Haemostatic changes in pregnancy

Impact of inherited bleeding disorders on pregnancy and postpartum hemorrhage

Inherited bleeding disorders are caused by various genetic defects in the proteins involved in haemostasis. Female patients or carriers are faced with the risk of haemorrhage throughout life. During pregnancy and postpartum, this complication affects the health of either the mother or the baby, or both. This retrospective cohort study was designed to assess the occurrence of obstetric bleeding in the three trimesters of pregnancy, along with primary and secondary postpartum haemorrhage among 100 women with inherited bleeding disorders. A questionnaire was designed in order to collect historical data. The patients were evaluated in three groups: haemophilia carriers, von Willebrand disease (VWD) and rare bleeding disorders. In comparison with normal women, significantly severe bleeding was observed among patients in all of the five stages. VWD patients showed a higher frequency of bleeding in first trimester but the rate of miscarriage was lower. Haemophilia carriers were threatened with bleeding complications during the prenatal period, but they also had the highest frequency of postpartum haemorrhage. Based on our results, vaginal bleeding is a serious threat in all three patient groups, especially during the first trimester of pregnancy and in the postpartum period.

Fibrinogen concentrate substitution therapy for obstetric hemorrhage complicated by coagulopathy

AIM

The aim of this study was to assess the efficacy and safety of fibrinogen concentrate therapy for women with obstetric hemorrhage complicated by dilutional or consumptive coagulopathy by retrospectively reviewing the medical records of relevant patients from a single tertiary center.

MATERIAL AND METHODS

Eighteen cases of coagulopathy (8 dilutional, 10 consumptive) administered fibrinogen concentrate at our center over the past 5 years for treating hypofibrinogenemia were identified. Hemoglobin levels, platelet counts, fibrinogen levels, prothrombin time, activated partial thromboplastin time, and D-dimer levels were examined before and after fibrinogen substitution. Units of red blood cells, fresh frozen plasma, and pooled platelet concentrates transfused; blood loss volume; patient outcomes; and adverse events were obtained from medical and laboratory records.

RESULTS

The overall response to fibrinogen concentrate was considered good in 12 cases, moderate in four, and poor in two. The response rate was good or moderate in 88% (7/8) of dilutional coagulopathy cases and 89% (9/10) of consumptive coagulopathy cases. Fibrinogen levels significantly increased after fibrinogen substitution therapy (approximately 40 mg/L per g fibrinogen concentrate) in both groups. Although prothrombin time and activated partial thromboplastin time improved after substitution, hemoglobin levels, platelet counts, and D-dimer levels remained unchanged. No serious adverse event was causally associated with fibrinogen substitution therapy.

CONCLUSION

Fibrinogen concentrate substitution therapy for obstetric hemorrhage increases fibrinogen levels and appears to be effective in managing dilutional or consumptive coagulopathy.

Endogenous oestradiol as a positive correlate of plasma fibrinogen among older postmenopausal women: a population-based study (the Three-City cohort study)

BACKGROUND

Plasma fibrinogen is a strong predictor of ischaemic arterial disease in women. Sex steroid hormones including hormone therapy may play an important role in the development of cardiovascular disease. However, whether endogenous sex steroid hormones influence the plasma fibrinogen concentrations among postmenopausal women remains unclear.

OBJECTIVES

To investigate the association of plasma fibrinogen levels with endogenous sex steroid hormones and sex hormone binding globulin (SHBG) among postmenopausal women.

METHODS

We used data from the French prospective Three-City cohort study that included 9294 noninstitutionalized men and women over 65 years of age. Total 17β-oestradiol (E2, pg/ml), total testosterone (T, ng/ml), SHBG (nm) and fibrinogen (g/l) were measured in stored plasmas in a subcohort of 602 randomly selected postmenopausal women who used neither hormone medication nor anticoagulation therapy. Multivariate linear regression models were used to estimate the regression coefficients assessed in fibrinogen unit by 1 SD increase in log-distribution of sex steroid hormones and SHBG.

RESULTS

E2 but neither T nor SHBG was positively associated with plasma fibrinogen levels (β = 0·148, P < 0·001). Adjustment for cardiovascular risk factors including diabetes made no substantial change to the results (β = 0·145, P < 0·001). The association of fibrinogen with E2 was stronger among women with body mass index over 25 kg/m(2) compared with those with normal weight (β = 0·156, P < 0·001 and β = 0·092, P = 0·02, respectively, P for interaction = 0·04).

