Placenta and fetal growth restriction

First-trimester placental ultrasound and maternal serum markers as predictors of small-for-gestational-age infants

OBJECTIVE

The objective of the study was to combine early, direct assessment of the placenta with indirect markers of placental development to identify pregnancies at greatest risk of delivering small-for-gestational age infants (SGA10).

STUDY DESIGN

We prospectively collected 3-dimensional ultrasound volume sets, uterine artery pulsatility index, and maternal serum of singleton pregnancies at 11-14 weeks. Placental volume (PV), quotient (placental quotient [PQ] = PV/gestational age), mean placental diameter (MPD) and chorionic diameters, and the placental morphology index (PMI = MPD/PQ and adjusts the lateral placental dimensions for quotient) were measured offline. Maternal serum was assayed for placental growth factor and placental protein-13. These variables were evaluated as predictors of SGA10.

RESULTS

Of the 578 pregnancies included in the study, 56 (9.7%) delivered SGA10. SGA10 pregnancies had a significantly smaller PV, PQ, MPD, and mean placental diameter and higher PMI compared with normal pregnancies (P < .001 for each). Each placental measure remained significantly associated with SGA10 after adjusting for confounders and significantly improved the performance of the model using clinical variables alone (P < .04 for each) with adjusted areas under the curve ranging from 0.71 to 0.74. Uterine artery pulsatility index did not remain significantly associated with SGA10 after adjusting for confounders (P = .06). Placental growth factor was significantly lower in SGA10 pregnancies (P = .02) and remained significant in adjusted models but failed to significantly improve the predictive performance of the models as measured by area under the curve (P > .3). Placental protein-13 was not associated with SGA10 (P = .99).

CONCLUSION

Direct assessment of placental size and shape with 3-dimensional ultrasound can serve as the foundation upon which to build a multivariable model for the early prediction of SGA.

Fetal sex and race modify the predictors of fetal growth

The objective of this study is unknown if fetal sex and race modify the impact of maternal pre-pregnancy body mass index (BMI), and smoking on fetal growth. The authors studied markers of fetal growth in singleton offspring of 8,801 primiparous, normotensive women, enrolled in the Collaborative Perinatal Project. The authors tested for departures from additivity between sex/race and each predictor. The head-to-chest circumference ratio (HCC) decreased more, while birthweight and ponderal index (PI) increased more for each 1 kg/m(2) increase in pre-pregnancy BMI among term females versus males (P = 0.07, P < 0.01 and P = 0.08, interaction respectively). For term offspring of White compared with Black women, smoking independent of "dose" was associated with larger reductions in growth (165 g vs. 68 g reduction in birthweight, P < 0.01, interaction), greater reduction in fetal placental ratio (P < 0.01, interaction), PI (P < 0.01, interaction), and greater increase in HCC (P = 0.02), respectively. The association of BMI and smoking with fetal size appeared to be reversed in term versus preterm infants. Our study provides evidence that the associations of pre-pregnancy BMI and smoking are not constant across sex and race. This finding may be relevant to sex and race differences in neonatal and long term health outcomes.

Macrosomia has its roots in early placental development

INTRODUCTION

We sought to determine if early placental size, as measured by 3-dimensional ultrasonography, is associated with an increased risk of delivering a macrosomic or large-for-gestational age (LGA) infant.

METHODS

We prospectively collected 3-dimensional ultrasound volume sets of singleton pregnancies at 11-14 weeks and 18-24 weeks. Birth weights were collected from the medical records. After delivery, the ultrasound volume set were used to measure the placental volume (PV) and placental quotient (PQ = PV/gestational age), as well as the mean placental and chorionic diameters (MPD and MCD, respectively). Placental measures were analyzed as predictors of macrosomia (birth weight ≥4000 g) and LGA (birth weight ≥90th percentile).

RESULTS

The 578 pregnancies with first trimester volumes included 44 (7.6%) macrosomic and 43 (7.4%) LGA infants. 373 subjects also had second trimester volumes available. A higher PV and PQ were both significantly associated with macrosomia and LGA in both the first and second trimesters. Second trimester MPD was significantly associated with both outcomes as well, while second trimester MCD was only associated with LGA. The above associations remained significant after adjusting for maternal demographic variables such as race, ethnicity, age and diabetes. Adjusted models yielded moderate prediction of macrosomia and LGA (AUC: 0.71-0.77).

CONCLUSIONS

Sonographic measurement of the early placenta can identify pregnancies at greater risk of macrosomia and LGA. Macrosomia and LGA are already determined in part by early placental growth and development.

Bilateral uterine vessel ligation as a model of intrauterine growth restriction in mice

BACKGROUND

Intrauterine growth restriction (IUGR) occurs in up to 10% of pregnancies and is considered as a major risk to develop various diseases in adulthood, such as cardiovascular diseases, insulin resistance, hypertension or end stage kidney disease. Several IUGR models have been developed in order to understand the biological processes linked to fetal growth retardation, most of them being rat or mouse models and nutritional models. In order to reproduce altered placental flow, surgical models have also been developed, and among them bilateral uterine ligation has been frequently used. Nevertheless, this model has never been developed in the mouse, although murine tools display multiple advantages for biological research. The aim of this work was therefore to develop a mouse model of bilateral uterine ligation as a surgical model of IUGR.

RESULTS

In this report, we describe the set up and experimental data obtained from three different protocols (P1, P2, P3) of bilateral uterine vessel ligation in the mouse. Ligation was either performed at the cervical end of each uterine horn (P1) or at the central part of each uterine horn (P2 and P3). Time of surgery was E16 (P1), E17 (P2) or E16.5 (P3). Mortality, maternal weight and abortion parameters were recorded, as well as placentas weights, fetal resorption, viability, fetal weight and size. Results showed that P1 in test animals led to IUGR but was also accompanied with high mortality rate of mothers (50%), low viability of fetuses (8%) and high resorption rate (25%). P2 and P3 improved most of these parameters (decreased mortality and improved pregnancy outcomes; improved fetal viability to 90% and 27%, respectively) nevertheless P2 was not associated to IUGR contrary to P3. Thus P3 experimental conditions enable IUGR with better pregnancy and fetuses outcomes parameters that allow its use in experimental studies.

CONCLUSIONS

Our results show that bilateral uterine artery ligation according to the protocol we have developed and validated can be used as a surgical mouse model of IUGR.

