Effect of aspirin in pregnant women is dependent on increase in bleeding time

The optimal dosage of aspirin for preventing preeclampsia in high-risk pregnant women: A network meta-analysis of 23 randomized controlled trials

This study aimed to assess the effectiveness and optimal dosage of aspirin in preventing preeclampsia in high-risk pregnant women. Traditional and network meta-analyses were conducted on data from 23 randomized controlled trials involving 10 547 pregnant women. The findings demonstrated that aspirin significantly reduced the incidence of preeclampsia (OR = 0.66, 95%CI [0.58, 0.75]), with the best preventive effect observed at a dosage of 80-100 mg/day (OR = 0.51, 95%CI [0.36, 0.72]). No significant differences were found in the occurrence of postpartum hemorrhage (OR = 1.03, 95%CI [0.79, 1.33]), small for gestational age (OR = 0.83, 95%CI [0.50, 1.35]), placental abruption (OR = 0.96, 95%CI [0.53, 1.73]), and intrauterine growth restriction (OR = 0.63, 95%CI [0.45, 1.86]) between women taking aspirin and those taking placebos. Different doses of aspirin showed a reduction in preeclampsia incidence, but there was no significant difference in efficacy between the dosage groups. Side effects did not significantly differ between placebo and different aspirin dosage groups. SUCRA analysis suggested that 80-100 mg/day may be the optimal dosage, prioritizing both effectiveness and minimizing side effects. Sensitivity analysis confirmed the robustness of the findings. However, improvements are needed in addressing issues like loss to follow-up, reporting bias, and publication bias. In conclusion, a dosage of 80-100 mg/day is recommended for preventing preeclampsia in high-risk pregnant women, although individual circumstances should be considered for optimizing the balance between effectiveness and safety.

Aspirin at 75 to 81 mg Daily for the Prevention of Preterm Pre-Eclampsia: Systematic Review and Meta-Analysis

Background: Aspirin at 150 mg daily, initiated in the 1st trimester of pregnancy, prevents preterm pre-eclampsia. We aimed to estimate whether a dose of 75 to 81 mg daily can help to prevent preterm pre-eclampsia as well. Methods: A systematic search was conducted using multiple databases and meta-analyses of randomized controlled trials (RCTs) that compared aspirin initiated in the first trimester of pregnancy to placebo or no treatment, following the PRISMA guidelines and the Cochrane risk of bias tool. Results: We retrieved 11 RCTs involving 13,981 participants. Five RCTs had a low risk of bias, one at unclear risk, and fiver had a high risk of bias. A pooled analysis demonstrated that doses of 75 to 81 mg of aspirin, compared to a placebo or no treatment, was not associated with a significant reduction in preterm pre-eclampsia (8 studies; 12,391 participants; relative risk, 0.66; 95% confidence interval: 0.27 to 1.62; p = 0.36), but there was a significant heterogeneity across the studies (I2 = 61%, p = 0.02). Conclusion: It cannot be concluded that taking 75 to 81 mg of aspirin daily reduces the risk of preterm pre-eclampsia. However, given the significant heterogeneity between the studies, the true effect that such a dose of aspirin would have on pregnancy outcomes could not be properly estimated.

Comparing aspirin 75 to 81 mg vs 150 to 162 mg for prevention of preterm preeclampsia: systematic review and meta-analysis

OBJECTIVE

This study aimed to compare 2 aspirin dosage regimens for the prevention of preterm preeclampsia (PE): 75 to 81 mg vs 150 to 162 mg taken daily starting in the first trimester of pregnancy.

DATA SOURCES

A systematic search was performed using PubMed, Embase, CINAHL, Web of Science, and Cochrane Central Register of Controlled Trials from January 1985 to April 2023.

STUDY ELIGIBILITY CRITERIA

The inclusion criteria were randomized controlled trials that compared the effect of 2 aspirin dosage regimens during pregnancy for the prevention of PE initiated in the first trimester of pregnancy. The intervention was an aspirin dosage between 150 and 162 mg daily, and the control was an aspirin dosage between 75 and 81 mg daily.