CONCLUSION

E2 emerges as a positive and independent correlate of plasma fibrinogen among postmenopausal women, especially in subjects who are overweight. These findings suggest a deleterious effect of endogenous oestrogens on cardiovascular risk profile among postmenopausal women.

ADHERENCE IN PREGNANCY: A SYSTEMATIC REVIEW OF THE LITERATURE

“Clinical decisions and research programs ultimately depend on the reliable and valid measurement of adherence. Yet, 50 years of research in this field have not provided the data necessary to answer critical measurement questions.”.

Chronic estradiol treatment reduces platelet responses and protects mice from thromboembolism through the hematopoietic estrogen receptor α

Although estrogens are known to have a deleterious effect on the venous thrombosis risk and a preventive action on the development of arterial atheroma, their effect on platelet function in vivo remains unclear. Here, we demonstrate that a chronic high physiologic level of estradiol (E2) in mice leads to a marked decrease in platelet responsiveness ex vivo and in vivo compared with ovariectomized controls. E2 treatment led to increased bleeding time and a resistance to thromboembolism. Hematopoietic chimera mice harboring a selective deletion of estrogen receptors (ERs) α or β were used to demonstrate that the effects of E2 were exclusively because of hematopoietic ERα. Within ERα the activation function-1 domain was not required for resistance to thromboembolism, as was previously shown for atheroprotection. This domain is mandatory for E2-mediated reproductive function and suggests that this role is controlled independently. Differential proteomics indicated that E2 treatment modulated the expression of platelet proteins including β1 tubulin and a few other proteins that may impact platelet production and activation. Overall, these data demonstrate a previously unrecognized role for E2 in regulating the platelet proteome and platelet function, and point to new potential antithrombotic and vasculoprotective therapeutic strategies.

New insights into the mechanisms of venous thrombosis

Venous thrombosis is a leading cause of morbidity and mortality in industrialized countries, especially in the elderly. Many risk factors have been identified for venous thrombosis that alter blood flow, activate the endothelium, and increase blood coagulation. However, the precise mechanisms that trigger clotting in large veins have not been fully elucidated. The most common site for initiation of the thrombus appears to be the valve pocket sinus, due to its tendency to become hypoxic. Activation of endothelial cells by hypoxia or possibly inflammatory stimuli would lead to surface expression of adhesion receptors that facilitate the binding of circulating leukocytes and microvesicles. Subsequent activation of the leukocytes induces expression of the potent procoagulant protein tissue factor that triggers thrombosis. Understanding the mechanisms of venous thrombosis may lead to the development of new treatments.

Evaluation of coagulation abnormalities among women with vaginal bleeding in the first trimester of pregnancy

OBJECTIVE

To compare blood coagulation parameters between pregnant women with vaginal bleeding in the first trimester of pregnancy and pregnant women with normal pregnancy in the first trimester.

METHODS

A prospective controlled study of 98 women in the first trimester of vital pregnancy was conducted at the University Medical Centre Maribor, Slovenia. The study group comprised women with vaginal bleeding (n=50) while the control group women with normal pregnancy, admitted for artificial abortion (n=48). Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, number of platelets, hemogram, coagulation factor VIII (FVIII) and von Willebrand factor (VWF) activity were compared between the 2 groups.

RESULTS

No significant between-group differences were detected in mean PT, fibrinogen concentration, FVIII, and VWF activity. Mean aPTT was significantly higher in the control group than the study group (32.47 versus 30.46 seconds; P<0.05). The mean number of platelets was significantly lower in the study group than the control group (181.69 versus 203.52×10(9)/L; P<0.05). All measured coagulation parameters, except VWF activity, were within normal ranges.

CONCLUSION

Coagulation abnormalities are rarely the cause of vaginal bleeding in the first trimester of pregnancy among women with no previous symptoms of bleeding disorders.

Hypercoagulable states

Hypercoagulable states can be inherited or acquired. Inherited hypercoagulable states can be caused by a loss of function of natural anticoagulant pathways or a gain of function in procoagulant pathways. Acquired hypercoagulable risk factors include a prior history of thrombosis, obesity, pregnancy, cancer and its treatment, antiphospholipid antibody syndrome, heparin-induced thrombocytopenia, and myeloproliferative disorders. Inherited hypercoagulable states combine with acquired risk factors to establish the intrinsic risk of venous thromboembolism for each individual. Venous thromboembolism occurs when the risk exceeds a critical threshold. Often a triggering factor, such as surgery, pregnancy, or estrogen therapy, is required to increase the risk above this critical threshold.

