Low-dose aspirin for prevention of adverse outcomes related to abnormal placentation

Pregnancy Associated Plasma Protein-A and Placental Growth Factor in a Sub-Saharan African Population: A Nested Cross-Sectional Study

Background

Baseline distributions of pregnancy disorders’ biomarkers PlGF and PAPP-A levels are primarily based on Western European populations of Caucasian ethnicity. Differences in PAPP-A and PlGF concentrations by ethnicity have been observed, with increased levels in Afro-Caribbean, East Asian, and South Asian women. Baseline concentrations of sub-Saharan African women have not been evaluated.

Objectives

To investigate PlGF and PAPP-A in a sub-Saharan African population and assess the performance of existing reference values of PAPP-A and PlGF.

Methods

A nested cross-sectional study was conducted in two public hospitals in Accra, Ghana. Out of the original 1010 women enrolled in the cohort, 398 participants were eligible for inclusion with a normotensive singleton gestation and serum samples taken between 56–97 days of pregnancy. PAPP-A and PlGF concentrations were measured with an automated immunoassay. Multiple of the median (MoM) values corrected for gestation and maternal weight for PAPP-A and PlGF were calculated using reference values of a Dutch perinatal screening laboratory based on over 10.000 samples, and PlGF manufacturer reference values, respectively.

Results

The PAPP-A median MoM was 2.34 (interquartile range (IQR) 1.24–3.97). Median PlGF MoM was 1.25 (IQR 0.95–1.80). Median MoM values for PAPP-A and PlGF tended to be slightly different for various Ghanaian ethnic subgroups.

Conclusions

PAPP-A and PlGF MoM values appear to be substantially higher in a sub-Saharan African population compared to the Caucasian or Afro-Caribbean MoM values previously reported. The difference suggests the need for a specific correction factor for this population to avoid underestimation of risk for fetal aneuploidies or placental disorders when using PAPP-A and PlGF MoM for screening purposes.

Impact of maternal serum levels of Visfatin, AFP, PAPP-A, sFlt-1 and PlGF at 11-13 weeks gestation on small for gestational age births

OBJECTIVE

Investigating potential value of maternal serum Visfatin, sFlt-1, PlGF, AFP, PAPP-A levels at first trimester for prediction of small for gestational age (SGA) at birth.

METHODS

Measurements were performed in 20 SGA and 65 control cases. Logistic regression analysis adjusted for age and weeks of pregnancy at data collection was performed to estimate odds ratios (OR), 95% confidence intervals (95% CI) and p values separately for each potential predictor. A multiple regression model was used to assess the impact of all the promising predictors adjusted for each other. Receiver operating characteristic (ROC) analysis was used to indicate the ability to discriminate between SGA cases and controls.

RESULTS

There was an association of serum PlGF levels (OR 0.53 per interquartile range [IQR] increase in PlGF; 95% CI 0.24-1.16), sFlt-1/PlGF ratio (OR 1.42 per IQR increase in sFlt-1/PlGF; 95% CI 1.03-1.96), serum Visfatin levels (OR 0.31 per IQR increase in Visfatin; 95% CI 0.10-0.95) and smoking (OR 4.24; 95% CI 1.10-16.37) with SGA at birth.

CONCLUSIONS

Associations between SGA and lower PlGF, Visfatin levels as well as increased sFlt-1/PlGF ratio and smoking status were detected which may contribute to predict SGA.

First trimester screening for pre-eclampsia

The commercial availability of tests in the first trimester of pregnancy that predict the later development of pre-eclampsia has prompted considerable debate regarding their clinical utility and the degree to which they fulfil the longstanding principles of screening. Such tests have been shown to achieve detection rates for early pre-eclampsia (requiring delivery prior to 34 weeks) of over 90%, for a false positive rate of 10%. However, their capacity to predict later onset pre-eclampsia, which accounts for the bulk of the disease burden, is much more limited. The relatively few studies validating the performance of these tests in different populations have demonstrated significant variations in performance. Moreover, prospective research confirming that the administration of aspirin to those screened to be high risk reduces the incidence of pre-eclampsia is yet to be completed, and there may be harms in restricting aspirin therapy to this group, given its broader beneficial effect. In light of these limitations, further development of these tests is recommended prior to their introduction to clinical practice.

