Gestational outcome in thrombophilic women with recurrent pregnancy loss treated by enoxaparin

Inherited and acquired thrombophilia are associated with recurrent pregnancy loss (RPL). We have evaluated the efficacy and safety of the low molecular weight heparin enoxaparin in 50 women, (mean age 26 +/- 3 years) with RPL (> or =3 losses in 1st, > or =2 losses in 2nd and > or =1 loss in 3rd trimester) who were found to harbor thrombophilia. Twenty-seven had a solitary thrombophilic defect, and twenty-three women had combined thrombophilic defects: 17--two defects and 6--three defects. Following diagnosis of thrombophilia, sixty-one subsequent pregnancies were treated with the low molecular weight heparin enoxaparin throughout gestation until 4 weeks after delivery. Dosage was 40 mg/day in women with solitary defect and 80 mg/day in combined defects. Aspirin, 75 mg daily was given in addition to enoxaparin to women with antiphospholipid syndrome. Forty-six out of 61 (75%) gestations treated by enoxaparin resulted in live birth compared to only 38/193 (20%) of the untreated pregnancies in these 50 women prior to diagnosis of thrombophilia (p <0.00001). In 23 women without a single living child following 82 untreated gestations, antithrombotic therapy resulted in 26/31 (84%) successful deliveries (p <0.0001). In 20 women with a prior living child, antithrombotic therapy improved successful delivery from 33/86 (38%) to 20/21 (95%) (p <0.0001). Enoxaparin dose of 40 mg/day resulted in live birth in 24/35 (69%) of gestations, compared to 19/23 (83%) gestations in women treated with 80 mg/day (p = 0.37). Only one thrombotic episode and one mild-bleeding episode were noticed during enoxaparin therapy. Enoxaparin is safe and effective in prevention of pregnancy loss in women with inherited and acquired thrombophilia.     

Vitamin K antagonists and pregnancy outcome. A multi-centre prospective study

Vitamin K antagonists (VKA) are known to act as teratogens; however, there is still uncertainty about the relative risk for birth defects and the most sensitive period. In a multi-centre (n = 12), observational, prospective study we compared 666 pregnant women exposed to phenprocoumon (n = 280), acenocoumarol (n = 226), fluindione (n = 99), warfarin (n = 63) and phenindione (n = 2) to a non-exposed control group (n = 1,094). Data were collected by institutes collaborating in the European Network of Teratology Information Services (ENTIS) during individual risk counselling between 1988 and 2004. Main outcome measures were coumarin embryopathy and other birth defects, miscarriage rate, birth-weight, and prematurity. The rate of major birth defects after 1st trimester exposure was significantly increased (OR 3.86, 95% CI 1.86-8.00). However, there were only two coumarin embryopathies (0.6%; both phenprocoumon). Prematurity was more frequent (16.0% vs. 7.6%, OR 2.61, 95% CI 1.76-3.86), mean gestational age at delivery (37.9 vs.39.4, p<0.001), and mean birth weight of term infants (3,166 g vs. 3,411 g; p < 0.001) were lower compared to the controls. Using the methodology of survival analysis, miscarriage rate reached 42% vs. 14% (hazard ratio 3.36; 95% CI 2.28-4.93). In conclusion, use of VKA during pregnancy increases the risk of structural defects and other adverse pregnancy outcomes. The risk for coumarin embryopathy is, however, very small, in particular when therapy during the 1(st) trimester did not take place later than week 8 after the 1(st) day of the last menstrual period. Therefore, elective termination of a wanted pregnancy is not recommended if (inadvertent) exposure took place in early pregnancy. Close follow-up by the obstetrician including level II ultrasound should be recommended in any case of VKA exposure during pregnancy.     