METHODS

Of note, 2 reviewers independently screened all citations, selected studies, and evaluated the risk of bias. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and applied the Cochrane risk of bias tool. The corresponding authors of the included studies were contacted to validate each of the collected results. The primary outcome was the risk of preterm preeclampsia, and the secondary outcomes included term preeclampsia, any preeclampsia regardless of gestational age, and severe preeclampsia. Relative risks with their 95% confidence interval were calculated for each study and pooled for global analysis.

RESULTS

Of note, 4 randomized controlled trials were retrieved involving 552 participants. Moreover, 2 randomized controlled trials were at unclear risk of bias, 1 trial at low risk of bias and 1 trial at high risk of bias, which did not have the information for the primary outcome. The pooled analysis demonstrated that an aspirin dosage of 150 to 162 mg was associated with a significant reduction of preterm preeclampsia, compared with an aspirin dosage of 75 to 81 mg (3 studies; 472 participants; relative risk, 0.34; 95% confidence interval, 0.15-0.79; P=.01; I2=0%). There was no significant effect on the risk of term preeclampsia (3 studies; 472 participants; relative risk, 0.57; 95% confidence interval, 0.12-2.64; P=.48; I2=64%) and all preeclampsia (4 studies; 552 participants; relative risk, 0.42; 95% confidence interval, 0.17-1.05; P=.06; I2=58%), but there was a reduction of severe preeclampsia (3 studies; 472 participantst; RR, 0.23; 95% CI, 0.09-0.62; P=.003; I2=0%).

CONCLUSION

When initiated in the first trimester of pregnancy, an aspirin dosage of 150 to 162 mg daily was associated with a lower risk of preterm PE than an aspirin dosage of 75 to 81 mg daily. However, the lack of large, high-quality studies limited the clinical scope of the current results taken alone.

Aspirin Responsiveness at a Dose of 80 mg and Its Impact on Birth Weight when Used in Twin Pregnancies: The GAP Pilot Randomized Trial

OBJECTIVE

Daily aspirin, started in the first trimester of pregnancy, is commonly used for the prevention of preeclampsia and fetal growth restriction in multiple gestation. However, the optimal dose remains controversial and the evidence for the use of aspirin in multiple pregnancies is scarce. We aimed to estimate the impact of 80 mg of aspirin in twin pregnancies.

STUDY DESIGN

We performed a pilot double-blind randomized trial of women with twin pregnancies recruited between 8 and 14 weeks of gestation. Fifty participants (25 in each group) were randomized to 80 mg of aspirin daily at bedtime or a placebo from randomization until 36 weeks of gestation. Primary and secondary outcomes included the birth weight of live infants, preeclampsia, and aspirin responsiveness evaluated by a platelet aggregation test (platelet function assay [PFA]-100).

RESULTS

All participants were followed until birth, including 48 and 47 live newborns in the aspirin and the placebo groups, respectively. The mean birth weight difference between the aspirin (2,385 ± 529 g) and placebo (2,224 ± 706 g) groups was of 179 g (95% confidence interval [CI]: -172-531 g, p = 0.32). We observed two (8%) cases of preeclampsia in the aspirin group and no case with placebo (p = 0.49). Most importantly,16 of 24 participants who received aspirin (67%; 95% CI: 45-84%) had a normal PFA-100 test at 22 to 23 weeks, including the two cases of preeclampsia, suggesting that the majority of the participants were nonresponsive to 80 mg of aspirin.

CONCLUSION

Our results suggest that the majority of women with twin pregnancies showed a lack of response to a daily dose of 80 mg of aspirin according to the PFA-100 test, compared with the expected 29% of nonresponsiveness in singleton pregnancies. A daily dose of 80 mg of aspirin is likely to be insufficient for the prevention of preeclampsia and other placenta-mediated complications in twin pregnancies.

KEY POINTS

· Most women with twin pregnancies are nonresponsive to a daily dose of 80-mg aspirin.. · An 80 mg aspirin dose is insufficient to prevent placenta-mediated complications in twin pregnancies.. · Randomized trials using 100 to 160 mg of aspirin in twin pregnancies are needed..

Effect of aspirin response signature gene expression on preterm birth and preeclampsia among women with lupus: a pilot study

BACKGROUND

Women with lupus have an increased risk of preeclampsia and preterm birth, and aspirin 81 mg/day is recommended as a preventative measure for preeclampsia. This pilot study quantified the association between a 60-gene aspirin response signature (ARS) gene expression with preterm birth and preeclampsia risk among women with lupus taking aspirin.