Analysis of homeobox gene action may reveal novel angiogenic pathways in normal placental vasculature and in clinical pregnancy disorders associated with abnormal placental angiogenesis

Homeobox genes are essential for both the development of the blood and lymphatic vascular systems, as well as for their maintenance in the adult. Homeobox genes comprise an important family of transcription factors, which are characterized by a well conserved DNA binding motif; the homeodomain. The specificity of the homeodomain allows the transcription factor to bind to the promoter regions of batteries of target genes and thereby regulates their expression. Target genes identified for homeodomain proteins have been shown to control fundamental cell processes such as proliferation, differentiation, and apoptosis. We and others have reported that homeobox genes are expressed in the placental vasculature, but our knowledge of their downstream target genes is limited. This review highlights the importance of studying the cellular and molecular mechanisms by which homeobox genes and their downstream targets may regulate important vascular cellular processes such as proliferation, migration, and endothelial tube formation, which are essential for placental vasculogenesis and angiogenesis. A better understanding of the molecular targets of homeobox genes may lead to new therapies for aberrant angiogenesis associated with clinically important pregnancy pathologies, including fetal growth restriction and preeclampsia.

Population-based placental weight ratio distributions

The placental weight ratio (PWR) is a health indicator that reflects the balance between fetal and placental growth. The PWR is defined as the placental weight divided by the birth weight, and it changes across gestation. Its ranges are not well established. We aimed to establish PWR distributions by gestational age and to investigate whether the PWR distributions vary by fetal growth adequacy, small, average, and large for gestational age (SGA, AGA, and LGA). The data came from a hospital based retrospective cohort, using all births at two London, Ontario hospitals in the past 10 years. All women who delivered a live singleton infant between 22 and 42 weeks of gestation were included (n = 41441). Nonparametric quantile regression was used to fit the curves. The results demonstrate decreasing PWR and dispersion, with increasing gestational age. A higher proportion of SGA infants have extreme PWRs than AGA and LGA, especially at lower gestational ages. On average, SGA infants had higher PWRs than AGA and LGA infants. The overall curves offer population standards for use in research studies. The curves stratified by fetal growth adequacy are the first of their kind, and they demonstrate that PWR differs for SGA and LGA infants.

Umbilical artery Doppler at 19 to 22 weeks of gestation in the prediction of adverse pregnancy outcomes

OBJECTIVE

The aim of this study was to determine the clinical utility of Doppler assessment of the umbilical artery in the second trimester scan for predicting adverse pregnancy outcomes.

METHODS

Singleton pregnancies that had undergone routine anomaly scan at 19 to 22 weeks of gestation with umbilical and uterine artery Doppler measurements. Receiver operating characteristic curves were constructed to evaluate the ability of umbilical artery pulsatility index (PI) to predict small for gestational age and preeclampsia.

RESULTS

The final study population comprised 4565 singleton pregnancies. Multiple regression analysis showed significant independent contribution of umbilical artery PI in predicting SGA <10th and SGA <5th centiles (adjusted odds ratios of 2.51 and 3.51, respectively). By using a cutoff of umbilical artery PI >90th centile, the likelihood ratio of SGA <5th centile is 2.3 (95% CI: 1.7-3.0).

CONCLUSIONS

Umbilical artery PI at 19 to 22 weeks of gestation is significantly associated with SGA below the tenth and fifth centiles. A multivariate model combining umbilical and uterine artery Doppler measurements with additional maternal and sonographic characteristics may help predict small for gestational age, particularly those below the fifth centile.

Maternal factors associated with fetal growth and birthweight are independent determinants of placental weight and exhibit differential effects by fetal sex

Introduction

Maternal nutritional and metabolic factors influence the developmental environment of the fetus. Virtually any nutritional factor in the maternal blood has to pass the placental membranes to reach the fetal blood. Placental weight is a commonly used measure to summarize placental growth and function. Placental weight is an independent determinant of fetal growth and birthweight and modifies the associations between maternal metabolic factors and fetal growth. We hypothesized that maternal factors known to be related to fetal growth, newborn size and body composition are determinants of placental weight and that effects of maternal metabolic factors on placental weight differ between the genders.

Methods

The STORK study is a prospective longitudinal study including 1031 healthy pregnant women of Scandinavian heritage with singleton pregnancies. Maternal determinants (parity, body mass index, gestational weight gain and fasting plasma glucose) of placental weight were explored by linear regression models, stratified by fetal sex.

Results

Parity, maternal BMI, gestational weight gain and fasting glucose had positive effects on placental weight. There was a sex specific effect in these associations. Fasting glucose was significantly associated with placental weight in females but not in males.

Conclusion

Maternal factors known to influence fetal growth, birthweight and neonatal body composition are determinants of placental weight. The effect of maternal factors on placental weight is influenced by sex as illustrated in the relation between maternal glucose and placental weight.

Maternal psychological distress and placental circulation in pregnancies after a previous offspring with congenital malformation

Introduction

Antenatal maternal psychological distress may be associated with reduced placental circulation, which could lead to lower birthweight. Studies investigating this in humans show mixed results, which may be partially due to type, strength and timing of distress. In addition, the arterial vascular resistance measures often used as outcome measures do not detect smaller changes in placental volume blood flow. We aimed to investigate the effect of a specific stressor, with increased levels of stress early in pregnancy, on the fetoplacental volume blood flow in third trimester.

Methods

This was a prospective observational study of 74 pregnant women with a congenital malformation in a previous fetus or child. Psychological distress was assessed twice, around 16 and 30 weeks' gestation. Psychometric measures were the General Health Questionnaire-28 (subscales anxiety and depression), Edinburgh Postnatal Depression Scale, and Impact of Event Scale-22 (subscales intrusion, avoidance, and arousal). Placental circulation was examined at 30 weeks, using Doppler ultrasonography, primarily as fetoplacental volume blood flow in the umbilical vein, normalized for abdominal circumference; secondarily as vascular resistance measures, obtained from the umbilical and the uterine arteries.

Results

Maternal distress in second but not third trimester was associated with increased normalized fetoplacental blood flow (P-values 0.006 and 0.013 for score > mean for depression and intrusion, respectively). Post-hoc explorations suggested that a reduced birthweight/placental weight ratio may mediate this association. Psychological distress did not affect vascular resistance measures in the umbilical and uterine arteries, regardless of adjustment for confounders.

Conclusions

In pregnant women with a previous fetus or child with a congenital malformation, higher distress levels in second trimester were associated with third trimester fetoplacental blood flow that was higher than expected for the size of the fetus. The results do not support placental blood flow reduction as a pathway between maternal distress and reduced birthweight.

Placental morphometry determines the birth weight

BACKGROUND

Placental morphometry determines the foetal development and adulthood disease pattern. Hence, in the present study the influence of placental weight, volume, surface area, and thickness were studied in different groups of birth weight by sex of the newborn.

MATERIAL AND METHODS

Present study was conducted on 164 consecutive singleton deliveries from a teaching hospital of Northern Karnataka, India. Multivariate linear regression models were constructed by maximum likelihood method after checking the linearity. The sensitivity, specificity and predictive values of regression models were computed to exhibit their utility for physicians.

