The placental factor in early- and late-onset normotensive fetal growth restriction

Utility of placental biomarkers and fetoplacental Dopplers in predicting likely placental pathology in early and late fetal growth restriction - A prospective study

INTRODUCTION

The aim of this study was to evaluate the association between placental abnormalities, placental biomarkers, and fetoplacental Dopplers in a cohort of pregnancies complicated by fetal growth restriction (FGR). We also ascertained the risk of perinatal mortality, severe neurological morbidity, and severe non-neurological morbidity by type of placental abnormality.

METHODS

This was a prospective cohort study. Multivariable logistic regression was used to evaluate the effect of early vs. late FGR, placental biomarkers and fetoplacental Dopplers on Maternal Vascular Malperfusion (MVM) which was the commonest placental abnormality identified.

RESULTS

There were 161 (53.5 %) early FGR and 140 (46.5 %) late FGR cases. MVM abnormalities were present in 154 (51.2 %), VUE in 45 (14.6 %), FVM in 16 (5.3 %), DVM in 14 (4.7 %) and CHI in 4 (1.3 %) cases. The odds of MVM were higher in early compared to late FGR cohort (OR 1.89, 95%CI 1.14, 3.14, p = 0.01). Low maternal PlGF levels <100 ng/L (OR 2.34, 95%CI 1.27,4.31, p = 0.01), high sFlt-1 level (OR 2.13, 95%CI 1.35, 3.36, p = 0.001) or elevated sFlt-1/PlGF ratio (OR 3.48, 95%CI 1.36, 8.91, p = 0.01) were all associated with MVM. Increased UA PI > 95th centile (OR 2.91, 95%CI 1.71, 4.95, p=<0.001) and mean UtA PI z-score (OR 1.74, 95%CI 1.15, 2.64, p = 0.01) were associated with higher odds of MVM. Rates of severe non-neurological morbidity were highest in the MVM, FVM, and CHI cohorts (44.8 %, 50 %, and 50 % respectively).

CONCLUSION

MVM was the commonest placental abnormality in FGR, particularly in early-onset disease. Low maternal PlGF levels, high sFlt-1 levels, elevated sFlt-1/PlGF ratio, and abnormal fetoplacental Dopplers were also significantly associated with MVM. MVM, FVM, and CHI abnormalities were associated with lower median birthweight, higher rates of preterm birth, operative birth for non-reassuring fetal status, and severe neonatal non-neurological morbidity.

Does decreased fetal growth estimation in the appropriate for gestational age range affect delivery outcomes?

PURPOSE

To study the effect of decreased estimated fetal weight (EFW) percentiles in appropriate for gestational age fetuses.

METHODS

This retrospective cohort study included women who had second and third trimester ultrasound examinations. Delivery and neonatal outcomes of pregnancies with decreased EFW of ≥  30 percentiles in EFW between ultrasound examinations (decreased growth group) and those without such a decrease (control group) were compared. Deliveries with EFW or birthweight below the 10th percentile were excluded.

RESULTS

Among 1610 deliveries, 57 were in the decreased growth group and 1553 in the control group. Maternal characteristics did not differ between the groups except for higher rate of nulliparity in the decreased growth group. We found similar rates of Category II/III monitoring, cesarean deliveries due to non-reassuring fetal heart rate and adverse neonatal outcomes. Neonatal birthweight was lower in the decreased growth group as compared to controls.

CONCLUSIONS

This study did not find association between the group of appropriate for gestational age fetuses with decreased growth, with adverse outcomes.

Placental Histopathological Lesions and Adverse Neonatal Outcomes in Patients with Inflammatory Bowel Diseases- A retrospective Cohort Study

Inflammatory bowel diseases (IBD) are significantly associated with adverse pregnancy and neonatal outcomes, though the pathomechanism is yet unknown. To investigate the relationship between IBD and adverse pregnancy outcomes by comparing neonatal outcomes and placental histopathology in two matched groups of patients with and without IBD. In this retrospective study, data of all patients who gave birth between 2008-2021 and were diagnosed with IBD were reviewed and compared to a control group matching two control cases for every IBD case. Neonatal outcomes and placental pathology were compared between the groups. Compared to the control group (n=76), the placentas of patients with IBD (n=36) were characterized by significantly lower placental weight (p < 0.001), and higher rates of maternal vascular malperfusion lesions (MVM, p < 0.001) and maternal and fetal inflammatory response lesions (p < 0.001). Neonates of patients with IBD were more frequently small for gestational age (SGA) (p=0.01), with increased rates of need for phototherapy (p = 0.03), respiratory morbidity and NICU admission (p < 0.001 for both outcomes). Multivariate logistic regression analyses adjusting for possible confounders (including maternal age, gestational age, chronic hypertension, smoking, and thrombophilia) confirmed the independent association between IBD and composite MVM lesions (aOR 4.31, p < 0.001), maternal inflammatory responses (aOR 40.22, p < 0.001) and SGA infants (aOR 4.31, p = 0.013). IBD is associated with increased rates of placental histopathological lesions and adverse pregnancy outcomes, including SGA infants. These novel findings imply the role of placental malperfusion and inflammatory processes in pregnancy complications of IBD patients, which should be followed accordingly. Approval of local ethics committee # WOMC-0219-20.

Effect of maternal serum albumin level on birthweight and gestational age: an analysis of 39200 singleton newborns

Background

Serum albumin plays a pivotal role in regulating plasma oncotic pressure and modulating fluid distribution among various body compartments. Previous research examining the association between maternal serum albumin levels and fetal growth yielded limited and inconclusive findings. Therefore, the specific influence of serum albumin on fetal growth remains poorly understood and warrants further investigation.

Methods

A retrospective study involved 39200 women who had a singleton live birth at a tertiary-care academic medical center during the period from January 2017 to December 2020. Women were categorized into four groups according to the quartile of albumin concentration during early pregnancy: Q1 group, ≤41.0 g/L; Q2 group, 41.1-42.6 g/L; Q3 group, 42.7-44.3 g/L and Q4 group, >44.3 g/L. The main outcome measures were mid-term estimated fetal weight, birthweight and gestational age. Multivariate linear and logistic regression analysis were performed to detect the independent effect of maternal serum albumin level on fetal growth after adjusting for important confounding variables.

Results

In the crude analysis, a significant inverse correlation was found between early pregnancy maternal serum albumin levels and fetal growth status, including mid-term ultrasound measurements, mid-term estimated fetal weight, birthweight, and gestational age. After adjustment for a number of confounding factors, mid-term estimated fetal weight, birthweight, and birth height decreased significantly with increasing albumin levels. Compared to the Q2 group, the Q4 group had higher rates of preterm birth (aOR, 1.16; 95% CI, 1.01-1.34), small-for-gestational-age (aOR, 1.27; 95% CI, 1.11-1.45) and low birthweight (aOR, 1.41; 95% CI, 1.18-1.69), and lower rate of large-for-gestational-age (aOR, 0.85; 95% CI, 0.78-0.94). Moreover, to achieve the optimal neonatal outcome, women with higher early pregnancy albumin levels required a greater reduction in albumin levels in later pregnancy stages.

Conclusions

A higher maternal serum albumin level during early pregnancy was associated with poor fetal growth, with the detrimental effects becoming apparent as early as the mid-gestation period. These findings provided vital information for clinicians to predict fetal growth status and identify cases with a high risk of adverse neonatal outcomes early on.

Prediction by uterine artery Doppler screening of small-for-gestational-age neonates at 19-24 weeks' gestation

OBJECTIVE

Small-for-gestational-age (SGA) neonates are at increased risk of perinatal mortality and morbidity. We aimed to investigate the performance of uterine artery pulsatility index (UtA-PI) at 19-24 weeks' gestation to predict the delivery of a SGA neonate in a Chinese population.

METHODS

This was a retrospective cohort study using data obtained between January 2010 and June 2018. Doppler ultrasonography was performed at 19-24 weeks' gestation. SGA was defined as birth weight below the 10th centile according to the INTERGROWTH-21st fetal growth standards. The performance of UtA-PI to predict the delivery of a SGA neonate was assessed using receiver-operating-characteristics (ROC)-curve analysis.

RESULTS

We included 6964 singleton pregnancies, of which 748 (11%) delivered a SGA neonate, including 115 (15%) women with preterm delivery. Increased UtA-PI was associated with an elevated risk of SGA, both in neonates delivered at or after 37 weeks' gestation (term SGA) and those delivered before 37 weeks (preterm SGA). The areas under the ROC curve (AUCs) for UtA-PI were 64.4% (95% CI, 61.5-67.3%) and 75.8% (95% CI, 69.3-82.3%) for term and preterm SGA, respectively. The performance of combined screening by maternal demographic/clinical characteristics and estimated fetal weight in the detection of term and preterm SGA was improved significantly by the addition of UtA-PI, although the increase in AUC was modest (2.4% for term SGA and 4.9% for preterm SGA).

CONCLUSIONS

This is the first Chinese study to evaluate the role of UtA-PI at 19-24 weeks' gestation in the prediction of the delivery of a neonate with SGA. The addition of UtA-PI to traditional risk factors improved the screening performance for SGA, and this improvement was greater in predicting preterm SGA compared with term SGA. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Systemic Oxidative Stress in Severe Early-Onset Fetal Growth Restriction Associates with Concomitant Pre-Eclampsia, Not with Severity of Fetal Growth Restriction

BACKGROUND

Placental insufficiency is an important mechanism underlying early-onset fetal growth restriction (eoFGR). Reduced placental function causes impaired metabolic and gaseous exchange. This unfavorable placental environment is among other processes characterized by increased oxidative stress. Systemic free thiols (FT) are known for their reactive oxygen species scavenging capacity, and higher plasma levels of FT are associated with a better outcome in a multitude of ischemic and inflammatory diseases. We aimed to investigate the relationships between systemic FT levels and maternal and perinatal clinical characteristics and outcomes.

STUDY DESIGN

In a post hoc analysis of the Dutch Strider study, a cohort of women with eoFGR, we investigated the association between the maternal redox status (FT) levels at study inclusion, placental biomarkers, and maternal and neonatal outcomes in 108 patients.