METHODS

The analysis included 48 RNA samples from 23 pregnancies in the Duke Autoimmunity Pregnancy Registry. RNA was isolated from peripheral blood, and quantitative polymerase chain reaction was performed for ARS genes. The primary outcome was poor pregnancy outcome (preeclampsia or preterm birth). Gene expression was modeled as a response to presence or absence of a poor pregnancy outcome using linear regression models, stratified by trimester.

RESULTS

Of the 23 pregnancies, nine delivered preterm and four had preeclampsia. Expression of PBX1 and MMD was higher in the second trimester among patients who experienced a poor pregnancy outcome compared to those who did not. However, in a global test of all ARS genes, we identified no association between expression of ARS genes and poor pregnancy outcomes.

CONCLUSION

Our pilot study identified two candidate genes that are reflective of the platelet function response to aspirin. Further work is needed to determine the role of these genes in identifying women with lupus at high risk for preeclampsia and preterm delivery despite aspirin therapy.

The role of aspirin dose on the prevention of preeclampsia and fetal growth restriction: systematic review and meta-analysis

BACKGROUND

Preeclampsia and fetal growth restriction are major causes of perinatal death and handicap in survivors. Randomized clinical trials have reported that the risk of preeclampsia, severe preeclampsia, and fetal growth restriction can be reduced by the prophylactic use of aspirin in high-risk women, but the appropriate dose of the drug to achieve this objective is not certain.

OBJECTIVE

We sought to estimate the impact of aspirin dosage on the prevention of preeclampsia, severe preeclampsia, and fetal growth restriction.

STUDY DESIGN

We performed a systematic review and meta-analysis of randomized controlled trials comparing the effect of daily aspirin or placebo (or no treatment) during pregnancy. We searched MEDLINE, Embase, Web of Science, and Cochrane Central Register of Controlled Trials up to December 2015, and study bibliographies were reviewed. Authors were contacted to obtain additional data when needed. Relative risks for preeclampsia, severe preeclampsia, and fetal growth restriction were calculated with 95% confidence intervals using random-effect models. Dose-response effect was evaluated using meta-regression and reported as adjusted R². Analyses were stratified according to gestational age at initiation of aspirin (≤16 and >16 weeks) and repeated after exclusion of studies at high risk of biases.

RESULTS

In all, 45 randomized controlled trials included a total of 20,909 pregnant women randomized to between 50-150 mg of aspirin daily. When aspirin was initiated at ≤16 weeks, there was a significant reduction and a dose-response effect for the prevention of preeclampsia (relative risk, 0.57; 95% confidence interval, 0.43-0.75; P < .001; R², 44%; P = .036), severe preeclampsia (relative risk, 0.47; 95% confidence interval, 0.26-0.83; P = .009; R², 100%; P = .008), and fetal growth restriction (relative risk, 0.56; 95% confidence interval, 0.44-0.70; P < .001; R², 100%; P = .044) with higher dosages of aspirin being associated with greater reduction of the 3 outcomes. Similar results were observed after the exclusion of studies at high risk of biases. When aspirin was initiated at >16 weeks, there was a smaller reduction of preeclampsia (relative risk, 0.81; 95% confidence interval, 0.66-0.99; P = .04) without relationship with aspirin dosage (R², 0%; P = .941). Aspirin initiated at >16 weeks was not associated with a risk reduction or a dose-response effect for severe preeclampsia (relative risk, 0.85; 95% confidence interval, 0.64-1.14; P = .28; R², 0%; P = .838) and fetal growth restriction (relative risk, 0.95; 95% confidence interval, 0.86-1.05; P = .34; R², not available; P = .563).

CONCLUSION

Prevention of preeclampsia and fetal growth restriction using aspirin in early pregnancy is associated with a dose-response effect. Low-dose aspirin initiated at >16 weeks' gestation has a modest or no impact on the risk of preeclampsia, severe preeclampsia, and fetal growth restriction. Women at high risk for those outcomes should be identified in early pregnancy.

