The use of low dose aspirin in pregnancy

Uteroplacental and Fetal 4D Flow MRI in the Pregnant Rhesus Macaque

BACKGROUND

Pregnancy complications are often associated with poor uteroplacental vascular adaptation and standard diagnostics are unable to reliably quantify flow in all uteroplacental vessels and have poor sensitivity early in gestation.

PURPOSE

To investigate the feasibility of using 4D flow MRI to assess total uteroplacental blood flow in pregnant rhesus macaques as a precursor to human studies.

STUDY TYPE

Retrospective feasibility study.

ANIMAL MODEL

Fifteen healthy, pregnant rhesus macaques ranging from the 1^st trimester to 3^rd trimester of gestation.

FIELD STRENGTH/SEQUENCE

Abdominal 4D flow MRI was performed on a 3.0T scanner with a radially undersampled phase contrast (PC) sequence. Reference ferumoxytol-enhanced angiograms were acquired with a 3D ultrashort echo time sequence with a center-out radial trajectory.

ASSESSMENT

Repeatability of flow measurements was assessed with scans performed same-day and on consecutive days in the uterine arteries and ovarian veins. In-flow was compared against out-flow in the uterus, umbilical cord, and fetal heart with a conservation of mass analysis. Conspicuity of uteroplacental vessels was qualitatively compared between PC angiograms derived from 4D flow data and ferumoxytol-enhanced angiograms.

STATISTICAL TESTS

Bland-Altman analysis was used to quantify same-day and consecutive-day repeatability.

RESULTS

Same-day flow measurements showed an average difference between scans of 13% in both the uterine arteries and ovarian veins, while consecutive-day measurements showed average differences of 22% and 24%, respectively. Comparisons of in-flow and out-flow showed average differences of 15% in the uterus, 8% in fetal heart, and 15% in the umbilical cord. PC angiograms showed similar depiction of main uteroplacental vessels as high-resolution, ferumoxytol-enhanced angiograms.

DATA CONCLUSION

4D flow MRI could be used in the rhesus macaque for repeatable flow measurements in the uteroplacental and fetal vasculature, setting the stage for future human studies.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:534-545.

A kinetic-based safety assessment of consumer exposure to salicylic acid from cosmetic products demonstrates no evidence of a health risk from developmental toxicity

Salicylic acid (SA) has a long history of safe use as ingredient in topical cosmetic products. In 2016, the Committee for Risk Assessment of the European Chemicals Agency proposed to classify SA as a Category 2 reproductive toxicant based on adverse developmental effects in animal toxicity studies. This hazard-based classification (based on mg/kg doses) requires a reassessment of the safety of the current SA concentrations in cosmetic consumer products. Herein, a safety reassessment was performed in which margins of safety were calculated based on literature data on the NOAEL plasma exposure levels from animal reproductive toxicity studies with ASA (rapidly converts to SA in plasma), human SA plasma levels from oral exposure to ASA and human dermal exposure to SA-containing cosmetic products. In addition, a literature review was performed, which shows that there are no adverse developmental effects despite extensive human clinical oral use of ASA up to the maximum recommended therapeutic doses. The plasma exposure-based safety assessment for SA combined with an absence of any clinical health risk with oral ASA use in the literature supports that there is an acceptable margin of safety for the consumer exposure to SA as authorized in the current EU cosmetic regulation.

Evidence and consensus recommendations for the pharmacological management of pain in India