RESULTS

FT were significantly lower in pregnancies complicated with eoFGR with concurrent maternal hypertensive disorders (pregnancy-induced hypertension; ρ = -0.281 p = 0.004, pre-eclampsia; ρ = -0.505 p = 0.000). In addition, lower FT levels were significantly associated with higher systolic (ρ = -0.348 p = 0.001) and diastolic blood pressure (ρ = -0.266 p = 0.014), but not with the severity of eoFGR. FT levels were inversely associated with sFlt (ρ = -0.366, p < 0.001). A strong relation between systemic FT levels and PlGF levels was observed in women with pre-eclampsia at delivery (ρ = 0.452, p = 0.002), which was not found in women without hypertensive disorders (ρ = 0.008, p = 0.958).

CONCLUSIONS

In women with pregnancies complicated with eoFGR, FT levels reflect the severity of maternal disease related to the underlying placental insufficiency rather than the severity of the placental dysfunction as reflected in eoFGR or perinatal outcomes.

Similarity network fusion to identify phenotypes of small-for-gestational-age fetuses

Fetal growth restriction (FGR) affects 5-10% of pregnancies, is the largest contributor to fetal death, and can have long-term consequences for the child. Implementation of a standard clinical classification system is hampered by the multiphenotypic spectrum of small fetuses with substantial differences in perinatal risks. Machine learning and multiomics data can potentially revolutionize clinical decision-making in FGR by identifying new phenotypes. Herein, we describe a cluster analysis of FGR based on an unbiased machine-learning method. Our results confirm the existence of two subtypes of human FGR with distinct molecular and clinical features based on multiomic analysis. In addition, we demonstrated that clusters generated by machine learning significantly outperform single data subtype analysis and biologically support the current clinical classification in predicting adverse maternal and neonatal outcomes. Our approach can aid in the refinement of clinical classification systems for FGR supported by molecular and clinical signatures.

Relationship between kisspeptin levels in the third trimester and late-onset fetal growth restriction: A case-control study

INTRODUCTION

We aimed to investigate whether maternal serum kisspeptin levels are associated with late-onset FGR and contribute to adverse perinatal outcomes.

METHOD

In this case-control study, a total of 90 pregnant women admitted to the perinatology clinic were enrolled. Forty-five of them were diagnosed with FGR and 45 women with healthy pregnancies formed the control group. Maternal serum levels of kisspeptin 1 were compared.

RESULTS

Median kisspeptin1 serum levels were higher in the group of patients with FGR according to gestational age than in the control group [79.4(3.9-230.2) pg/mL vs. 39.8(0.4-188.3) pg/mL; p = 0.001]. The optimal cut-off value for kisspeptin1 was 30.32 pg/mL, with a positive predictive value of 64.6% (95% CI; 0.54-0.86), negative predictive value of 87.5% (95% CI; 0.44-0.72), positive likelihood ratio 1.75 (95% CI; 1.31-2.32), negative likelihood ratio 0.14 (95% CI; 0.04-0.44).

DISCUSSION

Kisspeptin1 differed significantly in late-onset FGR compared with the control group. This difference from the control group can be used to estimate late-onset FGR.

Fetal growth restriction, neonatal morbidity and placental pathology in dichorionic twins-a comparison of twin-specific versus singleton growth charts‏‏

INTRODUCTION

Fetal growth restriction (FGR) in dichorionic diamniotic (DCDA) twin gestations is a known complication associated with adverse neonatal outcomes. The international guidelines have no consensus on whether to use singleton or twin-specific growth charts. Thus, we aimed to compare growth charts in correlation with pregnancy outcomes and placental histopathology.

METHODS

The medical files of all DCDA twin deliveries between 2010 and 2020 were reviewed. Birthweight percentile for gestational age (GA) for each individual neonate was assigned using the updated local singleton and twin-specific growth chart. We then divided the study population into two groups, neonates that were FGR based on the local singleton charts (FGR-singleton group) versus FGR on both twin-specific and singleton charts (FGR-twin group). Placental lesions were classified as lesions related to maternal or fetal malperfusion lesions (MVM, FVM), vascular and villous changes, and inflammatory lesions.

RESULTS

Overall, 185 neonates met the inclusion criteria. The FGR-twin group (59/185) had a higher rate of PE, lower GA at delivery, lower birthweight, and a higher rate of neonatal composite adverse outcomes compared to the FGR-singleton group. Moreover, placental pathology of the FGR-twin group demonstrated a higher rate of MVM lesions (p = 0.035).

DISCUSSION

In our cohort, neonates considered FGR based on twin-specific charts had worse neonatal outcomes with underlying placental insufficiency demonstrated by a higher rate of placental malperfusion vascular lesions. Our findings support using a twin-specific chart to diagnose FGR that is more clinically relevant.

Placental pathology is necessary to understand common pregnancy complications and achieve an improved taxonomy of obstetrical disease

The importance of a fully functioning placenta for a good pregnancy outcome is unquestioned. Loss of function can lead to pregnancy complications and is often detected by a thorough placental pathologic examination. Placental pathology has advanced the science and practice of obstetrics and neonatal-perinatal medicine by classifying diseases according to underlying biology and specific patterns of injury. Many past obstacles have limited the incorporation of placental findings into both clinical studies and day-to-day practice. Limitations have included variability in the nomenclature used to describe placental lesions, a shortage of perinatal pathologists fully competent to analyze placental specimens, and a troubling lack of understanding of placental diagnoses by clinicians. However, the potential use of placental pathology for phenotypic classification, improved understanding of the biology of adverse pregnancy outcomes, the development of treatment and prevention, and patient counseling has never been greater. This review, written partly in response to a recent critique published in a major obstetrics-gynecology journal, reexamines the role of placental pathology by reviewing current concepts of biology; explaining the most recent terminology; emphasizing the usefulness of specific diagnoses for obstetrician-gynecologists, neonatologists, and patients; previewing upcoming changes in recommendations for placental submission; and suggesting future improvements. These improvements should include further consideration of overall healthcare costs, cost-effectiveness, the clinical value added of placental assessment, improvements in placental pathology education and practice, and leveraging of placental pathology to identify new biomarkers of disease and evaluate novel therapies tailored to specific clinicopathologic phenotypes of both women and infants.

Is there an association between isolated sonographic abdominal circumference below the 10th percentile and placental vascular lesions?

OBJECTIVE

To study the association between prenatal diagnosis of isolated abdominal circumference (AC) below the 10th percentile (AC <10th) in appropriate for gestational age (AGA) neonates and placental vascular lesions.

METHODS

A prospective study was conducted of healthy women who underwent sonographic fetal biometric measurements, up to 7 days before delivery, and delivered AGA neonates. The study cohort was divided into those with and without prenatal isolated AC <10th. Placental histopathology lesions were classified into maternal and fetal vascular malperfusion (MVM, FVM) lesions.

RESULTS

Compared to the AC over 10th percentile group (n = 85), the AC <10th group (n = 85) was characterized by lower maternal body mass index, higher rate of smokers, and increased rate of induced labor (P = 0.029, P = 0.029, P = 0.001, respectively). There were no between-group differences regarding maternal age, gestational age, and neonatal outcome. Mean placental weight was lower in the isolated AC <10th (P < 0.001). The rate of MVM or FVM lesions did not differ between the groups. By multivariate logistic regression analysis, isolated AC <10th was not found to be associated with increased risk for placental vascular lesions.

CONCLUSION

Isolated AC <10th is associated with increased rate of induction of labor; however, it is not associated with increased placental vascular lesions.

Incidence, clinical features and perinatal outcome in anomalous fetuses with late-onset growth restriction: cohort study

OBJECTIVE

To describe the incidence, clinical features and perinatal outcome of late-onset fetal growth restriction (FGR) associated with genetic syndrome or aneuploidy, structural malformation or congenital infection.

METHODS

This was a retrospective multicenter cohort study of patients who attended one of four tertiary maternity hospitals in Italy. We included consecutive singleton pregnancies between 32 + 0 and 36 + 6 weeks' gestation with either fetal abdominal circumference (AC) or estimated fetal weight < 10^th percentile for gestational age or a reduction in AC of > 50 percentiles from the measurement at an ultrasound scan performed between 18 and 32 weeks. The study group consisted of pregnancies with late-onset FGR and a genetic syndrome or aneuploidy, structural malformation or congenital infection (anomalous late-onset FGR). The presence of congenital anomalies was ascertained postnatally in neonates with abnormal findings on antenatal investigation or detected after birth. The control group consisted of pregnancies with structurally and genetically normal fetuses with late-onset FGR. Composite adverse perinatal outcome was defined as the presence of at least one of stillbirth, 5-min Apgar score < 7, admission to the neonatal intensive care unit (NICU), need for respiratory support at birth, neonatal jaundice and neonatal hypoglycemia. The primary aims of the study were to assess the incidence and clinical features of anomalous late-onset FGR, and to compare the perinatal outcome of such cases with that of fetuses with non-anomalous late-onset FGR.

RESULTS

Overall, 1246 pregnancies complicated by late-onset FGR were included in the study, of which 120 (9.6%) were allocated to the anomalous late-onset FGR group. Of these, 11 (9.2%) had a genetic syndrome or aneuploidy, 105 (87.5%) had an isolated structural malformation, and four (3.3%) had a congenital infection. The most frequent structural defects associated with late-onset anomalous FGR were genitourinary malformations (28/105 (26.7%)) and limb malformation (21/105 (20.0%)). Compared with the non-anomalous late-onset FGR group, fetuses with anomalous late-onset FGR had an increased incidence of composite adverse perinatal outcome (35.9% vs 58.3%; P < 0.01). Newborns with anomalous, compared to those with non-anomalous, late-onset FGR showed a higher frequency of need for respiratory support at birth (25.8% vs 9.0%; P < 0.01), intubation (10.0% vs 1.1%; P < 0.01), NICU admission (43.3% vs 22.6%; P < 0.01) and longer hospital stay (median, 24 days (range, 4-250 days) vs 11 days (range, 2-59 days); P < 0.01).

CONCLUSIONS

Most pregnancies complicated by anomalous late-onset FGR have structural malformations rather than genetic abnormality or infection. Fetuses with anomalous late-onset FGR have an increased incidence of complications at birth and NICU admission and a longer hospital stay compared with fetuses with isolated late-onset FGR. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Latent class analysis of placental histopathology: a novel approach to classifying early and late preterm births

BACKGROUND

Neonatal morbidity attributable to prematurity predominantly occurs among early preterm births (<32 weeks) rather than late preterm births (32 to <37 weeks). Methods to distinguish early and late preterm births are lacking given the heterogeneity in pathophysiology and risk factors, including maternal obesity. Although preterm births are often characterized by clinical presentation (spontaneous or clinically indicated), classifying deliveries by placental features detected on histopathology reports may help identify subgroups of preterm births with similar etiology and risk factors. Latent class analysis is an empirical approach to characterize preterm births on the basis of observed combinations of placental features.