Prediction and prevention of early-onset pre-eclampsia: impact of aspirin after first-trimester screening

OBJECTIVE

To examine the effect of a combination of screening and treatment with low-dose aspirin on the prevalence of early-onset pre-eclampsia (PE).

METHODS

This was a retrospective analysis of two consecutive cohorts of women screened for early PE. The first cohort was observed to determine whether algorithms developed to screen for PE at 11 to 13 + 6 weeks' gestation could be applied to our population. High-risk women in the second cohort were advised on their risk and offered aspirin (150 mg at night), with treatment starting immediately after screening. The prevalence of early PE and the proportion of women with PE delivering at 34-37 weeks' gestation were compared between the cohorts.

RESULTS

In the observational and interventional cohorts, 3066 and 2717 women, respectively, were screened. There were 12 (0.4%) cases of early PE in the observational cohort and one (0.04%) in the interventional cohort (P < 0.01). Among all women with PE delivering before 37 weeks, 25 (0.83%) were in the observational cohort and 10 (0.37%) in the interventional cohort (P = 0.03).

CONCLUSIONS

A strategy of first-trimester screening for early PE coupled with prescription of aspirin to the high-risk group appears to be effective in reducing the prevalence of early PE.

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

Meta-analysis of randomized studies on the use of low-dose aspirin in women at high risk of preeclampsia (PE) has demonstrated that if treatment is initiated at ≤16 weeks' gestation, there is significant reduction in the risk of PE [relative risk (RR) 0.47, 95% confidence interval (CI) 0.36-0.62], fetal growth restriction (RR 0.46, 95% CI 0.33-0.64), preterm birth (RR 0.35, 95% CI 0.22-0.57) and perinatal death (RR 0.41, 95% CI 0.19-0.92), whereas the effect of treatment after 16 weeks is substantially less (RR 0.78, 95% CI 0.61-0.99; RR 0.98, 95% CI 0.88-1.08; RR 0.90, 95% CI 0.83-0.97; and RR 0.93, 95% CI 0.73-1.19, respectively). Moreover, the decrease in the risk of PE from early onset treatment seems to be related to the dose of aspirin, and a dose of >80 mg daily should be considered for optimal benefits.

ASPIRIN ADMINISTRATION FOR PREVENTION OF ADVERSE PREGNANCY OUTCOMES

The prophylactic use of low-dose aspirin for prevention of preeclampsia has been an important research question in obstetrics for the last three decades. In 1979, Crandon and Isherwood observed that nulliparous women who had taken aspirin regularly during pregnancy were less likely to have preeclampsia than women who did not. In 1985, Beaufils et al published the first randomized trial suggesting that 150 mg aspirin and 300 mg dipyridamole daily from 3 months’ gestation onwards decreased the risk of preeclampsia, fetal growth restriction and stillbirth in high-risk women. Subsequently, more than 50 trials have been carried out throughout the world and a meta-analysis of these studies reported that the administration of low-dose aspirin in high-risk pregnancies is associated with a decrease in the rate of preeclampsia by approximately 10%. Consequently, several national professional bodies recommend that high-risk pregnancies should be treated with aspirin (50–150 mg daily).

Prevention of preeclampsia with low-dose aspirin -- a systematic review and meta-analysis of the main randomized controlled trials

The purpose of this paper is to evaluate the effectiveness of low-dose aspirin in the prevention of preeclampsia in low-risk and high-risk women. We identified randomized clinical trials of the use of low-dose aspirin to prevent preeclampsia through the PUBMED search engine, and through the Cochran Library database. Twenty-two studies met our inclusion criteria, and were divided according to the studied population into 2 groups: trials with women at low risk for preeclampsia and trials with women at high risk. Effects were measured through the incidence of preeclampsia in women taking either placebo or aspirin, in studies where the relative risks and the 95% confidence intervals were calculated for both groups. A total of 33,598 women were studied, comprising 5 trials with 16,700 women at low-risk and 17 trials including 16,898 women at high risk. The incidence of preeclampsia was 3.75% (626/17,700), in the low-risk group, 9.01% (1,524/16,898) in the high-risk group, and 6.40% (2,150/33,598) overall. Low-dose aspirin had no statistically significantly effect on the incidence of preeclampsia in the low-risk group (RR = 0.95, 95% CI = 0.81-1.11), but had a small beneficial effect in the high-risk group (RR = 0.87, 95% CI = 0.79-0.96). Therefore, low-dose aspirin is mildly beneficial in terms of reducing the incidence of preeclampsia in women at high risk of developing preeclampsia.