Despite enormous progress in the field of pain management over the recent years, pain continues to be a highly prevalent medical condition worldwide. In the developing countries, pain is often an undertreated and neglected aspect of treatment. Awareness issues and several misconceptions associated with the use of analgesics, fear of adverse events - particularly with opioids and surgical methods of analgesia - are major factors contributing to suboptimal treatment of pain. Untreated pain, as a consequence, is associated with disability, loss of income, unemployment and considerable mortality; besides contributing majorly to the economic burden on the society and the health care system in general. Available guidelines suggest that a strategic treatment approach may be helpful for physicians in managing pain in real-world settings. The aim of this manuscript is to propose treatment recommendations for the management of different types of pain, based on the available evidence. Evidence search was performed by using MEDLINE (by PubMed) and Cochrane databases. The types of articles included in this review were based on randomized control studies, case-control or cohort studies, prospective and retrospective studies, systematic reviews, meta-analyses, clinical practice guidelines and evidence-based consensus recommendations. Articles were reviewed by a multidisciplinary expert panel and recommendations were developed. A stepwise treatment algorithm-based approach based on a careful diagnosis and evaluation of the underlying disease, associated comorbidities and type/duration of pain is proposed to assist general practitioners, physicians and pain specialists in clinical decision making.

Assessment of risk factors for infantile cataracts using a case-control study: National Birth Defects Prevention Study, 2000-2004

OBJECTIVE

To identify risk factors for infantile cataracts of unknown etiology.

DESIGN

Case-control study.

PARTICIPANTS

Case infants (n = 152) and control infants (n = 4205) enrolled in the National Birth Defects Prevention Study for birth years 2000-2004.

METHODS

Multivariate analysis was performed exploring associations for risk factors for bilateral and unilateral infantile cataracts of unknown etiology.

MAIN OUTCOME MEASURES

Infantile cataracts of unknown etiology.

RESULTS

Maternal interviews were completed for 43 case infants with bilateral and 109 with unilateral infantile cataracts of unknown etiology. Very low birth weight (<1500 g) was associated with both unilateral (adjusted odds ratio [OR], 6.0; 95% confidence interval [CI], 2.2-16.3) and bilateral (OR, 13.2; 95% CI, 4.2-41.1) cataracts, whereas low birth weight (1500-2499 g) was only associated with bilateral cataracts (OR, 3.3; 95% CI, 1.3-8.1). Infants with unilateral cataracts were more likely to be born to primigravid women (OR, 1.6; 95% CI, 1.0-2.7) than women with > or =2 previous pregnancies, although this was of borderline significance. Although not significant, effect estimates were elevated suggesting a possible association between unilateral cataracts and maternal substance abuse during pregnancy, and between bilateral cataracts and urinary tract infection during pregnancy and aspirin use during pregnancy.

CONCLUSIONS

Very low birth weight is associated with both bilateral and unilateral cataracts, whereas low birth weight is associated with bilateral cataracts and primigravidity with unilateral cataracts. Other associations, although not statistically significant, suggest risk factors that merit further research.

Platelet activation in pregnancy-induced hypertension

BACKGROUND

Although excess platelet activation, as indicated by increased plasma beta thromboglobulin (beta-TG), has been shown in pregnancy-induced hypertension (PIH), platelet adhesion, platelet morphology and a comparison of platelet and soluble (plasma) levels of the adhesion molecules P-selectin (pPsel and sPsel, respectively) have not been studied.

METHODS

We conducted a cross-sectional study of 35 consecutive women with PIH (age 31+/-6 years), 31 consecutive women with normotensive pregnancies (age 29+/-5 years) and 30 normotensive non pregnant women (age 30+/-5 years). Platelet adhesion was studied in vitro by binding to fibrinogen-coated microwells, platelet morphology [mass and volume by flow cytometry], whole-platelet P-selectin (pPsel) by ELISA of the lysate of 2 x 10(8) cells, and the plasma markers soluble P-selectin (sP-sel) and beta-TG, by ELISA.

RESULTS

The women with PIH had significantly raised sPsel, pPsel and (as expected) beta-TG (all p<0.05), when compared to the normotensive pregnant women and controls. However, in PIH platelet adhesion was similar to that in the normotensive pregnancy, but still higher than the normal controls (p<0.001). There was no difference among the three groups with respect to platelet mass and volume. pPsel and platelet adhesion correlated with gestational age and with systolic and diastolic blood pressure (all p<0.05).

CONCLUSIONS

Increased platelet activation and adhesion develop during normal pregnancy, with some indices being further altered in PIH.

