Low molecular weight heparin treatment during subsequent pregnancies of women with inherited thrombophilia and previous severe pregnancy complications

Low molecular weight heparin and pregnancy outcomes in women with inherited thrombophilia: A systematic review and meta-analysis

AIM

To determine whether the use of low molecular weight heparin (LMWH) improves the pregnancy outcomes in women with inherited thrombophilia by conducting a meta-analysis of randomized controlled trials and observational studies.

METHODS

A systematic literature search of several databases was conducted through September 19, 2020 to identify relevant studies. The outcomes of interest included live birth and adverse pregnancy outcomes (APOs). The overall risk estimates were pooled using random-effects meta-analysis.

RESULTS

Ten randomized controlled trials and 12 cohort studies were included. In the meta-analyses of randomized controlled trials, the effectiveness of LMWH-treatment was found to be statistically significant in decreasing the risk of APOs (risk ratio [RR] = 0.76; 95% confidence interval [CI]: 0.61-0.95; p = 0.020), rather than in increasing the rate of live birth (RR = 1.12; 95% CI: 0.93-1.34; p = 0.230). In the meta-analyses of cohort studies, results showed that the use of LMWH was associated with a significantly higher proportion of live birth (RR = 1.86; 95% CI: 1.09-3.19; p = 0.020) as well as a significantly lower ratio of APOs (RR = 0.46; 95% CI: 0.31-0.69; p < 0.001) in women with inherited thrombophilia.

CONCLUSIONS

The use of LMWH may have a potentially beneficial effect on reducing the risk of APOs and even increasing the live birth rate in women with inherited thrombophilia. Further well-designed clinical trials with large samples are needed to address the role of LMWH in improving pregnancy outcomes among pregnant women with inherited thrombophilia.

Pharmacological Interventions for the Prevention of Fetal Growth Restriction: A Systematic Review and Network Meta-Analysis

The prevention of fetal growth restriction (FGR) is challenging in clinical practice. To date, no meta-analysis summarized evidence on the relative benefits and harms of pharmacological interventions for FGR prevention. We performed a systematic review and network meta-analysis (NetMA), searching PubMed, Embase, Cochrane Library, and ClinicalTrials.gov from inception until November 2019. We included clinical trials and observational studies on singleton gestating women evaluating antiplatelet, anticoagulant, or other treatments, compared between each other or with controls (placebo or no treatment), and considering the pregnancy outcome FGR (primary outcome of the NetMA). Secondary efficacy outcomes included preterm birth, placental abruption, and fetal or neonatal death. Safety outcomes included bleeding and thrombocytopenia. Network meta-analyses using a frequentist framework were conducted to derive odds ratios (ORs) and 95% confidence intervals (CIs). Of 18,780 citations, we included 30 studies on 4,326 patients. Low molecular weight heparin (LMWH), alone or associated with low-dose aspirin (LDA), appeared more efficacious than controls in preventing FGR (OR 2.00, 95% CI 1.27-3.16 and OR 2.67, 95% CI 1.21-5.89 for controls vs. LMWH and LDA + LMWH, respectively). No difference between active treatments emerged in terms of FGR prevention, but estimates for treatments other than LMWH +/- LDA were imprecise. Only the confidence in the evidence regarding LMWH vs. controls was judged as moderate, according to the Confidence in Network Meta-Analysis framework. No treatment was associated with an increased risk of bleeding, although estimates were precise enough only for LMWH. These results should inform clinicians on the benefits of active pharmacological prophylaxis for FGR prevention.

Therapeutic Implications of Inherited Thrombophilia in Pregnancy

BACKGROUND

Inherited (hereditary) thrombophilia is a genetic disorder that affects coagulation, being responsible for more than 60% of idiopathic (spontaneous or unprovoked) thromboembolic events. Association of inherited thrombophilia with pregnancy increases the risk of thromboembolic disease, and it may be related to many complications, such as preeclampsia, recurrent miscarriage intrauterine growth restriction, early detachment of placenta, and prematurity.