Primary prevention of venous thromboembolism

Venous thromboembolism (VTE) is the most common cause of preventable in-hospital mortality and all hospitalized patients should be VTE risk assessed. The VTE risk should be weighed up against risk of bleeding on an individualized basis to guide choice of prophylaxis. The most common method of mechanical thromboprophylaxis is graduated compression stockings, although others, such as intermittent pneumatic devices, are available. Stockings have the greatest benefit when used in combination with pharmacological prophylaxis. However, stockings are contraindicated in some patients, including those with stroke or peripheral arterial disease. Various options for pharmacological thromboprophylaxis are available. The most commonly used agents are the low-molecular-weight heparins, but newer orally active agents may play an increasing role in the future.

No evidence that assisted reproduction increases the risk of thrombosis: a Danish national cohort study

BACKGROUND

Case reports have reported venous and arterial thromboses in women undergoing assisted reproduction. No large systematic studies on the risk of thrombosis have been published. The objective of our study was to investigate whether the risk of thrombosis is increased in women undergoing assisted reproduction.

METHODS

A national register-based cohort study was conducted on all women undergoing IVF or ICSI treatment in Denmark from 1994 to 2005. Data were obtained from the National Patient Registry and the IVF Registry. Women with prior malignant or cardiovascular disease were excluded. Thrombosis occurring within the first 6 and 12 months after assisted reproduction was considered potentially related to the treatment. Thromboses during pregnancy as well as the pregnancy-related diagnoses were excluded from the statistical analysis. The incidence rates of venous and arterial thromboses were compared with previously published estimates of the risk of thrombosis among young Danish women.

RESULTS

We analyzed 30 884 Danish women undergoing 75 141 treatments from 1994 to 2005. The mean age of the women at first treatment was 32.3 years. The delivery rate per cycle was 22%. The incidence rate ratio, with 95% confidence interval (CI), of venous thrombosis within 6 months was 0.95 (CI: 0.38-1.95). The incidence rate ratio of arterial thrombosis within 6 months was 0.36 (CI: 0.04-1.30).

CONCLUSIONS

Our study showed no evidence that assisted reproduction increases the risk of thrombosis.

A retrospective analysis of transfusion management for obstetric hemorrhage in a Japanese obstetric center

Background. Since cryoprecipitate, fibrinogen concentrate, or recombinant activated factor VII is not approved by public medical insurance in Japan, we retrospectively assessed blood product usage in patients with obstetric hemorrhage at our tertiary obstetric center. Material and Methods. 220 patients with obstetric hemorrhagic disorders who underwent blood product transfusion in our institution during a 5-year period were reviewed for the types and volumes of blood products transfused. Results. There was a significant positive correlation (P< 0.001) between the volume of RCC (red blood cell concentrate) transfused and that of FFP (fresh frozen plasma), irrespective of underlying obstetric disorders. The median of FFP to RCC ratio in each patient was 1.3-1.4, when 6 or more units of RCC were transfused. Conclusions. In transfusion for massive obstetric hemorrhage in terms of appropriate supplementation of coagulation factors, the transfusion of RCC : FFP = 1 : 1.3-1.4 may be desirable.

Risk of obstetric and thromboembolic complications in family members of women with previous adverse obstetric outcomes carrying common inherited thombophilias

BACKGROUND

Factor (F)V Leiden and the prothrombin 20210A mutation (PTm) are associated with the occurrence of obstetric complications, including pregnancy-related venous thromboembolism (VTE). It is not known whether family members of women with FV Leiden or PTm and previous obstetric complications have a higher risk of VTE or adverse obstetric outcomes.

METHODS

A retrospective family study including 563 relatives of 177 women with previous adverse outcomes carrying FV Leiden or PTm, referred between April 1993 and June 2010. A history of obstetric complications and VTE was obtained. Prevalence of VTE and obstetric complications in relatives with and without inherited thrombophilias was compared. Adjusted odd ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression models that controlled for predictors (age, FV Leiden and PTm).

RESULTS

Relatives carrying FV Leiden had a significant and independent risk for obstetric complications (OR: 1.98, 95% CI 1.03-3.83); this risk was not observed in the presence of PTm (OR: 1.03, 95% CI 0.46-2.32). The presence of FV Leiden or PTm in heterozygosis was significantly and independently associated with the occurrence of VTE (OR: 5.2, 95% CI: 1.70-15.91). Severe thrombophilias were strong risk factors for VTE (OR: 23.2, 95% CI: 6.0-89.85). Male gender was a significant and independent risk factor for VTE (OR: 3.49, 95% CI: 1.51-8.05). The risk did not change when relatives of women with a previous pregnancy-related VTE were excluded (OR: 3.49, 95% CI: 1.51-8.05).