Pathophysiology of preeclampsia: links with implantation disorders

The phenomenon of implantation anchors the embryo into the uterine wall and produces a hemochorial placenta that maintains the pregnancy and fetal growth. Implantation and placentation are intimately linked and cannot be dissociated either in time or in space. Preeclampsia is characterized by hypertension and proteinuria. It is secondary to an anomaly of the invasion of the uterine spiral arteries by extra-villous cytotrophoblast cells, associated with local disruptions of vascular tone, of immunological balance and inflammatory status, and sometimes with genetic predispositions. Preeclampsia is a disease of early pregnancy, a form of incomplete spontaneous abortion, but is expressed late in pregnancy. Aspirin may play a favorable role in implantation which is related to the genesis of preeclampsia and some cases of intra-uterine growth restriction. The most important points in obtaining a preventive effect from low-dose aspirin during the pregnancy are early treatment (before 13 weeks of gestation) and the prescription of a sufficient dose (more than 100 mg per day).

Aspirin (100 mg) used for prevention of pre-eclampsia in nulliparous women: the Essai Régional Aspirine Mère-Enfant study (Part 1)

OBJECTIVE

To reduce the incidence of pre-eclampsia in nulliparous women, in accordance with the suggestion of a recent meta-analysis that low dose aspirin might decrease this incidence by more than half if used early enough in and at a sufficient dose during pregnancy (more than 75 mg).

DESIGN

Multicentre randomised double-blinded placebo-controlled trial.

SETTING

Twenty eight centres in Northern of France and one in Belgium.

POPULATION

Three thousand and two hundred ninety-four nulliparous women recruited between 14 and 20 weeks.

METHODS

Randomisation to either 100 mg aspirin or placebo daily from inclusion through 34 weeks.

MAIN OUTCOME MEASURES

Preeclampsia was defined as hypertension (> or =140 and or 90 mmHg) associated with proteinuria (> or =0.5 g/L).

RESULTS

The aspirin (n = 1644) and placebo (n = 1650) groups did not differ significantly in the mothers' incidence of pre-eclampsia (28 of 1632 [1.7%] vs 26 of 1637 [1.6%]; relative risk, RR, 1.08, 95% CI 0.64-1.83), hypertension, HELLP syndrome or placental abruption, or in the children's incidence of perinatal deaths or birthweight below the 10th centile. The incidence of babies with birthweight below the third centile was significantly higher in the aspirin group, with no explanation. The incidence of maternal side effects was higher in the aspirin group, principally because of a significantly higher rate of haemorrhage.

CONCLUSIONS

Aspirin at a dose of 100 mg does not reduce the incidence of pre-eclampsia in nulliparous women. Aspirin (100 mg) is associated with an increase in bleeding complications.

Randomised comparison of uterine artery Doppler and aspirin (100 mg) with placebo in nulliparous women: the Essai Régional Aspirine Mère-Enfant study (Part 2)

OBJECTIVE

To assess the effectiveness of a pre-eclampsia prevention strategy based on routine uterine artery Doppler flow velocity waveform examination during the second trimester of pregnancy, followed by a prescription for 100 mg aspirin in the case of abnormal Doppler findings.

DESIGN

Multicentre randomised controlled trial.

SETTING

Eleven centres in the north of France and one in Belgium.

POPULATION

One thousand and eight hundred and fifty-three nulliparous women recruited between 14 and 20 weeks of gestation.

METHODS

Randomisation either to undergo a uterine Doppler examination between 22 and 24 week of gestation or to take a placebo. Women with abnormal Doppler waveforms received 100 mg of aspirin daily from Doppler examination through 36 weeks.

MAIN OUTCOME MEASURES

Pre-eclampsia was defined as hypertension (> or = 140 and/or 90 mmHg) associated with proteinuria (> or = 0.5 g/L).

