0.57; 95% confidence interval=0.29, 0.85) in this LRM population. Further, follow-up of infants who had abnormal umbilical artery blood flow showed that these infants had significantly less fat-free mass at ages 6 weeks, 10 weeks, 14 weeks, and 6 months, than those with normal umbilical artery blood flow (P<.015), confirming that CWDU was able to detect true FGR.

Thus, screening with CWDU can detect the fetus at risk of stillbirth, and infants likely to have suboptimal growth and development postnatally. Screening with CWDU in LRMs opens the door to a step change in preventing stillbirths in LMICs.

Transcerebellar diameter versus biparietal diameter for the measurement of gestational age in third trimester

Aim

To compare the accuracy of biparietal diameter and transcerebellar diameter in measuring the gestational age during the third trimester of pregnancy.

Material and methods

In this prospective observational study, 275 pregnant women with singleton pregnancy between 32 and 37 weeks gestational age were recruited from the outpatient clinics of both Helwan University Hospital and Ain Shams University Maternity Hospital, Cairo, Egypt, during the period from February 2021 to August 2021. Transcerebellar and biparietal diameters of the fetus were measured by a radiologist blinded to the women’s gestational age, and compared to the gestational age acquired from a reliable date of first day of last menstrual period.

Results

The gestational age calculated by first day of last menstrual period ranged from 32 to 37 weeks (34.35 ± 1.4), while estimated by transcerebellar and biparietal diameters ranged from 31 to 37 weeks (34.31 ± 1.39) and 31 to 39 weeks (34.32 ± 1.44), respectively. There was a strong positive correlation between gestational age and transcerebellar diameter (r = 0.98, p <0.001) as well as biparietal diameter (r = 0.87, p <0.001), yet a stronger correlation was with transcerebellar diameter. 93.6% of gestational age assessment by transcerebellar diameter was correct compared to only 79.9% by biparietal diameter.

Conclusions

Transcerebellar diameter is a reliable single sonographic fetal biometric parameter for the assessment of gestational age in third trimester of pregnancy.

Echocardiographic assessment of fetal cardiac function in the uterine artery ligation rat model of IUGR

BACKGROUND

Intrauterine growth restriction (IUGR) leads to cardiac dysfunction and adverse remodeling of the fetal heart, as well as a higher risk of postnatal cardiovascular diseases. The rat model of IUGR, via uterine artery ligation, is a popular model but its cardiac sequelae is not well investigated. Here, we performed an echocardiographic evaluation of its cardiac function to determine how well it can represent the disease in humans.

METHODS

Unilateral uterine artery ligation was performed at embryonic day 17 (E17) and echocardiography was performed at E19 and E20.

RESULTS

Growth-restricted fetuses were significantly smaller and lighter, and had an higher placenta-to-fetus weight ratio. Growth-restricted fetal hearts had reduced wall thickness-to-diameter ratio, indicating left ventricular (LV) dilatation, and they had elevated trans-mitral and trans-tricuspid E/A ratios and reduced left and right ventricular fractional shortening (FS), suggesting systolic and diastolic dysfunction. These were similar to human IUGR fetuses. However, growth-restricted rat fetuses did not demonstrate head-sparing effect, displayed a lower LV myocardial performance index, and ventricular outflow velocities were not significantly reduced, which were dissimilar to human IUGR fetuses.

CONCLUSIONS

Despite the differences, our results suggest that this IUGR model has significant cardiac dysfunction, and could be a suitable model for studying IUGR cardiovascular physiology.

IMPACT

Animal models of IUGR are useful, but their fetal cardiac function is not well studied, and it is unclear if they can represent human IUGR fetuses. We performed an echocardiographic assessment of the heart function of a fetal rat model of IUGR, created via maternal uterine artery ligation. Similar to humans, the model displayed LV dilatation, elevated E/A ratios, and reduced FS. Different from humans, the model displayed reduced MPI, and no significant outflow velocity reduction. Despite differences with humans, this rat model still displayed cardiac dysfunction and is suitable for studying IUGR cardiovascular physiology.

Estimation of gestational age using trans-cerebellar diameter: a sonographic study of a cohort of healthy pregnant women of Igbo ethnic origin in a suburb of Lagos, southwest Nigeria

AIM

To use a sonographic method to determine the usefulness of trans-cerebellar diameter (TCD) as an independent estimator of gestational age (GA).