Anxiety disorders following miscarriage

BACKGROUND: Several previous studies have established that miscarriage is a risk factor for depressive symptoms and disorder. By contrast, research on miscarriage as a possible risk factor for anxiety symptoms is inconclusive, and for anxiety disorders, sparse and uninformative. The current study examines the incidence of and relative risk for 3 DSM-III anxiety disorders (obsessive-compulsive disorder [OCD], panic disorder, and phobic disorders) within the 6 months following miscarriage. Adequate diagnostic data on other anxiety disorders were not available. METHOD: Using a cohort design, we tested whether women who miscarry are at increased risk for a first or recurrent episode of an anxiety disorder in the 6 months following loss. The miscarriage cohort consisted of women attending a medical center for spontaneous abortion (N = 229); the comparison group was a population-based cohort of women drawn from the community (N = 230). RESULTS: Among miscarrying women, 3.5% experienced a recurrent episode of OCD, compared with 0.4% of community women (relative risk [RR] = 8.0; 95% confidence interval [CI] = 1.0 to 63.7). The relative risk for noncomorbid panic disorder was substantial (RR = 3.6), albeit not statistically significant (95% CI = 0.8 to 17.2). There was no strong evidence for increased risk for phobic disorders or agoraphobia, combined or considered separately, in the 6 months following loss. Relative risk for all 3 disorders combined was 1.5 (95% CI = 0.9 to 2.3). CONCLUSION: In this first miscarriage cohort study using a concurrent frequency-matched comparison group, miscarriage was a substantial risk factor for an initial or recurrent episode of OCD. Given statistical power limitations of this investigation, the current findings do not preclude a possible contribution of miscarriage to risk for other anxiety disorders.     

Preeclampsia and pregnancy loss in women with a history of venous thromboembolism and prophylactic low-molecular-weight heparin (LMWH) during pregnancy

Limited data are available regarding complications of pregnancy and pregnancy outcome under prophylaxis with low-molecular-weight heparin (LMWH) in women with a history of thromboembolism (TE). We retrospectively evaluated pregnancy complications in a cohort of 80 women. All had a history of TE (76 venous, two arterial and two venous and arterial) and received prophylactic LMWH during 86 pregnancies. The rate of preeclampsia and stillbirth in these women was compared to that of a control group of 313 women without a history of TE and LMWH. Prophylaxis was started at a median of 10 weeks of gestation and usually continued until six weeks post partum. In 94% of the cases the outcome of pregnancy was favourable with a live birth. Four pregnancies (4.7%) ended in miscarriage. Two (2.3%) pregnancies were complicated by a thromboembolic event (one deep leg vein thrombosis and PRIND, respectively). One patient developed HELLP-syndrome. Severe preeclampsia occurred in three (3.8%) and stillbirth in one (1.3%) of the patients (n = 80), whereas this was the case in four (1.3%, odds ratio 3.01; 95% confidence interval (CI) 0.66-13.73, p = 0.15) and 10 (3.2%, OR = 0.38; 95% CI 0.05-3.04, p = 0.72) control women. Mean birth weight and standard deviation of infants was 3,160 +/- 930 g in patients and 3,300 +/- 540 g in controls (p = 0.11). We conclude that a favourable pregnancy outcome in women with a history of thromboembolism who use prophylactic LMWH during pregnancy can be expected. There was a trend towards a higher risk of preeclampsia, and these women should be carefully monitored for this complication.     

The association between adverse pregnancy outcomes and maternal factor V Leiden genotype: a meta-analysis

The conclusions of studies to date which evaluate a possible association between factor V Leiden and adverse pregnancy outcome have been conflicting. This study was undertaken to further investigate this association. Our objective was to evaluate the association between adverse pregnancy outcomes and maternal factor V Leiden genotype by meta-analysis. Inclusion criteria were: (a) cohort or case control design; (b) outcomes clearly defined as one of the following: first or second/ third trimester miscarriage or intrauterine death, preeclampsia, fetal growth retardation, or placental abruption; (c) both the case and control mothers tested for the factor V Leiden mutation; (d) sufficient data for calculation of an odds ratio. Both fixed and random effect models were used to pool results and heterogeneity and publication bias were checked. For first trimester fetal loss, the pooled odds ratio was heterogeneous (p=0.06) and no dose-response curve could be found. For second/third trimester fetal loss, there was a consistent and graded increase in risk: the odds ratio was 2.4 (95% CI 1.1-5.2) for isolated (non-recurrent) third trimester fetal loss, rising to 10.7 (95% CI 4.0-28.5) for those with 2 or more second/third trimester fetal losses. Factor V Leiden is associated with a 2.9 fold (95% CI 2.0-4.3) increased risk of severe preeclampsia, and a 4.8 fold (95% CI 2.4-9.4) increased risk of fetal growth retardation. These results support factor V Leiden testing for women with recurrent fetal loss in the second/third trimester. Women with only 1 event may also warrant testing if the fetal loss occurred in the third trimester. Conversely, in those women known to have the factor V Leiden mutation, monitoring for adverse pregnancy outcomes is warranted; whether this means increased vigilance or anti-coagulant prophylaxis is still contentious.     