CONCLUSIONS

Knowledge of thrombophilia status may help to better define the obstetric and thromboembolic risks in asymptomatic family members of women who suffered from obstetric complications.

Nitroglycerin prevents coagulopathies and foetal death associated with abnormal maternal inflammation in rats

Inflammation-associated foetal loss is often linked to maternal coagulopathies. Here, we characterised the role of maternal inflammation in the development of various systemic maternal coagulopathies and foetal death during mid-to-late gestation in rats. Since nitric oxide (NO) functions as an inhibitor of platelet aggregation and anti-oxidant, we also tested whether the NO mimetic nitroglycerin (glyceryl trinitrate, GTN) prevents inflammation-associated coagulopathies and foetal death. To induce chronic inflammation, pregnant Wistar rats were injected with low-doses of lipopolysaccharide (LPS; 10-40 μg/kg) on gestational days (GD) 13.5-16.5. To determine whether the effects of inflammation are mediated by tumour necrosis factor-α (TNF-α), the TNF-α inhibitor etanercept was injected on GD 13.5 and 15.5. Controls consisted of rats injected with saline. GTN was administered to LPS-treated rats via daily application of a transdermal patch on GD 12.5-16.5. Using thromboelastography (TEG), various coagulation parameters were assessed on GD 17.5; foetal viability was determined morphologically. Reference coagulation parameters were established based on TEG results obtained from control animals. LPS-treated rats exhibited distinct systemic coagulopathies: hypercoagulability, hypocoagulability, hyperfibrinolysis, and disseminated intravascular coagulation (DIC) stages I and III. A specific foetal death coagulation phenotype was observed, implicating TEG as a potential tool to identify inflammation-induced haemostatic alterations associated with pregnancy loss. Treatment with etanercept reduced the incidence of coagulopathy by 47%, while continuous delivery of GTN prevented foetal death and the inflammation-induced coagulopathies. These findings provide a rationale for investigating the use of GTN in the prevention of maternal coagulopathies and inflammation-mediated foetal death.

Abnormal inflammation leads to maternal coagulopathies associated with placental haemostatic alterations in a rat model of foetal loss

Spontaneous pregnancy loss is often associated with aberrant maternal inflammation and systemic coagulopathies. However, the role of inflammation in the development of obstetric coagulopathies is poorly understood. Further, questions remain as to whether systemic coagulopathies are linked to placental haemostatic alterations, and whether these local alterations contribute to a negative foetal outcome. Using a model of spontaneous foetal loss in which pregnant rats are given a single injection of bacterial lipopolysaccharide (LPS), we characterised the systemic maternal coagulation status following LPS administration using thromboelastography (TEG), a global haemostatic assay that measures the kinetics of clot formation. Systemic maternal coagulopathy was evident in 82% of LPS-treated rats. Specifically, we observed stage-I, -II, and -III disseminated intravascular coagulation (DIC) and hypercoagulability. Modulation of inflammation through inhibition of tumour necrosis factor α with etanercept resulted in a 62% reduction in the proportion of rats exhibiting coagulopathy. Moreover, inflammation-induced systemic coagulopathies were associated with placental haemostatic alterations, which included increased intravascular, decidual, and labyrinth fibrin deposition in cases of DIC-I and hypercoagulability, and an almost complete absence of fibrin deposition in cases of DIC-III. Furthermore, systemic and placental haemostatic alterations were associated with impaired utero-placental haemodynamics, and inhibition of these haemostatic alterations by etanercept was associated with maintenance of utero-placental haemodynamics. These findings indicate that modulation of maternal inflammation may be useful in the prevention of coagulopathies associated with complications of pregnancy.

Management of pregnancy and delivery in women with inherited bleeding disorders

Women with inherited bleeding disorders present a wide spectrum of clinical symptoms that vary from mild or moderate bleeding tendency to severe episodes. Monthly haemostatic changes affect these women during menstruation and ovulation. These events may be associated with significant bleeding and pain leading to the limitations in conducting daily activities and adverse effect on quality of life. Likewise, pregnancy and delivery are critical times for affected women. During pregnancy, they may be at greater risk of miscarriage and bleeding complications. In particular, recurrent miscarriage was observed in women with type 3 von Willebrand disease, afibrinogenaemia and severe factor XIII deficiency, and an optimal therapeutic plan is required during their pregnancy. Precautions must be taken at delivery in these women, since they could be at risk of bleeding. The lack of adequate information makes it very difficult to prepare evidence-based guidelines for the prevention of bleedings in affected women and their treatment. A multidisciplinary team of obstetricians, haematologists and paediatricians is required with a good knowledge of these disorders and an awareness of the potential maternal neonatal complications.