METHODS

A convenience sample of 257 healthy pregnant women of Igbo ethnic origin with singleton normal pregnancy whose GA ranged from 16 to 40 weeks were examined. GA was calculated from the date of onset of the last menstrual period (LMP) and was used as the standard criterion, while the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL) were used to estimate GA. TCD was measured and employed to derive regression models utilized to assess GA.

RESULTS

The mean TCD was 32.0 ± 11.6 mm; TCD had a strong positive linear relationship with GA (R = 0.988; R² = 0. 975; P =  < 0.001). The GA that was estimated using regression models, which were derived using the sonographically measured TCD, was closer to the actual GA in the second and third trimesters of pregnancy than the GA estimated using other fetal parameters.

CONCLUSION

In a population of healthy pregnant women of Igbo ethnic origin living in Oshodi, Lagos State, Nigeria, the sonographically measured TCD was more accurate as a single estimator of GA than BPD, HC, AC, and FL in the late stages of pregnancy. Subject to further validation, the nomograms derived using TCD proposed in the present study could be used as reliable GA estimators in the late stages of pregnancy among women who are unsure of the date of onset of their LMP.

Fetal Biometric Charts and Reference Equations for Pregnant Women Living in Port Said and Ismailia Governorates in Egypt

AIM:

To construct new fetal biometric charts and equations for some fetal biometric parameters for women between 12^th and 41^st weeks living in Ismailia and Port Said Governorates in Egypt.

MATERIAL AND METHODS:

This cross-sectional study was carried out on 656 Egyptian women (from Ismailia and Port Said governorates) with an uncomplicated pregnancy, and all were sure of their dates. The selected group was between the 12^th and 41^st weeks of gestation, recruited from the district general hospital in Ismailia and Port Said to measure ultrasonographically biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL), then for each measurement separate regression models were fitted to estimate both the mean and the Standard deviation at each gestational age.

RESULTS:

New Egyptian charts were reported for BPD, HC, AC, and FL. Reference equations for the dating of pregnancy were presented. The mean of the previous measurements at 12^th and 41^st weeks were as follows: (23.37, 98.72), (83.05, 336.12), (67.85, 332.57) and (12.50, 74.92) respectively.

CONCLUSION:

New fetal biometric charts and regression equations for pregnant women living in Port Said & Ismailia governorates in Egypt.

A proteomic clock of human pregnancy

BACKGROUND

Early detection of maladaptive processes underlying pregnancy-related pathologies is desirable because it will enable targeted interventions ahead of clinical manifestations. The quantitative analysis of plasma proteins features prominently among molecular approaches used to detect deviations from normal pregnancy. However, derivation of proteomic signatures sufficiently predictive of pregnancy-related outcomes has been challenging. An important obstacle hindering such efforts were limitations in assay technology, which prevented the broad examination of the plasma proteome.

OBJECTIVE

The recent availability of a highly multiplexed platform affording the simultaneous measurement of 1310 plasma proteins opens the door for a more explorative approach. The major aim of this study was to examine whether analysis of plasma collected during gestation of term pregnancy would allow identifying a set of proteins that tightly track gestational age. Establishing precisely timed plasma proteomic changes during term pregnancy is a critical step in identifying deviations from regular patterns caused by fetal and maternal maladaptations. A second aim was to gain insight into functional attributes of identified proteins and link such attributes to relevant immunological changes.

STUDY DESIGN

Pregnant women participated in this longitudinal study. In 2 subsequent sets of 21 (training cohort) and 10 (validation cohort) women, specific blood specimens were collected during the first (7-14 weeks), second (15-20 weeks), and third (24-32 weeks) trimesters and 6 weeks postpartum for analysis with a highly multiplexed aptamer-based platform. An elastic net algorithm was applied to infer a proteomic model predicting gestational age. A bootstrapping procedure and piecewise regression analysis was used to extract the minimum number of proteins required for predicting gestational age without compromising predictive power. Gene ontology analysis was applied to infer enrichment of molecular functions among proteins included in the proteomic model. Changes in abundance of proteins with such functions were linked to immune features predictive of gestational age at the time of sampling in pregnancies delivering at term.