Obstetric complications and pregnancy-related venous thromboembolism: the effect of low-molecular-weight heparin on their prevention in carriers of factor V Leiden or prothrombin G20210A mutation

Whether the administration of low-molecular-weight heparin (LMWH) during pregnancy is effective in preventing obstetric complications and pregnancy-related venous thromboembolism (VTE) in women who are carriers of factor V Leiden (FVL) and/or prothrombin variant G20210A (PTm) is controversial. This observational study investigated the possible efficacy of pharmacological treatment with LMWH ± aspirin (ASA) in pregnancy outcomes in 1,011 pregnancies of 416 women with thrombophilia (FVL and/or PTm). Most patients were chosen on the basis of previous obstetrical complications (36%), or because of familial or personal history of venous/arterial thromboembolism (28% and 18%, respectively); 74 patients (18%) were incidentally identified. The outcome was evaluated according to the type of treatment and of the period of pregnancy when the treatment was started. After adjustment for observation before and after diagnosis of thrombophilia, previous miscarriages and VTE, parity, age and centre, we observed that LMWH had a protective effect on miscarriages (odds ratio [OR] 0.52, 95% confidence interval [CI] 0.29-0.94) and VTE (OR 0.05, 95% CI 0.01-0.21). ASA appeared to have no effect on the prevention of obstetric complications and VTE. A nested analysis performed in 116 women with two or more obstetric complications confirmed that the highest number of live births was recorded in the group under LMWH prophylaxis (OR 0.19, 95% CI 0.05-0.75). These results suggest that LMWH prophylaxis reduces the risk of obstetric complications in carriers of FVL and/or PTm, particularly in those with previous obstetric events. Furthermore, LMWH prophylaxis reduces the risk of pregnancy-related VTE.     

Dabigatran, rivaroxaban and apixaban versus enoxaparin for thomboprophylaxis after total knee or hip arthroplasty: pool-analysis of phase III randomized clinical trials

Objectives

To compare the main efficacy and safety endpoints of the pivotal randomised clinical trials (RCTs) on venous thromboembolism (VTE) prevention after total hip (THR) or knee (TKR) replacement with the new oral anticoagulants (NAs) versus enoxaparin.

Methods

A pool-analysis of 10 RCTs that included 32.144 randomised patients was performed. Efficacy outcomes were total VTE and all-cause mortality, major VTE, and proximal DVT. Safety outcomes were major bleeding, and clinically relevant (major or non-major) bleeding.

Results

Overall, a significant effect favouring NAs was found for the primary efficacy outcome (RR 0.71; 95%CI 0.56-0.90), major VTE (RR 0.59; 95%CI 0.41-0.84), and proximal DVT (RR 0.51; 95%CI 0.35-0.76). Compared to enoxaparin 40 mg QD, rivaroxaban showed superiority (RR 0.50; 95%CI 0.34-0.73), followed by apixaban (RR 0.63; 95%CI 0.36-1.01) and dabigatran (RR 1.02; 95%CI 0.86-1.20). There was significant heterogeneity among trials and subgroups analysed for these efficacy outcomes. Major bleeding (RR 1.04; 95% CI 0.74-1.46) and clinically relevant bleeding (RR 1.03; 95%CI 0.88-1.21) was similar with NAs or enoxaparin. Rivaroxaban showed a trend toward more major bleeding episodes than enoxaparin (RR 1.88; 95%CI 0.92-3.82) and apixaban showed the lowest clinically relevant bleeding risk (RR 0.81; 95%CI 0.64-1.01).

Conclusions

Overall, NAs showed more efficacy and same safety when compared to the recommended dose of enoxaparin after THR and TKR. There are little differences in efficacy and bleeding risk among NAs and the type of prophylaxis that should be analysed further.     

