Katarina Bremme

Haemostatic changes in pregnancy

Normal pregnancy is accompanied by changes in the coagulation and fibrinolytic systems. These include increases in a number of clotting factors (I, II, VII, VIII, IX and XII), a decrease in protein S levels and inhibition of fibrinolysis. As gestation progresses, there is also a significant fall in the activity of activated protein C, an important anticoagulant. While these physiological changes may be important for minimizing intrapartum blood loss, they entail an increased risk of thromboembolism during pregnancy and the post-partum period.

Toxic and essential elements in placentas of Swedish women.

OBJECTIVES To evaluate interactions between toxic and essential elements in the mother-fetus relationship and possible predictors of trace element concentrations in placenta and cord blood. DESIGN AND METHODS A group of 106 Swedish women was investigated for concentrations of cadmium, lead, and several essential elements in placenta as well as cadmium, lead, zinc, and selenium in venous blood collected at gestational week (gw) 36 and umbilical cord blood. Relations between these elements and maternal and childs characteristics were examined. RESULTS The concentrations of cadmium in placenta ranged from 10 to 170 nmol/kg, with the median value (Md) being 46 nmol/kg. Cord blood cadmium (Md of 0.19 nmol/L) was only about 10% of that in maternal blood. Smokers had significantly higher cadmium concentrations in blood (p < 0.001) and placenta (p = 0.001) than non-smokers. The median placental concentration of lead was 26 nmol/kg (range 0-630 nmol/kg). The lead levels in cord blood (Md of 54 nmol/L) were almost the same as in maternal blood. Statistically significant negative associations were found between cord blood lead, on one hand, and childs weight, length, and head circumference, on the other. The placental levels (medians and ranges) of the essential elements (micromol/kg) were 160 (120-280) for zinc, 2.4 (2.0-3.3) for selenium, 15 (10-20) for copper, 0.084 (0.02-0.32) for cobalt, 0.055 (0.03-0.12) for molybdenum, and 1.2 (0. 65-5.1) for manganese, respectively. Several of the essential elements in placenta correlated significantly with each other. Multiparous mothers had significantly lower concentrations of zinc (p = 0.002) and selenium (p = 0.049) in serum as well as zinc (p = 0. 001) and calcium (p = 0.004) in placenta than nulliparous ones. Also, cord blood zinc decreased with parity. CONCLUSIONS The results showed that lead, but not cadmium crossed easily the placental barrier. There were no negative effects of cadmium on the zinc status. Cord blood lead, on the other hand, was a negative predictor of childs birth weight, length and head circumference, indicating that lead might have negative influence on growth in children even at very low exposure levels. There was a depletion of maternal stores of essential elements with increasing parity.

Expression and regulation of the pattern recognition receptors Toll‐like receptor‐2 and Toll‐like receptor‐4 in the human placenta

The placenta constitutes a physical and immunological barrier against invading infectious agents and has been suggested to be a pregnancy‐specific component of the innate immune system. The aim of this study was to investigate the presence and regulation of Toll‐like receptors‐2 and ‐4 (TLR2 and TLR4) in the human placenta, because these receptors are believed to be important for immune responses against pathogens. Twenty‐eight placentas from normal term pregnancies were analysed with immunohistochemistry, which showed a strong immunoreactivity for TLR2 and TLR4 in the villous and the intermediate trophoblasts. The regulation of TLR2 and TLR4 by microbial stimulus was assessed by incubating explants of term chorionic villi with zymosan or lipopolysaccharide (LPS) and analysed with real‐time reverse transcriptase–polymerase chain reaction. Stimulation with zymosan and LPS readily induced interleukin (IL)‐6 and IL‐8 cytokine production in the placenta cultures, whereas TLR2 and TLR4 mRNA and protein expression remained at the same high level as in unstimulated explants. These data suggests a novel mechanism for the fetoplacental unit to interact with micro‐organisms.