RESULTS

An independently validated model consisting of 74 proteins strongly predicted gestational age (P = 3.8 × 10^-14, R = 0.97). The model could be reduced to 8 proteins without losing its predictive power (P = 1.7 × 10^-3, R = 0.91). The 3 top ranked proteins were glypican 3, chorionic somatomammotropin hormone, and granulins. Proteins activating the Janus kinase and signal transducer and activator of transcription pathway were enriched in the proteomic model, chorionic somatomammotropin hormone being the top-ranked protein. Abundance of chorionic somatomammotropin hormone strongly correlated with signal transducer and activator of transcription-5 signaling activity in CD4 T cells, the endogenous cell-signaling event most predictive of gestational age.

CONCLUSION

Results indicate that precisely timed changes in the plasma proteome during term pregnancy mirror a proteomic clock. Importantly, the combined use of several plasma proteins was required for accurate prediction. The exciting promise of such a clock is that deviations from its regular chronological profile may assist in the early diagnoses of pregnancy-related pathologies, and point to underlying pathophysiology. Functional analysis of the proteomic model generated the novel hypothesis that chrionic somatomammotropin hormone may critically regulate T-cell function during pregnancy.

Non-Invasive Placental Perfusion Imaging in Pregnancies Complicated by Fetal Heart Disease Using Velocity-Selective Arterial Spin Labeled MRI

The placenta is a vital organ for fetal growth and development during pregnancy. Congenital heart disease (CHD) is a leading cause of morbidity and mortality in newborns. Despite the parallel development of the placenta and fetal heart early in pregnancy, very few studies suggested an association between placental dysfunction and fetal CHD. In this study, we report placental perfusion of healthy pregnancies and pregnancies complicated by fetal CHD measured using advanced fetal MRI techniques. We studied forty-eight pregnant women (31 healthy volunteers and 17 with fetal CHD) that underwent fetal MRI during their second or third trimester of pregnancy. Placental perfusion imaging was performed using velocity-selective arterial spin labeling (VSASL) and 3D image acquisition with whole-placenta coverage. In pregnancies with fetal CHD, global placental perfusion significantly decreased and regional variation of placental perfusion significantly increased with advancing gestational age; however, no such correlation was found in healthy pregnancies. Also, global placental perfusion was significantly higher in fetal CHD versus controls, in the lateral side-lying patient position versus supine, and in the posterior placental position versus anterior placental position. This study reports for the first time non-invasive whole-placenta perfusion imaging in utero. These data suggest that placental VSASL may serve as a potential biomarker of placental dysfunction in fetuses diagnosed with CHD.

Growth restriction: identifying fetuses at risk

PURPOSE

Examine risks of intrauterine growth restriction (IUGR) and composite perinatal outcomes with estimated fetal weights (EFW) 10-20th%, and compare outcomes using umbilical artery Doppler (UAD).

MATERIALS AND METHODS

Retrospective, cohort evaluating ultrasound (US) EFW 10-20th%, between 2002 and 2012. Cases were identified with EFW % 10-20. Controls, EFW >20th% were obtained for each case, matched by gestational age, and US date. Unadjusted and adjusted logistic regression was used for outcomes.

RESULTS

Seven hundred and sixty-seven cases met criteria with matched controls. Fetuses having EFW 10-20th% (GA 33.6 ± 3.7 weeks) had increased IUGR on follow up ultrasound (OR 26.5[10.2-68.7], p < .01), small for gestational age (SGA) (OR 9.2 [6.9-12.3], p < .01), neonatal intensive care unit (NICU) admissions (OR 2.4 [1.6-3.6], p < .01), and composite perinatal morbidity (OR 7.8 [6.0-10.1], p < .01) on adjusted analyses. Abnormal UAD in cases had greater rates of 5 min Apgar <7, NICU admission and composite morbidity (p < .05).

CONCLUSIONS

Pregnancies with EFW 10-20th% at the time of initial US are at increased risk for developing IUGR and being SGA at birth, with more NICU admissions and composite perinatal outcomes; abnormal UAD evaluation in cases conveyed further increase in outcomes.

Toward the automatic quantification of in utero brain development in 3D structural MRI: A review

Investigating the human brain in utero is important for researchers and clinicians seeking to understand early neurodevelopmental processes. With the advent of fast magnetic resonance imaging (MRI) techniques and the development of motion correction algorithms to obtain high-quality 3D images of the fetal brain, it is now possible to gain more insight into the ongoing maturational processes in the brain. In this article, we present a review of the major building blocks of the pipeline toward performing quantitative analysis of in vivo MRI of the developing brain and its potential applications in clinical settings. The review focuses on T1- and T2-weighted modalities, and covers state of the art methodologies involved in each step of the pipeline, in particular, 3D volume reconstruction, spatio-temporal modeling of the developing brain, segmentation, quantification techniques, and clinical applications. Hum Brain Mapp 38:2772-2787, 2017. © 2017 Wiley Periodicals, Inc.