Role of protein S and tissue factor pathway inhibitor in the development of activated protein C resistance early in pregnancy in women with a history of preeclampsia

Pregnancy increases the risk of venous thromboembolism. Particularly in early pregnancy, the thrombosis risk can be attributed to the changes in coagulation. Elevated thrombin generation and resistance to activated protein C (APC) are likely to contribute to the increased thrombosis risk during pregnancy. We studied changes and the determinants of thrombin generation and APC resistance in the first 16 weeks of gestation in women with history of preeclampsia. Additionally, we investigated the influence of pregnancy-induced haemodilution on the coagulation system. We measured thrombin generation, APC resistance and plasma levels of prothrombin, factor V, factor X, protein S and tissue factor pathway inhibitor (TFPI) in 30 non-pregnant and 21 pregnant women at 8, 12 and 16 weeks of gestation. All participants shared a history of a hypertensive complication in the preceding pregnancy. Thrombin generation and APC resistance were higher at eight weeks of pregnancy than in the non-pregnant state, and progressively increased between eight and 16 weeks of gestation. Changes in the TFPI and protein S levels accounted for ~70% of pregnancy-induced APC resistance. Interestingly, a significant correlation (slope 2.23; 95%CI: 1.56 to 2.91; r= 0.58) was observed between protein Stotal or protein Sfree levels and haematocrit. In conclusion, pregnancy induces a decrease of TFPIfree and protein Sfree levels that attenuates the function of the TFPI and protein C systems and results in elevated thrombin generation and increased APC resistance. Besides, our data suggest that pregnancy-dependent haemodilution may contribute to the decreased peripheral protein S levels.

Risks versus benefits of gastrointestinal endoscopy during pregnancy

Although gastrointestinal endoscopy is generally safe, its safety must be separately analyzed during pregnancy with regard to fetal safety. Fetal risks from endoscopic medications are minimized by avoiding FDA category D drugs, minimizing endoscopic medications, and anesthesiologist attendance at endoscopy. Esophagogastroduodenoscopy seems to be relatively safe for the fetus and may be performed when strongly indicated during pregnancy. Despite limited clinical data, endoscopic banding of esophageal varices and endoscopic hemostasis of nonvariceal upper gastrointestinal bleeding seems justifiable during pregnancy. Flexible sigmoidoscopy during pregnancy also appears to be relatively safe for the fetus and may be performed when strongly indicated. Colonoscopy may be considered in pregnant patients during the second trimester if there is a strong indication. Data on colonoscopy during the other trimesters are limited. Therapeutic endoscopic retrograde cholangiopancreatography seems to be relatively safe during pregnancy and should be performed for strong indications (for example, complicated choledocholithiasis). Endoscopic safety precautions during pregnancy include the performance of endoscopy in hospital by an expert endoscopist and only when strongly indicated, deferral of endoscopy to the second trimester whenever possible, and obstetric consultation.

[Thromboembolism and antithrombotic management in pregnancy]

Venous thromboembolism occurs approximately in 1 of 1000 pregnancies. It is one of the leading causes of maternal mortality. Physiologic changes associated with pregnancy and delivery favor for developing venous thromboembolism, and there are individual risk factors, too, contributing to its manifestation. The most frequent risk factors of venous thromboembolism developing during pregnancy are the previous venous thromboembolism and the thrombophilias, furthermore, some other diseases and some unique complications of pregnancy and delivery. Beyond mechanical prevention only heparin preparations can be used for preventing and treating venous thromboembolism in pregnancy and among them the low-molecular-weight heparins are preferred for applying. Dosage of low-molecular-weight heparin preparations is determined by the type and strength of thrombophilia. For treatment of venous thromboembolism presented during pregnancy subcutaneous 100 IU/kg low-molecular-weight heparin is generally used at every 12 hours. Postpartum the oral anticoagulants can be safely applied, too.

Controversies in postpartum contraception: when is it safe to start oral contraceptives after childbirth?