Treatments for stroke prevention in atrial fibrillation: a network meta-analysis and indirect comparisons versus dabigatran etexilate

Patients with atrial fibrillation at moderate to high risk of stroke are not always anticoagulated despite a lack of contraindications to vitamin K antagonists (VKAs) like warfarin. These patients are treated with aspirin, aspirin-clopidogrel combination therapy or even receive no thromboprophylaxis. The oral direct thrombin inhibitor, dabigatran etexilate 150 mg BID and 110 mg BID, might represent an alternative for these patients; however, no head-to-head clinical trial data exist versus these alternative treatments. A network meta-analysis (NMA) was performed to indirectly compare dabigatran etexilate with antiplatelets and placebo. Compared with placebo, dabigatran etexilate 150 mg BID was estimated to significantly reduce the risk of any stroke (ischaemic and haemorrhagic) by 75% (relative risk [RR] 0.25; 95% confidence interval [CI] 0.12-0.51), ischaemic stroke by 77% (RR 0.23; 95% CI 0.14-0.38), systemic embolism by 83% (RR 0.17; 95% CI 0.05-0.50) and mortality by 36% (RR 0.64; 95% CI 0.45-0.91). Dabigatran etexilate 150 mg BID was estimated to significantly reduce the risk of any stroke compared with aspirin monotherapy by 63% (RR 0.37; 95% CI 0.20-0.69) and aspirin plus clopidogrel by 61% (RR 0.39; 95% CI 0.21-0.72). Trends toward reduced risk with both dabigatran etexilate regimens were found for most clinical outcomes. Relative risk estimates of dabigatran etexilate versus adjusted-dose VKAs within the NMA were consistent with results from the head-to-head randomised trial of these two strategies. Indirect evidence suggests treatment with dabigatran etexilate offers benefit for the prevention of stroke, systemic embolism and mortality over antiplatelets and placebo. There was no indication of increased intracranial or extracranial haemorrhage with dabigatran etexilate compared to antiplatelet agents.     

Elevated factor VII as a risk factor for recurrent fetal loss. Relationship to factor VII gene polymorphisms

Haemostatic abnormalities can be detected in a portion of the women who have recurrent fetal loss. We measured factor VII coagulant activity (FVII:C) in 65 women with 3 or more fetal losses (recurrent cases), 31 women with one 2nd or 3rd trimester loss (late loss cases), and 81 women with only live births (controls). FVII:C was greater than 2 standard deviations above the mean for controls in 9 recurrent cases (13.8%) and 2 controls (2.5%) for an odds ratio of 6.35 (95% CI 1.32-30.52, p=0.012). In recurrent cases, mean levels were significantly higher than controls for FVII:C (p=0.003), FVII antigen (p=0.024), and FVIIa (p=0.001). Late loss cases had an odds ratio of 4.23 (95% CI 0.67-26.67, p=0.098) with FVII:C, FVII antigen, and FVIIa not significantly different from the controls. DNA was examined for the presence of mutations or polymorphisms in the promoter region of the FVII gene, using denaturing HPLC. Abnormal patterns were confirmed with direct sequencing. A previously reported polymorphism, -402 G>A, was found to be present in 11/14 subjects with elevated FVII:C (79%) and 43% of those with normal levels (p=0.029). FVII:C, FVII antigen and FVIIa varied significantly with genotype; however, genotype frequencies did not differ between controls and either case group. No other promoter polymorphisms were identified. This is the first report of a significant elevation of FVII in a population with recurrent fetal loss. These data suggest the need for further investigation of this potential risk factor.     

Mechanisms of antiphospholipid antibody-associated pregnancy complications

Women with antiphospholipid syndrome (APS) and antiphospholipid antibodies (aPL) are at high risk for recurrent spontaneous miscarriage and late pregnancy complications, such as preeclampsia and preterm labor. Recent clinical and experimental observations suggest that the pathophysiology of pregnancy failure in patients with APS may involve inflammation at the maternal-fetal interface and disruption of normal trophoblast function and survival, rather than a pro-thrombotic event. While treatment with heparin and aspirin from early pregnancy has been shown to significantly increase the live birth rate in recurrent miscarriage patients with APS, the incidence of severe late pregnancy complications still remains high. This review will discuss what is currently known about the mechanisms by which aPL may compromise pregnancy outcome.     