Maternal subclinical vascular changes in fetal growth restriction with and without pre-eclampsia

OBJECTIVE

To assess maternal vascular structure and function in pregnancies complicated by fetal growth restriction (FGR), in women with and without pre-eclampsia (PE) at the time of FGR diagnosis.

METHODS

We evaluated 124 women with a pregnancy complicated by FGR, of whom 60 had PE and 64 did not, and compared these findings to those of 110 normal women (controls). The group of FGR pregnancies without PE was further subdivided according to gestational age at FGR diagnosis into early onset (< 32 weeks) or late onset (≥ 32 weeks). Maternal carotid intima-media thickness (IMT), blood pressure (BP), carotid artery distensibility (CD), circumferential wall stress (CWS) and inferior vena cava (IVC) collapsibility were assessed by ultrasound at the time of FGR diagnosis.

RESULTS

Compared to controls, cases of FGR with PE showed increased maternal carotid IMT (0.425 (interquartile range (IQR), 0.381-0.486) vs 0.409 (IQR, 0.386-0.439) mm; P = 0.021), BP (mean, 109 (IQR, 101-117) vs 82  (IQR, 77-89) mmHg; P  < 0.001) and CWS (19.7 (IQR, 17.0-22.7) vs 12.2 (IQR, 11.1-13.7) kPa; P < 0.001), and reduced CD (25.3 (IQR, 15.7-35.6) vs 31.9 (IQR, 25.4-41.1) kPa(-1)  × 10(-3) ; P = 0.037) and IVC collapsibility indices (0.07 (IQR, 0.06-1.11) vs 0.10 (IQR, 0.06-0.13); P  =  0.136). Similarly, compared to controls, in cases of FGR without PE maternal carotid IMT (0.436  (IQR, 0.392-0.476) mm; P  = 0.001) and BP (88 (IQR, 81-95) mmHg; P < 0.001) were increased but CD and IVC collapsibility were similar. When analysis was subclassified according to gestational age at diagnosis, IMT and CWS were significantly increased only in early-onset FGR while BP was increased in both groups.

CONCLUSION

Normotensive women with pregnancy complicated by FGR share some subclinical vascular features with those of women with PE, which further reinforces the notion that, at least in a proportion of cases, there is a common placental disease that influences maternal cardiovascular features.

Other adverse pregnancy outcomes and future chronic disease

Cardiovascular disease is the leading cause of morbidity and mortality in females worldwide. Pregnancy is associated with significant physiologic changes that may function as a natural stress test to detect women at future risk. It is established that women who have had a pregnancy complicated by gestational diabetes or a hypertensive disorder of pregnancy are at increased risk of cardiovascular disease later in life, and there is growing evidence that women who deliver infants preterm or growth-restricted infants have an elevated risk as well. Consideration should be given to including these outcomes as indicators of cardiovascular risk. Pregnancy represents a teachable moment when it would be ideal to identify women at risk. Improved integration of women's primary health care and an enhanced knowledge base on the part of clinicians will be necessary to fully incorporate these findings into the clinical care of women.

Neurosonographic assessment of the corpus callosum as imaging biomarker of abnormal neurodevelopment in late-onset fetal growth restriction

OBJECTIVE

To explore corpus callosum (CC) developmental differences by ultrasound in late-onset small fetuses compared with adequate for gestational age (AGA) controls.

STUDY DESIGN

Ninety four small (estimated fetal weight <10th centile) and 71 AGA fetuses were included. Small fetuses were further subdivided into fetal growth restriction (IUGR, n = 64) and small for gestational age (SGA, n = 30) based on poor perinatal outcome factors, that is, birth weight <3rd centile and/or abnormal cerebroplacental ratio and/or uterine artery Doppler. The entire cohort was scanned to assess CC by transvaginal neurosonography obtaining axial, coronal and midsagittal images. CC length, thickness, total area and the areas after a subdivision in 7 portions were evaluated by semiautomatic software. Furthermore, the weekly average growth of the CC in each study group was calculated and compared.