AREAS OF UNCERTAINTY

Interpretation of a positive test for thrombophilia in pregnant women is difficult because they have many natural changes in the coagulation system. Genetic diagnosis of thrombophilia, after a thrombotic event or during a pregnancy complication, has a major importance, not only to define its etiology but also to determine the duration of anticoagulant treatment and risk stratification for prophylaxis treatment.

DATA SOURCES

Literature search was performed using electronic database (PubMed) between April 1981 and November 2018. We used different keywords and MeSH terms to generate the most relevant results related to the inherited thrombophilia and its impact on pregnancy.

RESULTS

Screening for inherited thrombophilia in young women is recommended in case of personal history of venous thromboembolism, first-degree relatives with a history of high-risk thrombophilia, or personal history of second-trimester miscarriage. Decision to recommend thromboprophylaxis with anticoagulant treatment in pregnant women with inherited thrombophilia is determined by history of venous thromboembolism, type and associated risk of inherited thrombophilia, and presence of additional risk factors. Low-molecular-weight heparins are the preferred agents for prophylaxis in pregnancy, while the doses vary depending on thrombophilia type, personal history, and associated risk factors.

CONCLUSIONS

Association between 2 procoagulant conditions, inherited thrombophilia and pregnancy, has an important impact for the mother and fetus. This review will summarize the impact of each inherited prothrombotic factor on cardiovascular and pregnancy outcomes and will discuss the role of anticoagulation treatment for women diagnosed with inherited thrombophilia.

Aspirin, low molecular weight heparin, or both in preventing pregnancy complications in women with recurrent pregnancy loss and factor V Leiden mutation

Objective: The aim of this study was to compare the effects of low molecular weight heparin (LMWH), LMWH plus low dose aspirin, or low dose aspirin only on pregnancy outcomes in recurrent pregnancy loss (RPL) patients with factor V Leiden mutation (FVLM).Materials and methods: A total of 2764 RPL patients were evaluated in for the etiology of RPL. Mutations in factor V Leiden homozygous and heterozygous were determined. Subsequently, 196 of these patients were diagnosed with FVLM and included in the study; of these 174 completed the study. At the sixth week of gestation of subsequent pregnancy participants were randomly distributed into three groups. Group A (n = 61) was composed of patients with an oral dose of 100 mg aspirin daily, Group B (n = 59) consisted of patients using 40 mg enoxaparin and 100 mg orally aspirin daily, and Group C (n = 54) included patients using 40 mg enoxaparin daily during pregnancy.Results: Among the 174 patients who completed the study, the live birth and miscarriage rates were similar for the three groups (p = .843 and p = .694, respectively). There was no significant difference among the groups in rates of eclampsia, placental abruption, intrauterine fetal growth restriction and gestational diabetes mellitus. The number of preeclamptic patients was significantly higher in Group A than Groups B and C. The levels of preterm birth was significantly higher in Group A than Groups B and C.Conclusion: Using low dose aspirin, LMWH plus aspirin, or LMWH alone yielded comparable live birth rates in RPL patients with FVLM. However, LMWH decreased the risk of preeclampsia in this group of patients. LMWH might therefore have a preventive role regarding preeclampsia.

Comparison of 2 approaches in management of pregnant women with inherited trombophilias: Prospective analytical cohort study