Stroke prevention with aspirin, warfarin and ximelagatran in patients with non-valvular atrial fibrillation: a systematic review and meta-analysis

OBJECTIVE: To compare the effectiveness of aspirin, warfarin, and ximelagatran as thromboprophylaxis in patients with non-valvular atrial fibrillation (NVAF). METHODS: Systematic review of randomised controlled trials in patients with NVAF treated with adjusted-dose warfarin and aspirin, fixed low-dose (FLD) warfarin, ximelagatran or placebo. Outcome measures studied were ischaemic stroke, systemic embolism, mortality and haemorrhage. Meta-analysis was performed using a fixed effects model. RESULTS: We identified 13 trials (n=14,423 participants) of sufficient quality to be included in the analysis. Adjusted-dose warfarin significantly reduced the risk of ischaemic stroke or systemic embolism compared with aspirin (relative risk [RR] 0.59; 95% confidence interval [CI]: 0.40 to 0.86), FLD warfarin (RR 0.36; 95% CI: 0.23 to 0.58), or placebo (RR 0.33; 95% CI: 0.24 to 0.45). However, aspirin and placebo had a lower risk of major bleeding compared to warfarin (RR 0.58; 95% CI: 0.35 to 0.97 and RR 0.45; 95% CI: 0.25 to 0.82, respectively). The oral direct thrombin inhibitor, ximelagatran was as effective as adjusted-dose warfarin in the prevention of ischaemic strokes or systemic emboli (RR 1.04; 95% CI: 0.77 to 1.40) with less risk of major bleeding (RR 0.74; 95% CI: 0.56 to 0.96). Adjusted-dose warfarin significantly reduced mortality compared to placebo (RR 0.69; 95% CI: 0.53 to 0.89), but not for any of the other comparisons (aspirin: RR 0.87; 95% CI: 0.67 to 1.13; FLD warfarin: RR 1.11; 95% CI: 0.81 to 1.52; ximelagatran: RR 1.04; 95% CI: 0.86 to 1.26). CONCLUSIONS: We have extended previous analyses, making this the largest systematic review and meta-analysis of thromboprophylaxis trial data in AF--and have included recent trials with the new oral direct thrombin inhibitor, ximelagatran. This systematic review confirms the superiority of anticoagulation therapy over aspirin as thromboprophylaxis in patients with NVAF. The new oral direct thrombin inhibitor, ximelagatran, appears as effective as adjusted-dose warfarin for the prevention of thromboembolic events in NVAF, with a lower risk of bleeding.     

The risk of fetal loss in family members of probands with factor V Leiden mutation.

In order to investigate the risk of fetal loss in carriers of factor V Leiden who are family members of probands with this mutation, we performed a retrospective cohort study including 109 women who had been pregnant at least once and were family members of 61 probands with venous thromboembolism and a single identified factor V Leiden mutation. The rate of pregnancies ending in unexplained fetal loss, early miscarriage, late miscarriage or stillbirth in women with the factor V Leiden was compared with that of women with normal genotype. In the 65 women who were carriers of factor V Leiden 31 of the 191 pregnancies (16.2% per pregnancy) resulted in unexplained fetal loss, as compared to 13 of the 121 pregnancies (10.7% per pregnancy) in the 44 non-carriers (relative risk, 1.5; 95% CI, 0.8-3.2). After the first trimester of pregnancy, 25 pregnancies (13.1% per pregnancy) among carriers of factor V Leiden ended in fetal loss, as compared to 7 (5.8% per pregnancy) among females with normal genotype (relative risk, 2.3; 95% CI, 1.01 to 5.1). We conclude that carriers of factor V Leiden who are family members of probands with this mutation have a statistically significant and clinically important risk of late miscarriage or stillbirth. Studies addressing the benefit-to-risk ratio of adopting routinary thromboprophylactic measures following the first trimester of pregnancy in these women are strongly indicated.     