[Can we prevent preeclampsia?]

Preeclampsia (PE), a specific complication of pregnancy, is one of the most frequent causes of maternal and fetal morbidity and mortality in the world. Recently, PE risk calculation algorithms allowing early detection of PE in the first trimester of pregnancy have been described. The aim of early detection would be to rapidly introduce an effective preventive treatment. The aim of our work is to study the different preventive treatments through the literature. Aspirin has some efficiency and reduces the risk of PE from 10 to 24%. It is most effective when the dose exceeds 75mg and when introduced before 16 gestational age. Early introduction of aspirin mainly prevents severe and preterm PE. Low molecular weight heparin (LMWH) and vitamin D appear to be promising therapy for PE but further research is required. Calcium administered at 1g/day reduces the risk of PE especially to patients with low baseline calcium intake. A low dose of calcium could also reduce the risk of PE but this must be confirmed. Other preventive measures (antioxidants, nitric oxide, progesterone, rest, exercise) do not reduce the incidence of PE.

Decidual Cox2 inhibition improves fetal and maternal outcomes in a preeclampsia-like mouse model

Preeclampsia (PE) is a disorder of pregnancy that manifests as late gestational maternal hypertension and proteinuria and can be life-threatening to both the mother and baby. It is believed that abnormal placentation is responsible for the cascade of events leading to the maternal syndrome. Embryo implantation is critical to establishing a healthy pregnancy. Defective implantation can cause adverse "ripple effects," leading to abnormal decidualization and placentation, retarded fetal development, and poor pregnancy outcomes, such as PE and fetal growth restriction. The precise mechanism(s) of implantation defects that lead to PE remain elusive. BPH/5 mice, which spontaneously develop the cardinal features of PE, show peri-implantation defects including upregulation of Cox2 and IL-15 at the maternal-fetal interface. This was associated with decreased decidual natural killer (dNK) cells, which have important roles in establishing placental perfusion. Interestingly, a single administration of a Cox2 inhibitor (celecoxib) during decidualization restrained Cox2 and IL-15 expression, restored dNK cell numbers, improved fetal growth, and attenuated late gestational hypertension in BPH/5 female mice. This study provides evidence that decidual overexpression of Cox2 and IL-15 may trigger the adverse pregnancy outcomes reflected in the preeclamptic syndrome, underscoring the idea that Cox2 inhibitor treatment is an effective strategy for the prevention of PE-associated fetal and maternal morbidity and mortality.

Preconception venous thromboembolism and placenta-mediated pregnancy complications

BACKGROUND

Placenta-mediated complications are leading causes of maternal and fetal morbidity and mortality. We hypothesized that a preconception history of venous thromboembolism (VTE) is associated with increased risk of placenta-mediated pregnancy complications.

METHODS

A nationwide population-based cohort study of all singleton pregnancies leading to delivery from 1997 to 2012 (n = 964 967). We obtained data on placenta-mediated pregnancy complications from the Danish Medical Birth Registry and data on VTE before pregnancy from the Danish National Patient Registry. We computed absolute risks, crude and adjusted risk differences (RDs) using a binomial regression model, and crude and adjusted risk ratios (RRs) from a modified Poisson regression model.

RESULTS

Overall, 1419 women had a preconception history of VTE, while 578 112 did not. Preeclampsia occurred in 4.2% of pregnancies in the VTE group and in 2.7% of pregnancies in a comparison cohort (adjusted RD = 1.3%, 95% confidence interval (CI) 0.6-2.0%; adjusted RR = 1.5, 95% CI 1.3-1.8). Stillbirth occurred in 0.7% of pregnancies in the VTE group and in 0.4% of pregnancies in the comparison cohort (adjusted RD = 0.3%, 95% CI 0.02-0.6%; adjusted RR = 1.8, 95% CI 1.1-3.0). Placental abruption occurred in 0.8% of pregnancies in the VTE group and in 0.5% of pregnancies in the comparison cohort (adjusted RD = 0.3%, 95% CI - 0.05-0.6%; adjusted RR = 1.6, 95% CI 1.1-2.4). Small-for-gestational-age infants accounted for 10.9% of live births in the VTE group and 9.8% of live births in the comparison cohort (adjusted RD = 0.6%, 95% CI - 0.5-1.7%; adjusted RR = 1.1, 95% CI 0.9-1.3).