OBJECTIVE

To identify histopathologic markers that can distinguish early (<32 weeks) and late preterm births (32 to <37 weeks) that are also associated with maternal obesity and neonatal outcomes.

STUDY DESIGN

Women with a singleton preterm birth at University of Pittsburgh Medical Center Magee-Womens Hospital (Pittsburgh, PA) from 2008 to 2012 and a placental evaluation (89% of preterm births) were stratified into early (n=900, 61% spontaneous) and late preterm births (n=3362, 57% spontaneous). Prepregnancy body mass index was self-reported at first prenatal visit and 16 abstracted placental features were analyzed. Placental subgroups (ie, latent classes) of early and late preterm births were determined separately by latent class analysis of placental features. The optimal number of latent classes was selected by comparing fit statistics. The probability of latent class membership across prepregnancy body mass indexes was estimated in early preterm births and in late preterm births by an extension of multinomial regression called pseudo-class regression, adjusting for race, smoking, education, and parity. The frequencies of severe neonatal morbidity (composite outcome: respiratory distress, bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, periventricular leukomalacia, patent ductus arteriosus, and retinopathy of prematurity), small-for-gestational-age, and length of neonatal intensive care unit stay were compared across latent classes by chi-square and Kruskal-Wallis tests.

RESULTS

Early preterm births were grouped into 4 latent classes based on placental histopathologic features: acute inflammation (38% of cases), maternal vascular malperfusion with inflammation (29%), maternal vascular malperfusion (25%), and fetal vascular thrombosis with hemorrhage (8%). As body mass index increased from 20 to 50kg/m2, the probability of maternal vascular malperfusion and fetal vascular thrombosis with hemorrhage increased, whereas the probability of maternal vascular malperfusion with inflammation decreased. There was minimal change in the probability of acute inflammation with increasing body mass index. Late preterm births also had 4 latent classes: maternal vascular malperfusion (22%), acute inflammation (12%), fetal vascular thrombosis with hemorrhage (9%), and low-risk pathology (58%). Body mass index was not associated with major changes in likelihood of the latent classes in late preterm births. Associations between body mass index and likelihood of the latent classes were not modified by type of delivery (spontaneous or indicated) in early or late preterm births. Maternal malperfusion and fetal vascular thrombosis with hemorrhage were associated with greater neonatal morbidity than the other latent classes in early and late preterm births.

CONCLUSION

Obesity may predispose women to early but not late preterm birth through placental vascular impairment. Latent class analysis of placental histopathologic data provides an evidence-based approach to group preterm births with shared underlying etiology and risk factors.

Is there an impact of fetal sex in dichorionic discordant twins on placental histopathological abnormalities?

INTRODUCTION

Growth discordancy in dichorionic diamniotic (DCDA) twin gestations is a known complication associated with adverse neonatal outcomes. We aimed to study the differences in placental pathology, in relation to fetal sex, in DCDA twin gestations complicated with growth discordancy.

METHODS

The medical files of all DCDA twin deliveries complicated by growth discordancy between 2010 and 2020 were reviewed. Growth discordance was defined as a gap between twin birthweights > 20%. A comparison was made between female vs. male growth discordant twins. Placental lesions were classified as lesions related to maternal or fetal malperfusion lesions (MVM, FVM), vascular and villous changes, and inflammatory lesions.

RESULTS

Included 174 DCDA twins. Eighty-eight were in the discordant female group and eighty-six in the discordant male group. The groups did not differ in maternal demographics, pregnancy characteristics, and neonatal outcome. The discordant male group had a higher rate of placental MVM lesions as compared to the discordant female group (p = 0.003). The increased rate of placental MVM lesions in the discordant male group compared to the discordant female group did not change whether its co-twin was of similar or opposite sex.

DISCUSSION

Higher rate of MVM lesions characterizes growth discordant male neonates in DCDA twin gestations. This finding could represent a different adaptation of male fetuses to a hostile intrauterine environment.

Placental histology following assisted hatching in fresh transfer cycles

PURPOSE

To assess placental histological findings following assisted hatching in fresh transfer in vitro fertilization cycles.

METHODS

Evaluation of a historic cohort of live singleton deliveries after fresh embryo transfer (ET) at a single university medical center between 2009 and 2017. We compared perinatal outcomes and placental histology in cases where assisted hatching was performed prior to ET (AH group) and cases with no AH (no AH group).

RESULTS

Overall, 166 deliveries following AH were compared to 494 deliveries with no AH. Patients' demographics were similar between the groups. Median antral follicle count was significantly lower in the AH group, median 11 (range 1-50) vs. 16 (range 1-80), p < 0.001, and the primary indication for infertility treatment significantly more often diminished ovarian reserve (p < 0.001). Cycle characteristics in the AH group included a higher gonadotropin dose employed, and a lower rate of single and blastocyte transfer. Pregnancies following AH were associated with less low-lying placentas, 0.6% vs. 6.2%, p = 0.001, and comparable for other perinatal outcomes. After adjusting for confounders, the rate of bilobated placentas was higher following AH, aOR 7.10, 95% CI 1.50-33.51. The rate of perivillous depositions was higher with AH, aOR, 95% CI 3.18, 1.46-6.93, and the rate of chorangiosis lower in this group, aOR, 95% CI 0.32, 0.11-0.93. The overall rate of vascular lesions was similar between the groups.

CONCLUSION

Pregnancies following AH are notable for a lower rate of placenta previa, yet a higher rate of bilobated placentas and perivillous depositions and less chorangiosis, warranting further investigation.

The thrifty phenotype hypothesis: The association between ultrasound and Doppler studies in fetal growth restriction and the development of adult disease

Barker pioneered the idea that the epidemic of coronary heart disease in Western countries in the 20th century, which paradoxically coincided with improved standards of living and nutrition, has its origin in fetal life. Indeed, there is substantial evidence associating low birthweight because of fetal growth restriction with an increased risk of vascular disease in later adult life. These conclusions led to the second part of the Barker hypothesis, the thrifty phenotype, in which adaptation to undernutrition in fetal life leads to permanent metabolic and endocrine changes. Such changes are beneficial if the undernutrition persists after birth but may predispose the individual to obesity and impaired glucose tolerance if conditions improve. The hypothesis assumes that a poor nutrient supply during a critical period of in utero life may "program" a permanent structural or functional change in the fetus, thereby altering the distribution of cell types, gene expression, or both. The fetus, in response to placental undernutrition and to maintain sufficient vascular supply to the brain, decreases resistance to blood flow in the middle cerebral artery. Simultaneously, because of the limited blood supply to the fetus, the arterial redistribution process is accompanied by increased resistance to flow to other fetal vital organs, such as the heart, kidneys, liver, and pancreas. It may explain why individuals exposed to ischemic changes in utero develop dyslipidemia, lower nephron number, and impaired glucose tolerance, all factors contributing to metabolic syndrome later in life. Nevertheless, support for the hypotheses comes mainly from studies in rodents and retrospective epidemiologic studies. This review focused on ultrasound and Doppler studies of human fetal growth restriction in several fetal organs: the placenta, fetal circulation, brain, heart, kidneys, adrenal glands, liver, and pancreas. Support for the hypothesis was provided by animal studies involving conditions that create fetuses with growth restriction with effects on various fetal organs and by human studies that correlate impaired fetal circulation with the in utero development and function of fetal organs.

Fetal Growth Restriction: Does an Integrated Maternal Hemodynamic-Placental Model Fit Better?

In recent years, a growing interest has arisen regarding the possible relationship between adverse pregnancy outcomes (APOs) and inadequate maternal hemodynamic adaptations to the pregnancy. A possible association between "placental syndromes," such as preeclampsia (PE) and fetal growth restriction (FGR), and subsequent maternal cardiovascular diseases (CVD) later in life has been reported. The two subtypes of FGR show different pathogenetic and clinical features. Defective placentation, due to a poor trophoblastic invasion of the maternal spiral arteries, is believed to play a central role in the pathogenesis of early-onset PE and FGR. Since placental functioning is dependent on the maternal cardiovascular system, a pre-existent or subsequent cardiovascular impairment may play a key role in the pathogenesis of early-onset FGR. Late FGR does not seem to be determined by a primary abnormal placentation in the first trimester. The pathological pathway of late-onset FGR may be due to a primary maternal cardiovascular maladaptation: CV system shows a flat profile and remains similar to those of non-pregnant women. Since the second trimester, when the placenta is already developed and increases its functional request, a hypovolemic state could lead to placental hypoperfusion and to an altered maturation of the placental villous tree and therefore to an altered fetal growth. Thus, this review focalizes on the possible relationship between maternal cardiac function and placentation in the development of both early and late-onset FGR. A better understanding of maternal hemodynamics in pregnancies complicated by FGR could bring various benefits in clinical practice, improving screening and therapeutic tools.

Physiopathology of late-onset fetal growth restriction

Fetal growth restriction (FGR) is defined as the inability of the fetus to reach its potential for genetic determination. FGR can have several causes, including genetic syndromes, chromosomal diseases, and infections; however, a vast majority of cases are probably attributed to impaired uterine and placental circulation. The relationships between abnormal placental development and FGR are complex, and studies are generally few, presenting confounding factors. Damage to the uteroplacental circulation associated with vasculogenesis and villus angiogenesis dysfunction are the main factors involved in subsequent FGR. The main receptors involved in FGR include hypoxia-inducible factor (HIF 1, 2, and 3), vascular endothelial growth factor (VEGF), placental growth factor (PlGF), vascular endothelial growth factor C (VEGF-C), soluble Flt-1, soluble endoglin (Seng), angiopoietin-1 and -2 (Ang-1 and Ang-2), tyrosine kinase receptor 1 (Flt-1), tyrosine kinase receptor 2 (Flt-2), vascular endothelial growth factor receptor (VEGFR) 1, 2 and 3, kinase domain receptor (KDR), and vascular endothelial growth factor receptor A (VEGFR-A). Furthermore, failure in trophoblastic invasion and remodeling of spiral arteries has been associated with FGR owing to poor placental perfusion. There are several possible causes for poor remodeling of spiral arteries, which probably vary on a case-to-case basis. Changes in the placental form, macroscopic and microscopic vascular lesions, inflammation, and genetic changes are also related to FGR. Based on gestational age at diagnosis, FGR can be classified as early- (˂32 weeks) and late-onset (≥32 weeks). Moreover, there exist several theories regarding possible pathophysiological differences between early- and late-onset FGR, with some postulating that it the same disease but at different stages or severity. Another hypothesis suggests that the change in the trophoblastic invasion of spiral arteries would be milder. In this article, we address the main mechanisms described in the pathophysiology of FGR and, later, the specific findings in late-onset FGR.