RESULTS

One thousand two hundred and fifty-three women (67%) were randomised into the systematic Doppler group and 617 (33%) into the placebo group. Of the 1175 patients in the Doppler group who underwent this examination, 239 (20.3%) had abnormal uterine artery Doppler and received a prescription for aspirin. Despite the aspirin prescription, the frequency of pre-eclampsia did not differ between the systematic Doppler group and the placebo group (28 of 1237 [2.3%] vs 9 of 616 [1.5%]; RR = 1.55, 95% CI 0.7-3.3). Furthermore, the groups did not differ in the frequency of children who were very small for their gestational age (< or =3rd centile) or for perinatal deaths. Compared with patients with normal Doppler findings, those with abnormal Doppler were at high risk of pre-eclampsia (RR = 5.5, 95% CI 2.5-12.2) and of giving birth to a small-for-gestational-age child (RR = 3.6, 95% CI 1.6-8.1).

CONCLUSION

Despite its sensitivity in screening for pre-eclampsia, routine uterine Doppler in the second trimester cannot be recommended for nulliparous patients.

Doppler sonography of uterine arteries at 20-23 weeks: risk assessment of adverse pregnancy outcome by quantification of impedance and notch

OBJECTIVE

To assess the diagnostic value of Doppler sonography of the uterine arteries (DSUA) at 20-23 gestational weeks as screening procedure in a low risk population.

PATIENTS AND METHODS

The study group consisted of 7508 singleton low-risk pregnancies. Doppler sonography of both uterine arteries was performed as routine part of anomaly scan. Impedance of both uterine arteries was registered using the mean PI of the two uterine arteries. In case of notch, "Notch-Index" was defined as (C-D)/C with D = post-systolic nadir and C = following zenith of the waveform. Outcome variables were placental abruption, pre-eclampsia, intrauterine growth retardation, intrauterine/neonatal death and preterm delivery before 32 completed gestational weeks. To discriminate normal and pathological waveform, incidence of adverse pregnancy outcome was related to four different definitions of pathological waveform. To describe the severity of impairment of perfusion, the frequency of adverse pregnancy outcome was related to different classes of impedance.

RESULTS

To find a simple discrimination between normal and pathological uterine perfusion, best diagnostic performance was reached by a definition using a combination of high impedance and notch (no notch and mean PI > P'95 or unilateral notch and mean PI > P'90 or bilateral notch and mean PI > P'50). The prevalence of notch in nulliparae (8.5%) was higher than in parae (4.7%) and decreased with increasing gestational age (20 weeks: 8.6%-23 weeks: 5.4%). We found a clear relation between elevation of impedance, depth of notch and frequency of adverse pregnancy outcome with a frequency of complications varying from 3.2% (mean PI < or = 0.8, mean NI = 0.1) to 38.4% (mean PI > 2.0, mean NI > 0.1).

CONCLUSION

Doppler sonography of the uterine arteries at 20-23 weeks has the capacity to predict at least a part of severe forms of adverse pregnancy outcome and to assess the probability of complications by quantification of the impairment of the uterine blood flow.

Administration time-dependent influence of aspirin on blood pressure in pregnant women

This study prospectively investigates the potential influence of low-dose aspirin on blood pressure in pregnant women who were at a higher risk of developing preeclampsia than that of the general obstetric population and who received aspirin at different times of the day according to their rest-activity cycle. A double-blind, randomized, controlled trial was conducted in 341 pregnant women (181 primipara) randomly assigned to 1 of 6 possible groups according to treatment (either placebo or aspirin, 100 mg/day, starting at 12 to 16 weeks of gestation) and the time of treatment: on awakening (time 1), 8 hours after awakening (time 2), or before bedtime (time 3). Blood pressure was automatically monitored for 48 consecutive hours every 4 weeks from the day of recruitment until delivery, as well as at puerperium. There was no effect of aspirin on blood pressure at time 1 (compared with placebo). A blood pressure reduction was highly statistically significant when aspirin was given at time 2 and, to a greater extent, at time 3 (mean reductions of 9.7/6.5 mm Hg in 24-hour mean for systolic/diastolic blood pressure at the time of delivery as compared with placebo given at bedtime). Differences in blood pressure among women receiving aspirin at different circadian times disappeared at puerperium (P>0.096). Results indicate a highly significant effect of aspirin on blood pressure that is markedly dependent on the time of aspirin administration with respect to the rest-activity cycle. Timed use of aspirin at low dose effectively contributes to blood pressure control in women at high risk for preeclampsia.