Anti-beta2-glycoprotein I antibodies are associated with pregnancy loss in women with the lupus anticoagulant

The presence of lupus anticoagulant (LA) predisposes to fetal loss and to venous and arterial thrombosis; however, a subgroup of women is unaffected by pregnancy loss. Currently, no predictive markers are available for the identification of women positive for LA at increased risk for pregnancy loss. It was the aim of our study to investigate whether increased anti-beta2-GPI-antibodies predict pregnancy loss in women positive for LA. We performed a cross-sectional study in a cohort of 39 women with persistent LA, who had in total 111 pregnancies. Fifteen women had exclusively normal pregnancies (30 pregnancies) and 24 women had pregnancy losses (81 pregnancies). Anti-beta2-GPI-antibodies were determined using a semiquantitative enzyme linked immunoassay (QUANTA Lite beta2 GPI IgG and IgM; Inova Diagnostics). Increased levels of anti-beta2-GPI antibodies were significantly associated with pregnancy loss [odds ratio (OR) 9.6, 95% confidence interval (CI) 1.6-56.4]. This risk was even higher in the subgroup of women (n = 16) with more than two miscarriages or fetal loss after the first trimester [OR 13.1, 95% CI 1.4-126.3]. There was no significant association between anticardiolipin antibodies and pregnancy loss [OR 3.5, 95% CI 0.7-17.6]. The co-existence of anti-beta2-GPI and anticardiolipin antibodies was also predictive for pregnancy loss [OR 6.1, 95% CI 1.3-29.7]. Interestingly, the prevalence of thrombosis was similar between women with normal pregnancy (87%) and those with pregnancy loss (75%). We conclude that increased levels of anti-beta2-GPI antibodies are predictive for pregnancy loss among women positive for LA, and that prophylactic treatment should be considered in these women even without a history of previous pregnancy loss.     

Racial and gender differences in the incidence of recurrent venous thromboembolism

Men have been reported to have a higher incidence of recurrent venous thromboembolism than women. However, it is not known if this gender effect holds among different racial/ethnic groups and for both venous thrombosis and pulmonary embolism. We conducted a retrospective analysis of 18- to 65-year-old Caucasian, African-American and Hispanic cases hospitalized in California with unprovoked venous thromboembolism. The principal outcome was recurrent venous thromboembolism 7-60 months after the index event. Among 11,514 cases that were followed for a mean of 3.0 years, men had a significantly higher rate (events/100 patient-years) of recurrent venous thromboembolism than women for both venous thrombosis [rate ratio (RR) = 1.5, 95% confidence interval (CI):1.3-1.8] and pulmonary embolism [RR = 1.3, 95%CI:1.0-1.6]. Among men the recurrence rate did not vary significantly between the racial/ethnic groups (p > 0.05). However, the recurrence rate among Hispanic women with venous thrombosis was significantly higher than in Caucasian women (p < 0.001) and was comparable to the rate in men. Both Hispanic and African-American women with pulmonary embolism had a higher recurrence rate compared with Caucasian women (p < 0.02) that was comparable to the rate in men. We conclude that women in California had a 40% lower risk of recurrent venous thromboembolism compared to men. Rates were comparable among men of different races, but there were significant inter-racial differences among women, which also varied with the type of initial event. The effect of gender on the risk of recurrent venous thromboembolism can not be generalized because it varies between racial/ethnic groups and with the type of index event.     

Pharmacokinetics of UH and LMWH are similar with respect to antithrombin activity