Association of Elevated Maternal Serum Total Bile Acids With Low Birth Weight and Intrauterine Fetal Growth Restriction

IMPORTANCE

Bile acids play essential roles in metabolic modulation. Excessive serum total bile acid (sTBA) levels during pregnancy are associated with adverse perinatal outcomes; however, their association with the risk of intrauterine growth restriction (IUGR) remains unclear.

OBJECTIVE

To investigate the association between maternal sTBA concentration during pregnancy and the risk of IUGR.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included pregnant individuals who delivered live singleton neonates and had regular antenatal examination records available at a hospital-based center in Shanghai, China, from 2014 to 2018. Data were analyzed from July to November 2020.

EXPOSURES

Maternal sTBA concentration during pregnancy.

MAIN OUTCOMES AND MEASURES

Fetal birth weight and probability of low birth weight (LBW) and IUGR.

RESULTS

This study included 68 245 singleton pregnancies with live births for analysis. The mean (SD) age of the pregnant individuals was 30.5 (3.8) years, 67 168 patients (98.4%) were Han, and 50 155 (73.5%) were nulliparous. Nonlinear regression models suggested that there was an inverted J-shaped association between maternal sTBA level during pregnancy and fetal birth weight, with a steep decrease in birth weight at high sTBA levels (estimated mean [SE] birth weight for sTBA of 40.8 ug/mL, 2879 [39.9] g) and greater birth weights at lower sTBA levels (estimated mean [SE] birth weight for sTBA 0.4 μg/mL, 3290 [3.9] g; and for 4.1 μg/mL, 3334 [1.6] g). Lower birth weight and a higher incidence of IUGR were observed in patients with gestational hypercholanemia (sTBA ≥4.08 μg/mL) compared with those without gestational hypercholanemia (birth weight: estimated adjusted mean [SE], 3309 [3.32] vs 3338 [0.80] g; P = .005; incidence of IUGR: 62 of 4467 [1.4%] vs 312 of 63 778 [0.5%]; P < .001). Moreover, compared with patients with sTBA concentrations of less than 4.08 μg/mL, those with gestational hypercholanemia had an increased risk of LBW (adjusted odds ratio [aOR], 1.29; 95% CI, 1.09-1.53) and IUGR (aOR, 2.18; 95% CI, 1.62-2.91). In addition, there was an additive interaction between hypertensive disorders in pregnancy (HDP) and hypercholanemia on LBW and IUGR risk. The highest risks of LBW and IUGR were found in pregnant individuals with both HDP and hypercholanemia compared with those with normotensive pregnancies with sTBA concentrations less than 4.08 μg/mL (LBW: aOR, 9.13; 95% CI, 6.88-12.12; IUGR: aOR, 19.14; 95% CI, 12.09-30.28).

CONCLUSIONS AND RELEVANCE

This study found that gestational hypercholanemia was associated with an increased risk of LBW and IUGR, especially in pregnant individuals with HDP. Therefore, it would be meaningful to monitor sTBA concentration during the follow-up of pregnancies with potential IUGR.

Does gestational age at term play a role in the association between cerebroplacental ratio and operative delivery for intrapartum fetal compromise?

INTRODUCTION

To assess the impact of gestational age at term on the association between cerebroplacental ratio (CPR) and operative delivery for intrapartum fetal compromise (IFC) and prognostic performance of CPR to predict operative delivery for IFC.

MATERIAL AND METHODS

This was a retrospective cohort study including 2052 singleton pregnancies delivered between 37⁺⁰ and 41⁺⁶  weeks of gestation in a single tertiary referral center over an 8-year period. CPR was measured within 1 week of delivery. IFC was defined as the presence of persistent pathological cardiotocography pattern or the combination of pathological cardiotocography pattern and fetal scalp pH < 7.20. Operative delivery included instrumental vaginal delivery and cesarean section. Pregnancies were grouped according to birthweight (small for gestational age [SGA, birthweight <10th centile] and appropriate for gestational age [AGA, birthweight 10th-90th centile]) and gestational age by week at delivery. Rates of operative delivery were compared between the subgroups. Prognostic value of CPR was assessed using receiver operating characteristic curve.

RESULTS

Of the study cohort, 308 (15%) had a CPR <10th centile, 374 (18%) operative delivery for IFC, and 298 (15%) were SGA at birth. Overall, the rates of operative delivery for IFC were higher in the low CPR group both in SGA (35% vs. 22%; p = 0.023) and in AGA (23% vs. 16%; p = 0.007). According to gestational age by week at delivery, fetuses with low CPR showed higher rates of operative delivery for IFC with advancing gestational age, mainly in pregnancies delivered at 40 weeks (54% vs. 23%; p = 0.004) and at 41 weeks (60% vs. 19%; p = 0.010) for SGA and at 41 weeks (39% vs. 20%; p = 0.001) for AGA. The predictive value of CPR remained stable throughout term and was poor both in SGA and in AGA.

CONCLUSIONS

Both SGA and AGA fetuses with low CPR showed higher rates of operative delivery for IFC at term with advancing gestational age. Prognostic value of CPR throughout term was poor.

Evaluation of Placental Micro-vascularization by Superb Micro-vascular Imaging Doppler in Cases of Intra-uterine Growth Restriction: A First Step

Superb micro-vascular imaging (SMI) Doppler has proven to be a valid method to assess normal placental micro-vascularization. In this study, we present the application of SMI Doppler to assess placental micro-vascularization in cases of placental insufficiency. We observed fewer secondary and tertiary villi in cases of intra-uterine growth restriction, as well as a lower pulsatile index of secondary villi. The observations made in our study stress the diagnostic potential of SMI Doppler in placental insufficiency.

Induction of labor in late FGR

Late-onset FGR is a peculiar condition characterized by the inability for the fetus to reach its growth potential diagnosed from 32 weeks of gestation. Placental insufficiency is among the leading causes of late FGR and is commonly due to a primary maternal cardiovascular non-adaptation potentially leading to fetal decompensation during labor especially once exposed to uterine hyperstimulation. Abnormalities that usually characterize late FGR include reduced fetal growth, decreased Amniotic Fluid Index, and loss of fetal heart rate variability at CTG. Fetal hemodynamics study by Doppler ultrasound significantly improved management of pregnancies affected by fetal growth restriction. A major issue when dealing with pregnancies complicated by late FGR is how to induce these women. Induction of labor (IOL) can be essentially accomplished by pharmacological and non-pharmacological agents. Recent studies suggested that the pregnancies complicated by late FGR should undergo a tailored approach for IOL in view of the higher risk of fetal decompensation following uterine hyperstimulation. The present review aims to provide an up to date on the different types of IOL which can guide clinical management.

Placental Lesions and Pregnancy Outcome in Anterior as Compared to Posterior Placenta Previa

The uterine location of placenta previa (PP), anterior vs. posterior has an impact on pregnancy outcome. We aimed to study maternal and neonatal outcome and placental histopathology lesions in anterior vs. posterior PP. The medical records and histopathology reports of all singleton cesarean deliveries (CD) performed due to PP, from 24 to 41 weeks, between 12.2008 and 10.2018, were reviewed. Placental lesions were classified into maternal and fetal vascular malperfusion lesions (MVM, FVM), maternal and fetal inflammatory responses (MIR, FIR). Gestational age (GA) at delivery was similar between the anterior PP (n = 67) and posterior PP (n = 105) groups. As compared to the posterior PP group, the anterior PP group had higher rate of previous CD (p < 0.001), placental accreta spectrum (p = 0.04), lower neonatal Hb at birth (p = 0.03), higher rate of neonatal blood transfusion (p = 0.007) and prolonged maternal hospitalization (p = 0.02). Placentas from the anterior PP group had lower weights (p = 0.035), with increased rate of MVM lesions (p = 0.017). The anterior PP location is associated with increased adverse maternal and neonatal outcome, lower placental weights and increased rate of malperfusion lesions. Abnormal placentation in the scarred uterine wall probably has an impact on placental function.

Effects of 'rescue' dose of antenatal corticosteroids on placental histopathology in preterm births

INTRODUCTION

Antenatal corticosteroids (ACS) are frequently used to reduce neonatal morbidity in preterm births (PTBs). A 'rescue' dose of ACS can be administer, if the risk of PTB remains. Some reports indicated that repeated doses of ACS might impact placental histology and possibly its function. We aimed to study whether repeated doses of ACS effect placental histopathology and pregnancy outcome.

METHODS

The medical files and placental reports of all PTB, at 24-33⁶/₇ weeks, between Nov 2008-Dec 2019, were reviewed. The study population was divided into three groups; no-ACS (PTBs without ACS treatment), one-ACS (PTBs after a full or partial ACS course), and rescue-ACS (PTBs after a 'rescue' course of ACS). Placental lesions were classified according to "Amsterdam" criteria into maternal and fetal vascular malperfusion lesions, maternal and fetal inflammatory responses and chronic villitis. Placental lesions and pregnancy outcome were compared between the study groups.

RESULTS

The no-ACS group (n = 58) was characterized by increased rates of PTB<28 weeks (p = 0.003), perinatal death (p < 0.001) and composite neonatal infectious morbidity (p = 0.022), as compared to the one-ACS group (n = 331) and the rescue-ACS group (n = 53). Placental MIR lesions were more common among the rescue-ACS group, compared to the one- and no-ACS groups (p = 0.022). Other placental lesions did not differ between the groups. On multivariate logistic regression analysis, MIR lesions were independently associated with rescue-ACS treatment (aOR 3.00, 95% CI 1.10-8/17, p = 0.031).

DISCUSSION

Rescue course of ACS is associated with increased rate of placental maternal inflammatory response. These findings probably result from maternal stress stimuli without an adverse impact on early neonatal outcome.

Placental disorders of pregnancy in subsequent IVF pregnancies - a sibling cohort

RESEARCH QUESTION

To assess whether the incidence of placental disorders of pregnancy decreases with increasing parity in repeat IVF pregnancies, in the same way as natural pregnancies.