Effects of PEG-hirudin in clotting parameters and platelet function and its interaction with aspirin in healthy volunteers

The purpose of this study was to investigate the pharmacodynamics of PEG-Hirudin and its potential interactions with acetylsalicylic acid (ASA 325 mg once daily from days 1-3). In a randomized, 2-way cross-over trial, 6 healthy volunteers received PEG-Hirudin (i.v. bolus of 0.2 mg/kg + 0.02 mg/kg/h for 24 hours) and placebo (i.v. bolus + 24-hour infusion). In a further randomized, 3-way cross-over trial another 9 healthy volunteers received ASA (325 mg) or oral placebo from days 1 to 3 and PEG-Hirudin (0.2 mg/kg + 0.02 mg/kg/h for 24 h) or i.v. placebo on day 3. Assessments included bleeding time (BT), collagen (1 microgram ml(-1))-induced platelet aggregation (CIPA), platelet adhesion, ecarin clotting time (ECT), activated clotting time (ACT), plasma anti-factor IIa activity (aIIa), and activated partial thromboplastin time (aPTT). Ten minutes after the PEG-Hirudin injection/starting the infusion, mean plasma concentration was 3.1 microgram/mL and aPTT, ECT, and ACT were prolonged up to 80, 309, and 233 seconds, respectively. During the last 8 hours of the 24-hour infusion mean PEG-Hirudin plasma concentration was 1.3 microgram/mL. In the interaction study, ASA significantly inhibited CIPA. At 6 hours after administration, on day 3 mean BT was 6.5 minutes after PEG-Hirudin alone, 18.2 minutes after ASA alone, and 32.9 minutes after combined administration of ASA and PEG-Hirudin. PEG-Hirudin (0.2 mg/kg + 0.02 mg/kg/h for 24 hours) administered alone or together with 325 mg ASA proved to be safe in healthy volunteers. Combined use of PEG-Hirudin and ASA significantly increased the mean bleeding time compared to ASA or PEG-Hirudin monodrug administration. None of the clotting parameters or platelet function tests correlated with the prolongation of the bleeding time.

[Pregnancy-related hypertension]

PURPOSE

Hypertension occurs in 10 to 15 p cent of pregnancies. Among them, 10 to 20% also have proteinuria. This situation defines preeclampsia, and involves a serious threat on fetal and even maternal prognosis. Presence of the hepatic (HELLP) syndrome still severely worsens the prognosis.

CURRENT KNOWLEDGE AND KEY POINTS

Pathophysiology of preeclampsia is based on a very early abnormality of placentation, leading to insufficient blood supply to the feto-placental unit. At the maternal level, the main consequence of placental ischemia is generalized endothelial dysfunction, responsible for systemic vasoconstriction and clotting abnormalities. In such a context, lowering blood pressure with drugs is quite inefficient, or even harmful. The prognosis of this disease is mainly related to the pertinence of obstetrical management.

FUTURE PROSPECTS AND PROJECTS

An early preventive strategy is the most logical approach of preeclampsia, its modalities remain under discussion.

Safe prescribing practices in pregnancy and lactation

Midwives and other health care providers face a dilemma when a pregnant woman develops a condition that usually is treated with a pharmacologic agent. Understanding of basic teratology associated with drugs as well as the FDA categorization of agents can assist professionals in recognizing which pharmaceuticals should be used or avoided. In addition to reviewing teratology, this article addresses the use of common drugs for the treatment of upper respiratory conditions, minor pain, gastrointestinal problems, psychiatric illnesses, and neurologic disorders. In each category, current evidence is presented pertaining to which agents should be recommended for pregnant women.