RESULTS

Small fetuses showed significantly shorter (small fetuses: 0.49 vs. AGA: 0.52; p < 0.01) and smaller CC (1.83 vs. 2.03; p < 0.01) with smaller splenium (0.47 vs. 0.55; p < 0.01) compared to controls. The CC growth rate was also reduced when compared to controls. Changes were more prominent in small fetuses with abnormal cerebroplacental Doppler suggesting fetal growth restriction.

CONCLUSIONS

Neurosonographic assessment of CC showed significantly altered callosal development, suggesting in-utero brain reorganization in small fetuses. This data support the potential value of CC assessment by US to monitor brain development in fetuses at risk.

Aortic and carotid intima-media thickness in term small-for-gestational-age newborns and relationship with prenatal signs of severity

OBJECTIVE

To assess carotid and aortic intima-media thickness (IMT) in term small-for-gestational-age (SGA) newborns with and without prenatal signs of severity.

METHODS

This prospective study comprised 67 cases diagnosed prenatally and 134 normally grown newborns. Cases were subclassified into SGA with no signs of severity and those with signs of severity, defined as a birth weight below the 3(rd) percentile or abnormal uterine artery Doppler or cerebroplacental ratio. Blood pressure and vascular IMT were evaluated.

RESULTS

SGA newborns showed a non-significant trend for higher values of blood pressure. IMT values were significantly increased in SGA newborns, with and without signs of severity, compared with controls. The magnitude of the increase was higher in SGA newborns with signs of severity.

CONCLUSIONS

Vascular IMT was increased in SGA newborns, irrespective of the presence or absence of prenatal signs of severity. This finding challenges the notion of 'constitutionally small' SGA, and supports the premise that the majority of SGA newborns have true growth restriction and suffer fetal cardiovascular programming.

Survival and neonatal morbidity among extremely preterm born infants in relation to gestational age based on the last menstrual period or ultrasonographic examination

OBJECTIVES

The aim of this study was to investigate the potential impact of gestational age (GA) estimation on the basis of the last menstrual period (LMP) in comparison with GA based on ultrasound examination on rates of survival and neonatal morbidity among extremely preterm infants.

METHODS

The Swedish national registry of infants born extremely preterm (Extremely Preterm Infants in Sweden Study), including infants born before 27 weeks of gestation, was used to identify 645 infants with available information. Incidences of stillbirth, survival, small for GA (SGA), and major neonatal morbidity were calculated in relationship to the GA estimated by each of the approaches.

RESULTS

Pregnancies, in general, appeared to be longer when GA was estimated by LMP than by ultrasound (17.2% of the pregnancies were longer than 27 weeks). The incidences of stillbirth, neonatal death, and major neonatal morbidity in relationship to GA were similar for both groups. The risks for SGA were elevated when GA according to ultrasound examination was at least 7 days shorter than GA based on the LMP.

CONCLUSIONS

In our cohort of infants born extremely preterm, estimation of GA on the basis of LMP indicated a longer pregnancy than estimated by ultrasound but did not influence the incidences of neonatal survival and morbidity.

Ethnicity-specific birthweight distributions improve identification of term newborns at risk for short-term morbidity

OBJECTIVE

We aimed to determine whether ethnicity-specific birthweight distributions more accurately identify newborns at risk for short-term neonatal morbidity associated with small for gestational age (SGA) birth than population-based distributions not stratified on ethnicity.

STUDY DESIGN

We examined 100,463 singleton term infants born to parents in Washington State between Jan. 1, 2006, and Dec. 31, 2008. Using multivariable logistic regression models, we compared the ability of an ethnicity-specific growth distribution and a population-based growth distribution to predict which infants were at increased risk for Apgar score <7 at 5 minutes, admission to the neonatal intensive care unit, ventilation, extended length of stay in hospital, hypothermia, hypoglycemia, and infection.

RESULTS

Newborns considered SGA by ethnicity-specific weight distributions had the highest rates of each of the adverse outcomes assessed-more than double those of infants only considered SGA by the population-based standards. When controlling for mother's age, parity, body mass index, education, gestational age, mode of delivery, and marital status, newborns considered SGA by ethnicity-specific birthweight distributions were between 2 and 7 times more likely to suffer from the adverse outcomes listed above than infants who were not SGA. In contrast, newborns considered SGA by population-based birthweight distributions alone were at no higher risk of any adverse outcome except hypothermia (adjusted odds ratio, 2.76; 95% confidence interval, 1.68-4.55) and neonatal intensive care unit admission (adjusted odds ratio, 1.40; 95% confidence interval, 1.18-1.67).