RESULTS

Gestational age exhibited positive relationship with birth weight. Placental parameters showed a positive and significant relationship (p<0.001) with birth weight and higher values in males. The birth weight was estimated by regression models using sex of the newborn and placental morphometry; weight (R(2)=0.474), surface area (R(2)=0.420), and volume (R(2)=0.477) at 95% confidence interval. Low birth weight babies in the study were correctly identified by placental weight, surface area, volume and sex of the newborn. Their sensitivity, specificity and predictive values have been specified.

CONCLUSION

Placental morphometry: weight, surface area, volume and sex of the baby determined the birth weight efficiently to initiate the corrective measures for planning better maternal care and to pacify mothers and their relatives.

Downstream targets of the homeobox gene DLX3 are differentially expressed in the placentae of pregnancies affected by human idiopathic fetal growth restriction

Human idiopathic fetal growth restriction (FGR) is associated with placental insufficiency. Previously, we reported that the expression of homeobox gene Distal-less 3 (DLX3) is increased in idiopathic FGR placentae and is a regulator of villous trophoblast differentiation. Here, we identify the downstream targets of DLX3 in trophoblast-derived cell lines. We modelled the high levels of DLX3 in FGR using an over-expression plasmid construct and complemented this using short-interference RNA (siRNA) for inactivation in cultured cells. Using a real-time PCR-based gene profiling, candidate target genes of DLX3 over-expression and inactivation were identified as regulators of trophoblast differentiation; GATA2 and PPARγ. The expression of GATA2 and PPARγ were further assessed in placental tissues and showed increased mRNA and protein levels in FGR-affected tissues compared with gestation-matched controls. We conclude that DLX3 orchestrates the expression of multiple regulators of trophoblast differentiation and that expression of these regulatory genes is abnormal in FGR.

Is hyperemesis gravidarum associated with placental weight and the placental weight-to-birth weight ratio? A population-based Norwegian cohort study

INTRODUCTION

Studies have suggested a link between placental weight, placental weight-to-birth weight ratio (PW/BW) and adult health. Hyperemesis gravidarum (HG) may also have implications for adult health. No studies on HG and placental characteristics have been identified. We therefore explored the relationship between HG, placental weight and the PW/BW-ratio in a population-based cohort.

METHODS

Singleton births to primiparous women between 1999 and 2009 with data on HG, placental weight and birth weight in the Medical Birth Registry of Norway (MBRN) comprised the study base (n = 200,390). HG was defined through ICD-10 code 021.0, 021.1 and 021.9. Gender and gestational age specific percentile curves for placenta weight and PW/BW ratio were used to define those below the 10th and above the 90th percentile of both outcomes. Associations between HG and dichotomous outcomes were studied by multiple logistic regression. Multiple linear regression was applied to study placental weight as a continuous variable. Male and female offspring were analyzed separately.

RESULTS

The prevalence of HG was 1.2%. Women with HG and female offspring had significantly higher risk of a PW/BW-ratio above the 90th percentile (OR = 1.17, 95% CI: 1.03-1.34). HG and PW/BW-ratio below the 10th percentile were inversely associated (OR = 0.70, 95% CI: 0.56-0.89). For male offspring no association was observed for HG and PW/BW-ratio below the 10th or above the 90th percentile.

DISCUSSION/CONCLUSIONS

We observed positive associations between HG and high PW/BW ratio limited to female offspring only. The high PW/BW-ratio suggests that there may be a possible link between HG and adult health.

Placental glucose transporter 3 (GLUT3) is up-regulated in human pregnancies complicated by late-onset intrauterine growth restriction

INTRODUCTION

Transport of glucose from maternal blood across the placental trophoblastic tissue barrier is critical to sustain fetal growth. The mechanism by which GLUTs are regulated in trophoblasts in response to ischemic hypoxia encountered with intrauterine growth restriction (IUGR) has not been suitably investigated.

OBJECTIVE

To investigate placental expression of GLUT1, GLUT3 and GLUT4 and possible mechanisms of GLUT regulation in idiopathic IUGR.

METHODS

We analyzed clinical, biochemical and histological data from placentas collected from women affected by idiopathic full-term IUGR (n = 10) and gestational age-matched healthy controls (n = 10).

RESULTS

We found increased GLUT3 protein expression in the trophoblast (cytotrophoblast greater than syncytiotrophoblast) on the maternal aspect of the placenta in IUGR compared to normal placenta, but no differences in GLUT1 or GLUT4 were found. No differential methylation of the GLUT3 promoter between normal and IUGR placentas was observed. Increased GLUT3 expression was associated with an increased nuclear concentration of HIF-1α, suggesting hypoxia may play a role in the up-regulation of GLUT3.

DISCUSSION

Further studies are needed to elucidate whether increased GLUT3 expression in IUGR is a marker for defective villous maturation or an adaptive response of the trophoblast in response to chronic hypoxia.

CONCLUSIONS

Patients with IUGR have increased trophoblast expression of GLUT3, as found under the low-oxygen conditions of the first trimester.

2D-Ultrasound and endocrinologic evaluation of placentation in early pregnancy and its relationship to fetal birthweight in normal pregnancies and pre-eclampsia

OBJECTIVES

To study the relationships between 2D ultrasound measurements of placentation and maternal serum (MS) levels of PAPP-A, inhibin A and fβhCG in early pregnancy and subsequent fetal growth in pregnancies with a normal and abnormal outcome.

STUDY DESIGN

Prospective population-based cohort study of 301 pregnancies with a normal outcome, 18 with a pregnancy complicated by pre-term delivery (PTD) and 14 with subsequent pre-eclampsia (PE).

MAIN OUTCOME MEASURES

Basal placental surface area, placental thickness, ellipsivity and volume; MS PAPP-A and fβhCG at 11-13 + 6 weeks, MS inhibin A at 15-22 weeks and birthweight centile at delivery.

RESULTS

In the normal group, the basal surface area showed a significantly (P < 0.001) positive correlation with placental thickness and placental ellipsivity. With the exception of placental ellipsivity, all other placental ultrasound parameters were significantly related with birthweight centile. Inhibin A showed a significant (P < 0.005) correlation with birthweight centiles. The basal plate surface area and MS PAPP-A were significantly (P < 0.01 and P < 0.001, respectively) lower and MS inhibin A significantly (P < 0.01) higher in PE than in controls. No changes were found in pregnancies complicated by PTD.

CONCLUSION

The basal plate surface area at 11-14 weeks reflects indirectly normal and abnormal placentation and development of the definitive placenta. Combined with MS PAPP-A and/or inhibin A levels this parameter could be useful in identifying from the end of the first trimester, pregnancies subsequently complicated with PE.