The timely initiation of contraception postpartum is an important consideration for breastfeeding and non-breastfeeding women; many women prefer oral contraceptive pills to other methods. In breastfeeding women, combined hormonal pills are not recommended prior to 6 weeks postpartum, due to effects on milk production. Although progestogen-only pills do not adversely affect milk, lack of data regarding possible effects on infants exposed to progestogens in breastmilk renders timing of initiation of this method controversial. In non-breastfeeding women, elevated risk of venous thromboembolism restricts use of combined hormonal pills prior to 21 days postpartum. From 21 to 42 days, use of combined hormonal pills should be assessed based on a woman's personal venous thromboembolism risk profile; after 42 days postpartum there is no restriction in the use of combined hormonal pills for otherwise healthy women. Non-breastfeeding women may safely use progestogen-only pills at any time during the postpartum.

Efficacy of obstetric thromboprophylaxis and long-term risk of recurrence of venous thromboembolism

OBJECTIVE

To study the efficacy of thromboprophylaxis with low molecular weight heparin (LMWH) in pregnant women with one previous venous thromboembolic event (VTE). Secondary aims were to study the long-term risk of secondary recurrence, bleeding and obstetric complications.

DESIGN

A prospective national study of long-term LMWH thromboprophylaxis in Sweden.

SETTINGS

All hospitals in Sweden during January 1998-December 2002,

PARTICIPANTS

Pregnant women with one previous VTE and controls drawn from the Swedish Medical Birth Registry. The women were cross-matched with the Swedish Hospital Discharge Register to identify all recurrences and to ascertain the annual risk of recurrence.

MAIN OUTCOME MEASURES

Recurrence of VTE, bleeding complications at delivery and obstetric complications.

RESULTS

326 of 393 registered women could be evaluated. The relative risk reduction in VTE was 88%. There was an absolute increased risk of VTE during the thromboprophylaxis period: 1.2% compared to 0.2% among controls (p<0.001). The risk during the immediate post-treatment period (43-100 days post-partum) was increased 28-fold. The annual incidence of VTE after delivery was 1%. The risk of hematoma and major blood loss at delivery was increased during thromboprophylaxis (p<0.001). There were no differences in the incidences of preeclampsia, intrauterine growth restriction or placental abruption.

CONCLUSIONS

The relative risk reduction in VTE during thromboprophylaxis was 88%. After pregnancy, the annual long-term risk of recurrence was 1%. The risk was most pronounced in the post-treatment period. There was an increased risk of bleeding complications among women given LMWH, but there was no effect on obstetric complications.

Risk of venous thromboembolism during the postpartum period: a systematic review

OBJECTIVE

To determine, from the literature, the risk of venous thromboembolism during the postpartum period.

DATA SOURCES

We searched PubMed and Cochrane Library databases for all articles (in all languages) published in peer-reviewed journals from database inception through May 2010 for evidence related to incidence of venous thromboembolism in postpartum women.

METHODS OF STUDY SELECTION

We included studies reporting relative risk, incidence rate, or cumulative incidence of venous thromboembolism in postpartum women.

TABULATION, INTEGRATION, AND RESULTS

We included 15 articles reporting findings from 13 studies. Two studies directly comparing venous thromboembolism during the first 6 weeks postpartum to nonpregnant, nonpostpartum women reported relative effect measures of 21.5 (rate ratio; 95% confidence interval [CI] unable to be calculated) and 84 (odds ratio; 95% CI 31.7-222.6), respectively. A third study reported relative effect measures for deep venous thrombosis (15.2, 95% CI 13.2-17.6; standardized incidence ratio) and pulmonary embolism (9.2, 95% CI 6.5-12.7) separately. Three studies reported incidence rates of venous thromboembolism during the postpartum period (range 25-99 per 10,000 woman-years). We compared these incidence rates to baseline rates among nonpregnant, nonpostpartum women reported in the literature to generate rate ratios; these rate ratios ranged from 2.5 to 21.5. Nine studies reported cumulative incidence proportions of postpartum venous thromboembolism, ranging from 0.14 to 3.24 per 1,000 deliveries at 6 weeks postpartum. Incidence of venous thromboembolism was highest immediately after delivery (standardized incidence ratio for deep venous thrombosis 115.1 [95% CI 96.4-137.0], and for pulmonary embolism 80.7 [95% CI 53.9-117.9]); between 4 and 6 weeks postpartum, risk declined but was still approximately five-times to seven-times that of nonpregnant, nonpostpartum women.

CONCLUSION

During the first 6 weeks postpartum, women's risk of venous thromboembolism increased 21.5-fold to 84-fold from baseline in nonpregnant, nonpostpartum women in studies that included an internal reference group. Although incidence of venous thromboembolism declined quickly after delivery, when this risk returns to baseline is not clear from current data.