Cadmium Exposure in Pregnancy and Lactation in Relation to Iron Status

OBJECTIVES The purpose of this study was to determine the impact of iron status on cadmium dose among pregnant women. METHODS Iron status and cadmium concentration in blood, urine, and placenta were determined among women followed for 2 years from early pregnancy. RESULTS Blood cadmium and urinary cadmium were correlated with iron status throughout the study period. Urinary cadmium increased longitudinally among women with exhausted iron stores during their pregnancy. The increase in urinary cadmium with age was more pronounced in multiparous than in nulliparous women. CONCLUSIONS Iron deficiency during pregnancy leads to increased cadmium absorption and body burden. Multiparous women exhibit additional increases with increasing age.

Arg506-Gln mutation in factor V and risk of thrombosis during pregnancy.

Seventy women with thrombosis in pregnancy were investigated for the presence of APC resistance and the associated Arg506–Gln mutation in coagulation factor V. The mutation was found in 46% of the investigated women. Carriers of the mutation were more prone to develop thrombosis in the first pregnancy (OR (odds ratio) = 3.41; P < 0.05) and had a higher probability of recurrence (OR = 3.86; P < 0.05) compared to non‐carriers. The incidence of miscarriage was not related to the mutation but its probability increased in women with thrombosis in a second or subsequent pregnancy (P < 0.025). Negative dynamics of APC response during pregnancy was observed in 20/22 women; eight of them developed APC resistance de novo. The suppression of APC response was independent of the mutation.

Use of recombinant activated factor VII in primary postpartum hemorrhage - The northern European registry 2000-2004

OBJECTIVE: To collect data from nine European countries for cases of obstetric hemorrhage between 2000 and 2004 in which recombinant activated factor VII (rFVIIa) was used. METHODS: The cases were identified through national surveys. Standardized case report forms included sociodemographic details, past medical and obstetric history, and details of the progress and management of labor in which the postpartum hemorrhage occurred. Clinicians were asked to describe subjectively the effect of rFVIIa administration using two mutually exclusive categories: 1) bleeding reduced or 2) bleeding unchanged or worse. RESULTS: A total of 113 forms were returned (88%) with 97 (86%) classified as treatment, and 16 (14%) as “secondary prophylaxis.” Clinicians noted improvements after a single dose for 80% of women in the treatment group, and for 75% in the secondary “prophylaxis” group. However, rFVIIa failed in 15 cases (13.8%). Few serious adverse events were noted related to rFVIIa administration; there were four cases of thromboembolism, one myocardial infarction, and one skin rash. CONCLUSION: Clinical reports and hematologic data suggest improvement for more than 80% of women after rFVIIa administration and few adverse effects. LEVEL OF EVIDENCE: II

Assessment of left ventricular structure and function in preeclampsia by echocardiography and cardiovascular biomarkers.

Aim To assess left ventricular (LV) structure and function in preeclampsia, a serious vascular-related pregnancy disorder, by Doppler tissue imaging (DTI) in combination with the levels of cardiovascular biomarkers. Material and methods Thirty-five pregnant women with preeclampsia and 30 with normal pregnancy, matched for age and gestational age were examined during pregnancy and 3–6 months after delivery. Transthoracic echocardiography and DTI were performed and blood levels of amino-terminal pro-brain natriuretic peptide (NT-pro-BNP), C-reactive protein (CRP), cystatin C and troponin I were analyzed. Results There were significant differences in LV and left atrial dimensions and function between the groups. A higher septal and lateral E/E′ ratio (E = early transmitral diastolic flow velocity and E′ = early diastolic myocardial velocity) (P < 0.0001, 0.0008) and higher levels of NT-pro-BNP, cystatin C, and lower cystatin C estimated GFR in ml/min per 1.73 m2 (P < 0.0001) were seen in the preeclampsia both during pregnancy and at follow-up. In addition the levels of E/E′ ratio lateral and NT-pro-BNP were higher in pregnant women with early-onset preeclampsia necessitating delivery before 34 weeks of gestation than those who developed preeclampsia and delivered at or after 34 weeks (P = 0.0004, 0.005). Conclusion In pregnancies complicated by preeclampsia, especially early-onset preeclampsia, the diastolic LV function is impaired and levels of biomarkers, NT-pro-BNP and cystatin C, are increased in comparison to normal pregnancy.