BACKGROUND: The ability to administer low molecular weight heparins (LMWH) subcutaneously without laboratory monitoring contributes to their popularity for the treatment of thrombotic disorders. Subcutaneous unfractionated heparin, although less expensive, is deemed to require routine laboratory monitoring on the basis of more variability in drug effect compared to LMWH. However, the more predictable pharmacokinetic profiles of low molecular weight heparins are largely based on anti-Xa activity, while antithrombin activity may be at least as important to their mechanisms of action. METHODS: We performed a clinical pharmacokinetic trial to compare the variability in peak antithrombin effect between subcutaneous unfractionated heparin and various LMWHs, all given in recommended weight-adjusted treatment doses. Sixty-one patients enrolled in a warfarin clinic were randomized to receive one of four different weight-adjusted subcutaneous heparin doses: unfractionated heparin, 250 units/kg (n=15); tinzaparin, 175 units/kg (n=15); dalteparin, 200 units/kg (n=15); or enoxaparin, 1 mg/kg (n=16). The areas under the curves of antithrombin levels during the first 3 h after administration were determined for each patient, and the coefficients of variation (CV) and 95% confidence intervals of the AUCs were compared among the treatment groups. RESULTS: There was no statistically significant difference in the coefficients of variation of antithrombin effect between unfractionated heparin (52.8, 95% CI: 32.6-72.9) and enoxaparin (56.5, 95% CI: 35.7-77.4) or dalteparin (43.5, 95% CI 25.4-61.6). Tinzaparin had statistically significant decrease in coefficients of variation (21.6, 95% CI: 12.2-30.9) relative to unfractionated heparin, dalteparin and enoxaparin. CONCLUSIONS: LMWHs, as a class of drugs, are no more predictable in antithrombin effect after subcutaneous injection than unfractionated heparin. There were considerable differences among LMWHs in the observed variability of antithrombin effects, with tinzaparin being somewhat more predictable than the other drugs tested.     

Is carbamazepine teratogenic? A prospective controlled study of 210 pregnancies

The Israeli Teratogen Information Service prospectively followed up 210 pregnancies with first trimester carbamazepine exposure. Pregnancy outcome was compared with that of two overlapping controls, matched and general (n = 629), exposed to nonteratogenic agents. Our study suggests a twofold increase in the rate of major congenital anomalies (12/160 [carbamazepine] versus 18/560 [general control]; relative risk 2.24; 95% CI 1.1-4.56) and a birth weight reduction of approximately 250 g after in utero exposure to carbamazepine.     

A multicentre prospective controlled study to determine the safety of trazodone and nefazodone use during pregnancy.

OBJECTIVES: Trazodone and nefazodone are phenylpiperazine antidepressants. Currently, there are no adequate, well-controlled studies on the fetal safety of these drugs. Our primary objective was to determine whether the use of trazodone or nefazodone during pregnancy is associated with an increased risk for major malformations. Secondary outcomes of interest included rates of spontaneous and therapeutic abortions, rates of premature labour, and birth weight. METHODS: Pregnant women from 5 centres who had been exposed to these drugs (n = 147) were enrolled in the study during their first trimester. We compared the women with 2 groups of women who took either other antidepressant drugs (n = 147) or nonteratogenic drugs (n = 147). All the women were followed up after delivery to ascertain pregnancy outcome and the health of the baby. RESULTS: We have completed 147 follow-ups. There were 121 (82.4%) live births, 20 (13.6%) spontaneous abortions, and 6 (4%) therapeutic abortions. Of the live births, there were 2 (1.6%) major malformations. In all cases, drug exposure occurred during the first trimester, with 52 (35%) of the women using these drugs throughout pregnancy. The mean gestational age at birth was 38 weeks (SD 4.2), and the mean birth weight was 3306.34 g (SD 655). We found no statistically significant differences among the 3 groups in any of the endpoints of interest that we examined. Of the sample, 58 women were exposed to trazodone, and 89 were exposed to nefazodone. CONCLUSION: Our results suggest that these drugs do not increase the rates of major malformations above the baseline rate of 1% to 3%.     