Venous thromboembolism in pregnancy

In Western nations, venous thromboembolism (VTE) is an important cause of morbidity and the most common cause of maternal death during pregnancy and the puerperium. Pregnancy is a hypercoagulable state in which coagulation is activated and thrombolysis inhibited. This prothrombotic risk is compounded when hereditary and acquired thrombophilias and other prothrombotic risk factors are present. The risk of venous thrombotic events is increased fivefold during pregnancy and 60-fold in the first 3 months after delivery (postpartum period) compared with nonpregnant women. Many of the signs and symptoms of VTE overlap those of a normal pregnancy, which complicates the diagnosis. Patients with history of previous VTE should use graduated compression stockings throughout pregnancy and the puerperium, and should receive postpartum anticoagulant prophylaxis. The indications for antepartum anticoagulant prophylaxis are somewhat controversial. This article reviews the management of VTE during pregnancy and in the postpartum period.

Ischemic Stroke during Pregnancy and Puerperium

Ischemic stroke during pregnancy and puerperium represents a rare occurrence but it could be a serious and stressful event for mothers, infants, and also families. Whenever it does occur, many concerns arise about the safety of the mother and the fetus in relation to common diagnostic tests and therapies leading to a more conservative approach. The physiological adaptations in the cardiovascular system and in the coagulability that accompany the pregnant state, which are more significant around delivery and in the postpartum period, likely contribute to increasing the risk of an ischemic stroke. Most of the causes of an ischemic stroke in the young may also occur in pregnant patients. Despite this, there are specific conditions related to pregnancy which may be considered when assessing this particular group of patients such as pre-eclampsia-eclampsia, choriocarcinoma, peripartum cardiomiopathy, amniotic fluid embolization, and postpartum cerebral angiopathy. This article will consider several questions related to pregnancy-associated ischemic stroke, dwelling on epidemiological and specific etiological aspects, diagnostic issue concerning the use of neuroimaging, and the related potential risks to the embryo and fetus. Therapeutic issues surrounding the use of anticoagulant and antiplatelets agents will be discussed along with the few available reports regarding the use of thrombolytic therapy during pregnancy.

Local anesthetic use in the pregnant and postpartum patient

The use of systemically absorbed drugs in the gravid and in the lactating patient is of concern to the dentist. This article reviews concerns for the health and safety of the mother, developing fetus, and neonate involving local anesthetics. The available literature on the use of local anesthetics for dentistry in the pregnant and postpartum patient is also reviewed. In addition, the physiology of the pregnant and postpartum woman is discussed because this is essential to understanding potential interplay with local anesthesia and the stress of a dental appointment.

Hypercoagulable states

Hypercoagulable states can be inherited or acquired. Inherited hypercoagulable states can be caused by a loss of function of natural anticoagulant pathways or a gain of function in procoagulant pathways. Acquired hypercoagulable risk factors include a prior history of thrombosis, obesity, pregnancy, cancer and its treatment, antiphospholipid antibody syndrome, heparin-induced thrombocytopenia, and myeloproliferative disorders. Inherited hypercoagulable states combine with acquired risk factors to establish the intrinsic risk of venous thromboembolism for each individual. Venous thromboembolism occurs when the risk exceeds a critical threshold. Often a triggering factor, such as surgery, pregnancy, or estrogen therapy, is required to increase the risk above this critical threshold.

Hypercortisolism and pregnancy upregulate von Willebrand factor through different mechanisms: report on a pregnant patient with Cushing's syndrome

Von Willebrand factor (VWF) is reportedly increased in pregnancy and Cushing's syndrome, inducing a hypercoagulable state. In Cushing's syndrome, VWF gene promoter polymorphisms modulate cortisol-dependent VWF upregulation, haplotype 1 (GCAG) and short GT-repeats (GT)(S) being the susceptible, and haplotype 2 (CTGA) and long GT-repeats (GT)(L) the protective pattern. We report on a Cushing's syndrome patient who became pregnant under hypercortisolism, in whom we monitored the evolution of her hypercoagulable state. During the active phase of Cushing's syndrome, the patient's VWF and factor VIII concentrations were normal, despite high urinary-free cortisol levels consistent with the presence of haplotype 2 and (GT)(L) alleles in the VWF gene promoter. VWF and factor VIII increased significantly and progressively after she became pregnant and peaked just before delivery, returning to normal 5 months later, while her hypercortisolism persisted. Our data indicate that two different mechanisms upregulate VWF under hypercortisolism and pregnancy, the latter being independent of the VWF promoter haplotypes sensitive to cortisol excess.