Previous adverse pregnancy outcomes (APO) in women with hereditary thrombophilia have emerged as new indications for prophylactic use of low-molecular-weight heparin (LMWH) during pregnancy. Recent meta-analysis conducted to establish if LMWH may prevent recurrent placenta-mediated pregnancy complications point to important therapeutic effect but these findings are absolutely not universal. Furthermore, previous studies regarding LMWH prophylaxis for APO in women with inherited thrombophilia were performed in high risk patients with previous adverse health outcomes in medical, family and/or obstetric history. Therefore, the aim of this study was to investigate the effects of LMWH prophylaxis on pregnancy outcomes in women with inherited thrombophilias regardless of the presence of previous adverse health outcomes in medical, family, and obstetric history.Prospective analytical cohort study included all referred women with inherited thrombophilia between 11 and 15 weeks of gestation and followed-up to delivery. Patients were allocated in group with LWMH prophylaxis (study group) and control group without LWMH prophylaxis. The groups were compared for laboratory parameters and Doppler flows of umbilical artery at 28 to 30th, 32nd to 34th and 36th to 38th gestational weeks (gw), and for obstetric and perinatal outcomes.The study group included 221 women and control group included 137 women. Mean resistance index of the umbilical artery Ri in 28 to 30, 32 to 34, and 36 to 38 gw were significantly higher in the control group compared to study group (0.71 ± 0.02 vs 0.69 ± 0.02; 0.67 ± 0.03 vs 0.64 ± 0.02; and 0.67 ± 0.05 vs 0.54 ± 0.08, respectively). Intrauterine fetal death (IUFD) and miscarriages were statistically significantly more frequent in control group compared to the patients in study (P < .001). The frequencies of fetal growth restriction (FGR) and APO were significantly higher in the control group compared to the study group (P = .008 and P < .001, respectively). In a multivariate regression model with APO as a dependent variable, only Ri was detected as a significant protective factor for APO, after adjusting for age and LMWH prophylaxis (P < .001).We have demonstrated better perinatal outcomes in women with LMWH prophylaxis for APO compared to untreated women.

Genetic risk assessment of thrombophilia in patients with adverse obstetric outcomes

OBJECTIVES

To investigate the incidence of inherited thrombophilias in patients with adverse obstetric outcomes and to compare detection rates of thrombophilias between standard blood tests and a novel genetic test.

METHODS

This is a case-control prospective study performed in Hospital Sant Joan de Déu in Barcelona, Spain. Cases had a history of intrauterine growth restriction requiring delivery before 34 weeks gestation, placental abruption before 34 weeks gestation, or severe preeclampsia. Controls had at least two normal, spontaneously conceived pregnancies at term, without complications or no underlying medical disease. At least 3 months after delivery, all case and control women underwent blood collection for standard blood tests for thrombophilias and saliva collection for the genetic test, which enables the diagnosis of 12 hereditary thrombophilias by analyzing genetic variants affecting different points of the blood coagulation cascade.

RESULTS

The study included 33 cases and 41 controls. There were no statistically significant differences between cases and controls in the standard blood tests for thrombophilias in plasma or the TiC test for genetic variables. One clinical-genetic model was generated using variables with the lowest P values: ABO, body mass index, C_rs5985, C_rs6025, and protein S. This model exhibited good prediction capacity, with an area under the curve of almost 0.7 (P <0.05), sensitivity of almost 67%, and specificity of 70%.

CONCLUSION

Although some association may exist between hypercoagulability and pregnancy outcomes, no significant direct correlation was observed between adverse obstetric outcomes and inherited thrombophilias when analyzed using either standard blood tests or the genetic test. Future studies with a larger sample size are required to create a clinical-genetic model that better discriminates women with a history of adverse pregnancy outcomes and an increased risk of poor outcomes in subsequent pregnancies.

Prevention of preeclampsia in high-risk patients with low-molecular-weight heparin: a meta-analysis

Objective: To assess the secondary preventive effect of low-molecular-weight heparin (LMWH) on pregnant women with prior early-onset or severe preeclampsia (PE).Methods: A systematic literature search of several databases was conducted for randomized controlled trials comparing LMWH with either aspirin or no treatment in pregnant women at a high risk of placental-mediated pregnancy complications (PMPCs). Odds ratios and associated 95% confidence intervals (CI) and weighted mean differences and 95% CI were calculated.Results: Seven studies including 1035 patients were evaluated. These studies showed a risk reduction in composite PMPC outcome (relative risk (RR) 0.635 (95% CI: 0.436-0.925); p=.018), PE (RR 0.522 (95% CI: 0.334-0.815); p=.004), a small-for-gestational-age neonate (RR 0.622 (95% CI: 0.440-0.880); p=.007), and an increase in gestational length (SMD 0.312 (95% CI: 0.017-0.607); p=.038) and neonatal weight (SMD 0.428 (95% CI: 0.066-0.791); p=.020).Conclusions: LMWH has a secondary preventive effect on early or severe PE and improves neonatal outcomes. In the future, additional large multicenter studies will need to focus on high-risk PE groups by more accurate screening to obtain more information before clinical application.