Primary, secondary, and tertiary prevention of pre-eclampsia

Pre-eclampsia remains one of the major obstetrical problems in less-developed countries. The causes of this condition are still unknown, thus effective primary prevention is not possible at this stage. Research in the past decade has identified some major risk factors for pre-eclampsia, and manipulation of these factors might result in a decrease in its frequency. In the early 1990s aspirin was thought to be the wonder drug in secondary prevention of pre-eclampsia. Results of large trials have shown that this is not the case: if there is an indication for using aspirin it is in the patient at a very high risk of developing severe early-onset disease. The calcium story followed a more or less similar pattern, with the difference that existing evidence shows that women with a low dietary calcium intake are likely to benefit from calcium supplementation. Proper antenatal care and timed delivery are of utmost importance in tertiary prevention of pre-eclampsia. There is evidence to suggest that the intrinsic direct effect of moderate degrees of maternal hypertension is beneficial to the fetus. Severe hypertension needs treatment. If antihypertensive is indicated, there is no clear choice of a drug. Hydralazine should no longer be thought of as the primary drug, most studies show a preference for calcium channel blockers.

Salicylate and cocaine: interactive toxicity during chicken mid-embryogenesis

Increased free radical production, due to ischemia and reperfusion, has been postulated as a cause of cocaine's (COC) developmental toxicity. Salicylate reacts with hydroxyl free radicals (*OH) to form stable, quantifiable reaction products, which can be measured with high-pressure liquid chromatography (HPLC). To determine if chicken embryos' brains and hearts were exposed to increased *OH concentrations after injection of COC, an injection of a nontoxic dose of sodium salicylate (NaSAL, 100 mg/kg egg, or 5 mg/egg), followed by 5 injections of COC (13.5 mg/kg or 0.675 mg/egg, every 1.5 h), was administered to eggs containing embryos on the 12th day of embryogenesis (E12). In addition to finding increased *OH concentrations in E12 embryonic hearts and brains, we observed that the developmental toxicity of COC, manifest as vascular disruption (hemorrhage) and lethality, was enhanced by NaSAL injection. These results confirm and extend results of similar experiments performed upon older embryos (E18), and indicate that increased &z.rad;OH concentration in embryonic tissues after COC exposure and toxic interactions of COC and NaSAL can also occur at an earlier stage of development. The results are discussed in light of possible exposure of human fetuses to both COC and salicylates, since COC-abusing pregnant women can be misdiagnosed with pre-eclampsia and aspirin is used to treat this syndrome.

[Aspirin and prevention of pre-eclampsia]

Aspirin is used in pregnant women in order to obviate the imbalance of prostanoids caused by a defective placentation, and also to counteract the widespread thrombotic tendency related to endothelial dysfunction. After a series of controlled trials which showed a very consistent effect of aspirin t prevent preeclampsia and fetal growth retardation, several recent large trials have cast the doubt, and even unbelief. Their results are analyzed in an explicative way. Discrepancies seem largely related to either studying very low-risk populations, or strong differences in aspirin dosage and/or term of introduction. In the last few years, several works have shown the critical importance of an early treatment, and also of a measurable biologic effect, which requires larger dosages than those used in the most recent trials. The doubt largely remains as for the adequate indications of this treatment. New data in the physiology of placentation suggest that it would be logical to give aspirin as early as the first wave of throphoblastic invasion. The effect of so an early treatment need to be evaluated. The search for early markers should be pursued. The combination of aspirin and heparin is under investigation. Finally, other ways of prevention, such as anti-oxidants, are also being studied.

Hypertension in pregnancy: new recommendations for management

Hypertension in pregnancy is a frequent complication that has substantial adverse perinatal outcomes. Hypertension may be preexisting (chronic) essential or secondary hypertension; a second entity is pregnancy induced (gestational hypertension, preeclampsia). Recent advances have identified newer markers for pregnancy hypertension: several potential candidate genes may explain the apparent family inheritance of preeclampsia, and some thrombophilic markers have been associated with the condition. Management options for mild to moderate hypertension include a short hospital stay to exclude ongoing severe hypertension and to ascertain fetal well-being. Outpatient care with appropriate maternal and fetal surveillance, including umbilical artery doppler velocimetry, is recommended for better perinatal outcomes. Acute care for severe hypertension includes the use of magnesium sulfate to prevent eclampsia and antihypertensive medication. Expeditious delivery is recommended when the maternal or fetal states cannot be stabilized. Follow-up after delivery allows the uncovering of any other coexisting hypertensive or cardiovascular disorder.