CONCLUSION

Ethnicity-specific birthweight distributions were significantly better at identifying the infants at higher risk of short-term neonatal morbidity, suggesting that their use could save resources and unnecessary parental anxiety.

Differences in cortical development assessed by fetal MRI in late-onset intrauterine growth restriction

OBJECTIVE

The objective of the study was to evaluate cortical development parameters by magnetic resonance imaging (MRI) in late-onset intrauterine growth-restricted (IUGR) fetuses and normally grown fetuses.

STUDY DESIGN

A total of 52 IUGR and 50 control fetuses were imaged using a 3T MRI scanner at 37 weeks of gestational age. T2 half-Fourier acquisition single-shot turbo spin-echo anatomical acquisitions were obtained in 3 planes. Cortical sulcation (fissures depth corrected by biparietal diameter), brain volumetry, and asymmetry indices were assessed by means of manual delineation and compared between cases and controls.

RESULTS

Late-onset IUGR fetuses had significantly deeper measurements in the left insula (late-onset IUGR: 0.293 vs control: 0.267; P = .02) and right insula (0.379 vs 0.318; P < .01) and the left cingulate fissure (0.096 vs 0.087; P = .03) and significantly lower intracranial (441.25 cm(3) vs 515.82 cm(3); P < .01), brain (276.47 cm(3) vs 312.07 cm(3); P < .01), and left opercular volumes (2.52 cm(3) vs 3.02 cm(3); P < .01). IUGR fetuses showed significantly higher right insular asymmetry indices.

CONCLUSION

Late-onset IUGR fetuses had a different pattern of cortical development assessed by MRI, supporting the existence of in utero brain reorganization. Cortical development could be useful to define fetal brain imaging-phenotypes characteristic of IUGR.

Response gene to complement 32 deficiency causes impaired placental angiogenesis in mice

AIMS

The objectives of this study are to determine the role of response gene to complement 32 (RGC-32) in the placental angiogenesis during pregnancy and explore the underlying mechanisms.

METHODS AND RESULTS

RGC-32-deficient (RGC32(-/-)) mice were generated from C57BL/6 embryonic stem cells with deletion of exon 2 and 3 of the RGC-32 gene. Most of the RGC32(-/-) mice can survive. However, their body sizes were much smaller compared with their wild-type littermates when they were born. By examining the embryo development and placentas at 16.5 days post-coitum, we found that RGC32(-/-) embryos and foetal placentas were significantly smaller than the wild-type. Further analysis showed that the labyrinth zone of RGC32(-/-) placenta was smaller with defective angiogenesis. Mechanistically, vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) and placental growth factor (PlGF) were significantly down-regulated in RGC32(-/-) placentas, suggesting that VEGFR2 and PlGF may mediate RGC-32 function in placental angiogenesis. Indeed, knockdown of RGC-32 by shRNA inhibited VEGF-induced endothelial cell proliferation, migration, and tube formation while blocking VEGFR2 expression. RGC-32 appeared to regulate VEGFR2 expression via activation of NF-kB. Moreover, RGC-32 regulated trophoblasts proliferation via control of PlGF expression.

CONCLUSION

Absence of RGC-32 caused foetal growth restriction through interrupting the placental angiogenesis, which was due to the decrease in VEGFR2 expression through the NF-kB-dependent pathway in endothelial cells and PlGF expression in trophoblasts.

Body composition and newborn birthweight in pregnancies of adolescent and mature women