CONCLUSION

Women with a history of VTE were at increased risk of placenta-mediated complications.

Urine proteomic studies in preeclampsia

Preeclampsia (PE) is a multisystem disorder of pregnancy that develops after 20 wk of gestation in previously normotensive women and complicates 5-8% of pregnancies. This rapidly progressive syndrome is usually diagnosed when the mother develops hypertension and proteinuria. The only effective treatment is delivery of the baby although early low-dose aspirin has been shown to significantly reduce the risk for PE. Recent advances in proteomic methods of protein separation, identification, and quantitation may allow for the identification of proteins and peptides that could facilitate early detection of disease, improve assessment of prognosis, and allow closer monitoring of women at risk for PE. This review summarizes all currently available markers for prediction and diagnosis of PE and presents urine proteomic studies performed for the identification of novel biomarkers.

Current controversies in prenatal diagnosis 2: prediction and prevention of adverse pregnancy outcomes requires a genomic rather than proteomic solution

From both presentations, it is clear that understanding the APO associated with placental dysfunction represents one of the greatest challenges in the field of prenatal screening, diagnosis, and therapy. Their clinical impact on the health of the mother and child was well recognized by the debaters, and both have agreed that there is a paucity of knowledge in the etiophysiopathology of placental dysfunction and the associated clinical phenotypes. They also agreed that this marked limitation in our understanding is a significant problem when designing a research protocol, and both stressed the importance of proper study designs. When focusing on the specific topics of the debate, they showed different opinions about the role of genomics in the search for relevant answers. Leslie Myatt pointed out that the genome does not define the cellular phenotype, and although the proteome itself does not define phenotype, it is much closer to it than the genome. Conversely, Rossa Chiu suggested that genomic approaches offer a better chance of achieving the answers than by proteomics alone. Actually, she hypothesized that through genomic approaches, or rather through systems biology, that is, including genomics, epigenomics, transcriptomics, and proteomics, there would be a better chance of obtaining the best answers. She also raised the possibility of the potential use of cell-free fetal nucleic acids in maternal plasma, which in turn are mainly of placental origin. Finally, both debaters and the audience agreed that there was not an exclusive proteomic or genomic 'solution', but that we need a larger spectrum of research strategies to include both proteomics and genomics and other systems biology approaches, combined with detailed and standardized clinical, laboratory, and epidemiological criteria in appropriately designed studies in order to start filling the significant gaps in our knowledge about this highly complex area of placental mediated adverse pregnancy outcomes.

Docosahexaenoic acid supplementation early in pregnancy may prevent deep placentation disorders

Uteroplacental ischemia may cause preterm birth, either due to preterm labor, preterm premature rupture of membranes, or medical indication (in the presence of preeclampsia or fetal growth restriction). Uteroplacental ischemia is the product of defective deep placentation, a failure of invasion, and transformation of the spiral arteries by the trophoblast. The failure of normal placentation generates a series of clinical abnormalities nowadays called "deep placentation disorders"; they include preeclampsia, fetal growth restriction, preterm labor, preterm premature rupture of membranes, in utero fetal death, and placental abruption. Early reports suggested that a LC-PUFAs (long chain polyunsaturated fatty acids) rich diet reduces the incidence of deep placentation disorders. Recent randomized controlled trials are inconsistent to show the benefit of docosahexaenoic acid (DHA) supplementation during pregnancy to prevent deep placentation disorders, but most of them showed that DHA supplementation was associated with lower risk of early preterm birth. We postulate that DHA supplementation, early in pregnancy, may reduce the incidence of deep placentation disorders. If our hypothesis is correct, DHA supplementation, early in pregnancy, will become a safe and effective strategy for primary prevention of highly relevant pregnancy diseases, such as preterm birth, preeclampsia, and fetal growth restriction.