Plasmodium falciparum malaria elicits inflammatory responses that dysregulate placental amino acid transport

Placental malaria (PM) can lead to poor neonatal outcomes, including low birthweight due to fetal growth restriction (FGR), especially when associated with local inflammation (intervillositis or IV). The pathogenesis of PM-associated FGR is largely unknown, but in idiopathic FGR, impaired transplacental amino acid transport, especially through the system A group of amino acid transporters, has been implicated. We hypothesized that PM-associated FGR could result from impairment of transplacental amino acid transport triggered by IV. In a cohort of Malawian women and their infants, the expression and activity of system A (measured by Na⁺-dependent ¹⁴C-MeAIB uptake) were reduced in PM, especially when associated with IV, compared to uninfected placentas. In an in vitro model of PM with IV, placental cells exposed to monocyte/infected erythrocytes conditioned medium showed decreased system A activity. Amino acid concentrations analyzed by reversed phase ultra performance liquid chromatography in paired maternal and cord plasmas revealed specific alterations of amino acid transport by PM, especially with IV. Overall, our data suggest that the fetoplacental unit responds to PM by altering its placental amino acid transport to maintain adequate fetal growth. However, IV more profoundly compromises placental amino acid transport function, leading to FGR. Our study offers the first pathogenetic explanation for FGR in PM.

Malaria infection during pregnancy can cause fetal growth restriction and low birthweight associated with high infant mortality and morbidity rates. The pathogenesis of fetal growth restriction in placental malaria is largely unknown, but in other pathological pregnancies, impaired transplacental amino acid transport has been implicated. In a cohort of Malawian women and their infants, we found that placental malaria, especially when associated with local inflammation, was associated with decreased expression and activity of an important group of amino acid placental transporters. Using an in vitro model of placental malaria with local inflammation, we discovered that maternal monocyte products could impair the activity of amino acid transporters on placental cells. Amino acid concentrations in paired maternal and cord plasmas revealed specific alterations of amino acid transport by placental malaria, especially with local inflammation. Overall, our data suggest that, more than malaria infection per se, the local inflammation it triggers compromises placental amino acid transport function, leading to fetal growth restriction. Greater understanding of the mechanisms involved, combined with interventions to improve fetal growth in malaria, are important priorities in areas of the world where the co-existence of malaria and maternal malnutrition threatens the health and lives of millions of young babies.

Role of p53-dependent placental apoptosis in the reproductive and developmental toxicities of caffeine in rodents

The aim of the present study was to evaluate the role of placental apoptosis in mediating the reproductive and developmental toxicity of caffeine in rodents. Female Kunming mice were treated with caffeine (60, 120 and 240 mg/kg per day) before and during pregnancy. The conception rate, maternal bodyweight gain, placental weight and indices of fetal developmental, including the rate of intrauterine growth retardation (IUGR; i.e. the actual number of fetuses exhibiting IUGR as a percentage of the total number of fetuses), were determined on gestational day (GD) 18. Female Wistar rats were treated with caffeine (20, 60 and 180 mg/kg per day) from GD11 to GD20. The IUGR rate, maternal plasma angiotensin (Ang) II and prolactin concentrations, placental pathology, expression of angiotensin AT(1) and AT(2) receptors and apoptosis-related proteins were measured on GD20. In mice, caffeine treatment dose-dependently reduced the total conception rate, delayed conception and decreased maternal bodyweight gain, placental weight, fetal bodyweight and fetal body and tail lengths, whereas the IUGR rate was increased. In rats, caffeine treatment dose-dependently decreased placental weight and fetal bodyweight and increased the IUGR rate. Abnormal placental structures and decreased maternal plasma prolactin concentrations were observed following 180 mg/kg per day caffeine treatment, which resulted in increases in renin-angiotensin system (RAS) activity, including maternal plasma AngII concentrations and placental AT(1B) and AT(2) receptor expression, and Bax and p53 expression, but decreases in placental Bcl-2 expression. On the basis of the results of the present study, it appears that caffeine ingestion has detrimental effects on the reproductive system and fetal development in rodents that are associated with chronic activation of the maternal and placental RAS, and induction of p53-dependent placental apoptosis.

Air pollution exposure and markers of placental growth and function: the generation R study

BACKGROUND

Air pollution exposure during pregnancy might affect placental growth and function, perhaps leading to pregnancy complications.

OBJECTIVE

We prospectively evaluated the associations of maternal air pollution exposure with markers of placental growth and function among 7,801 pregnant women in the Netherlands.

METHODS

We estimated levels of particulate matter ≤ 10 µm in aerodynamic diameter (PM10) and nitrogen dioxide (NO2) at the home address for different periods during pregnancy using dispersion modeling techniques. Pro- and anti-angiogenic factors [placental growth factor (PlGF) and soluble fms-like tyrosine kinase 1 (sFlt-1), respectively] were measured in first- and second-trimester maternal blood and in fetal cord blood samples at delivery. Pulsatility index of the uterine and umbilical arteries was measured by Doppler ultrasound in second and third trimester, and notching was assessed in third trimester. Placenta weight and birth weight were obtained from medical records.

RESULTS

Higher PM10 and NO2 exposure levels were associated with lower second-trimester maternal sFlt-1 and PlGF levels. PM10 and NO2 exposures averaged over total pregnancy were associated with higher sFlt-1 and lower PlGF levels in fetal cord blood, consistent with an anti-angiogenic state. PM10 and NO2 exposures were not consistently associated with second- or third-trimester placental resistance indices. NO2 exposure was associated with third-trimester notching (odds ratio 1.33; 95% CI: 0.99, 1.78 per 10-µg/m3 increase in the prior 2 months). PM10 and NO2 exposures were associated with lower placenta weight (-11.8 g; 95% CI: -20.9, -2.7, and -10.7 g; 95% CI: -19.0, -2.4, respectively, per 10-µg/m3 increase in the prior 2 months), but not with placenta to birth weight ratio.

CONCLUSIONS

Our results suggest that maternal air pollution exposure may influence markers of placental growth and function. Future studies are needed to confirm these findings and explore the maternal and fetal consequences.