DESIGN

This was a retrospective cohort of deliveries between November 2008 and January 2020, in a single university-affiliated medical centre. The study included women with only IVF-attained singleton pregnancies (no natural conception) with at least two deliveries, and compared the obstetric and perinatal outcomes between first, second and third deliveries. Each woman served as her own control. The primary outcome was the incidence of placental-related disorders of pregnancy, defined as small for gestational age (SGA) neonates and/or pre-eclampsia.

RESULTS

A total of 307 first deliveries, 307 second deliveries and 49 third deliveries by the same women were compared. A trend for a decreased rate of pre-eclampsia was noted with increased parity (P = 0.06) and a significant decrease in the rate of SGA: 11.7% for first delivery, 7.8% for second delivery and 2.0% for third (P = 0.04). This difference in SGA incidence was maintained in a matched sub-analysis of the 49 women with three deliveries (P = 0.04), and after adjustment for fresh/frozen embryo transfer (P = 0.03). Although SGA and pre-eclampsia were generally more common in IVF than natural pregnancies, their decrease with increasing parity mimicked that in natural pregnancies.

CONCLUSION

IVF pregnancies are associated with an increased risk of placental disorders of pregnancy. However, they exhibit a decrease in incidence with increasing parity.

Placenta praevia - does it really affect intrauterine fetal growth?

PURPOSE

Placenta praevia affects about 0.5% of pregnancies and due to constant increase in operative deliveries may become an important, clinical challenge throughout the next decades. Location of the placental plate within lower uterine segment is associated with increased risk of adverse perinatal outcomes. There were several reports pointing increased risk of small-for-gestational-age (SGA)/fetal growth restriction (FGR) in patients affected with abnormal location of the placenta. On the other hand, some studies ended up with opposite conclusions.

MATERIALS AND METHODS

Due to ambiguous results we have undertaken a case-control study to investigate intrauterine growth among this group. We ran a pilot study to precisely define maternal, obstetrical and neonatal characteristics in order to avoid cofounders. Our study incorporated 56 patients in singleton pregnancies affected with placenta praevia and 124 patients in the control group (between 35 and 37 weeks of gestation).

RESULTS

Nonetheless, there were no statistical differences in the birthweight between the study and control group (2882.5 g vs. 2805 g, p = ns). Moreover, rates of the newborns with birthweight corresponding <10th percentile and >90th did not differ significantly. Even further analysis that included parity did not reveal any differences between both groups.

CONCLUSION

Placenta praevia does not affect the intrauterine growth and shall not be considered as a risk factor for SGA/FGR. In patients affected with abnormal location of the placenta additional scans for fetal well-being assessment are not indicated.

Altered Levels of Decidual Immune Cell Subsets in Fetal Growth Restriction, Stillbirth, and Placental Pathology

Immune cells are critically involved in placental development and functioning, and inadequate regulation of the maternal immune system is associated with placental pathology and pregnancy complications. This study aimed to explore numbers of decidual immune cells in pregnancies complicated with fetal growth restriction (FGR) and stillbirth (SB), and in placentas with histopathological lesions: maternal vascular malperfusion (MVM), fetal vascular malperfusion (FVM), delayed villous maturation (DVM), chorioamnionitis (CA), and villitis of unknown etiology (VUE). Placental tissue from FGR (n = 250), SB (n = 64), and healthy pregnancies (n = 42) was included. Histopathological lesions were classified according to criteria developed by the Amsterdam Placental Workshop Group. Tissue slides were stained for CD68 (macrophages), CD206 (M2-like macrophages), CD3 (T cells), FOXP3 [regulatory T (Treg) cells], and CD56 [natural killer (NK) cells]. Cell numbers were analyzed in the decidua basalis using computerized morphometry. The Mann-Whitney U-test and Kruskal Wallis test with the Dunn's as post-hoc test were used for statistical analysis. Numbers of CD68⁺ macrophages were higher in FGR compared to healthy pregnancies (p < 0.001), accompanied by lower CD206⁺/CD68⁺ ratios (p < 0.01). In addition, in FGR higher numbers of FOXP3⁺ Treg cells were seen (p < 0.01) with elevated FOXP3⁺/CD3⁺ ratios (p < 0.01). Similarly, in SB elevated FOXP3⁺ Treg cells were found (p < 0.05) with a higher FOXP3+/CD3+ ratio (p < 0.01). Furthermore, a trend toward higher numbers of CD68⁺ macrophages was found (p < 0.1) in SB. Numbers of CD3⁺ and FOXP3⁺ cells were higher in placentas with VUE compared to placentas without lesions (p < 0.01 and p < 0.001), accompanied by higher FOXP3⁺/CD3⁺ ratios (p < 0.01). Elevated numbers of macrophages with a lower M2/total macrophage ratio in FGR suggest a role for a macrophage surplus in its pathogenesis and could specifically indicate involvement of inflammatory macrophages. Higher numbers of FOXP3⁺ Treg cells with higher Treg/total T cell ratios in VUE may be associated with impaired maternal-fetal tolerance and a compensatory response of Treg cells. The abundant presence of placental lesions in the FGR and SB cohorts might explain the increase of Treg/total T cell ratios in these groups. More functionality studies of the observed altered immune cell subsets are needed.

Placental Histopathology and Pregnancy Outcomes in "Early" vs. "Late" Placental Abruption

Placenta-associated pregnancy complications (fetal growth restriction and preeclampsia) are traditionally classified as "early" and "late" due to their different pathophysiology, histopathology, and pregnancy outcomes. As placental abruption (PA) represents another placenta-associated complication, we aimed to study if this categorization can be applied to PA as well. Pregnancy and placental reports of all pregnancies complicated by PA between November 2008 and January 2019 were reviewed. Maternal background, pregnancy outcomes, and placental histopathology were compared between cases of PA < 34 weeks (early PA group) vs. > 34 weeks (late PA group). Placental lesions were classified according to the "Amsterdam" criteria. The primary outcome was severe neonatal morbidity (≥ 1 severe neonatal complications: seizures, IVH, HIE, PVL, blood transfusion, NEC, or death). Included were 305 cases of PA, 71 (23.3%) in the early group and 234 (76.7%) in the late group. The early PA group was characterized by higher rates of vaginal bleeding upon presentation (p = 0.003), DIC (p = 0.018), and severe neonatal morbidity (p < 0.001). The late PA group was characterized by a higher rate of urgent Cesarean deliveries (p < 0.001). The early PA group was characterized by higher rates of placental maternal vascular malperfusion (MVM) lesions (p < 0.001), maternal inflammatory response (MIR) lesions (p < 0.001), placental hemorrhage (p < 0.001), and a lower feto-placental ratio (p < 0.001). Using regression analysis, we found that severe neonatal morbidity was independently associated with early abruption (aOR = 5.3, 95% CI = 3.9-7.6), placental MVM (aOR = 1.5, 95% CI = 1.2-1.9), placental MIR (aOR = 1.9, 95% CI = 1.4-2.3), and inversely associated with antenatal corticosteroids (aOR = 0.9, 95% CI = 0.6-0.98). "Early" and "late" PA significantly differ in their presentation, placental pathology, and pregnancy outcomes.

Placental-related disorders of pregnancy and IVF: does placental histological examination explain the excess risk?

RESEARCH QUESTION

What are the clinical characteristics of pregnancies complicated by fetal growth restriction (FGR) and preeclampsia in patients who have undergone IVF, and what is the correlation between these complications and histopathological placental findings in such pregnancies.

DESIGN

A retrospective cohort of patients who had delivered their babies at our institution who had been diagnosed with preeclampsia, whose babies had been diagnosed with FGR, or both. Deliveries in which the placenta was sent for histopathological examination were included. Computerized files and pathological reports were reviewed, and maternal, obstetric, neonatal outcomes and placental histopathological reports were compared between pregnancies conceived by IVF and controls. Placental lesions were classified according to the Amsterdam criteria.

RESULTS

Between December 2008 and December 2018, the placentas of 1114 singleton babies who had received a diagnosis of FGR, whose mothers had received a diagnosis of preeclampisa, or both, were examined. A total of 105 patients conceived with IVF and 1009 were conceived spontaneously. The IVF group was older, of lower parity and had a higher rate of diabetes and chronic hypertension. Deliveries occurred at an earlier gestational age, although birth weight was not significantly different between the groups. The rate of neonatal adverse composite outcome among IVF deliveries was significantly lower (59.0% versus 76.7%; P < 0.001). On placental examination, placental weight, maternal and fetal vascular malperfusion lesions were similar between the groups, whereas villitis of unknown etiology was significantly more common among the IVF group (16.2% versus 8.3%; P = 0.007).

CONCLUSION

Neonatal outcome is relatively favourable in IVF patients with placental-related diseases. Placental chronic villitis is more common in IVF patients, pointing to an additive immunological cause.

Aurora kinase mRNA expression is reduced with increasing gestational age and in severe early onset fetal growth restriction

INTRODUCTION

Oxidative damage and biochemical ageing are implicated in placental dysfunction and potentially fetal death. Cellular senescence may play a role in the pathophysiology of fetal growth restriction (FGR) and preeclampsia (PE). Aurora kinases (AURKA, B and C) are important regulators of cellular division in mitosis and meiosis with implications in cellular senescence. We aimed to investigate whether aurora kinase expression is altered with placental dysfunction or placental ageing.

METHODS

Placenta and blood was obtained across gestation from pregnancies complicated by PE, FGR or both PE and FGR, as well as gestation-matched control samples. Expression of AURKA, B and C mRNA was examined using real time qPCR in both the placenta and maternal circulation.

RESULTS

Placental aurora kinase expression decreased as gestation progressed: AURKA and AURKB were significantly reduced at 37-40 weeks, whereas AURKC was significantly reduced at 34-37 weeks, when compared to <34 weeks. In the maternal circulation, the mRNA level of AURKB was significantly reduced at >40 weeks compared to <34 weeks gestation. A significant reduction in AURKC was seen in FGR pregnancies <34 weeks compared to gestation-matched controls.

CONCLUSION

Placental AURK expression is reduced with increased gestation. Circulating AURKB mRNA reduces at >40 weeks gestation, when compared to <34 weeks. AURKC is significantly reduced in placentas from pregnancies complicated by severe early onset (<34 weeks) FGR compared with gestation-matched controls. The functional role of aurora kinase in the placenta and in gestational age warrants further investigation.