The Impact of Inherited Thrombophilia Types and Low Molecular Weight Heparin Treatment on Pregnancy Complications in Women with Previous Adverse Outcome

PURPOSE

To assess the distribution of births and spontaneous abortions, first-trimester abortion (FTA) and mid-trimester abortion (MTA), in untreated (n=128) and low molecular weight heparin (LMWH) treated pregnancies (n=50) of the same women with inherited thrombophilias and adverse pregnancy outcome (APO) in previous pregnancies. We particularly investigated the impact of LMWH on reducing the pregnancy complications in two thrombophilia types, "Conventional" and "Novel".

MATERIALS AND METHODS

50 women with inherited thrombophilia (26 Conventional and 24 Novel) and APO in previous pregnancies were included in the study. Conventional group included factor V Leiden (FVL), prothrombin G20210A (PT) mutations and antithrombin (AT), protein S (PS), and protein C (PC) deficiency, while the Novel group included methylentetrahydrofolate-reductase (MTHFR), plasminogen activator inhibitor-1 (PAI-1), and angiotensin converting enzyme (ACE) polymorphism. APO was defined as one of the following: preterm birth (PTB), fetal growth restriction (FGR), preeclampsia (PE), intrauterine fetal death (IUFD), placental abruption (PA) and deep venous thrombosis (DVT).

RESULTS

There was no difference in distribution of births and spontaneous abortions between Conventional and Novel thrombophilia in untreated pregnancies (χ²=2.7; p=0.100) and LMWH treated pregnancies (χ²=0.442; p=0.506). In untreaed pregnancies thrombophilia type did not have any impact on the frequency of FTA and MTA (χ²=0.14; p=0.711). In birth-ended pregnancies LMWH treatement reduced the incidence of IUFD (p=0.011) in Conventional and FGR, IUFD, and PTB in Novel thrombophilia group.

CONCLUSION

The equal impact of two thrombophilia types on the pregnancy outcomes and a more favorable effect of LMWH therapy on pregnancy complications in Novel thrombophilia group point the need for Novel thrombophilias screening and the future studies on this issue should be recommended.

SOMANZ guidelines for the management of hypertensive disorders of pregnancy 2014

This guideline is an evidence based, practical clinical approach to the management of Hypertensive Disorders of Pregnancy. Since the previous SOMANZ guideline published in 2008, there has been significant international progress towards harmonisation of definitions in relation to both the diagnosis and management of preeclampsia and gestational hypertension. This reflects increasing knowledge of the pathophysiology of these conditions, as well as their clinical manifestations. In addition, the guideline includes the management of chronic hypertension in pregnancy, an approach to screening, advice regarding prevention of hypertensive disorders of pregnancy, and discussion of recurrence risks and long term risk to maternal health. The literature reviewed included the previous SOMANZ Hypertensive Disorders of Pregnancy guideline from 2008 and its reference list, plus all other published National and International Guidelines on this subject. Medline, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Registry of Controlled Trials (CCRCT), National Institute for Health and Care Excellence (NICE) Evidence Search, and Database of Abstracts and Reviews of Effects (DARE) were searched for literature published between January 2007 and March, 2014.

IFPA Gábor Than Award Lecture: Recognition of placental failure is key to saving babies' lives

In high-income countries, placental failure is implicated in up to 65% of cases of stillbirth. Placental failure describes the situation where the placenta cannot meet the fetus' needs and may be the end-result of a variety of underlying pathological processes evident in the placental disc, membranes and umbilical cord. These include lesions with genetic, environmental, infectious, inflammatory, mechanical, metabolic, traumatic or vascular origin. Investigation of placental tissue from stillbirths and from pregnancies at an increased risk of stillbirth has demonstrated changes in macroscopic and microscopic structure which are themselves related to abnormal placental function. A better understanding and identification of placental failure may improve the management of pregnancy complications and of pregnancies after stillbirth (which have a 5-fold increased risk of stillbirth). The majority of current antenatal tests focus on the fetus and its response to the intrauterine environment; few of these investigations reduce stillbirths in low-risk pregnancies. However, some currently used investigations reflect placental development, structure and vascular function, while other investigations employed in clinical research settings such as the evaluation of placental structure and shape have a good predictive value for adverse fetal outcome. In addition, recent studies suggest that biomarkers of placental inflammation and deteriorating placental function can be detected in maternal blood suggesting that holistic evaluation of placental structure and function is possible. We anticipate that development of reliable tests of placental structure and function, coupled to assessment of fetal wellbeing offer a new opportunity to identify pregnancies at risk of stillbirth and to direct novel therapeutic strategies to prevent it.