Maternal weight and body composition during pregnancy are associated with placental and birth weight in rural Bangladesh

Placental growth is a strong predictor of fetal growth, but little is known about maternal predictors of placental growth in malnourished populations. Our objective was to investigate in a prospective study the associations of maternal weight and body composition [total body water (TBW) estimated by bioelectrical impedance and fat and fat-free mass derived from upper arm fat and muscle areas (UAFA, UAMA)] and changes in these with placental and birth weights. Within a cluster-randomized trial of maternal micronutrient supplementation, a subsample of 350 women was measured 3 times across gestation. Longitudinal analysis was used to examine independent associations of ∼10-wk measurements and ∼10-20 wk and ∼20-32 wk changes with birth outcomes. Weight, TBW, and UAMA, but not UAFA, at ∼10 wk were each positively and independently associated with placental weight and birth weight (P < 0.05). Of the maternal ∼10-20 wk changes in measurements, only TBW change and placental weight, and maternal weight and birth weight were positively associated (P < 0.05). Gains in weight, TBW, and UAMA from 20 to 32 wk were positively and UAFA gain was negatively associated with placental weight (P ≤ 0.01). Gains in weight and UAMA from 20 to 32 wk were positively associated with birth weight (P ≤ 0.01). Overall, higher maternal weight and measures of fat-free mass at ∼10 wk gestation and gains from 20 to 32 wk are independently associated with higher placental and birth weight.

Are there any differences in three-dimensional placental vascular indices obtained using conventional power Doppler and high-definition flow imaging?

OBJECTIVE

The purpose of this study was to determine whether there are differences in values and reproducibility of three-dimensional (3D) vascular indices obtained on placental volumes using power Doppler (PD) or high-definition flow imaging (HDFI) techniques.

METHODS

A prospective study was performed on 121 uncomplicated singleton pregnancies at 11 + 0 to 13 + 6 weeks of gestation. Two placental volumes were acquired from each pregnancy. Vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were then analyzed and compared. In order to assess the reproducibility of the measurements, two additional placental volumes obtained with both PD and HDFI were acquired in 31 pregnancies and the agreement assessed by intraclass correlation coefficients. Inter-observer variability was assessed by analyzing all the volumes by two observers blinded to each other's.

RESULTS

A significant relationship was observed between the vascular indices values obtained with the two techniques (VI Pearson's r=0.891 p<0.001; FI r=0.769 p<0.001; VFI r=0.847 p<0.001). The median values of VI, FI and VFI were significantly higher when obtained with HDFI imaging. In serial recordings, the ICCs resulted higher when volumes were acquired with HDFI rather than with PD techniques. Similarly, HDFI demonstrated a higher inter-observer reproducibility.

CONCLUSIONS

3D vascular indices calculated using HDFI are higher than those calculated using conventional PD. Although the relationship between the two methods is high, HDFI shows a better reproducibility suggesting its potential clinical application.

Placental pathology, birthweight discordance, and growth restriction in twin pregnancy: results of the ESPRiT Study

OBJECTIVE

We sought to evaluate the association between placental histological abnormalities and birthweight discordance and growth restriction in twin pregnancies.

STUDY DESIGN

We performed a multicenter, prospective study of twin pregnancies. Placentas were examined for evidence of infarction, retroplacental hemorrhage, chorangioma, subchorial fibrin, or abnormal villus maturation. Association of placental lesions with chorionicity, birthweight discordance, and growth restriction were assessed.

RESULTS

In all, 668 twin pairs were studied, 21.1% monochorionic and 78.9% dichorionic. Histological abnormalities were more frequent in placentas of smaller twins of birthweight discordant pairs (P = .02) and in placentas of small for gestational age infants (P = .0001) when compared to controls. The association of placental abnormalities with both birthweight discordance and small for gestational age was significant for dichorionic twins (P = .01 and .0001, respectively). No such association was seen in monochorionic twins.

CONCLUSION

In a large, prospective, multicenter study, we observed a strong relationship between abnormalities of placental histology and birthweight discordance and growth restriction in dichorionic, but not monochorionic, twin pregnancies.

Fetal growth versus birthweight: the role of placenta versus other determinants

Introduction

Birthweight is used as an indicator of intrauterine growth, and determinants of birthweight are widely studied. Less is known about determinants of deviating patterns of growth in utero. We aimed to study the effects of maternal characteristics on both birthweight and fetal growth in third trimester and introduce placental weight as a possible determinant of both birthweight and fetal growth in third trimester.

Methods

The STORK study is a prospective cohort study including 1031 healthy pregnant women of Scandinavian heritage with singleton pregnancies. Maternal determinants (age, parity, body mass index (BMI), gestational weight gain and fasting plasma glucose) of birthweight and fetal growth estimated by biometric ultrasound measures were explored by linear regression models. Two models were fitted, one with only maternal characteristics and one which included placental weight.

Results

Placental weight was a significant determinant of birthweight. Parity, BMI, weight gain and fasting glucose remained significant when adjusted for placental weight. Introducing placental weight as a covariate reduced the effect estimate of the other variables in the model by 62% for BMI, 40% for weight gain, 33% for glucose and 22% for parity. Determinants of fetal growth were parity, BMI and weight gain, but not fasting glucose. Placental weight was significant as an independent variable. Parity, BMI and weight gain remained significant when adjusted for placental weight. Introducing placental weight reduced the effect of BMI on fetal growth by 23%, weight gain by 14% and parity by 17%.

Conclusion

In conclusion, we find that placental weight is an important determinant of both birthweight and fetal growth. Our findings indicate that placental weight markedly modifies the effect of maternal determinants of both birthweight and fetal growth. The differential effect of third trimester glucose on birthweight and growth parameters illustrates that birthweight and fetal growth are not identical entities.

Differences in gene expression between first and third trimester human placenta: a microarray study

BACKGROUND

The human placenta is a rapidly developing organ that undergoes structural and functional changes throughout the pregnancy. Our objectives were to investigate the differences in global gene expression profile, the expression of imprinted genes and the effect of smoking in first and third trimester normal human placentas.

MATERIALS AND METHODS

Placental samples were collected from 21 women with uncomplicated pregnancies delivered at term and 16 healthy women undergoing termination of pregnancy at 9-12 weeks gestation. Placental gene expression profile was evaluated by Human Genome Survey Microarray v.2.0 (Applied Biosystems) and real-time polymerase chain reaction.

RESULTS

Almost 25% of the genes spotted on the array (n = 7519) were differentially expressed between first and third trimester placentas. Genes regulating biological processes involved in cell proliferation, cell differentiation and angiogenesis were up-regulated in the first trimester; whereas cell surface receptor mediated signal transduction, G-protein mediated signalling, ion transport, neuronal activities and chemosensory perception were up-regulated in the third trimester. Pathway analysis showed that brain and placenta might share common developmental routes. Principal component analysis based on the expression of 17 imprinted genes showed a clear separation of first and third trimester placentas, indicating that epigenetic modifications occur throughout pregnancy. In smokers, a set of genes encoding oxidoreductases were differentially expressed in both trimesters.

CONCLUSIONS

Differences in global gene expression profile between first and third trimester human placenta reflect temporal changes in placental structure and function. Epigenetic rearrangements in the human placenta seem to occur across gestation, indicating the importance of environmental influence in the developing feto-placental unit.