Placental histopathology in IVF pregnancies resulting from the transfer of frozen-thawed embryos compared with fresh embryos

PURPOSE

To study whether placentas of singleton pregnancies conceived after fresh embryo transfer (ET) contain more histopathological lesions compared with placentas of singleton pregnancies conceived after frozen-thawed embryo transfer (FET).

METHODS

A prospective cohort study of placental histopathology in 131 women with singleton IVF pregnancies who delivered at a single medical center, between December 2017 and May 2019. The prevalence of different placental histopathology lesions was compared between women who conceived after fresh ET and FET.

RESULTS

Women who conceived after fresh ET (n = 74) did not differ from women who conceived after FET (n = 57) with regard to maternal age, BMI, nulliparity, or infertility diagnosis. Gestational week at delivery was lower in pregnancies conceived after fresh ET (38.5 vs. 39.2 weeks, respectively, p = 0.04), and a trend for a lower birthweight following fresh ET was noted (3040 vs. 3216 g, respectively, p = 0.053). However, placental histopathology analysis from pregnancies conceived after fresh ET was comparable to pregnancies conceived after FET, with regard to the prevalence of maternal vascular malperfusion lesions (45.9% vs. 50.9%, respectively, p = 0.57), fetal vascular malperfusion lesions (17.6% vs. 21.1, p = 0.61), acute inflammatory response lesions (28.4% vs. 28.1%, respectively, p = 0.96), and chronic inflammatory response lesions (13.5% vs. 8.8%, respectively, p = 0.48).

CONCLUSION

Placental histopathology did not differ between IVF pregnancies conceived after fresh and frozen ET. These results are reassuring for clinicians and patients who wish to pursue with transferring fresh embryos.

Maternal tobacco use: A third-trimester risk factor for small-for-gestational-age pregnancy outcome

Background

Small for gestational age (SGA) is a well-known consequence of maternal smoking. Here, we newly examine the magnitude of SGA risk by week of gestational age.

Methods

Singleton live births (N = 3,032,928) with recorded birth weight, gestational age (22–44 weeks), and maternal tobacco use (Y/N) were categorized as to SGA (Y/N), based on 10th percentile gender-specific weights-for-age.

Results

SGA prevalence among tobacco users (19.5%) and non-users (9.1%) yielded a significant SGA prevalence rate ratio of 2.15 (2.13–2.16) and a significant adjusted odds ratio of 2.36 (2.34–2.38). The tobacco non-users’ rate was steadily near 9% across the week 22–44 gestational age range. The tobacco users’ rate was steady until week 33 when it rose monotonically through week 37 to about 20% at week 38 and remained high. This pattern for SGA by gestational week was similar for prevalence rates and adjusted ORs. Tobacco use only through week 33 was not seen to be an SGA risk factor. The magnitude of tobacco use as an SGA risk factor for late third trimester births increased during the period of preterm birth and became fully evident with a two-fold risk for full term infants.

Conclusion

We newly report the temporal pattern of tobacco-related SGA by week of gestational age. Tobacco-related SGA was only seen for late third trimester births – increasing during weeks 33–37 with a doubling during weeks 38–44. This pattern, informative for issues of mechanism, highlights the potential benefit of extending tobacco cessation programs through the third trimester of pregnancy.

Placental abnormalities differ in small for gestational age neonates in relation to their prenatal sonographic abdominal circumference measurements

Background: Antenatal detection of abdominal circumference (AC) <10th percentile, among small for gestational age (SGA) neonates, probably reflects the severity of their growth restriction. We aimed to study neonatal outcome and placental pathology among SGA neonates in correlation to their AC measurements.Methods: Maternal and neonatal computerized medical records and placental histopathology reports of all SGA neonates, (neonatal birth-weight ≤10th percentile), born between 24 and 42 weeks, during 2015-2018 were reviewed. Included cases with fetal biometric measurements conducted up to 7 days prior labor. Results were compared between cases with sonographic antenatal AC <10th percentile and neonates with sonographic antenatal AC ≥10th percentile. Placental lesions were classified according to "Amsterdam" Placental workshop criteria.Results: The AC <10th percentile group (n = 148) was characterized by higher rate of nulliparity (p = .003), and induction of labor (p = .009), as compared to the AC ≥10th percentile group (n = 41). There were no between groups differences in the rate of maternal BMI (kg/m²), hypertensive disorders, diabetes or smoking. Neonatal hypoglycemia was more common in the AC <10th percentile group as compared to the AC ≥10th percentile group (p = .04). Placentas from the AC <10th percentile group were smaller (p < .001), with more MVM lesions (p = .02) and chronic villitis (p = .04). By multivariate regression analysis, AC <10th percentile and maternal hypertensive disorders, were found to be independently associated with placental MVM lesions, aOR = 2.43 (95% CI 1.04, 5.88) and aOR = 3.15 (95% CI 1.06, 9.31), respectively.Conclusions: Higher rate of placental maternal malperfusion lesions, chronic villitis, and more neonatal hypoglycemia characterize SGA neonates with AC <10th percentile, pointing to the importance of AC measurement as an indicator for placental insufficiency.

Reduced fetal movements is twin pregnancies and the association with adverse neonatal outcomes

OBJECTIVE

Reduced fetal movements (RFM) is an obstetric complaint known to be associated with adverse neonatal outcomes and should serve as an alarming sign in obstetric triage. Whether this assumption holds for twin pregnancies, is still an obstetric enigma, and this complaint is sometimes overlooked in twins. We, therefore, aimed to study neonatal outcomes in twin pregnancies complicated by RFM. We hypothesised that in twin pregnancy, maternal ability to perceive RFM will be limited, and therefore, will not be associated with adverse neonatal outcome.

STUDY DESIGN

Included were all dichorionic twin pregnancies between 2009-2019 who presented to our obstetric triage at a gestational age >34 weeks with an isolated complaint of RFM and delivered during the subsequent two weeks (RFM group). The control group included patients with twin pregnancies (matched for gestational age and maternal age) who presented for routine assessment and reported regular fetal movements throughout pregnancy (no RFM group). Data regarding pregnancy, delivery, and neonatal outcomes were compared between the groups. The primary outcome was a composite of adverse neonatal outcomes, which included one or more of the following: neonatal hypoglycemia, respiratory morbidity, cerebral morbidity, phototherapy, neonatal sepsis, blood transfusions, necrotizing enterocolitis, or neonatal death. Multivariable regression analysis was used to identify independent associations with adverse neonatal outcomes.

RESULTS

Maternal demographics and gestational age at delivery did not differ between the RFM group (n = 83 pregnancies and 166 neonates) and the no RFM group (n = 83 pregnancies and 166 neonates). Neonatal birthweights, as well as the rate of birthweights <10th centile, did not differ between the groups. There were 2 cases of fetal demise diagnosed at triage in the RFM group. The rate of the primary outcome, as well as NICU admissions, were significantly higher in the RFM group compared to the no RFM group (29.5 % vs. 19.2 %, p = 0.01 and 32.5 % vs. 19.2 %, p = 0.001). In multivariable analysis RFM (aOR = 1.18, 95 % CI = 1.06-2.73), and GA at delivery (aOR = 0.88, 95 % CI = 0.67-0.97) were associated with adverse neonatal outcome-independent from background confounders.

CONCLUSION

Patients presented to obstetric triage with twin pregnancies and isolated RFM had higher rates of adverse neonatal outcomes and NICU admissions compared to twin pregnancies without RFM.

Distinctive patterns of placental lesions in pre-eclampsia vs small-for-gestational age and their association with fetoplacental Doppler

OBJECTIVES

To describe placental histopathological findings in a large cohort of pregnancies complicated by pre-eclampsia (PE) and/or small-for-gestational age (SGA), and to investigate their association with fetoplacental Doppler parameters.

METHODS

This was a prospective observational study of normotensive pregnancies with SGA (defined as birth weight < 10^th centile) (n = 184), PE pregnancies with a normally grown fetus (n = 102), pregnancies with both PE and SGA (n = 120) and uncomplicated pregnancies (n = 202). Uterine (UtA), umbilical (UA) and fetal middle cerebral (MCA) artery pulsatility indices (PI) were assessed. The cerebroplacental ratio (CPR) was calculated by dividing MCA-PI by UA-PI. Doppler parameters were considered abnormal when UtA-PI or UA-PI was > 95^th centile or MCA-PI or CPR was < 5^th centile. Placental lesions were categorized as vascular (maternal or fetal side), immunoinflammatory or other, according to the 2014 Amsterdam Placental Workshop Group Consensus Statement. Comparison between the study groups was performed using univariate and multiple regression analysis, and logistic regression was used to determine the relationship between abnormal Doppler parameters and placental lesions.

RESULTS

Maternal-side vascular lesions were significantly more common in PE pregnancies with SGA than in the other groups (PE + SGA, 73% vs PE, 46% vs SGA, 38% vs controls, 31%; P = 0.01) and included mainly two types of lesion: developmental (PE + SGA, 13% vs PE, 5% vs SGA, 3% vs controls, 1.5%; P < 0.001) and malperfusion (PE + SGA, 70% vs PE, 39% vs SGA, 32% vs controls, 25%; P = 0.001). In contrast, the incidence of fetal-side developmental lesions was significantly higher in normotensive SGA pregnancies than in controls and PE pregnancies (PE + SGA, 0% vs PE, 3% vs SGA, 8% vs controls, 2%; P = 0.001). All cases displayed a lower prevalence of infectious lesions than did controls, with the highest prevalence of immune lesions observed in pregnancies with both PE and SGA (PE + SGA, 18% vs PE, 8% vs SGA, 10% vs controls, 9%; P = 0.001). All fetoplacental Doppler parameters evaluated were associated with maternal-side vascular lesions, mainly malperfusion (mean UtA-PI: odds ratio (OR), 2.45 (95% CI, 1.51-3.97); UA-PI: OR, 2.05 (95% CI, 1.02-4.47); MCA-PI: OR, 2.75 (95% CI, 1.40-5.42); CPR: OR, 1.75 (95% CI, 1.04-2.95)). This association was evident mainly in the normotensive SGA group, being non-significant in controls or PE pregnancies without SGA. No significant associations were observed between fetoplacental Doppler parameters and other placental lesions in any of the study groups.

CONCLUSIONS

PE and SGA are associated with different patterns of placental histopathological lesions in accordance with the clinical manifestation of the placental disorder (maternal vs fetal). Fetoplacental Doppler findings show an association with placental malperfusion lesions on the maternal side, supporting the use of abnormal Doppler as a surrogate for placental insufficiency. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Do Doppler Changes Reflect Pathology of Placental Vascular Lesions in IUGR Pregnancies?