Placental lesions associated with acute atherosis

OBJECTIVE

Acute atherosis is a lesion of the spiral arteries characterized by fibrinoid necrosis of the vessel wall, an accumulation of fat-containing macrophages, and a mononuclear perivascular infiltrate, which can be found in patients with preeclampsia, fetal death, small-for-gestational age, spontaneous preterm labor/premature prelabor rupture of membrane, and spontaneous mid-trimester abortion. This lesion is thought to decrease blood flow to the intervillous space which may lead to other vascular lesions of the placenta. The objective of this study was to test whether there is an association between acute atherosis and placental lesions that are consistent with maternal vascular underperfusion (MVU), amniotic fluid infection (AFI), fetal vascular thrombo-occlusive disease (FVTOD) or chronic inflammation.

MATERIAL AND METHODS

A retrospective cohort study of pregnant women who delivered between July 1998 and July 2014 at Hutzel Women's Hospital/Detroit Medical Center was conducted examine 16 457 placentas. The frequency of placenta lesions (diagnosed using the criteria of the Perinatal Section of the Society for Pediatric Pathology) was compared between pregnancies with and without acute atherosis.

RESULTS

Among 16 457 women who were enrolled, 10.2% (1671/16 457) were excluded, leaving 14 786 women who contributed data for analysis. Among them, the prevalence of acute atherosis was 2.2% (326/14 786). Women with acute atherosis were more than six times as likely as those without to have placental lesions consistent with maternal underperfusion (adjusted odds ratio - aOR: 6.7; 95% CI 5.2-8.6). To a lesser degree, acute atherosis was also associated with greater risks of having either lesions consistent with FVTOD (aOR 1.7; 95% CI 1.2-2.3) or chronic chorioamnionitis (aOR 1.9; 95% CI 1.3-3), but not with other chronic inflammatory lesions, after adjusting for gestational age at delivery. In contrast, women with acute atherosis were 60% less likely to have lesions consistent with AFI, adjusting for gestational age at delivery (aOR 0.4; 95% CI 0.3-0.5).

CONCLUSIONS

Acute atherosis is associated with increased risks of having placental lesions consistent with MVU, and to a lesser extent, chronic chorioamnionitis and those consistent with FVTOD.

[Pharmacological thromboprophylaxis in gynecology and obstetrics]

Venous thromboembolism (VTE) is associated with high morbidity and mortality. Therefore, effective methods for safe thromboprophylaxis remain an ongoing challenge in daily clinical practice. This is especially true for pregnant women and patients with gynaecological malignancies. Low-molecular weight heparins continue to be agents of choice for pharmacological thromboprophylaxis postoperatively, in pregnant patients at risk, and during the puerperium. However, these drugs can cause bleeds or heparin-induced thrombocytopenia (type II). Based on recent revisions of corresponding guidelines, this article provides an overview of the current state of pharmacological thromboprophylaxis and discusses prevailing problems and unresolved issues.

Low molecular weight heparin treatment and impact of inherited thrombophilia type in pregnancies with previous adverse outcome

OBJECTIVE

To assess the impact of low molecular weight heparin (LMWH) treatment in 50 pregnancies of women with inherited thrombophilia and adverse pregnancy outcome (APO) in previous untreated pregnancies. The impact of "Conventional" (FVL, PT, AT, PC, PS) and "Novel" (MTHFR, PAI-1, ACE) thrombophilias on APO was investigated.