Residential proximity to major roads and placenta/birth weight ratio

Exposure to air pollution has been demonstrated to increase the risk of preterm birth and low birth weight. We examined whether proximity to major roads (as a marker of exposure to air pollution) is associated with increased placenta/birth weight ratio (as a biomarker of the placental transport function). Data on parental characteristics and birth outcomes were extracted from the database maintained by a major hospital in Shizuoka Prefecture, Japan. We restricted the analysis to mothers who delivered liveborn single births from 1997 to 2008 (n = 14,189). Using geocoded residential information, each birth was classified according to proximity to major roads. We examined the association between proximity to major roads and the placenta/birth weight ratio, using multiple linear regression. Proximity to major roads was associated with higher placenta/birth weight ratio. After adjusting for potential confounders, living within 200 m of a major road increased the ratio by 0.48% (95% CI = 0.15 to 0. 80). In addition, proximity to major roads was associated with lower placenta weight and birth weight. These observed associations were stronger among participants living closer to major roads. Exposure to traffic-related air pollution is associated with higher placenta/birth weight ratio. Impaired placental oxygen and nutrient transport function might be a mechanism for explaining the observed association between air pollution and low birth weight as well as preterm birth.

A common cause for a common phenotype: the gatekeeper hypothesis in fetal programming

Sub-optimal nutrition during pregnancy has been shown to have long-term effects on the health of offspring in both humans and animals. The most common outcomes of such programming are hypertension, obesity, dyslipidaemia and insulin resistance. This spectrum of disorders, collectively known as metabolic syndrome, appears to be the consequence of nutritional insult during early development, irrespective of the nutritional stress experienced. For example, diets low in protein diet, high in fat, or deficient in iron are all associated with programming of cardiovascular and metabolic disorders when fed during rat pregnancy. In this paper, we hypothesise that the nutritional stresses act on genes or gene pathways common to all of the insults. We have termed these genes and/or gene pathways the “gatekeepers” and hence developed the “gatekeeper hypothesis”. In this paper, we examine the background to the hypothesis and postulate some possible mechanisms or pathways that may constitute programming gatekeepers.

Placental morphologic features and chorionic surface vasculature at term are highly correlated with 3-dimensional sonographic measurements at 11 to 14 weeks

OBJECTIVES

The purpose of this study was to examine the potential for 3-dimensional sonographic measurement of the early placenta in predicting ultimate placental morphologic features at delivery.

METHODS

In this prospective cohort study, we collected 3-dimensional sonographic volume sets of placentas at 11 to 14 weeks and then collected the placentas after delivery. The sonographic data were manipulated to obtain various novel measurements of early gross placental morphologic features and the umbilical cord insertion location. The placental weight, chorionic plate area, cord location, and mean chorionic vascular density were obtained from the delivered postpartum placentas. Analyses were performed to identify potential early placental characteristics that were correlated with the ultimate placental morphologic features. The placental weight, cord marginality, and mean chorionic vascular density served as the outcome measures of interest.

RESULTS

Measurements of the early placental volume correlated with the delivered placental weight. An irregular early placental shape, as measured by sonography, was significantly inversely correlated with placental weight (P < .05). The placental morphologic index, a measure of a flatter placenta, was inversely correlated with both the placental weight and chorionic plate area, possibly indicating the importance of placental thickness even in the first trimester before villous arborization. In addition, early sonographic measures of the location of the umbilical cord insertion were significantly correlated with the ultimate marginality of the cord insertion as well as the mean chorionic vascular density (P < .05).

CONCLUSIONS

Many important ultimate placental morphologic features are likely predetermined early in pregnancy. Three-dimensional sonography may play an increasing role in the in utero evaluation of the early placenta.

Placenta/birthweight ratio and perinatal outcome: a retrospective cohort analysis

OBJECTIVE

The placenta weight/birthweight (PW/BW) ratio has been shown to be associated with certain long-term fetal outcomes; however, its association with short-term outcomes has not received much attention. Our aim was to assess the correlation between the PW/BW ratio and short-term adverse obstetrics outcomes in full-term, appropriate-for-gestational-age (AGA) newborns.

DESIGN

Retrospective cohort study analysis using data from the McGill Obstetrical and Neonatal Database.

SETTING

McGill University Health Centre in Montreal Canada.

POPULATION

AGA neonates.

METHODS

Three groups of full-term AGA neonates were created, according to their PW/BW ratio (high, normal and low), to be compared. Our primary outcome was the admission rate to the neonatal intensive care unit (NICU), and secondary outcomes included an Apgar score < 7 at 5 minutes, cord PH < 7.0, cord base excess (BE) ≤ 12, respiratory distress syndrome (RDS), patent ductus arteriosus (PDA), occurrence of apnoea episodes, breech presentation at delivery, caesarean section rate and status in discharge home. A logistic regression model was instituted to investigate the predictors for adverse obstetrics outcomes.

MAIN OUTCOME MEASURE

Admission to the NICU.

RESULTS

Compared with the group with normal PW/BW ratios, the high PW/BW ratio group was associated with increased rates of admission to the NICU, of Apgar scores < 7 at 5 minutes, of breech presentation and caesarean section. On the contrary, the low PW/BW ratio group showed decreased rates of NICU admission, breech presentation and caesarean section.

CONCLUSIONS

A high PW/BW ratio is significantly correlated with short-term adverse perinatal outcomes. This ratio may be used as a new and simple warning sign to predict the possibility of short-term health risks for newborns.

TERC telomerase subunit gene copy number in placentas from pregnancies complicated with intrauterine growth restriction

INTRODUCTION

intrauterine growth restriction (IUGR) is a significant cause of both short- and long-term morbidity and mortality. IUGR secondary to placental dysfunction is correlated with telomere shortening. Telomerase is an enzyme complex that elongates telomeres. One of its components is encoded by the telomerase RNA component gene (TERC), which serves as the RNA template for the addition of telomeric repeats. We hypothesized decreased TERC gene copy number in IUGR placentas as part of the mechanism of telomere shortening in placental dysfunction.

METHODS

we estimated the gene copy number of the TERC gene at 3q26 by applying FISH to trophoblasts of placental biopsies from five pregnancies with IUGR caused by placental insufficiency and compared them to placentas from five gestational-age matched, uncomplicated pregnancies.

RESULTS

significantly lower TERC gene copy number was observed in IUGR trophoblasts on the same chromosome and on other chromosomes, compared to the control samples (p<0.05).

CONCLUSIONS

the TERC gene copy number is decreased in IUGR trophoblasts. These results support the observations of telomere shortening and decreased telomerase activity in IUGR placentas. We suggest that these findings might play a role in the pathophysiology of IUGR, perhaps by promoting senescence in trophoblasts of IUGR placentas.