OBJECTIVES

Doppler assessment of uteroplacental (UP) and fetoplacental (FP) circulation detects abnormal waveforms in intrauterine growth-restricted (IUGR) pregnancies. Similarly, histopathology also reveals lesions of vascular compromise in IUGR placenta. We evaluated an association between Doppler and histopathological (HP) assessment of the maternal and fetal circulation in IUGR.

METHODS

IUGR cases with both Doppler and histopathology assessment were selected from our database. Doppler patterns recorded UP and FP insufficiency. The HP vascular lesions were classified as maternal vascular underperfusion and fetal thrombotic vasculopathy (FTV). IUGRs were grouped based on (i) presence of preeclampsia (PE), (ii) clinical onset (early vs late) of IUGR (early onset [EO]/late onset), and (iii) gestational age (term, T/preterm, PT).

RESULTS

Abnormal Doppler waveforms were present in 69 of the total 88 IUGR cases (78.4%). The most frequent pattern was fetoplacental insufficiency (FPI) (66%) which was combined with uteroplacental insufficiency (UPI) in 49%. HP showed vascular lesions in 52.3% and most frequent was FTV (38%). PE-associated IUGR (n = 49) had higher UPI pattern (75.5% vs 43.6%, P = .004), while normotensive IUGR had higher FPI pattern (28.2% vs 8.2%, P = .01). EO-IUGR (n = 55) and PT-IUGR (n = 52) had significant abnormal Doppler waveforms (P < .05) with higher combined patterns and brain sparing. Doppler was more sensitive for fetal vascular lesions than maternal (75.8% vs 66.7%). However, 42% of cases with normal Doppler findings showed HP vascular lesions.

CONCLUSION

IUGR pregnancies harbor significant vascular compromise. Fetal circulatory lesions were more common in IUGR pregnancies. In a significant number of cases with normal Doppler report, vascular lesions were identified on histopathology, emphasizing placental examination in all cases of IUGR.

Pathologic placental lesions in early and late fetal growth restriction

INTRODUCTION

The purpose of the study was to evaluate the differences in individual histopathologic placental lesions in pregnancies complicated by early-onset (<32 weeks at diagnosis) and late-onset (≥32 weeks at diagnosis) fetal growth restriction (FGR).

MATERIAL AND METHODS

A cohort study of 440 singleton pregnancies complicated by FGR, diagnosed according to standard ultrasonographic criteria, followed up and delivered at the same institution between 2010 and 2016. Placental lesions were classified according to the Amsterdam Placental Workshop Consensus Criteria. Pathologic examination of placentas from 113 healthy singleton term pregnancies served as controls. Binary and multinomial logistic regression models were used to evaluate the independent association of placental lesions with the type of FGR.

RESULTS

In our cohort the prevalences of early and late FGR were 37.3% (164/440) and 62.7% (276/440), respectively. The overall rates of preeclampsia (69/164 vs 59/276, P < 0.01) and absent/reversed umbilical artery pulsatility indices (61/164 vs 14/276, P < 0.001) were higher among early FGR than late FGR. Placental characteristics from early and late FGR pregnancies differed mainly in regard to maternal vascular malperfusion scores rather than fetal scores, with preeclampsia found to be a cofactor modulating the rates and severity of associated lesions. In the binary logistic analysis, recent infarcts (OR 2.44, 95% CI 1.2-5), distal villous hypoplasia (OR 1.8, 95% CI 1.0-3.2), atherosis (OR 2.71, 95% CI 1.35-5.47), persistent endovascular trophoblasts (OR 1.67, 95% CI 1.03-2.7), and a reduced fetal/placental weight score (OR 0.27, 95% CI 0.2-0.38) were independently associated with an increased likelihood of early FGR compared with late FGR. The sensitivity, specificity, and area under the curve of the model were 60% (95% CI 51.2-66.2), 89.1% (95% CI 84.9-92.3), and 0.81 (95% CI 0.77-0.85), respectively, suggesting a fair to good predictive value.

CONCLUSIONS

Individual placental lesions suggestive of increased rates of ischemia, defective remodeling of spiral arteries, peripheral hypoxia interfering with villus development, and reduced placental efficiency were significantly more common in early FGR than late FGR.

Maternal vascular malformation in the placenta is an indicator for fetal growth restriction irrespective of neonatal birthweight

INTRODUCTION

To study the association between placental pathology and neonatal birthweight and outcomes, and whether a combination of first trimester biomarkers and fetal growth velocity can predict placental lesions.

METHODS

The presence of maternal vascular malperfusion (MVM) lesions (Amsterdam criteria) was recorded in a retrospective cohort of singleton pregnancies in the Maastricht University Medical Centre, 2011-2018. First trimester maternal characteristics and PAPP-A, PlGF and sFlt-1 levels were collected. Fetal growth velocities were calculated (mm/week) from 20 to 32 weeks for abdominal circumference, biparietal diameter, head circumference and femur length. Data were compared between neonates with 'small for gestational age' (SGA < p10) and different categories of 'appropriate for gestational age (AGA)': AGAp10-30, AGAp30-50 and AGA > p50 (reference), using one-way ANOVA and post hoc test.

RESULTS

There were significantly more MVM lesions in the SGA group (94.6% p < .0001), but also in the AGAp10-30 (67.3% p < .0001) and AGAp30-50 (41.6% p = 0.002), compared to the reference AGA group (19.3%). The prediction of MVM for a 20% false-positive rate, with maternal characteristics was25.2%. The addition of birthweight percentile gave a prediction of 51.7% for MVM. However adding placental biomarkers and fetal growth velocities (instead of birthweight percentile) to the maternal characteristics, gave a prediction of 81.8% (PPV 49.5%, NPV 53.7%).

DISCUSSION

Placental MVM lesions correlated inversely with birthweight even in AGA neonates, and was associated with slower fetal growth and more adverse outcome in SGA neonates. A combination of first trimester biomarkers and fetal growth velocity had good prediction of placental MVM lesions, as an indicator of fetal growth restriction irrespective of neonatal weight.

Histological chorioamnionitis at term according to labor onset: a prospective controlled study

OBJECTIVE

To study the incidence of histological chorioamnionitis (HCA) in term pregnancies according to labor onset.

STUDY DESIGN

During 2013-6, term pregnancy placentas were prospectively sent to histopathology evaluation, and compared between patients with spontaneous onset labor, pre-labor ROM, labor induction and elective cesarean deliveries.

RESULTS

A total of 260 placentas were obtained, 65 from each group. Rates of HCA for the spontaneous labor, PROM, induction and CD groups were: 49, 32, 24 and 4%, respectively (p < 0.001). Composite neonatal outcome was non-significant between the study groups, and between cases with and without HCA. In a logistic regression model, after controlling for parity - gestational age, mode of delivery, ROM > 12 h and spontaneous onset of labor were found to be independent risk factors for HCA.

CONCLUSION

HCA at term is prevalent in spontaneous labor and supports the association between the inflammatory processes and activation of the physiological signals of parturition.

CD34 immunostain increases the sensitivity of placental diagnosis of fetal vascular malperfusion in stillbirth

INTRODUCTION

Postmortem regressive placental changes of stillbirth may obscure the pre-existing placental histomorphology. The objective is to find out whether the use of CD34 immunostain can increase the sensitivity of placental examination in the diagnosis of fetal vascular malperfusion (FVM).

METHODS

Twenty six independent clinical and 46 placental variables of 46 placentas from stillbirths were statistically compared to those of 92 placentas from livebirths. One histologically most unremarkable section per case was stained using double E-cadherin/CD34 immunostain (ECCD34). Clusters of avascular/hypovascular chorionic villi on hematoxylin and eosin (H&E) staining system and/or CD34 immunostaining, the latter also including endothelial CD34 positive debris in the villous stroma, were regarded as evidence of FVM.

RESULTS

The gestational age and cesarean section rate were statistically significantly lower and the induction of labor and mild erythroblastosis of fetal blood was higher, but the frequencies of clinical and placental features of umbilical cord compromise were not statistically significant between stillbirths and livebirths, respectively. By using H&E stain, 9 (19.6%) of stillbirths and 30 (32.6%) of livebirths showed clusters of avascular villi on H&E. By CD34, the rates of FVM increased to 23 (50%) and 34 (40%), respectively. The increase was statistically significant for stillbirths only (Chi square = 9.4, p = 0.002). By CD34, new clusters of hypovascular chorionic villi or villi with endothelial fragmentation were found in 23 stillbirth cases (50%) as opposed to livebirths (29 cases, 31.5%)(Chi square = 9.4, p = 0.002).

DISCUSSION

When compared with H&E stain, the CD34 increases sensitivity and/or upgrades FVM in placental examination in stillbirths but not in livebirths.

Placental transcriptional and histologic subtypes of normotensive fetal growth restriction are comparable to preeclampsia

BACKGROUND

Infants born small for gestational age because of pathologic placenta-mediated fetal growth restriction can be difficult to distinguish from those who are constitutionally small. Additionally, even among fetal growth-restricted pregnancies with evident placental disease, considerable heterogeneity in clinical outcomes and long-term consequences has been observed. Gene expression studies of fetal growth-restricted placentas also have limited consistency in their findings, which is likely due to the presence of different molecular subtypes of disease. In our previous study on preeclampsia, another heterogeneous placenta-centric disorder of pregnancy, we found that, by clustering placentas based only on their gene expression profiles, multiple subtypes of preeclampsia, including several with co-occurring suspected fetal growth restriction, could be identified.

OBJECTIVE

The purpose of this study was to discover placental subtypes of normotensive small-for-gestational-age pregnancies with suspected fetal growth restriction through the use of unsupervised clustering of placental gene expression data and to investigate their relationships with hypertensive suspected fetal growth-restricted placental subtypes.

STUDY DESIGN

A new dataset of 20 placentas from normotensive small-for-gestational-age pregnancies (birthweight <10th percentile for gestational age and sex) with suspected fetal growth restriction (ultrasound features of placental insufficiency) underwent genome-wide messenger RNA expression assessment and blinded detailed histopathologic evaluation. These samples were then combined with a subset of samples from our previously published preeclampsia cohort (n=77) to form an aggregate fetal growth-focused cohort (n=97) of placentas from normotensive small-for-gestational-age, hypertensive (preeclampsia and chronic hypertensive) small-for-gestational-age, and normotensive average-for-gestational-age pregnancies. Gene expression data were subjected to unsupervised clustering, and clinical and histopathologic features were correlated to the identified sample clusters.