Teenage pregnancy has been associated with adverse effects for the mother and the newborn (NB). In order to compare body composition (BC) between adolescents (Ad) and mature women (MW) during pregnancy and to determine the difference in birthweight and perinatal morbidity, pregnant Ad (n=40) and MW (n=227) were studied. BC changes between the second and third trimesters were determined by multifrequency bioelectrical impedance analysis, and birthweight and NB morbidity were evaluated. During the second and third trimesters of the pregnancy, fat mass was lower in the Ad group [16 kg (13-19)] than in the MW group [22 kg (17-27)] (P<0.01; median and quartiles 1-3). Fat-free mass increased by 3.09 kg (2.29-4.20) and 2.20 kg (1.0-3.59) (P≤0.01), and total body water increased by 2.77 L (0.84-4.49) vs. 2.04 L (0.55-3.89) (P=0.36), in the Ad and MW groups, respectively (median and quartiles 1-3). Birthweight was not significantly different between NBs of Ad (3223 ± 399 g) and NBs of MW (3312 ± 427 g, P=0.22). The youngest Ad (<18 year old, n=8) had NB with lower birthweight than MW (3031 ± 503 g, P=0.06). NBs of Ad mothers showed a non-significant trend towards a higher rate of morbidity relative to the NBs of MW. In conclusion, the BC of Ad differs from that of MW during pregnancy. In addition, the NB infants of Ad mothers tended to have a lower birthweight than those from MW, a result that suggests that the Ad should be in strict prenatal control.

Risk of morbid perinatal outcomes in small-for-gestational-age pregnancies: customized compared with conventional standards of fetal growth

OBJECTIVE

To estimate and compare the risk of morbid perinatal outcomes in pregnancies identified as small for gestational age (SGA) with customized compared with conventional standards of fetal growth.

METHODS

Ultrasound-derived estimates of fetal weight were used to generate a fetal growth trajectory (N=7,510). The gestational age at delivery and pathologic and physiologic variables from 5,072 pregnancies were used to calculate a customized threshold for SGA. In a separate analysis of 32,070 pregnancies, rates of morbid outcomes were compared in participants classified as SGA according to a population-based birth weight standard only (SGApop only), a customized standard only (SGAcust only), and both methods (SGAboth).

RESULTS

Eight-hundred seventy-five (2.7%) participants were SGApop only, 1,970 (6.1%) participants were SGAboth, and 609 (1.9%) participants were SGAcust only. The odds ratios of neonatal death in SGApop only and SGAcust only pregnancies were 1.78 (95% confidence interval [CI] 0.2-13.1) and 54.6 (95% CI 29.0-102.8), respectively. Rates of prematurity in the SGApop only and SGAcust only cohorts were 4.8% and 64.5%, respectively. After adjustment for the effect of prematurity, odds ratios of neonatal death in the SGApop only and SGAcust only cohorts were 4.8 (95% CI 0.6-37.0) and 2.9 (95% CI 1.4-6.1), respectively.

CONCLUSION

After adjustment for confounding stemming from premature delivery, there is little difference in the risk of adverse outcomes between SGAcust only and SGApop only participants. Adoption of customized fetal growth standards into clinical practice may not improve the ability to identify pregnancies with increased risk of perinatal morbidity.

The intensity of IUGR-induced transcriptome deregulations is inversely correlated with the onset of organ function in a rat model

A low-protein diet applied during pregnancy in the rat results in intrauterine growth restricted (IUGR) fetuses. In humans, IUGR is associated with increased perinatal morbidity, higher incidence of neuro-developmental defects and increased risk of adult metabolic anomalies, such as diabetes and cardiovascular disease. Development and function of many organs are affected by environmental conditions such as those inducing fetal and early postnatal growth restriction. This phenomenon, termed "fetal programming" has been studied unconnectedly in some organs, but very few studies (if any) have investigated at the same time several organs, on a more comparative basis. However, it is quite probable that IUGR affects differentially most organ systems, with possible persistent changes in gene expression. In this study we address transcriptional alterations induced by IUGR in a multi-organ perspective, by systematic analysis of 20-days rat fetuses. We show that (1) expressional alterations are apparently stronger in organs functioning late in foetal or postnatal life than in organs that are functioning early (2) hierarchical classification of the deregulations put together kidney and placenta in one cluster, liver, lungs and heart in another; (3) the epigenetic machinery is set up especially in the placenta, while its alterations are rather mild in other organs; (4) the genes appear deregulated in chromosome clusters; (5) the altered expression cascades varies from organ to organ, with noticeably a very significant modification of the complement and coagulation cascades in the kidney; (6) we found a significant increase in TF binding site for HNF4 proteins specifically for liver genes that are down-regulated in IUGR, suggesting that this decrease is achieved through the action of HNF transcription factors, that are themselves transcriptionnally induced in the liver by IUGR (x 1.84 fold). Altogether, our study suggests that a combination of tissue-specific mechanisms contributes to bring about tissue-driven modifications of gene cascades. The question of these cascades being activated to adapt the organ to harsh environmental condition, or as an endpoint consequence is still raised.