Placental pathology in fetal growth restriction

OBJECTIVES

One of the causes of intrauterine fetal growth restriction (FGR) can be pathology of the placenta. The aim of this study was to compare macroscopic and microscopic changes of the placentas from intrauterine growth restricted fetuses with those from normally developed fetuses, in order to test the hypothesis that vascular damage due to decreased maternal vascular perfusion may be responsible for FGR.

STUDY DESIGN

Between May 2007 and December 2008 we performed detailed macroscopic and histological examination of singleton placentas of 50 consecutive neonates with fetal growth restriction (FGR group) and compared them to 50 normal fetuses, born next to an FGR case, as a control group.

RESULTS

Gestational age, birth weight, spontaneous delivery rate, mean weight of the placenta and the fetal-placental weight ratio were all lower in the FGR group than in the control group (p<0.05). Thickening of the villous trophoblastic basal membrane, incidence of villous infarction, presence of thrombi or haematomas and the incidence of villitis were more common in the FGR group than in the controls (p<0.05). There were, however, no significant differences in perivillous fibrin deposition, stromal fibrosis and cytotrophoblast proliferation between the groups. In FGR women who smoked, intervillous haematomas and villous infarction were more common (p<0.05) than in controls.

CONCLUSIONS

All macroscopic and microscopic pathological changes associated with FGR were directly linked to reduction of placental blood flow. As smoking is a main risk factor for these placental abnormalities these results emphasize the need to persuade women to quit smoking not only during pregnancy, but even better long before pregnancy.

Association between placental morphology and childhood systolic blood pressure

We tested hypotheses that disproportionately large placental size and vascular lesions were associated with high systolic blood pressure (SBP); and these associations might be more evident with age. The sample included 13 273 of 40 666 full-term singletons in the Collaborative Perinatal Project. Placentas were examined by pathologists blinded of pregnancy courses and outcomes. The 4-month and 7-year SBPs were measured with palpation and auscultation methods, respectively. We found that placental weight (adjusted mean difference corresponding to an increase by 1 SD 0.50 [95% CI, 0.33 to 0.68]) and placenta-fetus weight ratio (0.37 [95% CI, 0.19 to 0.54]) was positively associated with 7-year SBP but not associated with 4-month SBP. Placental largest and smallest diameters and area were negatively associated with 4-month SBP but positively with 7-year SBP. Placental thickness was negatively associated with 4-month SBP only. Placental volume was negatively associated with 4-month SBP (-0.60 [95% CI, - 0.85 to -0.35]) but positively associated with 7-year SBP (0.48 [95% CI, 0.30 to 0.67]). Thrombi in cord vessels (adjusted mean difference versus absence 2.73 [95% CI, - 0.03 to 5.50]) and decidual vessels (2.58 [95% CI, 0.24 to 4.91]), villous microinfarcts (1.63 [95% CI, 0.71 to 2.55]), necrosis at the decidual margin (1.57 [95% CI, 0.54 to 2.59]), and basalis (3.44 [95% CI, 1.55 to 5.32]) were associated with higher 4-month SBP only. We conclude that placental inefficiency, reflected by disproportionately large weight and size, predicts long-term blood pressure, whereas vascular resistance and lesions may only influence short-term blood pressure.

Placenta weight percentile curves for singleton and twins deliveries

OBJECTIVE

To establish updated placental percentile nomograms in a large North American population for singleton and twin gestations for the use of researchers and clinicians.

STUDY DESIGN

Data was extracted from our computerized registry; McGill Obstetrics and Neonatal Database (MOND). The registry includes all the obstetrical data on all deliveries at the McGill University, including placental weight, placental pathologies, maternal and perinatal complications. 20,635 singleton deliveries and 527 twin deliveries were included. Placental weight, gestational age at delivery, birth weight and gender were retrieved. Tables and figures for the 3rd,10th,25th, 50th, 75th 90th, and 97th percentile of placental weight by gestational age, placental weight by birth weight and placental to birth weight ratio by gestational age were produced.

RESULTS

Tables and figures are presented for placental percentiles curves according to gestational age, gestational weight and gender for singleton and twin deliveries. In addition, tables and figures are presented for the ratio of placental weight to birth weight.

CONCLUSIONS

Population percentile curves have been produced for placental weight and for the ratio of placental weight to birth weight to for singleton and twin deliveries.

Novel 3-dimensional placental measurements in early pregnancy as predictors of adverse pregnancy outcomes

OBJECTIVE

We sought to determine whether novel approaches to volumetric assessment of the early placenta can yield significant predictors of adverse outcome.

METHODS

We measured placental volume (PV) at 11 to 14 weeks using virtual organ computer-aided analysis and normalized the PV to the crown-rump length (CRL) to yield the placental quotient (PQ = PV/CRL). We also calculated the mean placental diameter (MPD) from 4 measurements taken at 45 degrees intervals to serve as a surrogate for the fetal-maternal surface area. On the fetal side, the distance from the cord insertion (CI) to the placental margin was measured every 45 degrees. Mean cord distance (MCD) is proposed as a novel descriptor of the chorionic plate and CI. Sonographic variables were analyzed as predictors of a composite adverse pregnancy outcome (COMP = small for gestational age [SGA], preeclampsia, spontaneous preterm birth, or neonatal intensive care unit admission).

RESULTS

A total of 135 patients were included, and 40 (29.6%) had an adverse outcome. The mean PQ (P = .02) and MCD (P = .02) were significantly lower in patients with COMP, although MPD was not significantly different (P = .26). A PQ of less than 1.00 (relative risk [RR], 2.3 [95% confidence interval, 1.4-2.7]) and an MCD of less than 4.00 cm (RR, 1.8 [1.1-2.9]) conferred an increased risk for COMP. Prediction models adjusting for parity and race yielded favorable characteristics [PV: area under the curve [AUC], 0.796; P = .04; PQ: AUC, 0.802; P = .03; MCD: AUC, 0.800; P = .04; and MPD: AUC, 0.782; P = .07). Secondary models targeting SGA as the sole outcome also showed excellent prediction (PV: AUC, 0.820; PQ: AUC, 0.810; MCD: AUC, 0.827; and MPD: AUC, 0.795).

CONCLUSIONS

In addition to volume, 3-dimensional sonography allows for novel techniques to measure other aspects of gross placental morphologic characteristics and CI, which can yield promising biologically plausible early predictors of fetal growth and adverse perinatal outcome.

Telomeres are shorter in placental trophoblasts of pregnancies complicated with intrauterine growth restriction (IUGR)

OBJECTIVE

Telomeres are nucleoprotein structures located at the termini of chromosomes, and protect them from fusion and degradation. Telomeres are progressively shortened with each mitotic cycle and by environmental factors. We hypothesized that antepartum stress can lead to accelerated telomere shortening in placental trophoblasts, and plays a role in intrauterine growth restriction (IUGR).