Primary habitual abortions are associated with high frequency of factor V Leiden mutation.

OBJECTIVE To analyze the prevalence of the mutation G1691A in factor V gene (Leiden mutation), of mutation C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, and of polymorphism in G20210A in the prothrombin gene in women with recurrent abortions; further, to identify a subgroup at higher risk of being carriers of these mutations. DESIGN Prospective case control evaluation. SETTING University clinic. PATIENT(S) Eighty-four women with 3 or more consecutive miscarriages were compared with 69 controls. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Polymerase chain reactions were performed to identify the mutations G1691A in factor V and C677T in MTHFR genes and the polymorphism G20210A in the prothrombin gene. RESULT(S) In women with primary habitual abortions, 27.8% carried the Leiden mutation. No difference was observed in the prevalence of mutation C677T in the MTHFR gene or in polymorphism G20210A in the prothrombin gene. CONCLUSION(S) The Leiden mutation may play a considerable role for women having primary recurrent abortions.

Thromboprophylaxis with low molecular mass heparin, 'Fragmin' (dalteparin), during pregnancy--a longitudinal safety study.

Twenty-five women with previous verified thromboembolic complications were treated with delteparin (Fragmin) during pregnancy and puerperium. Women with known hereditary thrombophilia (antithrombin, protein C and protein S deficiencies) or with phospholipid antibodies were excluded. The dose at entry was calculated according to body weight and thereafter monitored by anti-FXa activity aiming at 0.20-0.40 IU/ml plasma 3 h post injection. Dalteparin or dextran was used during delivery. Twenty-two women completed the study and 14 of these could be given the same dose throughout pregnancy. There was an increased dose response postpartum. There were no thromboembolic recurrences or severe bleeding complications. The level of antithrombin activity remained normal. Our thrombosis-prone pregnant women had initially increased levels of thrombin markers but no further increase was observed during the dalteparin thromboprophylaxis. Retrospectively, three heterozygous and three homozygous individuals for the FV Leiden mutation leading to activated protein C resistance were identified. In conclusion, dalteparin could safely be used as thromboprophylaxis during pregnancy in these thrombosis-prone women. Women weighing 50-79 kg at entry could be treated with 5000 IU of dalteparin once daily during pregnancy, without monitoring. Postpartum, many of the women were given a reduced dose.

A pharmacokinetic study of dalteparin (Fragmin®) during late pregnancy

Seventeen women with previously verified thromboembolism were included in a pharmacokinetic evaluation of dalteparin during the third trimester of pregnancy. The bioavailability of morning subcutaneous administration of dalteparin (crossover study) was also compared with that in the evening. Fifteen women injected themselves subcutaneously with 5000 IU and two with 2500 IU dalteparin once daily. An anti-FXa activity of 0.20-0.40 IU/ml 3 h after injection was obtained. The means +/- SD, when comparing morning and evening doses for 5000 IU, were: Cmax 0.21 +/- 0.05 and 0.20 +/- 0.05 IU anti-FXa/ml, AUC 0-24 h 1.97 +/- 0.46 and 1.93 +/- 0.55 IU x h/ml and tmax 3.71 +/- 0.89 and 4.32 +/- 1.60 h, respectively (NS). The two regimens were equivalent. A measurable anticoagulant effect was still observed 16 h after injection of 5000 IU dalteparin. The half-lives after a morning and an evening dose of 5000 IU dalteparin were 4.92 +/- 2.80 and 3.87 +/- 1.15 h, respectively (NS). There were no changes in thrombin marker levels during the two pharmacokinetic measurements.