RESULTS

Clustering of the aggregate dataset revealed 3 transcriptional subtypes of placentas from normotensive small-for-gestational-age/suspected fetal growth-restricted pregnancies, with differential enrichment of clinical and histopathologic findings. The first subtype exhibited either no placental disease or mild maternal vascular malperfusion lesions, and, co-clustered with the healthy average-for-gestational-age control subjects; the second subtype showed more severe evidence of hypoxic damage and lesions of maternal vascular malperfusion, and the third subtype demonstrated an immune/inflammatory response and histologic features of a maternal-fetal interface disturbance. Furthermore, all 3 of these normotensive small-for-gestational-age subtypes co-clustered with a group of placentas from hypertensive small-for-gestational-age pregnancies with more severe clinical outcomes, but very comparable transcriptional and histologic placental profiles.

CONCLUSION

Overall, this study provides evidence for at least 2 pathologic placental causes of normotensive small-for-gestational-age, likely representing true fetal growth restriction. These subtypes also show considerable similarity in gene expression and histopathology to our previously identified "canonical" and "immunologic" preeclampsia placental subtypes. Furthermore, we discovered a subtype of normotensive small-for-gestational-age (with suspected fetal growth restriction) with minimal placental disease that may represent both constitutionally small infants and mild fetal growth restriction, although these cannot be distinguished with the currently available data. Future work that focuses on the identification of etiology-driven biomarkers and therapeutic interventions for each subtype of fetal growth restriction is warranted.

More Maternal Vascular Malperfusion and Chorioamnionitis in Placentas After Expectant Management vs. Immediate Delivery in Fetal Growth Restriction at (Near) Term: A Further Analysis of the DIGITAT Trial

Objective: Management of late fetal growth restriction (FGR) is limited to adequate fetal monitoring and optimal timing of delivery. The Disproportionate Intrauterine Growth Intervention Trial At Term (DIGITAT) trial compared induction of labor with expectant management in pregnancies at (near) term complicated by suspected FGR. Findings of the DIGITAT trial were that expectant monitoring prolonged pregnancy for 10 days and increased birth weight with only 130 grams. This resulted in more infants born below the 2.3rd percentile compared to induction of labor, respectively, 12.5% in induction of labor and 30.6% in expectant monitoring group. The main placental lesions associated with FGR are maternal vascular malperfusion, fetal vascular malperfusion, and villitis of unknown etiology. We investigated whether placentas of pregnancies complicated with FGR in the expectant monitoring group reveal more and more severe pathology due to pregnancy prolongation. Material and methods: The DIGITAT trial was a multicenter, randomized controlled trial with suspected FGR beyond 36 + 0 weeks. We now analyzed all available cases (n = 191) for placental pathology. The macroscopic details were collected and histological slides were recorded and classified by a single perinatal pathologist, blinded for pregnancy details and outcome. The different placental lesions were scored based on the latest international criteria for placental lesions as defined in the Amsterdam Placental Workshop Group Consensus Statement. Results: The presence of maternal vascular malperfusion and chorioamnionitis were higher in the expectant management group (p < 0.05 and p < 0.01, respectively). No differences in placental weight and maturation of the placenta between the induction of labor and the expectant management group were seen. Fetal vascular malperfusion, villitis of unknown etiology and nucleated red blood cell count did not differ between the groups. Conclusion: Expectant management of late FGR is associated with increased maternal vascular malperfusion and chorioamnionitis. This may have implications for fetal and neonatal outcome, such as programming in the developing child influencing health outcomes later in life.

Defining early vs late fetal growth restriction by placental pathology

INTRODUCTION

Although early and late fetal growth restriction have been suggested to be distinct entities, the optimal gestational age cut-off that differentiates the two conditions is currently unclear and has been arbitrarily set in previous studies between 32 and 37 weeks. We aimed to use placental pathology findings to determine that optimal gestational age cut-off between early and late fetal growth restriction.

MATERIAL AND METHODS

A retrospective cohort study of all women with singleton gestation who gave birth to a neonate diagnosed as small-for-gestational age (small-for-gestational age, defined as birthweight <10th percentile for gestational age) at a tertiary referral center between January 2001 and December 2015, and for whom placental pathology was available. Placental abnormalities were classified into lesions associated with maternal vascular malperfusion (MVM), fetal vascular malperfusion, placental hemorrhage and chronic villitis. Placental findings were analyzed as a function of gestational age at birth. The analysis was repeated in the subgroups of women without hypertensive complications of pregnancy (to reflect changes associated with isolated small-for-gestational age) and of neonates with severe small-for-gestational age (defined as birthweight <5th percentile), which are more likely to represent true fetal growth restriction.

RESULTS

A total of 895 women met the inclusion criteria. The only histological finding that changed with gestational age was MVM pathology, which decreased in frequency with increasing gestational age. We identified a considerable drop in the rate of MVM lesions at 33 weeks of gestation. The rate of MVM pathology in placentas of infants born before 33^0/7  weeks was significantly higher than that observed in placentas of infants born at 33^0/7  weeks or longer: 71.6% vs 27.4%, P < 0.001 for ≥2 MVM lesions, and 35.5% vs 3.5%, P < 0.001 for ≥3 MVM lesions. These findings persisted in the subgroups of women without hypertensive complications of pregnancy (n = 662) and of neonates with severe small-for-gestational age (n = 464).

CONCLUSIONS

Using placental pathology as a direct measure of the mechanisms underlying fetal growth restriction, the optimal gestational age at birth cut-off which differentiates early from late fetal growth restriction appears to be 33^0/7  weeks.

Association Between Prepregnancy Cardiovascular Function and Subsequent Preeclampsia or Fetal Growth Restriction

Preeclampsia and fetal growth restriction during pregnancy are associated with increased risk of maternal cardiovascular disease later in life. It is unclear whether this association is causal or driven by similar antecedent risk factors. Clarification requires recruitment before conception which is methodologically difficult with high attrition rates and loss of outcome numbers to nonconception/miscarriage. Few prospective studies have, therefore, been adequately powered to address these questions. We recruited 530 healthy women (mean age: 35.0 years) intending to conceive and assessed cardiac output, cardiac index, stroke volume, total peripheral resistance, mean arterial pressure, and heart rate before pregnancy. Participants were followed to completion of subsequent pregnancy with repeat longitudinal assessments. Of 356 spontaneously conceived pregnancies, 15 (4.2%) were affected by preeclampsia and fetal growth restriction. Women who subsequently developed preeclampsia/fetal growth restriction had lower preconception cardiac output (4.9 versus 5.8 L/min; P=0.002) and cardiac index (2.9 versus 3.3 L/min per meter²; P=0.031) while mean arterial pressure (87.1 versus 82.3 mm Hg; P=0.05) and total peripheral resistance (1396.4 versus 1156.1 dynes sec cm^-5; P<0.001) were higher. Longitudinal trajectories for cardiac output and total peripheral resistance were similar between affected and healthy pregnancies, but the former group showed a more exaggerated fall in mean arterial pressure in the first trimester, followed by a steeper rise and a steeper fall to postpartum values. Significant relationships were observed between cardiac output, total peripheral resistance, and mean arterial pressure and gestational epoch. We conclude that in healthy women, an altered prepregnancy hemodynamic phenotype is associated with the subsequent development of preeclampsia/fetal growth restriction.

Diagnosis and surveillance of late-onset fetal growth restriction

By consensus, late fetal growth restriction is that diagnosed >32 weeks. This condition is mildly associated with a higher risk of perinatal hypoxic events and suboptimal neurodevelopment. Histologically, it is characterized by the presence of uteroplacental vascular lesions (especially infarcts), although the incidence of such lesions is lower than in preterm fetal growth restriction. Screening procedures for fetal growth restriction need to identify small babies and then differentiate between those who are healthy and those who are pathologically small. First- or second-trimester screening strategies provide detection rates for late smallness for gestational age <50% for 10% of false positives. Compared to clinically indicated ultrasonography in the third trimester, universal screening triples the detection rate of late smallness for gestational age. As opposed to early third-trimester ultrasound, scanning late in pregnancy (around 37 weeks) increases the detection rate for birthweight <3rd centile. Contrary to early fetal growth restriction, umbilical artery Doppler velocimetry alone does not provide good differentiation between late smallness for gestational age and fetal growth restriction. A combination of biometric parameters (with severe smallness usually defined as estimated fetal weight or abdominal circumference <3rd centile) with Doppler criteria of placental insufficiency (either in the maternal [uterine Doppler] or fetal [cerebroplacental ratio] compartments) offers a classification tool that correlates with the risk for adverse perinatal outcome. There is no evidence that induction of late fetal growth restriction at term improves perinatal outcomes nor is it a cost-effective strategy, and it may increase neonatal admission when performed <38 weeks.

Pathophysiology of placental-derived fetal growth restriction

Placental-related fetal growth restriction arises primarily due to deficient remodeling of the uterine spiral arteries supplying the placenta during early pregnancy. The resultant malperfusion induces cell stress within the placental tissues, leading to selective suppression of protein synthesis and reduced cell proliferation. These effects are compounded in more severe cases by increased infarction and fibrin deposition. Consequently, there is a reduction in villous volume and surface area for maternal-fetal exchange. Extensive dysregulation of imprinted and nonimprinted gene expression occurs, affecting placental transport, endocrine, metabolic, and immune functions. Secondary changes involving dedifferentiation of smooth muscle cells surrounding the fetal arteries within placental stem villi correlate with absent or reversed end-diastolic umbilical artery blood flow, and with a reduction in birthweight. Many of the morphological changes, principally the intraplacental vascular lesions, can be imaged using ultrasound or magnetic resonance imaging scanning, enabling their development and progression to be followed in vivo. The changes are more severe in cases of growth restriction associated with preeclampsia compared to those with growth restriction alone, consistent with the greater degree of maternal vasculopathy reported in the former and more extensive macroscopic placental damage including infarcts, extensive fibrin deposition and microscopic villous developmental defects, atherosis of the spiral arteries, and noninfectious villitis. The higher level of stress may activate proinflammatory and apoptotic pathways within the syncytiotrophoblast, releasing factors that cause the maternal endothelial cell activation that distinguishes between the 2 conditions. Congenital anomalies of the umbilical cord and placental shape are the only placental-related conditions that are not associated with maldevelopment of the uteroplacental circulation, and their impact on fetal growth is limited.