METHODS

Placental biopsies were derived from 16 pregnancies complicated with IUGR and from 13 uncomplicated pregnancies. Fluorescence-in-situ protocol was used to determine telomere length. Immunohistochemistry for hTERT was performed to assess telomerase activity. Clinical and histopathological characteristics were collected to ensure that IUGR was secondary to placental insufficiency. Fluorescence-in-situ-hybridization was used to rule out aneuploidy as a reason for shortened telomeres.

RESULTS

The number and intensity of telomeres staining and telomerase activity were significantly lower in the IUGR placentas. No aneuploidy was detected for the chromosomes checked in the placental biopsies.

CONCLUSIONS

Telomeres are shorter in trophoblasts of IUGR placentas.

Placental vascular lesion differences in pregnancy-induced hypertension and normotensive fetal growth restriction

OBJECTIVE

Pregnancy-induced hypertension/preeclampsia (PIH) and fetal growth restriction (FGR) share a common placental origin. The pathologic classification that divides placental lesions to maternal or fetal origin was compared between these disorders.

STUDY DESIGN

Placentas from pregnancies that were complicated by PIH, normotensive FGR, or by both (combined) were analyzed, and lesions were classified as those consistent with maternal under-perfusion and with fetal thromboocclusive disease.

RESULTS

Maternal vascular lesions were more common in the PIH group and combined group (61% and 59%, respectively), compared with the FGR group (16.2%; P < .001), and villous lesions were more common in the combined group, compared with the FGR and PIH groups (79.5%, 53.5%, and 46.9%, respectively; P = .004). Fetal villous changes were observed in 16.2% in the FGR group, compared with 3.1% in the PIH group (P = .03), and chronic villitis was 15.2% in the FGR group vs 1.6% in the PIH group (P = .004).

CONCLUSION

Placental lesions correspond with different clinical presentations.

Placental MRI in intrauterine fetal growth restriction

OBJECTIVE

Our objectives were to determine if MR imaging of the placenta could demonstrate a specific placental phenotype in small for gestational age fetuses with increasing severity of fetal growth restriction, and if MRI findings at the time of scan could be used to predict fetal or neonatal mortality.

METHOD

We included singleton growth restricted fetuses with increasing severity of fetal growth restriction secondary to placental insufficiency. 20 growth restricted fetuses and 28 normal fetuses were scanned once during pregnancy at varying gestations. MRI scans were performed on a 1.5T system using ssFSE sequences through the uterus. Data was collected on the severity of fetal growth restriction and pregnancy outcome, including clinical neonatal details, perinatal mortality, and birthweight and centile. Placental volume, maximal placental thickness, the placental thickness to volume ratio, the placenta to amniotic fluid signal intensity ratio, and the presence of abnormal signal intensity consistent with placental pathology were noted. In a subset of patients, histopathological diagnosis was compared with the MRI appearance of the placenta.

RESULTS

There was a significant increase in the placental volume affected by pathology in growth restricted fetuses (p < 0.001). The placental appearance was also thickened and globular, with an increase in the placental thickness to volume ratio (p < 0.001). Although placental volume increased with increasing gestation, it remained reduced in the growth restricted fetuses (p = 0.003). There was a significant correlation between the severity of fetal growth restriction and the placental volume affected by pathology, the placental thickness to volume ratio, and the placental volume. ROC analysis showed that fetal or neonatal death was predicted by the percentage of abnormal signal intensity consistent with placental pathology (p = 0.002). The presence of a thickened, globular placenta and a maximal placental thickness to volume ratio above the 95% confidence limit for gestation was significantly associated with an increased incidence of fetal or neonatal mortality (relative risk = 1.615, p = 0.001 and relative risk = 7, p < 0.001).

CONCLUSIONS

The MRI appearance of the placenta provides an indication of the severity and underlying disease process in fetal growth restriction. In units where MRI imaging of the growth restricted fetus occurs, we suggest that the assessment of the placenta should also occur as it may contribute to management decisions in cases at the threshold of viability. It may have a role to play in monitoring disease severity, and the effect of future interventions designed to improve placental function.

Placental weight in pregnancies with trisomy confined to the placenta

OBJECTIVE

Mosaicism with trisomy confined to the placenta is present in ~1% of ongoing pregnancies at the time of chorionic villus sampling. Some studies have found reduced fetal growth in confined placental trisomy. The objective of this study was to assess placental weight and feto-placental weight ratio in pregnancies with trisomy confined to the placenta, and to correlate them with the level of trisomy in the three major placental lineages.

METHODS

We conducted a retrospective study of 69 pregnancies with prenatally diagnosed mosaic trisomy in which the trisomic cells were confined to the placenta. Placental weight and feto-placental weight ratio were compared to those of matched controls, and placental weight was also analyzed for associations with the type and level of trisomy. Placental pathology was also reviewed.

RESULTS

The pregnancies with mosaic trisomy were found to have lower placental weights than matched controls, but normal feto-placental weight ratios. Placental weight was not associated with the type or level of trisomic cells in the three placental lineages at term (chorionic plate, chorionic villus mesenchyme, and trophoblast). There were no pathognomonic findings on routine placental pathology of the trisomic placentas.

CONCLUSION

Although placental weight was reduced (with normal feto-placental weight ratio) in pregnancies with trisomy confined to the placenta, the level of placental trisomy was not correlated with placental weight. Thus, trisomy may alter placental function rather than have a direct hypoplastic effect on placental growth. More in-depth studies beyond routine pathology are required to identify how trisomy affects placental function.

Placental weight relative to birth weight and long-term cardiovascular mortality: findings from a cohort of 31,307 men and women

Birth weight is inversely associated with risk of adult cardiovascular disease, and evidence exists that fetal adaptation to challenges in the intrauterine environment may adversely affect long-term cardiovascular health. The placenta is in a key position to mediate such effects because adequate placental function is necessary for delivery of nutrients, oxygen, and hormones to the fetus. This prospective population study based on data from the hospital birth charts of 31,307 Norwegian men and women born between 1934 and 1959 assessed whether placental weight relative to birth weight was associated with risk of death from cardiovascular disease in adulthood. During 45 years of follow-up, 382 people died from cardiovascular disease (median age, 51.3 years). Results showed that the placenta-to-birth-weight ratio was positively associated with cardiovascular disease mortality; the sex- and cohort-adjusted hazard ratio for the highest versus the lowest third was 1.38 (95% confidence interval: 1.07, 1.77). The authors concluded that a disproportionately large placenta relative to birth weight was associated with increased risk of cardiovascular disease death. This finding suggests that placental function is important in the association of intrauterine factors with cardiovascular disease later in life.