Preliminary results on pregnancy outcomes in women using lamotrigine

PURPOSE: In 1992, the International Lamotrigine Pregnancy Registry was initiated to enroll prospectively and to monitor pregnancies exposed to lamotrigine (LTG) for the occurrence of major birth defects. This study presents results as of September 2001 on 168 outcomes exposed to LTG monotherapy and 166 outcomes after pregnancies exposed to LTG polytherapy during the first trimester. METHODS: LTG pregnancy exposures are voluntarily reported to the registry by health care providers before they are aware of each pregnancy outcome. Pregnancy-outcome ascertainment is obtained through subsequent follow-up with the reporting health care provider, and each reported birth defect is reviewed by an expert pediatrician. The percentage with major birth defects in pregnancies with known birth defect status was calculated for LTG monotherapy and for polytherapy stratified by trimester of exposure. RESULTS: The registry identified 334 first-trimester LTG pregnancy outcomes exposed to LTG monotherapy or polytherapy during the first trimester and involving either a live birth with or without a major birth defect or an abortion with a major birth defect. After exposure to LTG monotherapy, the percentage with major birth defects exposed to LTG monotherapy was three (1.8%) of 168 [95% confidence interval (CI), 0.5-5.5%]. There were five (10%) major birth defects observed in 50 outcomes after LTG polytherapy involving valproic acid (VPA; 95% CI, 3.7-22.6%) during the first trimester. The observed proportion of major defects after LTG polytherapy without VPA during the first trimester was five (4.3%) of 116 (95% CI, 1.6-10.3%). No specific patterns of major birth defects in any subgroup or within the registry as a whole were observed. CONCLUSIONS: The sample sizes for individual regimens are too small to rule out small increases in frequency of all major birth defects or even large increases in frequency of rare major birth defects. However, the percentage of outcomes with major birth defects after LTG monotherapy in this study and in another similar pregnancy registry in the United Kingdom did not differ from that reported in the recent literature for women with epilepsy receiving antiepileptic drug monotherapy (4%). The frequency of major malformations after exposures of LTG-VPA is higher than that after the LTG monotherapy or LTG polytherapy regimens without VPA. Although there are published data on frequency of major malformations after VPA exposures in pregnancy, between-study differences in methods and source populations and the wide confidence intervals around the estimate for LTG and VPA limit the utility of comparison with such data, and no conclusions are made at this time about this combination. The continued registration of exposed pregnancies to an exposure registry as early as possible in the pregnancy before any knowledge of the outcome, and before any prenatal testing, will enhance the power of such data.     

Arterial antithrombotic effects of aspirin, heparin, enoxaparin and clopidogrel alone, or in combination, in the rat

INTRODUCTION: Many antithrombotic drugs may have a deleterious effect on normal haemostasis leading to bleeding complications. The aim of this study was to determine if sub-therapeutic (low) doses of antithrombotic agents, when administered in combination, have enhanced efficacy without augmentation of bleeding time. MATERIALS AND METHODS: The antithrombotic effects of i.v. aspirin (4-30 mg/kg), heparin (100-500 U/kg), enoxaparin (4-30 mg/kg) and clopidogrel (10-20 mg/kg) were studied in a rat Folts-like preparation of carotid arterial thrombosis. The frequency of cyclic flow reductions (CFRs; indicating occlusive thrombus formation) and bleeding time were measured. Drug doses that were singly ineffective at preventing occlusive thrombus formation were tested in the following combinations: aspirin (10 mg/kg) with heparin (250 U/kg); aspirin (4 mg/kg) with enoxaparin (4 mg/kg); and aspirin (10 mg/kg) with clopidogrel (10 mg/kg). RESULTS: Control period (pretreatment) CFRs were not significantly different between groups; average 7.0+/-0.3 CFRs/30 min (n=64). Tail bleeding time before drug(s) was 3.1+/-0.1 min (n=86). When administered alone, aspirin (4-30 mg/kg), heparin (250 U/kg) or enoxaparin (4 mg/kg) had no effect on CFRs or bleeding time. Heparin (500 U/kg), enoxaparin (10 and 30 mg/kg) and clopidogrel (20 mg/kg) significantly decreased CFRs. Single administration of heparin (500 U/kg) or enoxaparin (30 mg/kg) increased bleeding time by 4- or 11-fold. When co-administered, aspirin 10 mg/kg and heparin 250 U/kg decreased CFRs, but also increased bleeding time by 11-fold. However, combination of aspirin and enoxaparin (4 mg/kg each), or aspirin and clopidogrel (10 mg/kg each), decreased CFRs with no effect on bleeding. CONCLUSIONS: In a preparation of arterial thrombosis in the rat, combinations of sub-efficacious (low) doses of aspirin with enoxaparin or clopidogrel inhibited thrombus formation without augmenting bleeding time. However, low-dose aspirin combined with heparin, whilst inhibiting thrombus formation, exacerbated bleeding time. If these findings translate into the clinic, the use of effective low-dose combinations may have therapeutic advantages.