METHODS

The primary outcomes (PO) were: early and late pregnancy loss (EPL, LPL), preterm birth (PTB) or term birth (TB) compared to the last untreated pregnancies of the same women. Secondary outcomes (SO) were APO in LMWH treated and last untreated pregnancies ended with birth. PO and SO were compared in relation to the thrombophilia type.

RESULTS

LMWH decreased EPL and LPL rate and improved TB rate compared with last untreated pregnancies (p < 0.001). There were less PTB (p = 0.019) and no cases of intrauterine fetal death (IUFD) (p = 0.0019) in LWMH-treated pregnancies. The division to Conventional and Novel thrombophilias showed: (a) difference between pregnancy losses and birth rate (p = 0.0069) and (b) no difference in the prevalence of APO in untreated pregnancies ended with birth.

CONCLUSIONS

LMWH treatment improves pregnancy outcome in women with inherited thrombophilia and APO in previous pregnancies. Novel thrombophilias have the equal impact on the pregnancy outcome compared to the Conventional thrombophilias.

Overview of low molecular weight heparin for preventative treatment of adverse obstetric outcomes related to abnormal placentation

Different proportions of cases of preterm and severe preeclampsia, placental abruption, fetal growth restriction, and fetal death share a common causal pathway of abnormal placental implantation. Documentation of an association between the risk of such adverse pregnancy outcomes (APOs) and inherited thrombophilias prompted initial studies to evaluate the benefit of anticoagulants for the prevention of recurrences both in patients with and without inherited thrombophilias. Prenatal administration of low molecular weight heparin (LMWH) has been evaluated in case control, cohort and randomized clinical trials. The evidence suggests a benefit of LMWH in the reduction of recurrences of APOs, with a number needed to treat of 6 (95% confidence interval: 4-10) to prevent one case of recurrent APOs. Such benefit is independent of the presence of inherited thrombophilias or the administration of low dose aspirin. Further studies are needed to establish the optimal duration for the prophylaxis, to better delineate the mechanism of action of LMWH and to explore the role, if any, of maternal serum markers and uterine artery Doppler findings in the modulation of the LMWH prophylaxis.

Low-molecular weight heparin increases circulating sFlt-1 levels and enhances urinary elimination

Rationale

Preeclampsia is a devastating medical complication of pregnancy which leads to maternal and fetal morbidity and mortality. While the etiology of preeclampsia is unclear, human and animal studies suggest that excessive circulating levels of soluble fms-like tyrosine-kinase-1 (sFlt-1), an alternatively spliced variant of VEGF-receptor1, contribute to the signs and symptoms of preeclampsia. Since sFlt-1 binds to heparin and heparan sulfate proteoglycans, we hypothesized that the anticoagulant heparin, which is often used in pregnancy, may interfere with the levels, distribution and elimination of sFlt-1 in vivo.

Objective

We systematically determined serum and urine levels of angiogenic factors in preeclamptic women before and after administration of low molecular weight heparin and further characterized the interaction with heparin in biochemical studies.

Methods and Results

Serum and urine samples were used to measure sFlt-1 levels before and after heparin administration. Serum levels of sFlt-1 increased by 25% after heparin administration in pregnant women. The magnitude of the increase in circulating sFlt-1 correlated with initial sFlt-1 serum levels. Urinary sFlt-1 levels were also elevated following heparin administration and levels of elimination were dependent on the underlying integrity of the glomerular filtration barrier. Biochemical binding studies employing cation exchange chromatography revealed that heparin bound sFlt-1 had decreased affinity to negatively charged surfaces when compared to sFlt-1 alone.

Conclusion

Low molecular weight heparin administration increased circulating sFlt1 levels and enhanced renal elimination. We provide evidence that both effects may be due to heparin binding to sFlt1 and masking the positive charges on sFlt1 protein.

Individual risk assessment of adverse pregnancy outcome by multivariate regression analysis may serve as basis for drug intervention studies: retrospective analysis of 426 high-risk patients including ethical aspects

OBJECTIVE

To identify patients at very high risk for adverse pregnancy outcome (APO) at the 20- to 23-week scan and to assess the effectiveness of Aspirin (ASS) and low molecular weight heparin (LMWH) starting after this examination.