Platelet activation in the hypertensive disorders of pregnancy

The hypertensive disorders of pregnancy, including gestational hypertension, pre-eclampsia and eclampsia, continue to be an important cause of maternal morbidity and mortality. Abnormal placentation is considered to be the main instigating factor, which then leads to widespread maternal endothelial activation and dysfunction. This endothelial perturbation leads to the release of many substances into the circulation, many of which result in platelet activation. For example, there is an imbalance between the levels of prostacyclin (a vasodilator and platelet inhibitor) and thromboxane (a platelet activator and vasoconstrictor), which then results in the maintenance of high blood pressure and complications. It is also likely that platelets play an important part in the pathogenesis of hypertension in pregnancy. The use of antiplatelet drugs has been shown to be effective in reducing the incidence of gestational hypertension in women at high risk and in preventing the complications associated with it. In addition, some antihypertensive agents are effective in reversing platelet activation in essential hypertension and, therefore, their use in pregnancy-induced hypertension may be beneficial in more ways than simply blood pressure reduction.

Randomized controlled trial using low-dose aspirin in the prevention of pre-eclampsia in women with abnormal uterine artery Doppler at 23 weeks' gestation

OBJECTIVE

Pre-eclampsia, which is a major cause of perinatal and maternal morbidity and mortality, is thought to be due to impaired perfusion of the placenta. There is contradictory evidence that the administration of low-dose aspirin may provide effective prophylaxis against the subsequent development of pre-eclampsia. In this study we tested the hypothesis that in women identified as being at high-risk for pre-eclampsia, because of impaired flow in the uterine arteries, the prophylactic use of low-dose aspirin from 23 weeks of gestation can reduce the incidence of pre-eclampsia.

METHODS

We used color and pulsed Doppler to measure the flow in the uterine arteries in 19,950 singleton pregnancies at 22-24 weeks of gestation. Those women exhibiting increased impedance were recruited into a randomized study of aspirin 150 mg per day or placebo. We compared the two groups for the incidence of pre-eclampsia and the other consequences of impaired placentation.

RESULTS

The screening study identified 844 women (4.2%) as being at high risk of uteroplacental insufficiency. After exclusion and refusal, 560 women were randomly allocated to aspirin 150 mg or placebo per day until 36 weeks' gestation. There were no significant differences between the aspirin and placebo groups in either the incidence of pre-eclampsia (18% vs. 19%, P = 0.6) or pre-eclampsia requiring delivery below 34 weeks (6% vs. 8%, P = 0.36). Furthermore, the administration of aspirin did not significantly alter the incidence of preterm delivery (24% vs. 27%, P = 0.46), birth weight below the 5th centile (22% vs. 24%, P = 0.4), perinatal death (3% vs. 1%, P = 0.33) or placental abruption (4% vs. 2%, P = 0.12).

CONCLUSION

In pregnancies with impaired placentation, as demonstrated by increased impedance to flow in the uterine arteries, the daily administration of 150 mg aspirin after 23 weeks of gestation does not prevent the subsequent development of pre-eclampsia.

Prevention of pre-eclampsia: status and perspectives 2000

Because pre-eclampsia is a relatively common complication of pregnancy and forms a major cause of maternal, fetal, and neonatal morbidity and mortality, attempts at prevention are justified, but hampered by the fact that as yet no reliable and acceptable screening tests for women at risk are available. Analysis of the many interventions advocated to prevent or delay the onset of pre-eclampsia reveals that dietary calcium supplementation and prophylactic low-dose aspirin treatment have shown promise of efficacy in small randomized, placebo-controlled trials, but the results of large, multicenter trials are generally disappointing. The disappointing results obtained in large, multicenter trials may in part be explained by the lack of strict criteria for inclusion, late initiation of treatment, use of ill-defined end points, different timing of aspirin ingestion, and low patient compliance. Recent evidence that supplementation with vitamins C and E could prevent pre-eclampsia awaits confirmation. Future clinical trials on prevention of pre-eclampsia should be based on results of basic research.