Venous thromboembolism in pregnancy

Low molecular weight heparins (LMWHs) appear to be as safe and effective as unfractionated heparin (UFH) for venous thromboembolic disease (VTED) treatment or prophylaxis during pregnancy. Experience with other parenteral anticoagulant drugs is very limited, and no alternative oral anticoagulants are available to date. In addition to cost, challenges of long-term LMWH use during pregnancy that have not been addressed by controlled clinical trials include a) ideal dosing as pregnancy advances, b) the need for LMWH monitoring by anti-Xa activity levels, and c) ideal therapeutic management as the delivery date nears. Because therapeutic-intensity anticoagulation during pregnancy is challenging, many practitioners favor a more "aggressive" approach toward VTED prophylaxis in women perceived to be at very high risk of thrombosis during pregnancy. Best evidence to date suggests that most women with thrombophilias or with a previous "situational" VTED event probably do not require VTED prophylaxis antepartum, but postpartum anticoagulation prophylaxis is recommended for a few weeks. For those with a history of previous idiopathic VTED or VTED associated with "hormonal challenge" (such as with contraceptive use or previous pregnancy), prophylaxis beginning antepartum may be considered and discussed with the patient. Selected cases of "severe" thrombophilia are probably best managed by initiation of pharmacologic VTED prophylaxis antepartum. However, it must be emphasized that data from prospective controlled clinical trials are lacking.

Unexplained fetal loss: the fetal side of thrombophilia

Carrier status of the fetus for factor V polymorphism or double homozygosity for mutant alleles of the PAI-1 4 G/4 G and MTHFR T677 T polymorphisms must be considered risk factors for intrauterine fetal death. The clinical implications of these data need to be addressed in a prospective study to confirm our preliminary data and to answer the question of whether or not double homozygous individuals should be treated with low molecular-weight heparin and/or low-dose aspirin.

[Pregnancy follow-up and outcome in women with superficial vascular malformations]

Superficial vascular malformations (MAV), so far called "superficial angioma", are uncommon and often unknown. The last classification, done by the "International Society for the Study of Vascular Anomalies", is essential to avoid diagnostic and therapeutic mistakes. Extramedullar localisations are rare. The coexistence of a pregnancy and a MAV states two problems: the medical and paraclinic supervision of the volume of the MAV and its risk of thrombosis with the choice of thrombosis prevention, and the mode of delivery and type of anaesthesia depending on its anatomical location. We revised the management of pregnant women with a MAV illustrating possible troubles to deal with. We reported the cases of two women having for the first one a pharyngolaryngeal MAV, the second a cutaneous MAV located on the leg and needing a multidisciplinary management with obstetricians, anaesthesists, hematologists, dermatologists, ENT, radiologists and pediatricians.

Natural coagulation inhibitors and active protein c resistance in preeclampsia

INTRODUCTION

The etiology of preeclampsia is not fully established. A few studies have shown a relationship between natural coagulation inhibitors and preeclampsia.

OBJECTIVES

The purpose of this study was to investigate the status of natural coagulation inhibitors and active protein C resistance (APC-R) in preeclampsia.

PATIENTS AND METHODS

We studied 70 women with preeclampsia recruited consecutively and 70 healthy pregnant and 70 nonpregnant women as controls. Plasma protein C (PC), free protein S (fPS), antithrombin III (ATIII) and APC-R were evaluated.

RESULTS

ATIII values were found to be significantly lower in preeclamptic patients than in the control groups (p< 0.001). Nevertheless, there was no significant difference between the healthy pregnant and nonpregnant women groups (p=0.141). The fPS values of the preeclamptic and healthy pregnant groups were lower than that of the nonpregnant group (p< 0.001), and the fPS value of the preeclamptic pregnant women was lower than that of healthy pregnant women (p<0.001). The PC value of the preeclamptic pregnant women was lower than that of the control groups (p< 0.001). The PC value of the healthy pregnant women was lower than that of the nonpregnant women (p< 0.001). The mean APC activity values were lower in the preeclamptic patients than that of the control groups (p< 0.001, p< 0.001). The APC-R positivity rates of the preeclamptic groups were higher than that of the control groups (p<0.001).

CONCLUSIONS

This study demonstrated that ATIII, fPS, PC values and APC resistance were lower and APC-R positivity was higher in preeclamptic women than in normal pregnant and nonpregnant women.