PATIENTS AND METHODS

By applying an algorithm based on multivariate logistic regression analysis using the parameters maternal age, parity, body mass index (BMI), mean pulsatility index of both uterine arteries (meanPI), presence of uni- or bilateral notch, and depth of notch (mean notch index (meanNI), we retrospectively calculated the individual risk for APO of 21,302 singleton pregnancies. We isolated a subgroup of 426 patients with the highest calculated probability for APO (cpAPO > 27.8 %). 147 had been treated with ASS; 73 with LMWH, 15 patients with a combination of ASS and LMWH, and 191 patients had not received anticoagulants.

RESULTS

Administration of ASS starting after 20 gestational weeks in comparison to non-treated patients significantly reduced the frequency of intrauterine/neonatal death (IUD/NND), preeclampsia <33 weeks (PE < 33), and preterm delivery <33 weeks (PD < 33), while the frequency of IUGR showed a tendency to be elevated (P = 0.061). The subgroup of high-risk patients treated with LMWH was characterised by a higher a priori risk for APO and showed no significant reduction of any form of APO but an increased frequency of PE.

CONCLUSION

Individual assessment of risk for APO by applying a simple algorithm based on biometrical/biographical as well as sonographic parameters may serve as basis for drug intervention studies. The administration of ASS in high-risk patients starting after 20 gestational weeks reduced the frequency of most of the severe forms of adverse pregnancy outcome in high-risk patients. A complication-reducing effect of LMWH starting after 20 weeks of gestation in patients could not be proven. From an ethical point of view, it may not be justified any more to preclude high-risk patients from administration of ASS or to perform studies of ASS against placebo.

Inherited thrombophilia: diagnosis and anticoagulation treatment in pregnancy

The association between inherited thrombophilia and deep vein thrombosis is well established. Adverse pregnancy outcomes, sometimes called placenta-mediated complications, have been attributed to excessive thrombosis and inflammation at the uteroplacental interface. This linkage resulted in widespread screening for thrombophilia in women with adverse pregnancy outcome. Anticoagulant therapy was initially liberally administered for prevention of adverse pregnancy outcome. Well-designed randomized trials were initiated and the results of some of these randomized trials have provided critical evidence-based data to serve as a guide for clinicians faced with managing patients with one or more of the common obstetric complications.

[Hereditary thrombophilias and placental-mediated pregnancy complications in the II./III. trimester]

Placental-mediated pregnancy complications (PmC) like preeclampsia, intrauterine growth restriction and placental abruption are common causes of fetal and maternal morbidity and mortality. The high prevalence of hereditary thrombophilias in case-control studies associated with pathological morphological findings of the placenta in these cases gave evidence for the association between hereditary thrombophilias and PmC. However, data from the literature are inconsistent, since subsequent prospective cohort studies could not demonstrate significant associations between inherited thrombophilia and PmC. Because of the multifactorial aetiology of PmC it may be difficult to prove, that hereditary thrombophilias are independent risk factors for PmC. Current guidelines do not recommend screening for inherited thrombophilias in patients with previous PmC. Evidence from current in vitro studies have shown, that heparin has beneficial non-anticoagulatory effects on trophoblast invasion. Retrospective case-control studies and recently published randomised controlled cohort studies have shown, that prophylactic administration of low-molecular-weight heparin (LWH), started in early pregnancy, may lead to a significant reduction in the incidence of PmC in subsequent pregnancies in patients with and without hereditary thrombophilias and previous PmC.

CONCLUSION

Large, well-designed multicenter studies are needed to elucidate the role of hereditary thrombophilias in cases of PmC and to confirm the benefit of LWH for subsequent pregnancy outcomes.