Effects of nonsteroidal anti-inflammatory therapy on platelets

Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) can produce a mild, systemic hemostatic defect by inhibiting normal platelet function. Aspirin acetylates and permanently inactivates cyclooxygenase (COX), while nonaspirin NSAIDs reversibly block COX; thus, all of these drugs cause platelet dysfunction by inhibiting the formation of thromboxane A2, a platelet-activating and vasoconstricting eicosanoid. However, spontaneous bleeding complications outside the gastrointestinal tract very rarely result from the use of aspirin and other NSAIDs in individuals who are otherwise hemostatically normal. Most types of surgery are not usually associated with clinically significant bleeding in patients taking these drugs, making it typically unnecessary to discontinue them and thus delay surgery for the purpose of restoring normal hemostasis. Exceptions may include operations at sites where optimal hemostasis is critical, surgical manipulation of the genitourinary tract and oral cavity, and possibly cardiac surgery. Factors that increase the risk of bleeding with aspirin and other NSAIDs include coexisting coagulation abnormalities and the simultaneous use of alcohol or anticoagulants.

Drug management of hypertensive disorders of pregnancy

Drugs used in the acute and long-term management of hypertension in pregnancy and the preeclampsia-eclampsia syndrome have been reviewed and their therapeutic effects and maternal and fetal adverse effects have been considered. The review also focuses on recent developments in the areas of prevention and management of pre-eclampsia-eclampsia syndrome. Although a number of new drugs have emerged, as potentially useful in the management of hypertension in pregnancy and pre-eclampsia-eclampsia syndrome, some remain at the cornerstone of therapy; for example, methyldopa for long-term treatment of chronic hypertension, hydralazine or nifedipine for rapid reduction of severely elevated blood pressure, and magnesium sulphate for eclampsia. Some of these agents, especially the calcium antagonists, show promise in that their use is associated with fewer side effects. Safety for the fetus, however, has not been adequately evaluated yet. Neither aspirin nor calcium supplements appear to improve the outcome in pregnancy. Currently, the dilemma whether to treat hypertension in pregnancy and pre-eclampsia-eclampsia syndrome with old, established, cost-effective drugs or the promising newer drugs provides an interesting academic challenge.

Aspirin-interleukin-3 interrelationships in patients with anti-phospholipid syndrome

PROBLEM

Previously we reported on the generation of experimental anti-phospholipid syndrome (APS) in mice. These models were employed to evaluate the efficacy of various novel therapeutic modalities including interleukin-3 (IL-3) and low dose aspirin. The efficacy of the latter was found to be interrelated. Low dose aspirin is capable of inhibiting the activity of the enzyme cyclooxygenase which is responsible for the metabolism of arachidonic acid towards the production of prostaglandins. This shifts the metabolism of arachidonic acid to the other pathway and leads to an overproduction of leukotrienes. The leukotrienes act as stimulators of IL-3 production, a positive cytokine in pregnancy which enhances placental and fetal development. In the current study we evaluated the IL-3 levels in pregnant women with APS and expanded our knowledge on the interrelationships between aspirin, arachidonic acid metabolites and IL-3 in the human system.

METHODS

IL-3 levels were recorded in the serum of pregnant women with APS and compared to a control pregnant group. In addition peripheral blood mononuclear cells from healthy subjects were incubated with different concentrations of aspirin or with arachidonic acid metabolites (Leukotriene B4, C4 or PGE2), and IL-3 production in the culture fluids was evaluated.

RESULTS

Serum level of IL-3 in pregnant patients with primary APS, APS secondary to SLE and SLE was lower in comparison to the control group. The in vitro studies revealed that only low dose aspirin (10 mg/microliters) stimulated IL-3 production while higher doses of the drug failed to induce the cytokine generation. Leukotriene B4 and C4 were stimulatory whereas PGE2 acted as inhibitor of IL-3 production.

CONCLUSIONS

The serum level of IL-3 is decreased to pregnant women with primary or secondary APS. Low dose aspirin is capable of stimulating IL-3 production in vitro most probably through an elevation of leukotriene production, which may explain its beneficial activity in preventing the manifestations of APS.