Preeclampsia - Aetiology, Current Diagnostics and Clinical Management, New Therapy Options and Future Perspectives

Preeclampsia is a multisystem disease for which the exact causes have not yet been sufficiently clarified. However, in the past few years it has become clear that a placental imbalance between angiogenic and anti-angiogenic proteins is the decisive pathogenetic factor for the occurrence of preeclampsia. With the possibility to measure these angiogenic factors (sFlt-1/PlGF ratio) in maternal blood full new diagnostic possibilities have been opened that enable the certain diagnosis or exclusion of the diseases as well as a short-term prognosis to be made. In secondary prevention the current data situation for ASA confirms a moderate but measurable utility. The management concept depends on gestational age. In the case of early clinical manifestations (< 34th week of pregnancy) the clinical management in a perinatal centre remains unchanged with foeto-maternal monitoring and induction of pulmonary maturation, symptomatic therapy under careful blood pressure lowering and determination of the optimal delivery time. A balance must be made here between foetal immaturity and maternal risks upon prolongations. The pathomechanism of anti-angiogenic overload with sFlt-1 provides a starting point for first therapeutic interventions. The present article gives an overview of current diagnostic options and presents possible future therapeutic perspectives for discussion.

Low-molecular-weight heparin added to aspirin in the prevention of recurrent early-onset pre-eclampsia in women with inheritable thrombophilia: the FRUIT-RCT

BACKGROUND

Early-onset hypertensive disorders (HD) of pregnancy and small-for-gestational age infants (SGA) are associated with placental vascular thrombosis, these often recur and are also associated with inheritable thrombophilia. Aspirin reduces the recurrence risk.

OBJECTIVES

Adding low-molecular-weight heparin (LMWH) to aspirin at < 12 weeks gestation reduces the recurrence of HD in women with previous early-onset HD (pre-eclampsia, hemolysis, elevated liver enzymes and low platelets [HELLP] syndrome and eclampsia) and/or SGA, in the context of inheritable thrombophilia without antiphospholipid antibodies.

PATIENTS/METHODS

In a multicenter randomized control trial (RCT), 139 women included were< 12 weeks gestation.

INCLUSION CRITERIA

previous delivery< 34 weeks gestation with HD and/or SGA; inheritable thrombophilia (protein C deficiency, protein S deficiency, activated protein C resistance, factor V Leiden heterozygosity and prothrombin gene G20210A mutation heterozygosity); and no antiphospholipid antibodies detected.

INTERVENTION

either daily LMWH (dalteparin, 5000 IU weight-adjusted dosage) with aspirin 80 mg or aspirin 80 mg alone.

MAIN OUTCOME MEASURES

PRIMARY OUTCOMES

recurrent HD onset (i) < 34 weeks gestation and (ii) irrespective of gestational age.

SECONDARY OUTCOMES

recurrent SGA, preterm birth, maternal/neonatal hospitalization, spontaneous abortion and individual HD. Analysis by intention-to-treat.

RESULTS

Low-molecular-weight heparin with aspirin reduced recurrent HD onset < 34 weeks gestation (risk difference [RD] 8.7%: confidence interval [CI] of RD 1.9–15.5%; P = 0.012; number needed to treat [NNT] 12). Recurrent HD irrespective of gestational age was not different between the arms. No women withdrew as a result of adverse effects.

TRIAL REGISTRATION

http://www.isrctn.org) (isrctn87325378).

CONCLUSIONS

Adding LMWH to aspirin at < 12 weeks gestation reduces recurrent HD onset < 34 weeks gestation in women with inheritable thrombophilia and prior delivery for HD/SGA <34 weeks. However, close monitoring of the mother and fetus remains important throughout pregnancy.

Is heparin a placental anticoagulant in high-risk pregnancies?

Randomized control trials show beneficial effects of heparin in high-risk pregnancies to prevent preeclampsia and intrauterine growth restriction. However, the lack of placental pathology data in these trials challenges the assumption that heparin is a placental anticoagulant. Recent data show that placental infarction is probably associated with abnormalities in development of the placenta, characterized by poor maternal perfusion and an abnormal villous trophoblast compartment in contact with maternal blood, than with maternal thrombophilia. At-risk pregnancies may therefore be predicted by noninvasive prenatal testing of placental function in mid-pregnancy. Heparin has diverse cellular functions that include direct actions on the trophoblast. Dissecting the non-anticoagulant actions of heparin may indicate novel and safer therapeutic targets to prevent the major placental complications of pregnancy.